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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * SLUB: A slab allocator that limits cache line use instead of queuing
4 * objects in per cpu and per node lists.
5 *
6 * The allocator synchronizes using per slab locks or atomic operatios
7 * and only uses a centralized lock to manage a pool of partial slabs.
8 *
9 * (C) 2007 SGI, Christoph Lameter
10 * (C) 2011 Linux Foundation, Christoph Lameter
11 */
12
13 #include <linux/mm.h>
14 #include <linux/swap.h> /* struct reclaim_state */
15 #include <linux/module.h>
16 #include <linux/bit_spinlock.h>
17 #include <linux/interrupt.h>
18 #include <linux/bitops.h>
19 #include <linux/slab.h>
20 #include "slab.h"
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/kasan.h>
24 #include <linux/cpu.h>
25 #include <linux/cpuset.h>
26 #include <linux/mempolicy.h>
27 #include <linux/ctype.h>
28 #include <linux/debugobjects.h>
29 #include <linux/kallsyms.h>
30 #include <linux/kfence.h>
31 #include <linux/memory.h>
32 #include <linux/math64.h>
33 #include <linux/fault-inject.h>
34 #include <linux/stacktrace.h>
35 #include <linux/prefetch.h>
36 #include <linux/memcontrol.h>
37 #include <linux/random.h>
38
39 #include <trace/events/kmem.h>
40
41 #include "internal.h"
42
43 /*
44 * Lock order:
45 * 1. slab_mutex (Global Mutex)
46 * 2. node->list_lock
47 * 3. slab_lock(page) (Only on some arches and for debugging)
48 *
49 * slab_mutex
50 *
51 * The role of the slab_mutex is to protect the list of all the slabs
52 * and to synchronize major metadata changes to slab cache structures.
53 *
54 * The slab_lock is only used for debugging and on arches that do not
55 * have the ability to do a cmpxchg_double. It only protects:
56 * A. page->freelist -> List of object free in a page
57 * B. page->inuse -> Number of objects in use
58 * C. page->objects -> Number of objects in page
59 * D. page->frozen -> frozen state
60 *
61 * If a slab is frozen then it is exempt from list management. It is not
62 * on any list except per cpu partial list. The processor that froze the
63 * slab is the one who can perform list operations on the page. Other
64 * processors may put objects onto the freelist but the processor that
65 * froze the slab is the only one that can retrieve the objects from the
66 * page's freelist.
67 *
68 * The list_lock protects the partial and full list on each node and
69 * the partial slab counter. If taken then no new slabs may be added or
70 * removed from the lists nor make the number of partial slabs be modified.
71 * (Note that the total number of slabs is an atomic value that may be
72 * modified without taking the list lock).
73 *
74 * The list_lock is a centralized lock and thus we avoid taking it as
75 * much as possible. As long as SLUB does not have to handle partial
76 * slabs, operations can continue without any centralized lock. F.e.
77 * allocating a long series of objects that fill up slabs does not require
78 * the list lock.
79 * Interrupts are disabled during allocation and deallocation in order to
80 * make the slab allocator safe to use in the context of an irq. In addition
81 * interrupts are disabled to ensure that the processor does not change
82 * while handling per_cpu slabs, due to kernel preemption.
83 *
84 * SLUB assigns one slab for allocation to each processor.
85 * Allocations only occur from these slabs called cpu slabs.
86 *
87 * Slabs with free elements are kept on a partial list and during regular
88 * operations no list for full slabs is used. If an object in a full slab is
89 * freed then the slab will show up again on the partial lists.
90 * We track full slabs for debugging purposes though because otherwise we
91 * cannot scan all objects.
92 *
93 * Slabs are freed when they become empty. Teardown and setup is
94 * minimal so we rely on the page allocators per cpu caches for
95 * fast frees and allocs.
96 *
97 * page->frozen The slab is frozen and exempt from list processing.
98 * This means that the slab is dedicated to a purpose
99 * such as satisfying allocations for a specific
100 * processor. Objects may be freed in the slab while
101 * it is frozen but slab_free will then skip the usual
102 * list operations. It is up to the processor holding
103 * the slab to integrate the slab into the slab lists
104 * when the slab is no longer needed.
105 *
106 * One use of this flag is to mark slabs that are
107 * used for allocations. Then such a slab becomes a cpu
108 * slab. The cpu slab may be equipped with an additional
109 * freelist that allows lockless access to
110 * free objects in addition to the regular freelist
111 * that requires the slab lock.
112 *
113 * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
114 * options set. This moves slab handling out of
115 * the fast path and disables lockless freelists.
116 */
117
118 #ifdef CONFIG_SLUB_DEBUG
119 #ifdef CONFIG_SLUB_DEBUG_ON
120 DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
121 #else
122 DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
123 #endif
124 #endif
125
126 static inline bool kmem_cache_debug(struct kmem_cache *s)
127 {
128 return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
129 }
130
131 void *fixup_red_left(struct kmem_cache *s, void *p)
132 {
133 if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
134 p += s->red_left_pad;
135
136 return p;
137 }
138
139 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
140 {
141 #ifdef CONFIG_SLUB_CPU_PARTIAL
142 return !kmem_cache_debug(s);
143 #else
144 return false;
145 #endif
146 }
147
148 /*
149 * Issues still to be resolved:
150 *
151 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
152 *
153 * - Variable sizing of the per node arrays
154 */
155
156 /* Enable to test recovery from slab corruption on boot */
157 #undef SLUB_RESILIENCY_TEST
158
159 /* Enable to log cmpxchg failures */
160 #undef SLUB_DEBUG_CMPXCHG
161
162 /*
163 * Mininum number of partial slabs. These will be left on the partial
164 * lists even if they are empty. kmem_cache_shrink may reclaim them.
165 */
166 #define MIN_PARTIAL 5
167
168 /*
169 * Maximum number of desirable partial slabs.
170 * The existence of more partial slabs makes kmem_cache_shrink
171 * sort the partial list by the number of objects in use.
172 */
173 #define MAX_PARTIAL 10
174
175 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
176 SLAB_POISON | SLAB_STORE_USER)
177
178 /*
179 * These debug flags cannot use CMPXCHG because there might be consistency
180 * issues when checking or reading debug information
181 */
182 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
183 SLAB_TRACE)
184
185
186 /*
187 * Debugging flags that require metadata to be stored in the slab. These get
188 * disabled when slub_debug=O is used and a cache's min order increases with
189 * metadata.
190 */
191 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
192
193 #define OO_SHIFT 16
194 #define OO_MASK ((1 << OO_SHIFT) - 1)
195 #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
196
197 /* Internal SLUB flags */
198 /* Poison object */
199 #define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
200 /* Use cmpxchg_double */
201 #define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
202
203 /*
204 * Tracking user of a slab.
205 */
206 #define TRACK_ADDRS_COUNT 16
207 struct track {
208 unsigned long addr; /* Called from address */
209 #ifdef CONFIG_STACKTRACE
210 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
211 #endif
212 int cpu; /* Was running on cpu */
213 int pid; /* Pid context */
214 unsigned long when; /* When did the operation occur */
215 };
216
217 enum track_item { TRACK_ALLOC, TRACK_FREE };
218
219 #ifdef CONFIG_SYSFS
220 static int sysfs_slab_add(struct kmem_cache *);
221 static int sysfs_slab_alias(struct kmem_cache *, const char *);
222 #else
223 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
224 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
225 { return 0; }
226 #endif
227
228 static inline void stat(const struct kmem_cache *s, enum stat_item si)
229 {
230 #ifdef CONFIG_SLUB_STATS
231 /*
232 * The rmw is racy on a preemptible kernel but this is acceptable, so
233 * avoid this_cpu_add()'s irq-disable overhead.
234 */
235 raw_cpu_inc(s->cpu_slab->stat[si]);
236 #endif
237 }
238
239 /*
240 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
241 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
242 * differ during memory hotplug/hotremove operations.
243 * Protected by slab_mutex.
244 */
245 static nodemask_t slab_nodes;
246
247 /********************************************************************
248 * Core slab cache functions
249 *******************************************************************/
250
251 /*
252 * Returns freelist pointer (ptr). With hardening, this is obfuscated
253 * with an XOR of the address where the pointer is held and a per-cache
254 * random number.
255 */
256 static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
257 unsigned long ptr_addr)
258 {
259 #ifdef CONFIG_SLAB_FREELIST_HARDENED
260 /*
261 * When CONFIG_KASAN_SW/HW_TAGS is enabled, ptr_addr might be tagged.
262 * Normally, this doesn't cause any issues, as both set_freepointer()
263 * and get_freepointer() are called with a pointer with the same tag.
264 * However, there are some issues with CONFIG_SLUB_DEBUG code. For
265 * example, when __free_slub() iterates over objects in a cache, it
266 * passes untagged pointers to check_object(). check_object() in turns
267 * calls get_freepointer() with an untagged pointer, which causes the
268 * freepointer to be restored incorrectly.
269 */
270 return (void *)((unsigned long)ptr ^ s->random ^
271 swab((unsigned long)kasan_reset_tag((void *)ptr_addr)));
272 #else
273 return ptr;
274 #endif
275 }
276
277 /* Returns the freelist pointer recorded at location ptr_addr. */
278 static inline void *freelist_dereference(const struct kmem_cache *s,
279 void *ptr_addr)
280 {
281 return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
282 (unsigned long)ptr_addr);
283 }
284
285 static inline void *get_freepointer(struct kmem_cache *s, void *object)
286 {
287 object = kasan_reset_tag(object);
288 return freelist_dereference(s, object + s->offset);
289 }
290
291 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
292 {
293 prefetch(object + s->offset);
294 }
295
296 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
297 {
298 unsigned long freepointer_addr;
299 void *p;
300
301 if (!debug_pagealloc_enabled_static())
302 return get_freepointer(s, object);
303
304 freepointer_addr = (unsigned long)object + s->offset;
305 copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
306 return freelist_ptr(s, p, freepointer_addr);
307 }
308
309 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
310 {
311 unsigned long freeptr_addr = (unsigned long)object + s->offset;
312
313 #ifdef CONFIG_SLAB_FREELIST_HARDENED
314 BUG_ON(object == fp); /* naive detection of double free or corruption */
315 #endif
316
317 freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
318 *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
319 }
320
321 /* Loop over all objects in a slab */
322 #define for_each_object(__p, __s, __addr, __objects) \
323 for (__p = fixup_red_left(__s, __addr); \
324 __p < (__addr) + (__objects) * (__s)->size; \
325 __p += (__s)->size)
326
327 static inline unsigned int order_objects(unsigned int order, unsigned int size)
328 {
329 return ((unsigned int)PAGE_SIZE << order) / size;
330 }
331
332 static inline struct kmem_cache_order_objects oo_make(unsigned int order,
333 unsigned int size)
334 {
335 struct kmem_cache_order_objects x = {
336 (order << OO_SHIFT) + order_objects(order, size)
337 };
338
339 return x;
340 }
341
342 static inline unsigned int oo_order(struct kmem_cache_order_objects x)
343 {
344 return x.x >> OO_SHIFT;
345 }
346
347 static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
348 {
349 return x.x & OO_MASK;
350 }
351
352 /*
353 * Per slab locking using the pagelock
354 */
355 static __always_inline void slab_lock(struct page *page)
356 {
357 VM_BUG_ON_PAGE(PageTail(page), page);
358 bit_spin_lock(PG_locked, &page->flags);
359 }
360
361 static __always_inline void slab_unlock(struct page *page)
362 {
363 VM_BUG_ON_PAGE(PageTail(page), page);
364 __bit_spin_unlock(PG_locked, &page->flags);
365 }
366
367 /* Interrupts must be disabled (for the fallback code to work right) */
368 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
369 void *freelist_old, unsigned long counters_old,
370 void *freelist_new, unsigned long counters_new,
371 const char *n)
372 {
373 VM_BUG_ON(!irqs_disabled());
374 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
375 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
376 if (s->flags & __CMPXCHG_DOUBLE) {
377 if (cmpxchg_double(&page->freelist, &page->counters,
378 freelist_old, counters_old,
379 freelist_new, counters_new))
380 return true;
381 } else
382 #endif
383 {
384 slab_lock(page);
385 if (page->freelist == freelist_old &&
386 page->counters == counters_old) {
387 page->freelist = freelist_new;
388 page->counters = counters_new;
389 slab_unlock(page);
390 return true;
391 }
392 slab_unlock(page);
393 }
394
395 cpu_relax();
396 stat(s, CMPXCHG_DOUBLE_FAIL);
397
398 #ifdef SLUB_DEBUG_CMPXCHG
399 pr_info("%s %s: cmpxchg double redo ", n, s->name);
400 #endif
401
402 return false;
403 }
404
405 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
406 void *freelist_old, unsigned long counters_old,
407 void *freelist_new, unsigned long counters_new,
408 const char *n)
409 {
410 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
411 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
412 if (s->flags & __CMPXCHG_DOUBLE) {
413 if (cmpxchg_double(&page->freelist, &page->counters,
414 freelist_old, counters_old,
415 freelist_new, counters_new))
416 return true;
417 } else
418 #endif
419 {
420 unsigned long flags;
421
422 local_irq_save(flags);
423 slab_lock(page);
424 if (page->freelist == freelist_old &&
425 page->counters == counters_old) {
426 page->freelist = freelist_new;
427 page->counters = counters_new;
428 slab_unlock(page);
429 local_irq_restore(flags);
430 return true;
431 }
432 slab_unlock(page);
433 local_irq_restore(flags);
434 }
435
436 cpu_relax();
437 stat(s, CMPXCHG_DOUBLE_FAIL);
438
439 #ifdef SLUB_DEBUG_CMPXCHG
440 pr_info("%s %s: cmpxchg double redo ", n, s->name);
441 #endif
442
443 return false;
444 }
445
446 #ifdef CONFIG_SLUB_DEBUG
447 static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
448 static DEFINE_SPINLOCK(object_map_lock);
449
450 /*
451 * Determine a map of object in use on a page.
452 *
453 * Node listlock must be held to guarantee that the page does
454 * not vanish from under us.
455 */
456 static unsigned long *get_map(struct kmem_cache *s, struct page *page)
457 __acquires(&object_map_lock)
458 {
459 void *p;
460 void *addr = page_address(page);
461
462 VM_BUG_ON(!irqs_disabled());
463
464 spin_lock(&object_map_lock);
465
466 bitmap_zero(object_map, page->objects);
467
468 for (p = page->freelist; p; p = get_freepointer(s, p))
469 set_bit(__obj_to_index(s, addr, p), object_map);
470
471 return object_map;
472 }
473
474 static void put_map(unsigned long *map) __releases(&object_map_lock)
475 {
476 VM_BUG_ON(map != object_map);
477 spin_unlock(&object_map_lock);
478 }
479
480 static inline unsigned int size_from_object(struct kmem_cache *s)
481 {
482 if (s->flags & SLAB_RED_ZONE)
483 return s->size - s->red_left_pad;
484
485 return s->size;
486 }
487
488 static inline void *restore_red_left(struct kmem_cache *s, void *p)
489 {
490 if (s->flags & SLAB_RED_ZONE)
491 p -= s->red_left_pad;
492
493 return p;
494 }
495
496 /*
497 * Debug settings:
498 */
499 #if defined(CONFIG_SLUB_DEBUG_ON)
500 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
501 #else
502 static slab_flags_t slub_debug;
503 #endif
504
505 static char *slub_debug_string;
506 static int disable_higher_order_debug;
507
508 /*
509 * slub is about to manipulate internal object metadata. This memory lies
510 * outside the range of the allocated object, so accessing it would normally
511 * be reported by kasan as a bounds error. metadata_access_enable() is used
512 * to tell kasan that these accesses are OK.
513 */
514 static inline void metadata_access_enable(void)
515 {
516 kasan_disable_current();
517 }
518
519 static inline void metadata_access_disable(void)
520 {
521 kasan_enable_current();
522 }
523
524 /*
525 * Object debugging
526 */
527
528 /* Verify that a pointer has an address that is valid within a slab page */
529 static inline int check_valid_pointer(struct kmem_cache *s,
530 struct page *page, void *object)
531 {
532 void *base;
533
534 if (!object)
535 return 1;
536
537 base = page_address(page);
538 object = kasan_reset_tag(object);
539 object = restore_red_left(s, object);
540 if (object < base || object >= base + page->objects * s->size ||
541 (object - base) % s->size) {
542 return 0;
543 }
544
545 return 1;
546 }
547
548 static void print_section(char *level, char *text, u8 *addr,
549 unsigned int length)
550 {
551 metadata_access_enable();
552 print_hex_dump(level, kasan_reset_tag(text), DUMP_PREFIX_ADDRESS,
553 16, 1, addr, length, 1);
554 metadata_access_disable();
555 }
556
557 /*
558 * See comment in calculate_sizes().
559 */
560 static inline bool freeptr_outside_object(struct kmem_cache *s)
561 {
562 return s->offset >= s->inuse;
563 }
564
565 /*
566 * Return offset of the end of info block which is inuse + free pointer if
567 * not overlapping with object.
568 */
569 static inline unsigned int get_info_end(struct kmem_cache *s)
570 {
571 if (freeptr_outside_object(s))
572 return s->inuse + sizeof(void *);
573 else
574 return s->inuse;
575 }
576
577 static struct track *get_track(struct kmem_cache *s, void *object,
578 enum track_item alloc)
579 {
580 struct track *p;
581
582 p = object + get_info_end(s);
583
584 return kasan_reset_tag(p + alloc);
585 }
586
587 static void set_track(struct kmem_cache *s, void *object,
588 enum track_item alloc, unsigned long addr)
589 {
590 struct track *p = get_track(s, object, alloc);
591
592 if (addr) {
593 #ifdef CONFIG_STACKTRACE
594 unsigned int nr_entries;
595
596 metadata_access_enable();
597 nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
598 TRACK_ADDRS_COUNT, 3);
599 metadata_access_disable();
600
601 if (nr_entries < TRACK_ADDRS_COUNT)
602 p->addrs[nr_entries] = 0;
603 #endif
604 p->addr = addr;
605 p->cpu = smp_processor_id();
606 p->pid = current->pid;
607 p->when = jiffies;
608 } else {
609 memset(p, 0, sizeof(struct track));
610 }
611 }
612
613 static void init_tracking(struct kmem_cache *s, void *object)
614 {
615 if (!(s->flags & SLAB_STORE_USER))
616 return;
617
618 set_track(s, object, TRACK_FREE, 0UL);
619 set_track(s, object, TRACK_ALLOC, 0UL);
620 }
621
622 static void print_track(const char *s, struct track *t, unsigned long pr_time)
623 {
624 if (!t->addr)
625 return;
626
627 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
628 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
629 #ifdef CONFIG_STACKTRACE
630 {
631 int i;
632 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
633 if (t->addrs[i])
634 pr_err("\t%pS\n", (void *)t->addrs[i]);
635 else
636 break;
637 }
638 #endif
639 }
640
641 void print_tracking(struct kmem_cache *s, void *object)
642 {
643 unsigned long pr_time = jiffies;
644 if (!(s->flags & SLAB_STORE_USER))
645 return;
646
647 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
648 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
649 }
650
651 static void print_page_info(struct page *page)
652 {
653 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
654 page, page->objects, page->inuse, page->freelist, page->flags);
655
656 }
657
658 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
659 {
660 struct va_format vaf;
661 va_list args;
662
663 va_start(args, fmt);
664 vaf.fmt = fmt;
665 vaf.va = &args;
666 pr_err("=============================================================================\n");
667 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
668 pr_err("-----------------------------------------------------------------------------\n\n");
669
670 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
671 va_end(args);
672 }
673
674 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
675 {
676 struct va_format vaf;
677 va_list args;
678
679 va_start(args, fmt);
680 vaf.fmt = fmt;
681 vaf.va = &args;
682 pr_err("FIX %s: %pV\n", s->name, &vaf);
683 va_end(args);
684 }
685
686 static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
687 void **freelist, void *nextfree)
688 {
689 if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
690 !check_valid_pointer(s, page, nextfree) && freelist) {
691 object_err(s, page, *freelist, "Freechain corrupt");
692 *freelist = NULL;
693 slab_fix(s, "Isolate corrupted freechain");
694 return true;
695 }
696
697 return false;
698 }
699
700 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
701 {
702 unsigned int off; /* Offset of last byte */
703 u8 *addr = page_address(page);
704
705 print_tracking(s, p);
706
707 print_page_info(page);
708
709 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
710 p, p - addr, get_freepointer(s, p));
711
712 if (s->flags & SLAB_RED_ZONE)
713 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
714 s->red_left_pad);
715 else if (p > addr + 16)
716 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
717
718 print_section(KERN_ERR, "Object ", p,
719 min_t(unsigned int, s->object_size, PAGE_SIZE));
720 if (s->flags & SLAB_RED_ZONE)
721 print_section(KERN_ERR, "Redzone ", p + s->object_size,
722 s->inuse - s->object_size);
723
724 off = get_info_end(s);
725
726 if (s->flags & SLAB_STORE_USER)
727 off += 2 * sizeof(struct track);
728
729 off += kasan_metadata_size(s);
730
731 if (off != size_from_object(s))
732 /* Beginning of the filler is the free pointer */
733 print_section(KERN_ERR, "Padding ", p + off,
734 size_from_object(s) - off);
735
736 dump_stack();
737 }
738
739 void object_err(struct kmem_cache *s, struct page *page,
740 u8 *object, char *reason)
741 {
742 slab_bug(s, "%s", reason);
743 print_trailer(s, page, object);
744 }
745
746 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
747 const char *fmt, ...)
748 {
749 va_list args;
750 char buf[100];
751
752 va_start(args, fmt);
753 vsnprintf(buf, sizeof(buf), fmt, args);
754 va_end(args);
755 slab_bug(s, "%s", buf);
756 print_page_info(page);
757 dump_stack();
758 }
759
760 static void init_object(struct kmem_cache *s, void *object, u8 val)
761 {
762 u8 *p = kasan_reset_tag(object);
763
764 if (s->flags & SLAB_RED_ZONE)
765 memset(p - s->red_left_pad, val, s->red_left_pad);
766
767 if (s->flags & __OBJECT_POISON) {
768 memset(p, POISON_FREE, s->object_size - 1);
769 p[s->object_size - 1] = POISON_END;
770 }
771
772 if (s->flags & SLAB_RED_ZONE)
773 memset(p + s->object_size, val, s->inuse - s->object_size);
774 }
775
776 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
777 void *from, void *to)
778 {
779 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
780 memset(from, data, to - from);
781 }
782
783 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
784 u8 *object, char *what,
785 u8 *start, unsigned int value, unsigned int bytes)
786 {
787 u8 *fault;
788 u8 *end;
789 u8 *addr = page_address(page);
790
791 metadata_access_enable();
792 fault = memchr_inv(kasan_reset_tag(start), value, bytes);
793 metadata_access_disable();
794 if (!fault)
795 return 1;
796
797 end = start + bytes;
798 while (end > fault && end[-1] == value)
799 end--;
800
801 slab_bug(s, "%s overwritten", what);
802 pr_err("INFO: 0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
803 fault, end - 1, fault - addr,
804 fault[0], value);
805 print_trailer(s, page, object);
806
807 restore_bytes(s, what, value, fault, end);
808 return 0;
809 }
810
811 /*
812 * Object layout:
813 *
814 * object address
815 * Bytes of the object to be managed.
816 * If the freepointer may overlay the object then the free
817 * pointer is at the middle of the object.
818 *
819 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
820 * 0xa5 (POISON_END)
821 *
822 * object + s->object_size
823 * Padding to reach word boundary. This is also used for Redzoning.
824 * Padding is extended by another word if Redzoning is enabled and
825 * object_size == inuse.
826 *
827 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
828 * 0xcc (RED_ACTIVE) for objects in use.
829 *
830 * object + s->inuse
831 * Meta data starts here.
832 *
833 * A. Free pointer (if we cannot overwrite object on free)
834 * B. Tracking data for SLAB_STORE_USER
835 * C. Padding to reach required alignment boundary or at mininum
836 * one word if debugging is on to be able to detect writes
837 * before the word boundary.
838 *
839 * Padding is done using 0x5a (POISON_INUSE)
840 *
841 * object + s->size
842 * Nothing is used beyond s->size.
843 *
844 * If slabcaches are merged then the object_size and inuse boundaries are mostly
845 * ignored. And therefore no slab options that rely on these boundaries
846 * may be used with merged slabcaches.
847 */
848
849 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
850 {
851 unsigned long off = get_info_end(s); /* The end of info */
852
853 if (s->flags & SLAB_STORE_USER)
854 /* We also have user information there */
855 off += 2 * sizeof(struct track);
856
857 off += kasan_metadata_size(s);
858
859 if (size_from_object(s) == off)
860 return 1;
861
862 return check_bytes_and_report(s, page, p, "Object padding",
863 p + off, POISON_INUSE, size_from_object(s) - off);
864 }
865
866 /* Check the pad bytes at the end of a slab page */
867 static int slab_pad_check(struct kmem_cache *s, struct page *page)
868 {
869 u8 *start;
870 u8 *fault;
871 u8 *end;
872 u8 *pad;
873 int length;
874 int remainder;
875
876 if (!(s->flags & SLAB_POISON))
877 return 1;
878
879 start = page_address(page);
880 length = page_size(page);
881 end = start + length;
882 remainder = length % s->size;
883 if (!remainder)
884 return 1;
885
886 pad = end - remainder;
887 metadata_access_enable();
888 fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
889 metadata_access_disable();
890 if (!fault)
891 return 1;
892 while (end > fault && end[-1] == POISON_INUSE)
893 end--;
894
895 slab_err(s, page, "Padding overwritten. 0x%p-0x%p @offset=%tu",
896 fault, end - 1, fault - start);
897 print_section(KERN_ERR, "Padding ", pad, remainder);
898
899 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
900 return 0;
901 }
902
903 static int check_object(struct kmem_cache *s, struct page *page,
904 void *object, u8 val)
905 {
906 u8 *p = object;
907 u8 *endobject = object + s->object_size;
908
909 if (s->flags & SLAB_RED_ZONE) {
910 if (!check_bytes_and_report(s, page, object, "Redzone",
911 object - s->red_left_pad, val, s->red_left_pad))
912 return 0;
913
914 if (!check_bytes_and_report(s, page, object, "Redzone",
915 endobject, val, s->inuse - s->object_size))
916 return 0;
917 } else {
918 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
919 check_bytes_and_report(s, page, p, "Alignment padding",
920 endobject, POISON_INUSE,
921 s->inuse - s->object_size);
922 }
923 }
924
925 if (s->flags & SLAB_POISON) {
926 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
927 (!check_bytes_and_report(s, page, p, "Poison", p,
928 POISON_FREE, s->object_size - 1) ||
929 !check_bytes_and_report(s, page, p, "Poison",
930 p + s->object_size - 1, POISON_END, 1)))
931 return 0;
932 /*
933 * check_pad_bytes cleans up on its own.
934 */
935 check_pad_bytes(s, page, p);
936 }
937
938 if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
939 /*
940 * Object and freepointer overlap. Cannot check
941 * freepointer while object is allocated.
942 */
943 return 1;
944
945 /* Check free pointer validity */
946 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
947 object_err(s, page, p, "Freepointer corrupt");
948 /*
949 * No choice but to zap it and thus lose the remainder
950 * of the free objects in this slab. May cause
951 * another error because the object count is now wrong.
952 */
953 set_freepointer(s, p, NULL);
954 return 0;
955 }
956 return 1;
957 }
958
959 static int check_slab(struct kmem_cache *s, struct page *page)
960 {
961 int maxobj;
962
963 VM_BUG_ON(!irqs_disabled());
964
965 if (!PageSlab(page)) {
966 slab_err(s, page, "Not a valid slab page");
967 return 0;
968 }
969
970 maxobj = order_objects(compound_order(page), s->size);
971 if (page->objects > maxobj) {
972 slab_err(s, page, "objects %u > max %u",
973 page->objects, maxobj);
974 return 0;
975 }
976 if (page->inuse > page->objects) {
977 slab_err(s, page, "inuse %u > max %u",
978 page->inuse, page->objects);
979 return 0;
980 }
981 /* Slab_pad_check fixes things up after itself */
982 slab_pad_check(s, page);
983 return 1;
984 }
985
986 /*
987 * Determine if a certain object on a page is on the freelist. Must hold the
988 * slab lock to guarantee that the chains are in a consistent state.
989 */
990 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
991 {
992 int nr = 0;
993 void *fp;
994 void *object = NULL;
995 int max_objects;
996
997 fp = page->freelist;
998 while (fp && nr <= page->objects) {
999 if (fp == search)
1000 return 1;
1001 if (!check_valid_pointer(s, page, fp)) {
1002 if (object) {
1003 object_err(s, page, object,
1004 "Freechain corrupt");
1005 set_freepointer(s, object, NULL);
1006 } else {
1007 slab_err(s, page, "Freepointer corrupt");
1008 page->freelist = NULL;
1009 page->inuse = page->objects;
1010 slab_fix(s, "Freelist cleared");
1011 return 0;
1012 }
1013 break;
1014 }
1015 object = fp;
1016 fp = get_freepointer(s, object);
1017 nr++;
1018 }
1019
1020 max_objects = order_objects(compound_order(page), s->size);
1021 if (max_objects > MAX_OBJS_PER_PAGE)
1022 max_objects = MAX_OBJS_PER_PAGE;
1023
1024 if (page->objects != max_objects) {
1025 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
1026 page->objects, max_objects);
1027 page->objects = max_objects;
1028 slab_fix(s, "Number of objects adjusted.");
1029 }
1030 if (page->inuse != page->objects - nr) {
1031 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
1032 page->inuse, page->objects - nr);
1033 page->inuse = page->objects - nr;
1034 slab_fix(s, "Object count adjusted.");
1035 }
1036 return search == NULL;
1037 }
1038
1039 static void trace(struct kmem_cache *s, struct page *page, void *object,
1040 int alloc)
1041 {
1042 if (s->flags & SLAB_TRACE) {
1043 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1044 s->name,
1045 alloc ? "alloc" : "free",
1046 object, page->inuse,
1047 page->freelist);
1048
1049 if (!alloc)
1050 print_section(KERN_INFO, "Object ", (void *)object,
1051 s->object_size);
1052
1053 dump_stack();
1054 }
1055 }
1056
1057 /*
1058 * Tracking of fully allocated slabs for debugging purposes.
1059 */
1060 static void add_full(struct kmem_cache *s,
1061 struct kmem_cache_node *n, struct page *page)
1062 {
1063 if (!(s->flags & SLAB_STORE_USER))
1064 return;
1065
1066 lockdep_assert_held(&n->list_lock);
1067 list_add(&page->slab_list, &n->full);
1068 }
1069
1070 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1071 {
1072 if (!(s->flags & SLAB_STORE_USER))
1073 return;
1074
1075 lockdep_assert_held(&n->list_lock);
1076 list_del(&page->slab_list);
1077 }
1078
1079 /* Tracking of the number of slabs for debugging purposes */
1080 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1081 {
1082 struct kmem_cache_node *n = get_node(s, node);
1083
1084 return atomic_long_read(&n->nr_slabs);
1085 }
1086
1087 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1088 {
1089 return atomic_long_read(&n->nr_slabs);
1090 }
1091
1092 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1093 {
1094 struct kmem_cache_node *n = get_node(s, node);
1095
1096 /*
1097 * May be called early in order to allocate a slab for the
1098 * kmem_cache_node structure. Solve the chicken-egg
1099 * dilemma by deferring the increment of the count during
1100 * bootstrap (see early_kmem_cache_node_alloc).
1101 */
1102 if (likely(n)) {
1103 atomic_long_inc(&n->nr_slabs);
1104 atomic_long_add(objects, &n->total_objects);
1105 }
1106 }
1107 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1108 {
1109 struct kmem_cache_node *n = get_node(s, node);
1110
1111 atomic_long_dec(&n->nr_slabs);
1112 atomic_long_sub(objects, &n->total_objects);
1113 }
1114
1115 /* Object debug checks for alloc/free paths */
1116 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1117 void *object)
1118 {
1119 if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1120 return;
1121
1122 init_object(s, object, SLUB_RED_INACTIVE);
1123 init_tracking(s, object);
1124 }
1125
1126 static
1127 void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr)
1128 {
1129 if (!kmem_cache_debug_flags(s, SLAB_POISON))
1130 return;
1131
1132 metadata_access_enable();
1133 memset(kasan_reset_tag(addr), POISON_INUSE, page_size(page));
1134 metadata_access_disable();
1135 }
1136
1137 static inline int alloc_consistency_checks(struct kmem_cache *s,
1138 struct page *page, void *object)
1139 {
1140 if (!check_slab(s, page))
1141 return 0;
1142
1143 if (!check_valid_pointer(s, page, object)) {
1144 object_err(s, page, object, "Freelist Pointer check fails");
1145 return 0;
1146 }
1147
1148 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1149 return 0;
1150
1151 return 1;
1152 }
1153
1154 static noinline int alloc_debug_processing(struct kmem_cache *s,
1155 struct page *page,
1156 void *object, unsigned long addr)
1157 {
1158 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1159 if (!alloc_consistency_checks(s, page, object))
1160 goto bad;
1161 }
1162
1163 /* Success perform special debug activities for allocs */
1164 if (s->flags & SLAB_STORE_USER)
1165 set_track(s, object, TRACK_ALLOC, addr);
1166 trace(s, page, object, 1);
1167 init_object(s, object, SLUB_RED_ACTIVE);
1168 return 1;
1169
1170 bad:
1171 if (PageSlab(page)) {
1172 /*
1173 * If this is a slab page then lets do the best we can
1174 * to avoid issues in the future. Marking all objects
1175 * as used avoids touching the remaining objects.
1176 */
1177 slab_fix(s, "Marking all objects used");
1178 page->inuse = page->objects;
1179 page->freelist = NULL;
1180 }
1181 return 0;
1182 }
1183
1184 static inline int free_consistency_checks(struct kmem_cache *s,
1185 struct page *page, void *object, unsigned long addr)
1186 {
1187 if (!check_valid_pointer(s, page, object)) {
1188 slab_err(s, page, "Invalid object pointer 0x%p", object);
1189 return 0;
1190 }
1191
1192 if (on_freelist(s, page, object)) {
1193 object_err(s, page, object, "Object already free");
1194 return 0;
1195 }
1196
1197 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1198 return 0;
1199
1200 if (unlikely(s != page->slab_cache)) {
1201 if (!PageSlab(page)) {
1202 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1203 object);
1204 } else if (!page->slab_cache) {
1205 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1206 object);
1207 dump_stack();
1208 } else
1209 object_err(s, page, object,
1210 "page slab pointer corrupt.");
1211 return 0;
1212 }
1213 return 1;
1214 }
1215
1216 /* Supports checking bulk free of a constructed freelist */
1217 static noinline int free_debug_processing(
1218 struct kmem_cache *s, struct page *page,
1219 void *head, void *tail, int bulk_cnt,
1220 unsigned long addr)
1221 {
1222 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1223 void *object = head;
1224 int cnt = 0;
1225 unsigned long flags;
1226 int ret = 0;
1227
1228 spin_lock_irqsave(&n->list_lock, flags);
1229 slab_lock(page);
1230
1231 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1232 if (!check_slab(s, page))
1233 goto out;
1234 }
1235
1236 next_object:
1237 cnt++;
1238
1239 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1240 if (!free_consistency_checks(s, page, object, addr))
1241 goto out;
1242 }
1243
1244 if (s->flags & SLAB_STORE_USER)
1245 set_track(s, object, TRACK_FREE, addr);
1246 trace(s, page, object, 0);
1247 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1248 init_object(s, object, SLUB_RED_INACTIVE);
1249
1250 /* Reached end of constructed freelist yet? */
1251 if (object != tail) {
1252 object = get_freepointer(s, object);
1253 goto next_object;
1254 }
1255 ret = 1;
1256
1257 out:
1258 if (cnt != bulk_cnt)
1259 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1260 bulk_cnt, cnt);
1261
1262 slab_unlock(page);
1263 spin_unlock_irqrestore(&n->list_lock, flags);
1264 if (!ret)
1265 slab_fix(s, "Object at 0x%p not freed", object);
1266 return ret;
1267 }
1268
1269 /*
1270 * Parse a block of slub_debug options. Blocks are delimited by ';'
1271 *
1272 * @str: start of block
1273 * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1274 * @slabs: return start of list of slabs, or NULL when there's no list
1275 * @init: assume this is initial parsing and not per-kmem-create parsing
1276 *
1277 * returns the start of next block if there's any, or NULL
1278 */
1279 static char *
1280 parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1281 {
1282 bool higher_order_disable = false;
1283
1284 /* Skip any completely empty blocks */
1285 while (*str && *str == ';')
1286 str++;
1287
1288 if (*str == ',') {
1289 /*
1290 * No options but restriction on slabs. This means full
1291 * debugging for slabs matching a pattern.
1292 */
1293 *flags = DEBUG_DEFAULT_FLAGS;
1294 goto check_slabs;
1295 }
1296 *flags = 0;
1297
1298 /* Determine which debug features should be switched on */
1299 for (; *str && *str != ',' && *str != ';'; str++) {
1300 switch (tolower(*str)) {
1301 case '-':
1302 *flags = 0;
1303 break;
1304 case 'f':
1305 *flags |= SLAB_CONSISTENCY_CHECKS;
1306 break;
1307 case 'z':
1308 *flags |= SLAB_RED_ZONE;
1309 break;
1310 case 'p':
1311 *flags |= SLAB_POISON;
1312 break;
1313 case 'u':
1314 *flags |= SLAB_STORE_USER;
1315 break;
1316 case 't':
1317 *flags |= SLAB_TRACE;
1318 break;
1319 case 'a':
1320 *flags |= SLAB_FAILSLAB;
1321 break;
1322 case 'o':
1323 /*
1324 * Avoid enabling debugging on caches if its minimum
1325 * order would increase as a result.
1326 */
1327 higher_order_disable = true;
1328 break;
1329 default:
1330 if (init)
1331 pr_err("slub_debug option '%c' unknown. skipped\n", *str);
1332 }
1333 }
1334 check_slabs:
1335 if (*str == ',')
1336 *slabs = ++str;
1337 else
1338 *slabs = NULL;
1339
1340 /* Skip over the slab list */
1341 while (*str && *str != ';')
1342 str++;
1343
1344 /* Skip any completely empty blocks */
1345 while (*str && *str == ';')
1346 str++;
1347
1348 if (init && higher_order_disable)
1349 disable_higher_order_debug = 1;
1350
1351 if (*str)
1352 return str;
1353 else
1354 return NULL;
1355 }
1356
1357 static int __init setup_slub_debug(char *str)
1358 {
1359 slab_flags_t flags;
1360 char *saved_str;
1361 char *slab_list;
1362 bool global_slub_debug_changed = false;
1363 bool slab_list_specified = false;
1364
1365 slub_debug = DEBUG_DEFAULT_FLAGS;
1366 if (*str++ != '=' || !*str)
1367 /*
1368 * No options specified. Switch on full debugging.
1369 */
1370 goto out;
1371
1372 saved_str = str;
1373 while (str) {
1374 str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1375
1376 if (!slab_list) {
1377 slub_debug = flags;
1378 global_slub_debug_changed = true;
1379 } else {
1380 slab_list_specified = true;
1381 }
1382 }
1383
1384 /*
1385 * For backwards compatibility, a single list of flags with list of
1386 * slabs means debugging is only enabled for those slabs, so the global
1387 * slub_debug should be 0. We can extended that to multiple lists as
1388 * long as there is no option specifying flags without a slab list.
1389 */
1390 if (slab_list_specified) {
1391 if (!global_slub_debug_changed)
1392 slub_debug = 0;
1393 slub_debug_string = saved_str;
1394 }
1395 out:
1396 if (slub_debug != 0 || slub_debug_string)
1397 static_branch_enable(&slub_debug_enabled);
1398 if ((static_branch_unlikely(&init_on_alloc) ||
1399 static_branch_unlikely(&init_on_free)) &&
1400 (slub_debug & SLAB_POISON))
1401 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1402 return 1;
1403 }
1404
1405 __setup("slub_debug", setup_slub_debug);
1406
1407 /*
1408 * kmem_cache_flags - apply debugging options to the cache
1409 * @object_size: the size of an object without meta data
1410 * @flags: flags to set
1411 * @name: name of the cache
1412 *
1413 * Debug option(s) are applied to @flags. In addition to the debug
1414 * option(s), if a slab name (or multiple) is specified i.e.
1415 * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1416 * then only the select slabs will receive the debug option(s).
1417 */
1418 slab_flags_t kmem_cache_flags(unsigned int object_size,
1419 slab_flags_t flags, const char *name)
1420 {
1421 char *iter;
1422 size_t len;
1423 char *next_block;
1424 slab_flags_t block_flags;
1425 slab_flags_t slub_debug_local = slub_debug;
1426
1427 /*
1428 * If the slab cache is for debugging (e.g. kmemleak) then
1429 * don't store user (stack trace) information by default,
1430 * but let the user enable it via the command line below.
1431 */
1432 if (flags & SLAB_NOLEAKTRACE)
1433 slub_debug_local &= ~SLAB_STORE_USER;
1434
1435 len = strlen(name);
1436 next_block = slub_debug_string;
1437 /* Go through all blocks of debug options, see if any matches our slab's name */
1438 while (next_block) {
1439 next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1440 if (!iter)
1441 continue;
1442 /* Found a block that has a slab list, search it */
1443 while (*iter) {
1444 char *end, *glob;
1445 size_t cmplen;
1446
1447 end = strchrnul(iter, ',');
1448 if (next_block && next_block < end)
1449 end = next_block - 1;
1450
1451 glob = strnchr(iter, end - iter, '*');
1452 if (glob)
1453 cmplen = glob - iter;
1454 else
1455 cmplen = max_t(size_t, len, (end - iter));
1456
1457 if (!strncmp(name, iter, cmplen)) {
1458 flags |= block_flags;
1459 return flags;
1460 }
1461
1462 if (!*end || *end == ';')
1463 break;
1464 iter = end + 1;
1465 }
1466 }
1467
1468 return flags | slub_debug_local;
1469 }
1470 #else /* !CONFIG_SLUB_DEBUG */
1471 static inline void setup_object_debug(struct kmem_cache *s,
1472 struct page *page, void *object) {}
1473 static inline
1474 void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) {}
1475
1476 static inline int alloc_debug_processing(struct kmem_cache *s,
1477 struct page *page, void *object, unsigned long addr) { return 0; }
1478
1479 static inline int free_debug_processing(
1480 struct kmem_cache *s, struct page *page,
1481 void *head, void *tail, int bulk_cnt,
1482 unsigned long addr) { return 0; }
1483
1484 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1485 { return 1; }
1486 static inline int check_object(struct kmem_cache *s, struct page *page,
1487 void *object, u8 val) { return 1; }
1488 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1489 struct page *page) {}
1490 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1491 struct page *page) {}
1492 slab_flags_t kmem_cache_flags(unsigned int object_size,
1493 slab_flags_t flags, const char *name)
1494 {
1495 return flags;
1496 }
1497 #define slub_debug 0
1498
1499 #define disable_higher_order_debug 0
1500
1501 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1502 { return 0; }
1503 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1504 { return 0; }
1505 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1506 int objects) {}
1507 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1508 int objects) {}
1509
1510 static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
1511 void **freelist, void *nextfree)
1512 {
1513 return false;
1514 }
1515 #endif /* CONFIG_SLUB_DEBUG */
1516
1517 /*
1518 * Hooks for other subsystems that check memory allocations. In a typical
1519 * production configuration these hooks all should produce no code at all.
1520 */
1521 static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1522 {
1523 ptr = kasan_kmalloc_large(ptr, size, flags);
1524 /* As ptr might get tagged, call kmemleak hook after KASAN. */
1525 kmemleak_alloc(ptr, size, 1, flags);
1526 return ptr;
1527 }
1528
1529 static __always_inline void kfree_hook(void *x)
1530 {
1531 kmemleak_free(x);
1532 kasan_kfree_large(x);
1533 }
1534
1535 static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
1536 {
1537 kmemleak_free_recursive(x, s->flags);
1538
1539 /*
1540 * Trouble is that we may no longer disable interrupts in the fast path
1541 * So in order to make the debug calls that expect irqs to be
1542 * disabled we need to disable interrupts temporarily.
1543 */
1544 #ifdef CONFIG_LOCKDEP
1545 {
1546 unsigned long flags;
1547
1548 local_irq_save(flags);
1549 debug_check_no_locks_freed(x, s->object_size);
1550 local_irq_restore(flags);
1551 }
1552 #endif
1553 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1554 debug_check_no_obj_freed(x, s->object_size);
1555
1556 /* Use KCSAN to help debug racy use-after-free. */
1557 if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
1558 __kcsan_check_access(x, s->object_size,
1559 KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
1560
1561 /* KASAN might put x into memory quarantine, delaying its reuse */
1562 return kasan_slab_free(s, x);
1563 }
1564
1565 static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1566 void **head, void **tail)
1567 {
1568
1569 void *object;
1570 void *next = *head;
1571 void *old_tail = *tail ? *tail : *head;
1572 int rsize;
1573
1574 if (is_kfence_address(next)) {
1575 slab_free_hook(s, next);
1576 return true;
1577 }
1578
1579 /* Head and tail of the reconstructed freelist */
1580 *head = NULL;
1581 *tail = NULL;
1582
1583 do {
1584 object = next;
1585 next = get_freepointer(s, object);
1586
1587 if (slab_want_init_on_free(s)) {
1588 /*
1589 * Clear the object and the metadata, but don't touch
1590 * the redzone.
1591 */
1592 memset(kasan_reset_tag(object), 0, s->object_size);
1593 rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad
1594 : 0;
1595 memset((char *)kasan_reset_tag(object) + s->inuse, 0,
1596 s->size - s->inuse - rsize);
1597
1598 }
1599 /* If object's reuse doesn't have to be delayed */
1600 if (!slab_free_hook(s, object)) {
1601 /* Move object to the new freelist */
1602 set_freepointer(s, object, *head);
1603 *head = object;
1604 if (!*tail)
1605 *tail = object;
1606 }
1607 } while (object != old_tail);
1608
1609 if (*head == *tail)
1610 *tail = NULL;
1611
1612 return *head != NULL;
1613 }
1614
1615 static void *setup_object(struct kmem_cache *s, struct page *page,
1616 void *object)
1617 {
1618 setup_object_debug(s, page, object);
1619 object = kasan_init_slab_obj(s, object);
1620 if (unlikely(s->ctor)) {
1621 kasan_unpoison_object_data(s, object);
1622 s->ctor(object);
1623 kasan_poison_object_data(s, object);
1624 }
1625 return object;
1626 }
1627
1628 /*
1629 * Slab allocation and freeing
1630 */
1631 static inline struct page *alloc_slab_page(struct kmem_cache *s,
1632 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1633 {
1634 struct page *page;
1635 unsigned int order = oo_order(oo);
1636
1637 if (node == NUMA_NO_NODE)
1638 page = alloc_pages(flags, order);
1639 else
1640 page = __alloc_pages_node(node, flags, order);
1641
1642 return page;
1643 }
1644
1645 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1646 /* Pre-initialize the random sequence cache */
1647 static int init_cache_random_seq(struct kmem_cache *s)
1648 {
1649 unsigned int count = oo_objects(s->oo);
1650 int err;
1651
1652 /* Bailout if already initialised */
1653 if (s->random_seq)
1654 return 0;
1655
1656 err = cache_random_seq_create(s, count, GFP_KERNEL);
1657 if (err) {
1658 pr_err("SLUB: Unable to initialize free list for %s\n",
1659 s->name);
1660 return err;
1661 }
1662
1663 /* Transform to an offset on the set of pages */
1664 if (s->random_seq) {
1665 unsigned int i;
1666
1667 for (i = 0; i < count; i++)
1668 s->random_seq[i] *= s->size;
1669 }
1670 return 0;
1671 }
1672
1673 /* Initialize each random sequence freelist per cache */
1674 static void __init init_freelist_randomization(void)
1675 {
1676 struct kmem_cache *s;
1677
1678 mutex_lock(&slab_mutex);
1679
1680 list_for_each_entry(s, &slab_caches, list)
1681 init_cache_random_seq(s);
1682
1683 mutex_unlock(&slab_mutex);
1684 }
1685
1686 /* Get the next entry on the pre-computed freelist randomized */
1687 static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1688 unsigned long *pos, void *start,
1689 unsigned long page_limit,
1690 unsigned long freelist_count)
1691 {
1692 unsigned int idx;
1693
1694 /*
1695 * If the target page allocation failed, the number of objects on the
1696 * page might be smaller than the usual size defined by the cache.
1697 */
1698 do {
1699 idx = s->random_seq[*pos];
1700 *pos += 1;
1701 if (*pos >= freelist_count)
1702 *pos = 0;
1703 } while (unlikely(idx >= page_limit));
1704
1705 return (char *)start + idx;
1706 }
1707
1708 /* Shuffle the single linked freelist based on a random pre-computed sequence */
1709 static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1710 {
1711 void *start;
1712 void *cur;
1713 void *next;
1714 unsigned long idx, pos, page_limit, freelist_count;
1715
1716 if (page->objects < 2 || !s->random_seq)
1717 return false;
1718
1719 freelist_count = oo_objects(s->oo);
1720 pos = get_random_int() % freelist_count;
1721
1722 page_limit = page->objects * s->size;
1723 start = fixup_red_left(s, page_address(page));
1724
1725 /* First entry is used as the base of the freelist */
1726 cur = next_freelist_entry(s, page, &pos, start, page_limit,
1727 freelist_count);
1728 cur = setup_object(s, page, cur);
1729 page->freelist = cur;
1730
1731 for (idx = 1; idx < page->objects; idx++) {
1732 next = next_freelist_entry(s, page, &pos, start, page_limit,
1733 freelist_count);
1734 next = setup_object(s, page, next);
1735 set_freepointer(s, cur, next);
1736 cur = next;
1737 }
1738 set_freepointer(s, cur, NULL);
1739
1740 return true;
1741 }
1742 #else
1743 static inline int init_cache_random_seq(struct kmem_cache *s)
1744 {
1745 return 0;
1746 }
1747 static inline void init_freelist_randomization(void) { }
1748 static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1749 {
1750 return false;
1751 }
1752 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1753
1754 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1755 {
1756 struct page *page;
1757 struct kmem_cache_order_objects oo = s->oo;
1758 gfp_t alloc_gfp;
1759 void *start, *p, *next;
1760 int idx;
1761 bool shuffle;
1762
1763 flags &= gfp_allowed_mask;
1764
1765 if (gfpflags_allow_blocking(flags))
1766 local_irq_enable();
1767
1768 flags |= s->allocflags;
1769
1770 /*
1771 * Let the initial higher-order allocation fail under memory pressure
1772 * so we fall-back to the minimum order allocation.
1773 */
1774 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1775 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1776 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1777
1778 page = alloc_slab_page(s, alloc_gfp, node, oo);
1779 if (unlikely(!page)) {
1780 oo = s->min;
1781 alloc_gfp = flags;
1782 /*
1783 * Allocation may have failed due to fragmentation.
1784 * Try a lower order alloc if possible
1785 */
1786 page = alloc_slab_page(s, alloc_gfp, node, oo);
1787 if (unlikely(!page))
1788 goto out;
1789 stat(s, ORDER_FALLBACK);
1790 }
1791
1792 page->objects = oo_objects(oo);
1793
1794 account_slab_page(page, oo_order(oo), s, flags);
1795
1796 page->slab_cache = s;
1797 __SetPageSlab(page);
1798 if (page_is_pfmemalloc(page))
1799 SetPageSlabPfmemalloc(page);
1800
1801 kasan_poison_slab(page);
1802
1803 start = page_address(page);
1804
1805 setup_page_debug(s, page, start);
1806
1807 shuffle = shuffle_freelist(s, page);
1808
1809 if (!shuffle) {
1810 start = fixup_red_left(s, start);
1811 start = setup_object(s, page, start);
1812 page->freelist = start;
1813 for (idx = 0, p = start; idx < page->objects - 1; idx++) {
1814 next = p + s->size;
1815 next = setup_object(s, page, next);
1816 set_freepointer(s, p, next);
1817 p = next;
1818 }
1819 set_freepointer(s, p, NULL);
1820 }
1821
1822 page->inuse = page->objects;
1823 page->frozen = 1;
1824
1825 out:
1826 if (gfpflags_allow_blocking(flags))
1827 local_irq_disable();
1828 if (!page)
1829 return NULL;
1830
1831 inc_slabs_node(s, page_to_nid(page), page->objects);
1832
1833 return page;
1834 }
1835
1836 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1837 {
1838 if (unlikely(flags & GFP_SLAB_BUG_MASK))
1839 flags = kmalloc_fix_flags(flags);
1840
1841 return allocate_slab(s,
1842 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1843 }
1844
1845 static void __free_slab(struct kmem_cache *s, struct page *page)
1846 {
1847 int order = compound_order(page);
1848 int pages = 1 << order;
1849
1850 if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
1851 void *p;
1852
1853 slab_pad_check(s, page);
1854 for_each_object(p, s, page_address(page),
1855 page->objects)
1856 check_object(s, page, p, SLUB_RED_INACTIVE);
1857 }
1858
1859 __ClearPageSlabPfmemalloc(page);
1860 __ClearPageSlab(page);
1861 /* In union with page->mapping where page allocator expects NULL */
1862 page->slab_cache = NULL;
1863 if (current->reclaim_state)
1864 current->reclaim_state->reclaimed_slab += pages;
1865 unaccount_slab_page(page, order, s);
1866 __free_pages(page, order);
1867 }
1868
1869 static void rcu_free_slab(struct rcu_head *h)
1870 {
1871 struct page *page = container_of(h, struct page, rcu_head);
1872
1873 __free_slab(page->slab_cache, page);
1874 }
1875
1876 static void free_slab(struct kmem_cache *s, struct page *page)
1877 {
1878 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
1879 call_rcu(&page->rcu_head, rcu_free_slab);
1880 } else
1881 __free_slab(s, page);
1882 }
1883
1884 static void discard_slab(struct kmem_cache *s, struct page *page)
1885 {
1886 dec_slabs_node(s, page_to_nid(page), page->objects);
1887 free_slab(s, page);
1888 }
1889
1890 /*
1891 * Management of partially allocated slabs.
1892 */
1893 static inline void
1894 __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1895 {
1896 n->nr_partial++;
1897 if (tail == DEACTIVATE_TO_TAIL)
1898 list_add_tail(&page->slab_list, &n->partial);
1899 else
1900 list_add(&page->slab_list, &n->partial);
1901 }
1902
1903 static inline void add_partial(struct kmem_cache_node *n,
1904 struct page *page, int tail)
1905 {
1906 lockdep_assert_held(&n->list_lock);
1907 __add_partial(n, page, tail);
1908 }
1909
1910 static inline void remove_partial(struct kmem_cache_node *n,
1911 struct page *page)
1912 {
1913 lockdep_assert_held(&n->list_lock);
1914 list_del(&page->slab_list);
1915 n->nr_partial--;
1916 }
1917
1918 /*
1919 * Remove slab from the partial list, freeze it and
1920 * return the pointer to the freelist.
1921 *
1922 * Returns a list of objects or NULL if it fails.
1923 */
1924 static inline void *acquire_slab(struct kmem_cache *s,
1925 struct kmem_cache_node *n, struct page *page,
1926 int mode, int *objects)
1927 {
1928 void *freelist;
1929 unsigned long counters;
1930 struct page new;
1931
1932 lockdep_assert_held(&n->list_lock);
1933
1934 /*
1935 * Zap the freelist and set the frozen bit.
1936 * The old freelist is the list of objects for the
1937 * per cpu allocation list.
1938 */
1939 freelist = page->freelist;
1940 counters = page->counters;
1941 new.counters = counters;
1942 *objects = new.objects - new.inuse;
1943 if (mode) {
1944 new.inuse = page->objects;
1945 new.freelist = NULL;
1946 } else {
1947 new.freelist = freelist;
1948 }
1949
1950 VM_BUG_ON(new.frozen);
1951 new.frozen = 1;
1952
1953 if (!__cmpxchg_double_slab(s, page,
1954 freelist, counters,
1955 new.freelist, new.counters,
1956 "acquire_slab"))
1957 return NULL;
1958
1959 remove_partial(n, page);
1960 WARN_ON(!freelist);
1961 return freelist;
1962 }
1963
1964 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1965 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1966
1967 /*
1968 * Try to allocate a partial slab from a specific node.
1969 */
1970 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1971 struct kmem_cache_cpu *c, gfp_t flags)
1972 {
1973 struct page *page, *page2;
1974 void *object = NULL;
1975 unsigned int available = 0;
1976 int objects;
1977
1978 /*
1979 * Racy check. If we mistakenly see no partial slabs then we
1980 * just allocate an empty slab. If we mistakenly try to get a
1981 * partial slab and there is none available then get_partial()
1982 * will return NULL.
1983 */
1984 if (!n || !n->nr_partial)
1985 return NULL;
1986
1987 spin_lock(&n->list_lock);
1988 list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
1989 void *t;
1990
1991 if (!pfmemalloc_match(page, flags))
1992 continue;
1993
1994 t = acquire_slab(s, n, page, object == NULL, &objects);
1995 if (!t)
1996 continue; /* cmpxchg raced */
1997
1998 available += objects;
1999 if (!object) {
2000 c->page = page;
2001 stat(s, ALLOC_FROM_PARTIAL);
2002 object = t;
2003 } else {
2004 put_cpu_partial(s, page, 0);
2005 stat(s, CPU_PARTIAL_NODE);
2006 }
2007 if (!kmem_cache_has_cpu_partial(s)
2008 || available > slub_cpu_partial(s) / 2)
2009 break;
2010
2011 }
2012 spin_unlock(&n->list_lock);
2013 return object;
2014 }
2015
2016 /*
2017 * Get a page from somewhere. Search in increasing NUMA distances.
2018 */
2019 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
2020 struct kmem_cache_cpu *c)
2021 {
2022 #ifdef CONFIG_NUMA
2023 struct zonelist *zonelist;
2024 struct zoneref *z;
2025 struct zone *zone;
2026 enum zone_type highest_zoneidx = gfp_zone(flags);
2027 void *object;
2028 unsigned int cpuset_mems_cookie;
2029
2030 /*
2031 * The defrag ratio allows a configuration of the tradeoffs between
2032 * inter node defragmentation and node local allocations. A lower
2033 * defrag_ratio increases the tendency to do local allocations
2034 * instead of attempting to obtain partial slabs from other nodes.
2035 *
2036 * If the defrag_ratio is set to 0 then kmalloc() always
2037 * returns node local objects. If the ratio is higher then kmalloc()
2038 * may return off node objects because partial slabs are obtained
2039 * from other nodes and filled up.
2040 *
2041 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2042 * (which makes defrag_ratio = 1000) then every (well almost)
2043 * allocation will first attempt to defrag slab caches on other nodes.
2044 * This means scanning over all nodes to look for partial slabs which
2045 * may be expensive if we do it every time we are trying to find a slab
2046 * with available objects.
2047 */
2048 if (!s->remote_node_defrag_ratio ||
2049 get_cycles() % 1024 > s->remote_node_defrag_ratio)
2050 return NULL;
2051
2052 do {
2053 cpuset_mems_cookie = read_mems_allowed_begin();
2054 zonelist = node_zonelist(mempolicy_slab_node(), flags);
2055 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2056 struct kmem_cache_node *n;
2057
2058 n = get_node(s, zone_to_nid(zone));
2059
2060 if (n && cpuset_zone_allowed(zone, flags) &&
2061 n->nr_partial > s->min_partial) {
2062 object = get_partial_node(s, n, c, flags);
2063 if (object) {
2064 /*
2065 * Don't check read_mems_allowed_retry()
2066 * here - if mems_allowed was updated in
2067 * parallel, that was a harmless race
2068 * between allocation and the cpuset
2069 * update
2070 */
2071 return object;
2072 }
2073 }
2074 }
2075 } while (read_mems_allowed_retry(cpuset_mems_cookie));
2076 #endif /* CONFIG_NUMA */
2077 return NULL;
2078 }
2079
2080 /*
2081 * Get a partial page, lock it and return it.
2082 */
2083 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
2084 struct kmem_cache_cpu *c)
2085 {
2086 void *object;
2087 int searchnode = node;
2088
2089 if (node == NUMA_NO_NODE)
2090 searchnode = numa_mem_id();
2091
2092 object = get_partial_node(s, get_node(s, searchnode), c, flags);
2093 if (object || node != NUMA_NO_NODE)
2094 return object;
2095
2096 return get_any_partial(s, flags, c);
2097 }
2098
2099 #ifdef CONFIG_PREEMPTION
2100 /*
2101 * Calculate the next globally unique transaction for disambiguation
2102 * during cmpxchg. The transactions start with the cpu number and are then
2103 * incremented by CONFIG_NR_CPUS.
2104 */
2105 #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
2106 #else
2107 /*
2108 * No preemption supported therefore also no need to check for
2109 * different cpus.
2110 */
2111 #define TID_STEP 1
2112 #endif
2113
2114 static inline unsigned long next_tid(unsigned long tid)
2115 {
2116 return tid + TID_STEP;
2117 }
2118
2119 #ifdef SLUB_DEBUG_CMPXCHG
2120 static inline unsigned int tid_to_cpu(unsigned long tid)
2121 {
2122 return tid % TID_STEP;
2123 }
2124
2125 static inline unsigned long tid_to_event(unsigned long tid)
2126 {
2127 return tid / TID_STEP;
2128 }
2129 #endif
2130
2131 static inline unsigned int init_tid(int cpu)
2132 {
2133 return cpu;
2134 }
2135
2136 static inline void note_cmpxchg_failure(const char *n,
2137 const struct kmem_cache *s, unsigned long tid)
2138 {
2139 #ifdef SLUB_DEBUG_CMPXCHG
2140 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2141
2142 pr_info("%s %s: cmpxchg redo ", n, s->name);
2143
2144 #ifdef CONFIG_PREEMPTION
2145 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2146 pr_warn("due to cpu change %d -> %d\n",
2147 tid_to_cpu(tid), tid_to_cpu(actual_tid));
2148 else
2149 #endif
2150 if (tid_to_event(tid) != tid_to_event(actual_tid))
2151 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2152 tid_to_event(tid), tid_to_event(actual_tid));
2153 else
2154 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2155 actual_tid, tid, next_tid(tid));
2156 #endif
2157 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2158 }
2159
2160 static void init_kmem_cache_cpus(struct kmem_cache *s)
2161 {
2162 int cpu;
2163
2164 for_each_possible_cpu(cpu)
2165 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
2166 }
2167
2168 /*
2169 * Remove the cpu slab
2170 */
2171 static void deactivate_slab(struct kmem_cache *s, struct page *page,
2172 void *freelist, struct kmem_cache_cpu *c)
2173 {
2174 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
2175 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
2176 int lock = 0, free_delta = 0;
2177 enum slab_modes l = M_NONE, m = M_NONE;
2178 void *nextfree, *freelist_iter, *freelist_tail;
2179 int tail = DEACTIVATE_TO_HEAD;
2180 struct page new;
2181 struct page old;
2182
2183 if (page->freelist) {
2184 stat(s, DEACTIVATE_REMOTE_FREES);
2185 tail = DEACTIVATE_TO_TAIL;
2186 }
2187
2188 /*
2189 * Stage one: Count the objects on cpu's freelist as free_delta and
2190 * remember the last object in freelist_tail for later splicing.
2191 */
2192 freelist_tail = NULL;
2193 freelist_iter = freelist;
2194 while (freelist_iter) {
2195 nextfree = get_freepointer(s, freelist_iter);
2196
2197 /*
2198 * If 'nextfree' is invalid, it is possible that the object at
2199 * 'freelist_iter' is already corrupted. So isolate all objects
2200 * starting at 'freelist_iter' by skipping them.
2201 */
2202 if (freelist_corrupted(s, page, &freelist_iter, nextfree))
2203 break;
2204
2205 freelist_tail = freelist_iter;
2206 free_delta++;
2207
2208 freelist_iter = nextfree;
2209 }
2210
2211 /*
2212 * Stage two: Unfreeze the page while splicing the per-cpu
2213 * freelist to the head of page's freelist.
2214 *
2215 * Ensure that the page is unfrozen while the list presence
2216 * reflects the actual number of objects during unfreeze.
2217 *
2218 * We setup the list membership and then perform a cmpxchg
2219 * with the count. If there is a mismatch then the page
2220 * is not unfrozen but the page is on the wrong list.
2221 *
2222 * Then we restart the process which may have to remove
2223 * the page from the list that we just put it on again
2224 * because the number of objects in the slab may have
2225 * changed.
2226 */
2227 redo:
2228
2229 old.freelist = READ_ONCE(page->freelist);
2230 old.counters = READ_ONCE(page->counters);
2231 VM_BUG_ON(!old.frozen);
2232
2233 /* Determine target state of the slab */
2234 new.counters = old.counters;
2235 if (freelist_tail) {
2236 new.inuse -= free_delta;
2237 set_freepointer(s, freelist_tail, old.freelist);
2238 new.freelist = freelist;
2239 } else
2240 new.freelist = old.freelist;
2241
2242 new.frozen = 0;
2243
2244 if (!new.inuse && n->nr_partial >= s->min_partial)
2245 m = M_FREE;
2246 else if (new.freelist) {
2247 m = M_PARTIAL;
2248 if (!lock) {
2249 lock = 1;
2250 /*
2251 * Taking the spinlock removes the possibility
2252 * that acquire_slab() will see a slab page that
2253 * is frozen
2254 */
2255 spin_lock(&n->list_lock);
2256 }
2257 } else {
2258 m = M_FULL;
2259 if (kmem_cache_debug_flags(s, SLAB_STORE_USER) && !lock) {
2260 lock = 1;
2261 /*
2262 * This also ensures that the scanning of full
2263 * slabs from diagnostic functions will not see
2264 * any frozen slabs.
2265 */
2266 spin_lock(&n->list_lock);
2267 }
2268 }
2269
2270 if (l != m) {
2271 if (l == M_PARTIAL)
2272 remove_partial(n, page);
2273 else if (l == M_FULL)
2274 remove_full(s, n, page);
2275
2276 if (m == M_PARTIAL)
2277 add_partial(n, page, tail);
2278 else if (m == M_FULL)
2279 add_full(s, n, page);
2280 }
2281
2282 l = m;
2283 if (!__cmpxchg_double_slab(s, page,
2284 old.freelist, old.counters,
2285 new.freelist, new.counters,
2286 "unfreezing slab"))
2287 goto redo;
2288
2289 if (lock)
2290 spin_unlock(&n->list_lock);
2291
2292 if (m == M_PARTIAL)
2293 stat(s, tail);
2294 else if (m == M_FULL)
2295 stat(s, DEACTIVATE_FULL);
2296 else if (m == M_FREE) {
2297 stat(s, DEACTIVATE_EMPTY);
2298 discard_slab(s, page);
2299 stat(s, FREE_SLAB);
2300 }
2301
2302 c->page = NULL;
2303 c->freelist = NULL;
2304 }
2305
2306 /*
2307 * Unfreeze all the cpu partial slabs.
2308 *
2309 * This function must be called with interrupts disabled
2310 * for the cpu using c (or some other guarantee must be there
2311 * to guarantee no concurrent accesses).
2312 */
2313 static void unfreeze_partials(struct kmem_cache *s,
2314 struct kmem_cache_cpu *c)
2315 {
2316 #ifdef CONFIG_SLUB_CPU_PARTIAL
2317 struct kmem_cache_node *n = NULL, *n2 = NULL;
2318 struct page *page, *discard_page = NULL;
2319
2320 while ((page = slub_percpu_partial(c))) {
2321 struct page new;
2322 struct page old;
2323
2324 slub_set_percpu_partial(c, page);
2325
2326 n2 = get_node(s, page_to_nid(page));
2327 if (n != n2) {
2328 if (n)
2329 spin_unlock(&n->list_lock);
2330
2331 n = n2;
2332 spin_lock(&n->list_lock);
2333 }
2334
2335 do {
2336
2337 old.freelist = page->freelist;
2338 old.counters = page->counters;
2339 VM_BUG_ON(!old.frozen);
2340
2341 new.counters = old.counters;
2342 new.freelist = old.freelist;
2343
2344 new.frozen = 0;
2345
2346 } while (!__cmpxchg_double_slab(s, page,
2347 old.freelist, old.counters,
2348 new.freelist, new.counters,
2349 "unfreezing slab"));
2350
2351 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2352 page->next = discard_page;
2353 discard_page = page;
2354 } else {
2355 add_partial(n, page, DEACTIVATE_TO_TAIL);
2356 stat(s, FREE_ADD_PARTIAL);
2357 }
2358 }
2359
2360 if (n)
2361 spin_unlock(&n->list_lock);
2362
2363 while (discard_page) {
2364 page = discard_page;
2365 discard_page = discard_page->next;
2366
2367 stat(s, DEACTIVATE_EMPTY);
2368 discard_slab(s, page);
2369 stat(s, FREE_SLAB);
2370 }
2371 #endif /* CONFIG_SLUB_CPU_PARTIAL */
2372 }
2373
2374 /*
2375 * Put a page that was just frozen (in __slab_free|get_partial_node) into a
2376 * partial page slot if available.
2377 *
2378 * If we did not find a slot then simply move all the partials to the
2379 * per node partial list.
2380 */
2381 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2382 {
2383 #ifdef CONFIG_SLUB_CPU_PARTIAL
2384 struct page *oldpage;
2385 int pages;
2386 int pobjects;
2387
2388 preempt_disable();
2389 do {
2390 pages = 0;
2391 pobjects = 0;
2392 oldpage = this_cpu_read(s->cpu_slab->partial);
2393
2394 if (oldpage) {
2395 pobjects = oldpage->pobjects;
2396 pages = oldpage->pages;
2397 if (drain && pobjects > slub_cpu_partial(s)) {
2398 unsigned long flags;
2399 /*
2400 * partial array is full. Move the existing
2401 * set to the per node partial list.
2402 */
2403 local_irq_save(flags);
2404 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2405 local_irq_restore(flags);
2406 oldpage = NULL;
2407 pobjects = 0;
2408 pages = 0;
2409 stat(s, CPU_PARTIAL_DRAIN);
2410 }
2411 }
2412
2413 pages++;
2414 pobjects += page->objects - page->inuse;
2415
2416 page->pages = pages;
2417 page->pobjects = pobjects;
2418 page->next = oldpage;
2419
2420 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2421 != oldpage);
2422 if (unlikely(!slub_cpu_partial(s))) {
2423 unsigned long flags;
2424
2425 local_irq_save(flags);
2426 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2427 local_irq_restore(flags);
2428 }
2429 preempt_enable();
2430 #endif /* CONFIG_SLUB_CPU_PARTIAL */
2431 }
2432
2433 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2434 {
2435 stat(s, CPUSLAB_FLUSH);
2436 deactivate_slab(s, c->page, c->freelist, c);
2437
2438 c->tid = next_tid(c->tid);
2439 }
2440
2441 /*
2442 * Flush cpu slab.
2443 *
2444 * Called from IPI handler with interrupts disabled.
2445 */
2446 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2447 {
2448 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2449
2450 if (c->page)
2451 flush_slab(s, c);
2452
2453 unfreeze_partials(s, c);
2454 }
2455
2456 static void flush_cpu_slab(void *d)
2457 {
2458 struct kmem_cache *s = d;
2459
2460 __flush_cpu_slab(s, smp_processor_id());
2461 }
2462
2463 static bool has_cpu_slab(int cpu, void *info)
2464 {
2465 struct kmem_cache *s = info;
2466 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2467
2468 return c->page || slub_percpu_partial(c);
2469 }
2470
2471 static void flush_all(struct kmem_cache *s)
2472 {
2473 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1);
2474 }
2475
2476 /*
2477 * Use the cpu notifier to insure that the cpu slabs are flushed when
2478 * necessary.
2479 */
2480 static int slub_cpu_dead(unsigned int cpu)
2481 {
2482 struct kmem_cache *s;
2483 unsigned long flags;
2484
2485 mutex_lock(&slab_mutex);
2486 list_for_each_entry(s, &slab_caches, list) {
2487 local_irq_save(flags);
2488 __flush_cpu_slab(s, cpu);
2489 local_irq_restore(flags);
2490 }
2491 mutex_unlock(&slab_mutex);
2492 return 0;
2493 }
2494
2495 /*
2496 * Check if the objects in a per cpu structure fit numa
2497 * locality expectations.
2498 */
2499 static inline int node_match(struct page *page, int node)
2500 {
2501 #ifdef CONFIG_NUMA
2502 if (node != NUMA_NO_NODE && page_to_nid(page) != node)
2503 return 0;
2504 #endif
2505 return 1;
2506 }
2507
2508 #ifdef CONFIG_SLUB_DEBUG
2509 static int count_free(struct page *page)
2510 {
2511 return page->objects - page->inuse;
2512 }
2513
2514 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2515 {
2516 return atomic_long_read(&n->total_objects);
2517 }
2518 #endif /* CONFIG_SLUB_DEBUG */
2519
2520 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2521 static unsigned long count_partial(struct kmem_cache_node *n,
2522 int (*get_count)(struct page *))
2523 {
2524 unsigned long flags;
2525 unsigned long x = 0;
2526 struct page *page;
2527
2528 spin_lock_irqsave(&n->list_lock, flags);
2529 list_for_each_entry(page, &n->partial, slab_list)
2530 x += get_count(page);
2531 spin_unlock_irqrestore(&n->list_lock, flags);
2532 return x;
2533 }
2534 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2535
2536 static noinline void
2537 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2538 {
2539 #ifdef CONFIG_SLUB_DEBUG
2540 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2541 DEFAULT_RATELIMIT_BURST);
2542 int node;
2543 struct kmem_cache_node *n;
2544
2545 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2546 return;
2547
2548 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2549 nid, gfpflags, &gfpflags);
2550 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2551 s->name, s->object_size, s->size, oo_order(s->oo),
2552 oo_order(s->min));
2553
2554 if (oo_order(s->min) > get_order(s->object_size))
2555 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2556 s->name);
2557
2558 for_each_kmem_cache_node(s, node, n) {
2559 unsigned long nr_slabs;
2560 unsigned long nr_objs;
2561 unsigned long nr_free;
2562
2563 nr_free = count_partial(n, count_free);
2564 nr_slabs = node_nr_slabs(n);
2565 nr_objs = node_nr_objs(n);
2566
2567 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2568 node, nr_slabs, nr_objs, nr_free);
2569 }
2570 #endif
2571 }
2572
2573 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2574 int node, struct kmem_cache_cpu **pc)
2575 {
2576 void *freelist;
2577 struct kmem_cache_cpu *c = *pc;
2578 struct page *page;
2579
2580 WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2581
2582 freelist = get_partial(s, flags, node, c);
2583
2584 if (freelist)
2585 return freelist;
2586
2587 page = new_slab(s, flags, node);
2588 if (page) {
2589 c = raw_cpu_ptr(s->cpu_slab);
2590 if (c->page)
2591 flush_slab(s, c);
2592
2593 /*
2594 * No other reference to the page yet so we can
2595 * muck around with it freely without cmpxchg
2596 */
2597 freelist = page->freelist;
2598 page->freelist = NULL;
2599
2600 stat(s, ALLOC_SLAB);
2601 c->page = page;
2602 *pc = c;
2603 }
2604
2605 return freelist;
2606 }
2607
2608 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2609 {
2610 if (unlikely(PageSlabPfmemalloc(page)))
2611 return gfp_pfmemalloc_allowed(gfpflags);
2612
2613 return true;
2614 }
2615
2616 /*
2617 * Check the page->freelist of a page and either transfer the freelist to the
2618 * per cpu freelist or deactivate the page.
2619 *
2620 * The page is still frozen if the return value is not NULL.
2621 *
2622 * If this function returns NULL then the page has been unfrozen.
2623 *
2624 * This function must be called with interrupt disabled.
2625 */
2626 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2627 {
2628 struct page new;
2629 unsigned long counters;
2630 void *freelist;
2631
2632 do {
2633 freelist = page->freelist;
2634 counters = page->counters;
2635
2636 new.counters = counters;
2637 VM_BUG_ON(!new.frozen);
2638
2639 new.inuse = page->objects;
2640 new.frozen = freelist != NULL;
2641
2642 } while (!__cmpxchg_double_slab(s, page,
2643 freelist, counters,
2644 NULL, new.counters,
2645 "get_freelist"));
2646
2647 return freelist;
2648 }
2649
2650 /*
2651 * Slow path. The lockless freelist is empty or we need to perform
2652 * debugging duties.
2653 *
2654 * Processing is still very fast if new objects have been freed to the
2655 * regular freelist. In that case we simply take over the regular freelist
2656 * as the lockless freelist and zap the regular freelist.
2657 *
2658 * If that is not working then we fall back to the partial lists. We take the
2659 * first element of the freelist as the object to allocate now and move the
2660 * rest of the freelist to the lockless freelist.
2661 *
2662 * And if we were unable to get a new slab from the partial slab lists then
2663 * we need to allocate a new slab. This is the slowest path since it involves
2664 * a call to the page allocator and the setup of a new slab.
2665 *
2666 * Version of __slab_alloc to use when we know that interrupts are
2667 * already disabled (which is the case for bulk allocation).
2668 */
2669 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2670 unsigned long addr, struct kmem_cache_cpu *c)
2671 {
2672 void *freelist;
2673 struct page *page;
2674
2675 stat(s, ALLOC_SLOWPATH);
2676
2677 page = c->page;
2678 if (!page) {
2679 /*
2680 * if the node is not online or has no normal memory, just
2681 * ignore the node constraint
2682 */
2683 if (unlikely(node != NUMA_NO_NODE &&
2684 !node_isset(node, slab_nodes)))
2685 node = NUMA_NO_NODE;
2686 goto new_slab;
2687 }
2688 redo:
2689
2690 if (unlikely(!node_match(page, node))) {
2691 /*
2692 * same as above but node_match() being false already
2693 * implies node != NUMA_NO_NODE
2694 */
2695 if (!node_isset(node, slab_nodes)) {
2696 node = NUMA_NO_NODE;
2697 goto redo;
2698 } else {
2699 stat(s, ALLOC_NODE_MISMATCH);
2700 deactivate_slab(s, page, c->freelist, c);
2701 goto new_slab;
2702 }
2703 }
2704
2705 /*
2706 * By rights, we should be searching for a slab page that was
2707 * PFMEMALLOC but right now, we are losing the pfmemalloc
2708 * information when the page leaves the per-cpu allocator
2709 */
2710 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2711 deactivate_slab(s, page, c->freelist, c);
2712 goto new_slab;
2713 }
2714
2715 /* must check again c->freelist in case of cpu migration or IRQ */
2716 freelist = c->freelist;
2717 if (freelist)
2718 goto load_freelist;
2719
2720 freelist = get_freelist(s, page);
2721
2722 if (!freelist) {
2723 c->page = NULL;
2724 stat(s, DEACTIVATE_BYPASS);
2725 goto new_slab;
2726 }
2727
2728 stat(s, ALLOC_REFILL);
2729
2730 load_freelist:
2731 /*
2732 * freelist is pointing to the list of objects to be used.
2733 * page is pointing to the page from which the objects are obtained.
2734 * That page must be frozen for per cpu allocations to work.
2735 */
2736 VM_BUG_ON(!c->page->frozen);
2737 c->freelist = get_freepointer(s, freelist);
2738 c->tid = next_tid(c->tid);
2739 return freelist;
2740
2741 new_slab:
2742
2743 if (slub_percpu_partial(c)) {
2744 page = c->page = slub_percpu_partial(c);
2745 slub_set_percpu_partial(c, page);
2746 stat(s, CPU_PARTIAL_ALLOC);
2747 goto redo;
2748 }
2749
2750 freelist = new_slab_objects(s, gfpflags, node, &c);
2751
2752 if (unlikely(!freelist)) {
2753 slab_out_of_memory(s, gfpflags, node);
2754 return NULL;
2755 }
2756
2757 page = c->page;
2758 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2759 goto load_freelist;
2760
2761 /* Only entered in the debug case */
2762 if (kmem_cache_debug(s) &&
2763 !alloc_debug_processing(s, page, freelist, addr))
2764 goto new_slab; /* Slab failed checks. Next slab needed */
2765
2766 deactivate_slab(s, page, get_freepointer(s, freelist), c);
2767 return freelist;
2768 }
2769
2770 /*
2771 * Another one that disabled interrupt and compensates for possible
2772 * cpu changes by refetching the per cpu area pointer.
2773 */
2774 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2775 unsigned long addr, struct kmem_cache_cpu *c)
2776 {
2777 void *p;
2778 unsigned long flags;
2779
2780 local_irq_save(flags);
2781 #ifdef CONFIG_PREEMPTION
2782 /*
2783 * We may have been preempted and rescheduled on a different
2784 * cpu before disabling interrupts. Need to reload cpu area
2785 * pointer.
2786 */
2787 c = this_cpu_ptr(s->cpu_slab);
2788 #endif
2789
2790 p = ___slab_alloc(s, gfpflags, node, addr, c);
2791 local_irq_restore(flags);
2792 return p;
2793 }
2794
2795 /*
2796 * If the object has been wiped upon free, make sure it's fully initialized by
2797 * zeroing out freelist pointer.
2798 */
2799 static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
2800 void *obj)
2801 {
2802 if (unlikely(slab_want_init_on_free(s)) && obj)
2803 memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
2804 0, sizeof(void *));
2805 }
2806
2807 /*
2808 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2809 * have the fastpath folded into their functions. So no function call
2810 * overhead for requests that can be satisfied on the fastpath.
2811 *
2812 * The fastpath works by first checking if the lockless freelist can be used.
2813 * If not then __slab_alloc is called for slow processing.
2814 *
2815 * Otherwise we can simply pick the next object from the lockless free list.
2816 */
2817 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2818 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
2819 {
2820 void *object;
2821 struct kmem_cache_cpu *c;
2822 struct page *page;
2823 unsigned long tid;
2824 struct obj_cgroup *objcg = NULL;
2825
2826 s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags);
2827 if (!s)
2828 return NULL;
2829
2830 object = kfence_alloc(s, orig_size, gfpflags);
2831 if (unlikely(object))
2832 goto out;
2833
2834 redo:
2835 /*
2836 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2837 * enabled. We may switch back and forth between cpus while
2838 * reading from one cpu area. That does not matter as long
2839 * as we end up on the original cpu again when doing the cmpxchg.
2840 *
2841 * We should guarantee that tid and kmem_cache are retrieved on
2842 * the same cpu. It could be different if CONFIG_PREEMPTION so we need
2843 * to check if it is matched or not.
2844 */
2845 do {
2846 tid = this_cpu_read(s->cpu_slab->tid);
2847 c = raw_cpu_ptr(s->cpu_slab);
2848 } while (IS_ENABLED(CONFIG_PREEMPTION) &&
2849 unlikely(tid != READ_ONCE(c->tid)));
2850
2851 /*
2852 * Irqless object alloc/free algorithm used here depends on sequence
2853 * of fetching cpu_slab's data. tid should be fetched before anything
2854 * on c to guarantee that object and page associated with previous tid
2855 * won't be used with current tid. If we fetch tid first, object and
2856 * page could be one associated with next tid and our alloc/free
2857 * request will be failed. In this case, we will retry. So, no problem.
2858 */
2859 barrier();
2860
2861 /*
2862 * The transaction ids are globally unique per cpu and per operation on
2863 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2864 * occurs on the right processor and that there was no operation on the
2865 * linked list in between.
2866 */
2867
2868 object = c->freelist;
2869 page = c->page;
2870 if (unlikely(!object || !page || !node_match(page, node))) {
2871 object = __slab_alloc(s, gfpflags, node, addr, c);
2872 } else {
2873 void *next_object = get_freepointer_safe(s, object);
2874
2875 /*
2876 * The cmpxchg will only match if there was no additional
2877 * operation and if we are on the right processor.
2878 *
2879 * The cmpxchg does the following atomically (without lock
2880 * semantics!)
2881 * 1. Relocate first pointer to the current per cpu area.
2882 * 2. Verify that tid and freelist have not been changed
2883 * 3. If they were not changed replace tid and freelist
2884 *
2885 * Since this is without lock semantics the protection is only
2886 * against code executing on this cpu *not* from access by
2887 * other cpus.
2888 */
2889 if (unlikely(!this_cpu_cmpxchg_double(
2890 s->cpu_slab->freelist, s->cpu_slab->tid,
2891 object, tid,
2892 next_object, next_tid(tid)))) {
2893
2894 note_cmpxchg_failure("slab_alloc", s, tid);
2895 goto redo;
2896 }
2897 prefetch_freepointer(s, next_object);
2898 stat(s, ALLOC_FASTPATH);
2899 }
2900
2901 maybe_wipe_obj_freeptr(s, object);
2902
2903 if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object)
2904 memset(kasan_reset_tag(object), 0, s->object_size);
2905
2906 out:
2907 slab_post_alloc_hook(s, objcg, gfpflags, 1, &object);
2908
2909 return object;
2910 }
2911
2912 static __always_inline void *slab_alloc(struct kmem_cache *s,
2913 gfp_t gfpflags, unsigned long addr, size_t orig_size)
2914 {
2915 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr, orig_size);
2916 }
2917
2918 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2919 {
2920 void *ret = slab_alloc(s, gfpflags, _RET_IP_, s->object_size);
2921
2922 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2923 s->size, gfpflags);
2924
2925 return ret;
2926 }
2927 EXPORT_SYMBOL(kmem_cache_alloc);
2928
2929 #ifdef CONFIG_TRACING
2930 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2931 {
2932 void *ret = slab_alloc(s, gfpflags, _RET_IP_, size);
2933 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2934 ret = kasan_kmalloc(s, ret, size, gfpflags);
2935 return ret;
2936 }
2937 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2938 #endif
2939
2940 #ifdef CONFIG_NUMA
2941 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2942 {
2943 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, s->object_size);
2944
2945 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2946 s->object_size, s->size, gfpflags, node);
2947
2948 return ret;
2949 }
2950 EXPORT_SYMBOL(kmem_cache_alloc_node);
2951
2952 #ifdef CONFIG_TRACING
2953 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2954 gfp_t gfpflags,
2955 int node, size_t size)
2956 {
2957 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, size);
2958
2959 trace_kmalloc_node(_RET_IP_, ret,
2960 size, s->size, gfpflags, node);
2961
2962 ret = kasan_kmalloc(s, ret, size, gfpflags);
2963 return ret;
2964 }
2965 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2966 #endif
2967 #endif /* CONFIG_NUMA */
2968
2969 /*
2970 * Slow path handling. This may still be called frequently since objects
2971 * have a longer lifetime than the cpu slabs in most processing loads.
2972 *
2973 * So we still attempt to reduce cache line usage. Just take the slab
2974 * lock and free the item. If there is no additional partial page
2975 * handling required then we can return immediately.
2976 */
2977 static void __slab_free(struct kmem_cache *s, struct page *page,
2978 void *head, void *tail, int cnt,
2979 unsigned long addr)
2980
2981 {
2982 void *prior;
2983 int was_frozen;
2984 struct page new;
2985 unsigned long counters;
2986 struct kmem_cache_node *n = NULL;
2987 unsigned long flags;
2988
2989 stat(s, FREE_SLOWPATH);
2990
2991 if (kfence_free(head))
2992 return;
2993
2994 if (kmem_cache_debug(s) &&
2995 !free_debug_processing(s, page, head, tail, cnt, addr))
2996 return;
2997
2998 do {
2999 if (unlikely(n)) {
3000 spin_unlock_irqrestore(&n->list_lock, flags);
3001 n = NULL;
3002 }
3003 prior = page->freelist;
3004 counters = page->counters;
3005 set_freepointer(s, tail, prior);
3006 new.counters = counters;
3007 was_frozen = new.frozen;
3008 new.inuse -= cnt;
3009 if ((!new.inuse || !prior) && !was_frozen) {
3010
3011 if (kmem_cache_has_cpu_partial(s) && !prior) {
3012
3013 /*
3014 * Slab was on no list before and will be
3015 * partially empty
3016 * We can defer the list move and instead
3017 * freeze it.
3018 */
3019 new.frozen = 1;
3020
3021 } else { /* Needs to be taken off a list */
3022
3023 n = get_node(s, page_to_nid(page));
3024 /*
3025 * Speculatively acquire the list_lock.
3026 * If the cmpxchg does not succeed then we may
3027 * drop the list_lock without any processing.
3028 *
3029 * Otherwise the list_lock will synchronize with
3030 * other processors updating the list of slabs.
3031 */
3032 spin_lock_irqsave(&n->list_lock, flags);
3033
3034 }
3035 }
3036
3037 } while (!cmpxchg_double_slab(s, page,
3038 prior, counters,
3039 head, new.counters,
3040 "__slab_free"));
3041
3042 if (likely(!n)) {
3043
3044 if (likely(was_frozen)) {
3045 /*
3046 * The list lock was not taken therefore no list
3047 * activity can be necessary.
3048 */
3049 stat(s, FREE_FROZEN);
3050 } else if (new.frozen) {
3051 /*
3052 * If we just froze the page then put it onto the
3053 * per cpu partial list.
3054 */
3055 put_cpu_partial(s, page, 1);
3056 stat(s, CPU_PARTIAL_FREE);
3057 }
3058
3059 return;
3060 }
3061
3062 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
3063 goto slab_empty;
3064
3065 /*
3066 * Objects left in the slab. If it was not on the partial list before
3067 * then add it.
3068 */
3069 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
3070 remove_full(s, n, page);
3071 add_partial(n, page, DEACTIVATE_TO_TAIL);
3072 stat(s, FREE_ADD_PARTIAL);
3073 }
3074 spin_unlock_irqrestore(&n->list_lock, flags);
3075 return;
3076
3077 slab_empty:
3078 if (prior) {
3079 /*
3080 * Slab on the partial list.
3081 */
3082 remove_partial(n, page);
3083 stat(s, FREE_REMOVE_PARTIAL);
3084 } else {
3085 /* Slab must be on the full list */
3086 remove_full(s, n, page);
3087 }
3088
3089 spin_unlock_irqrestore(&n->list_lock, flags);
3090 stat(s, FREE_SLAB);
3091 discard_slab(s, page);
3092 }
3093
3094 /*
3095 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
3096 * can perform fastpath freeing without additional function calls.
3097 *
3098 * The fastpath is only possible if we are freeing to the current cpu slab
3099 * of this processor. This typically the case if we have just allocated
3100 * the item before.
3101 *
3102 * If fastpath is not possible then fall back to __slab_free where we deal
3103 * with all sorts of special processing.
3104 *
3105 * Bulk free of a freelist with several objects (all pointing to the
3106 * same page) possible by specifying head and tail ptr, plus objects
3107 * count (cnt). Bulk free indicated by tail pointer being set.
3108 */
3109 static __always_inline void do_slab_free(struct kmem_cache *s,
3110 struct page *page, void *head, void *tail,
3111 int cnt, unsigned long addr)
3112 {
3113 void *tail_obj = tail ? : head;
3114 struct kmem_cache_cpu *c;
3115 unsigned long tid;
3116
3117 memcg_slab_free_hook(s, &head, 1);
3118 redo:
3119 /*
3120 * Determine the currently cpus per cpu slab.
3121 * The cpu may change afterward. However that does not matter since
3122 * data is retrieved via this pointer. If we are on the same cpu
3123 * during the cmpxchg then the free will succeed.
3124 */
3125 do {
3126 tid = this_cpu_read(s->cpu_slab->tid);
3127 c = raw_cpu_ptr(s->cpu_slab);
3128 } while (IS_ENABLED(CONFIG_PREEMPTION) &&
3129 unlikely(tid != READ_ONCE(c->tid)));
3130
3131 /* Same with comment on barrier() in slab_alloc_node() */
3132 barrier();
3133
3134 if (likely(page == c->page)) {
3135 void **freelist = READ_ONCE(c->freelist);
3136
3137 set_freepointer(s, tail_obj, freelist);
3138
3139 if (unlikely(!this_cpu_cmpxchg_double(
3140 s->cpu_slab->freelist, s->cpu_slab->tid,
3141 freelist, tid,
3142 head, next_tid(tid)))) {
3143
3144 note_cmpxchg_failure("slab_free", s, tid);
3145 goto redo;
3146 }
3147 stat(s, FREE_FASTPATH);
3148 } else
3149 __slab_free(s, page, head, tail_obj, cnt, addr);
3150
3151 }
3152
3153 static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
3154 void *head, void *tail, int cnt,
3155 unsigned long addr)
3156 {
3157 /*
3158 * With KASAN enabled slab_free_freelist_hook modifies the freelist
3159 * to remove objects, whose reuse must be delayed.
3160 */
3161 if (slab_free_freelist_hook(s, &head, &tail))
3162 do_slab_free(s, page, head, tail, cnt, addr);
3163 }
3164
3165 #ifdef CONFIG_KASAN_GENERIC
3166 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
3167 {
3168 do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
3169 }
3170 #endif
3171
3172 void kmem_cache_free(struct kmem_cache *s, void *x)
3173 {
3174 s = cache_from_obj(s, x);
3175 if (!s)
3176 return;
3177 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
3178 trace_kmem_cache_free(_RET_IP_, x, s->name);
3179 }
3180 EXPORT_SYMBOL(kmem_cache_free);
3181
3182 struct detached_freelist {
3183 struct page *page;
3184 void *tail;
3185 void *freelist;
3186 int cnt;
3187 struct kmem_cache *s;
3188 };
3189
3190 /*
3191 * This function progressively scans the array with free objects (with
3192 * a limited look ahead) and extract objects belonging to the same
3193 * page. It builds a detached freelist directly within the given
3194 * page/objects. This can happen without any need for
3195 * synchronization, because the objects are owned by running process.
3196 * The freelist is build up as a single linked list in the objects.
3197 * The idea is, that this detached freelist can then be bulk
3198 * transferred to the real freelist(s), but only requiring a single
3199 * synchronization primitive. Look ahead in the array is limited due
3200 * to performance reasons.
3201 */
3202 static inline
3203 int build_detached_freelist(struct kmem_cache *s, size_t size,
3204 void **p, struct detached_freelist *df)
3205 {
3206 size_t first_skipped_index = 0;
3207 int lookahead = 3;
3208 void *object;
3209 struct page *page;
3210
3211 /* Always re-init detached_freelist */
3212 df->page = NULL;
3213
3214 do {
3215 object = p[--size];
3216 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3217 } while (!object && size);
3218
3219 if (!object)
3220 return 0;
3221
3222 page = virt_to_head_page(object);
3223 if (!s) {
3224 /* Handle kalloc'ed objects */
3225 if (unlikely(!PageSlab(page))) {
3226 BUG_ON(!PageCompound(page));
3227 kfree_hook(object);
3228 __free_pages(page, compound_order(page));
3229 p[size] = NULL; /* mark object processed */
3230 return size;
3231 }
3232 /* Derive kmem_cache from object */
3233 df->s = page->slab_cache;
3234 } else {
3235 df->s = cache_from_obj(s, object); /* Support for memcg */
3236 }
3237
3238 if (is_kfence_address(object)) {
3239 slab_free_hook(df->s, object);
3240 __kfence_free(object);
3241 p[size] = NULL; /* mark object processed */
3242 return size;
3243 }
3244
3245 /* Start new detached freelist */
3246 df->page = page;
3247 set_freepointer(df->s, object, NULL);
3248 df->tail = object;
3249 df->freelist = object;
3250 p[size] = NULL; /* mark object processed */
3251 df->cnt = 1;
3252
3253 while (size) {
3254 object = p[--size];
3255 if (!object)
3256 continue; /* Skip processed objects */
3257
3258 /* df->page is always set at this point */
3259 if (df->page == virt_to_head_page(object)) {
3260 /* Opportunity build freelist */
3261 set_freepointer(df->s, object, df->freelist);
3262 df->freelist = object;
3263 df->cnt++;
3264 p[size] = NULL; /* mark object processed */
3265
3266 continue;
3267 }
3268
3269 /* Limit look ahead search */
3270 if (!--lookahead)
3271 break;
3272
3273 if (!first_skipped_index)
3274 first_skipped_index = size + 1;
3275 }
3276
3277 return first_skipped_index;
3278 }
3279
3280 /* Note that interrupts must be enabled when calling this function. */
3281 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3282 {
3283 if (WARN_ON(!size))
3284 return;
3285
3286 memcg_slab_free_hook(s, p, size);
3287 do {
3288 struct detached_freelist df;
3289
3290 size = build_detached_freelist(s, size, p, &df);
3291 if (!df.page)
3292 continue;
3293
3294 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_);
3295 } while (likely(size));
3296 }
3297 EXPORT_SYMBOL(kmem_cache_free_bulk);
3298
3299 /* Note that interrupts must be enabled when calling this function. */
3300 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3301 void **p)
3302 {
3303 struct kmem_cache_cpu *c;
3304 int i;
3305 struct obj_cgroup *objcg = NULL;
3306
3307 /* memcg and kmem_cache debug support */
3308 s = slab_pre_alloc_hook(s, &objcg, size, flags);
3309 if (unlikely(!s))
3310 return false;
3311 /*
3312 * Drain objects in the per cpu slab, while disabling local
3313 * IRQs, which protects against PREEMPT and interrupts
3314 * handlers invoking normal fastpath.
3315 */
3316 local_irq_disable();
3317 c = this_cpu_ptr(s->cpu_slab);
3318
3319 for (i = 0; i < size; i++) {
3320 void *object = kfence_alloc(s, s->object_size, flags);
3321
3322 if (unlikely(object)) {
3323 p[i] = object;
3324 continue;
3325 }
3326
3327 object = c->freelist;
3328 if (unlikely(!object)) {
3329 /*
3330 * We may have removed an object from c->freelist using
3331 * the fastpath in the previous iteration; in that case,
3332 * c->tid has not been bumped yet.
3333 * Since ___slab_alloc() may reenable interrupts while
3334 * allocating memory, we should bump c->tid now.
3335 */
3336 c->tid = next_tid(c->tid);
3337
3338 /*
3339 * Invoking slow path likely have side-effect
3340 * of re-populating per CPU c->freelist
3341 */
3342 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3343 _RET_IP_, c);
3344 if (unlikely(!p[i]))
3345 goto error;
3346
3347 c = this_cpu_ptr(s->cpu_slab);
3348 maybe_wipe_obj_freeptr(s, p[i]);
3349
3350 continue; /* goto for-loop */
3351 }
3352 c->freelist = get_freepointer(s, object);
3353 p[i] = object;
3354 maybe_wipe_obj_freeptr(s, p[i]);
3355 }
3356 c->tid = next_tid(c->tid);
3357 local_irq_enable();
3358
3359 /* Clear memory outside IRQ disabled fastpath loop */
3360 if (unlikely(slab_want_init_on_alloc(flags, s))) {
3361 int j;
3362
3363 for (j = 0; j < i; j++)
3364 memset(kasan_reset_tag(p[j]), 0, s->object_size);
3365 }
3366
3367 /* memcg and kmem_cache debug support */
3368 slab_post_alloc_hook(s, objcg, flags, size, p);
3369 return i;
3370 error:
3371 local_irq_enable();
3372 slab_post_alloc_hook(s, objcg, flags, i, p);
3373 __kmem_cache_free_bulk(s, i, p);
3374 return 0;
3375 }
3376 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3377
3378
3379 /*
3380 * Object placement in a slab is made very easy because we always start at
3381 * offset 0. If we tune the size of the object to the alignment then we can
3382 * get the required alignment by putting one properly sized object after
3383 * another.
3384 *
3385 * Notice that the allocation order determines the sizes of the per cpu
3386 * caches. Each processor has always one slab available for allocations.
3387 * Increasing the allocation order reduces the number of times that slabs
3388 * must be moved on and off the partial lists and is therefore a factor in
3389 * locking overhead.
3390 */
3391
3392 /*
3393 * Mininum / Maximum order of slab pages. This influences locking overhead
3394 * and slab fragmentation. A higher order reduces the number of partial slabs
3395 * and increases the number of allocations possible without having to
3396 * take the list_lock.
3397 */
3398 static unsigned int slub_min_order;
3399 static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3400 static unsigned int slub_min_objects;
3401
3402 /*
3403 * Calculate the order of allocation given an slab object size.
3404 *
3405 * The order of allocation has significant impact on performance and other
3406 * system components. Generally order 0 allocations should be preferred since
3407 * order 0 does not cause fragmentation in the page allocator. Larger objects
3408 * be problematic to put into order 0 slabs because there may be too much
3409 * unused space left. We go to a higher order if more than 1/16th of the slab
3410 * would be wasted.
3411 *
3412 * In order to reach satisfactory performance we must ensure that a minimum
3413 * number of objects is in one slab. Otherwise we may generate too much
3414 * activity on the partial lists which requires taking the list_lock. This is
3415 * less a concern for large slabs though which are rarely used.
3416 *
3417 * slub_max_order specifies the order where we begin to stop considering the
3418 * number of objects in a slab as critical. If we reach slub_max_order then
3419 * we try to keep the page order as low as possible. So we accept more waste
3420 * of space in favor of a small page order.
3421 *
3422 * Higher order allocations also allow the placement of more objects in a
3423 * slab and thereby reduce object handling overhead. If the user has
3424 * requested a higher mininum order then we start with that one instead of
3425 * the smallest order which will fit the object.
3426 */
3427 static inline unsigned int slab_order(unsigned int size,
3428 unsigned int min_objects, unsigned int max_order,
3429 unsigned int fract_leftover)
3430 {
3431 unsigned int min_order = slub_min_order;
3432 unsigned int order;
3433
3434 if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
3435 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3436
3437 for (order = max(min_order, (unsigned int)get_order(min_objects * size));
3438 order <= max_order; order++) {
3439
3440 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
3441 unsigned int rem;
3442
3443 rem = slab_size % size;
3444
3445 if (rem <= slab_size / fract_leftover)
3446 break;
3447 }
3448
3449 return order;
3450 }
3451
3452 static inline int calculate_order(unsigned int size)
3453 {
3454 unsigned int order;
3455 unsigned int min_objects;
3456 unsigned int max_objects;
3457 unsigned int nr_cpus;
3458
3459 /*
3460 * Attempt to find best configuration for a slab. This
3461 * works by first attempting to generate a layout with
3462 * the best configuration and backing off gradually.
3463 *
3464 * First we increase the acceptable waste in a slab. Then
3465 * we reduce the minimum objects required in a slab.
3466 */
3467 min_objects = slub_min_objects;
3468 if (!min_objects) {
3469 /*
3470 * Some architectures will only update present cpus when
3471 * onlining them, so don't trust the number if it's just 1. But
3472 * we also don't want to use nr_cpu_ids always, as on some other
3473 * architectures, there can be many possible cpus, but never
3474 * onlined. Here we compromise between trying to avoid too high
3475 * order on systems that appear larger than they are, and too
3476 * low order on systems that appear smaller than they are.
3477 */
3478 nr_cpus = num_present_cpus();
3479 if (nr_cpus <= 1)
3480 nr_cpus = nr_cpu_ids;
3481 min_objects = 4 * (fls(nr_cpus) + 1);
3482 }
3483 max_objects = order_objects(slub_max_order, size);
3484 min_objects = min(min_objects, max_objects);
3485
3486 while (min_objects > 1) {
3487 unsigned int fraction;
3488
3489 fraction = 16;
3490 while (fraction >= 4) {
3491 order = slab_order(size, min_objects,
3492 slub_max_order, fraction);
3493 if (order <= slub_max_order)
3494 return order;
3495 fraction /= 2;
3496 }
3497 min_objects--;
3498 }
3499
3500 /*
3501 * We were unable to place multiple objects in a slab. Now
3502 * lets see if we can place a single object there.
3503 */
3504 order = slab_order(size, 1, slub_max_order, 1);
3505 if (order <= slub_max_order)
3506 return order;
3507
3508 /*
3509 * Doh this slab cannot be placed using slub_max_order.
3510 */
3511 order = slab_order(size, 1, MAX_ORDER, 1);
3512 if (order < MAX_ORDER)
3513 return order;
3514 return -ENOSYS;
3515 }
3516
3517 static void
3518 init_kmem_cache_node(struct kmem_cache_node *n)
3519 {
3520 n->nr_partial = 0;
3521 spin_lock_init(&n->list_lock);
3522 INIT_LIST_HEAD(&n->partial);
3523 #ifdef CONFIG_SLUB_DEBUG
3524 atomic_long_set(&n->nr_slabs, 0);
3525 atomic_long_set(&n->total_objects, 0);
3526 INIT_LIST_HEAD(&n->full);
3527 #endif
3528 }
3529
3530 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3531 {
3532 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3533 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3534
3535 /*
3536 * Must align to double word boundary for the double cmpxchg
3537 * instructions to work; see __pcpu_double_call_return_bool().
3538 */
3539 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3540 2 * sizeof(void *));
3541
3542 if (!s->cpu_slab)
3543 return 0;
3544
3545 init_kmem_cache_cpus(s);
3546
3547 return 1;
3548 }
3549
3550 static struct kmem_cache *kmem_cache_node;
3551
3552 /*
3553 * No kmalloc_node yet so do it by hand. We know that this is the first
3554 * slab on the node for this slabcache. There are no concurrent accesses
3555 * possible.
3556 *
3557 * Note that this function only works on the kmem_cache_node
3558 * when allocating for the kmem_cache_node. This is used for bootstrapping
3559 * memory on a fresh node that has no slab structures yet.
3560 */
3561 static void early_kmem_cache_node_alloc(int node)
3562 {
3563 struct page *page;
3564 struct kmem_cache_node *n;
3565
3566 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3567
3568 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3569
3570 BUG_ON(!page);
3571 if (page_to_nid(page) != node) {
3572 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3573 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3574 }
3575
3576 n = page->freelist;
3577 BUG_ON(!n);
3578 #ifdef CONFIG_SLUB_DEBUG
3579 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3580 init_tracking(kmem_cache_node, n);
3581 #endif
3582 n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL);
3583 page->freelist = get_freepointer(kmem_cache_node, n);
3584 page->inuse = 1;
3585 page->frozen = 0;
3586 kmem_cache_node->node[node] = n;
3587 init_kmem_cache_node(n);
3588 inc_slabs_node(kmem_cache_node, node, page->objects);
3589
3590 /*
3591 * No locks need to be taken here as it has just been
3592 * initialized and there is no concurrent access.
3593 */
3594 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3595 }
3596
3597 static void free_kmem_cache_nodes(struct kmem_cache *s)
3598 {
3599 int node;
3600 struct kmem_cache_node *n;
3601
3602 for_each_kmem_cache_node(s, node, n) {
3603 s->node[node] = NULL;
3604 kmem_cache_free(kmem_cache_node, n);
3605 }
3606 }
3607
3608 void __kmem_cache_release(struct kmem_cache *s)
3609 {
3610 cache_random_seq_destroy(s);
3611 free_percpu(s->cpu_slab);
3612 free_kmem_cache_nodes(s);
3613 }
3614
3615 static int init_kmem_cache_nodes(struct kmem_cache *s)
3616 {
3617 int node;
3618
3619 for_each_node_mask(node, slab_nodes) {
3620 struct kmem_cache_node *n;
3621
3622 if (slab_state == DOWN) {
3623 early_kmem_cache_node_alloc(node);
3624 continue;
3625 }
3626 n = kmem_cache_alloc_node(kmem_cache_node,
3627 GFP_KERNEL, node);
3628
3629 if (!n) {
3630 free_kmem_cache_nodes(s);
3631 return 0;
3632 }
3633
3634 init_kmem_cache_node(n);
3635 s->node[node] = n;
3636 }
3637 return 1;
3638 }
3639
3640 static void set_min_partial(struct kmem_cache *s, unsigned long min)
3641 {
3642 if (min < MIN_PARTIAL)
3643 min = MIN_PARTIAL;
3644 else if (min > MAX_PARTIAL)
3645 min = MAX_PARTIAL;
3646 s->min_partial = min;
3647 }
3648
3649 static void set_cpu_partial(struct kmem_cache *s)
3650 {
3651 #ifdef CONFIG_SLUB_CPU_PARTIAL
3652 /*
3653 * cpu_partial determined the maximum number of objects kept in the
3654 * per cpu partial lists of a processor.
3655 *
3656 * Per cpu partial lists mainly contain slabs that just have one
3657 * object freed. If they are used for allocation then they can be
3658 * filled up again with minimal effort. The slab will never hit the
3659 * per node partial lists and therefore no locking will be required.
3660 *
3661 * This setting also determines
3662 *
3663 * A) The number of objects from per cpu partial slabs dumped to the
3664 * per node list when we reach the limit.
3665 * B) The number of objects in cpu partial slabs to extract from the
3666 * per node list when we run out of per cpu objects. We only fetch
3667 * 50% to keep some capacity around for frees.
3668 */
3669 if (!kmem_cache_has_cpu_partial(s))
3670 slub_set_cpu_partial(s, 0);
3671 else if (s->size >= PAGE_SIZE)
3672 slub_set_cpu_partial(s, 2);
3673 else if (s->size >= 1024)
3674 slub_set_cpu_partial(s, 6);
3675 else if (s->size >= 256)
3676 slub_set_cpu_partial(s, 13);
3677 else
3678 slub_set_cpu_partial(s, 30);
3679 #endif
3680 }
3681
3682 /*
3683 * calculate_sizes() determines the order and the distribution of data within
3684 * a slab object.
3685 */
3686 static int calculate_sizes(struct kmem_cache *s, int forced_order)
3687 {
3688 slab_flags_t flags = s->flags;
3689 unsigned int size = s->object_size;
3690 unsigned int freepointer_area;
3691 unsigned int order;
3692
3693 /*
3694 * Round up object size to the next word boundary. We can only
3695 * place the free pointer at word boundaries and this determines
3696 * the possible location of the free pointer.
3697 */
3698 size = ALIGN(size, sizeof(void *));
3699 /*
3700 * This is the area of the object where a freepointer can be
3701 * safely written. If redzoning adds more to the inuse size, we
3702 * can't use that portion for writing the freepointer, so
3703 * s->offset must be limited within this for the general case.
3704 */
3705 freepointer_area = size;
3706
3707 #ifdef CONFIG_SLUB_DEBUG
3708 /*
3709 * Determine if we can poison the object itself. If the user of
3710 * the slab may touch the object after free or before allocation
3711 * then we should never poison the object itself.
3712 */
3713 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
3714 !s->ctor)
3715 s->flags |= __OBJECT_POISON;
3716 else
3717 s->flags &= ~__OBJECT_POISON;
3718
3719
3720 /*
3721 * If we are Redzoning then check if there is some space between the
3722 * end of the object and the free pointer. If not then add an
3723 * additional word to have some bytes to store Redzone information.
3724 */
3725 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3726 size += sizeof(void *);
3727 #endif
3728
3729 /*
3730 * With that we have determined the number of bytes in actual use
3731 * by the object. This is the potential offset to the free pointer.
3732 */
3733 s->inuse = size;
3734
3735 if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
3736 s->ctor)) {
3737 /*
3738 * Relocate free pointer after the object if it is not
3739 * permitted to overwrite the first word of the object on
3740 * kmem_cache_free.
3741 *
3742 * This is the case if we do RCU, have a constructor or
3743 * destructor or are poisoning the objects.
3744 *
3745 * The assumption that s->offset >= s->inuse means free
3746 * pointer is outside of the object is used in the
3747 * freeptr_outside_object() function. If that is no
3748 * longer true, the function needs to be modified.
3749 */
3750 s->offset = size;
3751 size += sizeof(void *);
3752 } else if (freepointer_area > sizeof(void *)) {
3753 /*
3754 * Store freelist pointer near middle of object to keep
3755 * it away from the edges of the object to avoid small
3756 * sized over/underflows from neighboring allocations.
3757 */
3758 s->offset = ALIGN(freepointer_area / 2, sizeof(void *));
3759 }
3760
3761 #ifdef CONFIG_SLUB_DEBUG
3762 if (flags & SLAB_STORE_USER)
3763 /*
3764 * Need to store information about allocs and frees after
3765 * the object.
3766 */
3767 size += 2 * sizeof(struct track);
3768 #endif
3769
3770 kasan_cache_create(s, &size, &s->flags);
3771 #ifdef CONFIG_SLUB_DEBUG
3772 if (flags & SLAB_RED_ZONE) {
3773 /*
3774 * Add some empty padding so that we can catch
3775 * overwrites from earlier objects rather than let
3776 * tracking information or the free pointer be
3777 * corrupted if a user writes before the start
3778 * of the object.
3779 */
3780 size += sizeof(void *);
3781
3782 s->red_left_pad = sizeof(void *);
3783 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3784 size += s->red_left_pad;
3785 }
3786 #endif
3787
3788 /*
3789 * SLUB stores one object immediately after another beginning from
3790 * offset 0. In order to align the objects we have to simply size
3791 * each object to conform to the alignment.
3792 */
3793 size = ALIGN(size, s->align);
3794 s->size = size;
3795 s->reciprocal_size = reciprocal_value(size);
3796 if (forced_order >= 0)
3797 order = forced_order;
3798 else
3799 order = calculate_order(size);
3800
3801 if ((int)order < 0)
3802 return 0;
3803
3804 s->allocflags = 0;
3805 if (order)
3806 s->allocflags |= __GFP_COMP;
3807
3808 if (s->flags & SLAB_CACHE_DMA)
3809 s->allocflags |= GFP_DMA;
3810
3811 if (s->flags & SLAB_CACHE_DMA32)
3812 s->allocflags |= GFP_DMA32;
3813
3814 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3815 s->allocflags |= __GFP_RECLAIMABLE;
3816
3817 /*
3818 * Determine the number of objects per slab
3819 */
3820 s->oo = oo_make(order, size);
3821 s->min = oo_make(get_order(size), size);
3822 if (oo_objects(s->oo) > oo_objects(s->max))
3823 s->max = s->oo;
3824
3825 return !!oo_objects(s->oo);
3826 }
3827
3828 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
3829 {
3830 s->flags = kmem_cache_flags(s->size, flags, s->name);
3831 #ifdef CONFIG_SLAB_FREELIST_HARDENED
3832 s->random = get_random_long();
3833 #endif
3834
3835 if (!calculate_sizes(s, -1))
3836 goto error;
3837 if (disable_higher_order_debug) {
3838 /*
3839 * Disable debugging flags that store metadata if the min slab
3840 * order increased.
3841 */
3842 if (get_order(s->size) > get_order(s->object_size)) {
3843 s->flags &= ~DEBUG_METADATA_FLAGS;
3844 s->offset = 0;
3845 if (!calculate_sizes(s, -1))
3846 goto error;
3847 }
3848 }
3849
3850 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3851 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3852 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3853 /* Enable fast mode */
3854 s->flags |= __CMPXCHG_DOUBLE;
3855 #endif
3856
3857 /*
3858 * The larger the object size is, the more pages we want on the partial
3859 * list to avoid pounding the page allocator excessively.
3860 */
3861 set_min_partial(s, ilog2(s->size) / 2);
3862
3863 set_cpu_partial(s);
3864
3865 #ifdef CONFIG_NUMA
3866 s->remote_node_defrag_ratio = 1000;
3867 #endif
3868
3869 /* Initialize the pre-computed randomized freelist if slab is up */
3870 if (slab_state >= UP) {
3871 if (init_cache_random_seq(s))
3872 goto error;
3873 }
3874
3875 if (!init_kmem_cache_nodes(s))
3876 goto error;
3877
3878 if (alloc_kmem_cache_cpus(s))
3879 return 0;
3880
3881 free_kmem_cache_nodes(s);
3882 error:
3883 return -EINVAL;
3884 }
3885
3886 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3887 const char *text)
3888 {
3889 #ifdef CONFIG_SLUB_DEBUG
3890 void *addr = page_address(page);
3891 unsigned long *map;
3892 void *p;
3893
3894 slab_err(s, page, text, s->name);
3895 slab_lock(page);
3896
3897 map = get_map(s, page);
3898 for_each_object(p, s, addr, page->objects) {
3899
3900 if (!test_bit(__obj_to_index(s, addr, p), map)) {
3901 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3902 print_tracking(s, p);
3903 }
3904 }
3905 put_map(map);
3906 slab_unlock(page);
3907 #endif
3908 }
3909
3910 /*
3911 * Attempt to free all partial slabs on a node.
3912 * This is called from __kmem_cache_shutdown(). We must take list_lock
3913 * because sysfs file might still access partial list after the shutdowning.
3914 */
3915 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3916 {
3917 LIST_HEAD(discard);
3918 struct page *page, *h;
3919
3920 BUG_ON(irqs_disabled());
3921 spin_lock_irq(&n->list_lock);
3922 list_for_each_entry_safe(page, h, &n->partial, slab_list) {
3923 if (!page->inuse) {
3924 remove_partial(n, page);
3925 list_add(&page->slab_list, &discard);
3926 } else {
3927 list_slab_objects(s, page,
3928 "Objects remaining in %s on __kmem_cache_shutdown()");
3929 }
3930 }
3931 spin_unlock_irq(&n->list_lock);
3932
3933 list_for_each_entry_safe(page, h, &discard, slab_list)
3934 discard_slab(s, page);
3935 }
3936
3937 bool __kmem_cache_empty(struct kmem_cache *s)
3938 {
3939 int node;
3940 struct kmem_cache_node *n;
3941
3942 for_each_kmem_cache_node(s, node, n)
3943 if (n->nr_partial || slabs_node(s, node))
3944 return false;
3945 return true;
3946 }
3947
3948 /*
3949 * Release all resources used by a slab cache.
3950 */
3951 int __kmem_cache_shutdown(struct kmem_cache *s)
3952 {
3953 int node;
3954 struct kmem_cache_node *n;
3955
3956 flush_all(s);
3957 /* Attempt to free all objects */
3958 for_each_kmem_cache_node(s, node, n) {
3959 free_partial(s, n);
3960 if (n->nr_partial || slabs_node(s, node))
3961 return 1;
3962 }
3963 return 0;
3964 }
3965
3966 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
3967 {
3968 void *base;
3969 int __maybe_unused i;
3970 unsigned int objnr;
3971 void *objp;
3972 void *objp0;
3973 struct kmem_cache *s = page->slab_cache;
3974 struct track __maybe_unused *trackp;
3975
3976 kpp->kp_ptr = object;
3977 kpp->kp_page = page;
3978 kpp->kp_slab_cache = s;
3979 base = page_address(page);
3980 objp0 = kasan_reset_tag(object);
3981 #ifdef CONFIG_SLUB_DEBUG
3982 objp = restore_red_left(s, objp0);
3983 #else
3984 objp = objp0;
3985 #endif
3986 objnr = obj_to_index(s, page, objp);
3987 kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
3988 objp = base + s->size * objnr;
3989 kpp->kp_objp = objp;
3990 if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size || (objp - base) % s->size) ||
3991 !(s->flags & SLAB_STORE_USER))
3992 return;
3993 #ifdef CONFIG_SLUB_DEBUG
3994 trackp = get_track(s, objp, TRACK_ALLOC);
3995 kpp->kp_ret = (void *)trackp->addr;
3996 #ifdef CONFIG_STACKTRACE
3997 for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
3998 kpp->kp_stack[i] = (void *)trackp->addrs[i];
3999 if (!kpp->kp_stack[i])
4000 break;
4001 }
4002 #endif
4003 #endif
4004 }
4005
4006 /********************************************************************
4007 * Kmalloc subsystem
4008 *******************************************************************/
4009
4010 static int __init setup_slub_min_order(char *str)
4011 {
4012 get_option(&str, (int *)&slub_min_order);
4013
4014 return 1;
4015 }
4016
4017 __setup("slub_min_order=", setup_slub_min_order);
4018
4019 static int __init setup_slub_max_order(char *str)
4020 {
4021 get_option(&str, (int *)&slub_max_order);
4022 slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
4023
4024 return 1;
4025 }
4026
4027 __setup("slub_max_order=", setup_slub_max_order);
4028
4029 static int __init setup_slub_min_objects(char *str)
4030 {
4031 get_option(&str, (int *)&slub_min_objects);
4032
4033 return 1;
4034 }
4035
4036 __setup("slub_min_objects=", setup_slub_min_objects);
4037
4038 void *__kmalloc(size_t size, gfp_t flags)
4039 {
4040 struct kmem_cache *s;
4041 void *ret;
4042
4043 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4044 return kmalloc_large(size, flags);
4045
4046 s = kmalloc_slab(size, flags);
4047
4048 if (unlikely(ZERO_OR_NULL_PTR(s)))
4049 return s;
4050
4051 ret = slab_alloc(s, flags, _RET_IP_, size);
4052
4053 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
4054
4055 ret = kasan_kmalloc(s, ret, size, flags);
4056
4057 return ret;
4058 }
4059 EXPORT_SYMBOL(__kmalloc);
4060
4061 #ifdef CONFIG_NUMA
4062 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
4063 {
4064 struct page *page;
4065 void *ptr = NULL;
4066 unsigned int order = get_order(size);
4067
4068 flags |= __GFP_COMP;
4069 page = alloc_pages_node(node, flags, order);
4070 if (page) {
4071 ptr = page_address(page);
4072 mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
4073 PAGE_SIZE << order);
4074 }
4075
4076 return kmalloc_large_node_hook(ptr, size, flags);
4077 }
4078
4079 void *__kmalloc_node(size_t size, gfp_t flags, int node)
4080 {
4081 struct kmem_cache *s;
4082 void *ret;
4083
4084 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4085 ret = kmalloc_large_node(size, flags, node);
4086
4087 trace_kmalloc_node(_RET_IP_, ret,
4088 size, PAGE_SIZE << get_order(size),
4089 flags, node);
4090
4091 return ret;
4092 }
4093
4094 s = kmalloc_slab(size, flags);
4095
4096 if (unlikely(ZERO_OR_NULL_PTR(s)))
4097 return s;
4098
4099 ret = slab_alloc_node(s, flags, node, _RET_IP_, size);
4100
4101 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
4102
4103 ret = kasan_kmalloc(s, ret, size, flags);
4104
4105 return ret;
4106 }
4107 EXPORT_SYMBOL(__kmalloc_node);
4108 #endif /* CONFIG_NUMA */
4109
4110 #ifdef CONFIG_HARDENED_USERCOPY
4111 /*
4112 * Rejects incorrectly sized objects and objects that are to be copied
4113 * to/from userspace but do not fall entirely within the containing slab
4114 * cache's usercopy region.
4115 *
4116 * Returns NULL if check passes, otherwise const char * to name of cache
4117 * to indicate an error.
4118 */
4119 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
4120 bool to_user)
4121 {
4122 struct kmem_cache *s;
4123 unsigned int offset;
4124 size_t object_size;
4125 bool is_kfence = is_kfence_address(ptr);
4126
4127 ptr = kasan_reset_tag(ptr);
4128
4129 /* Find object and usable object size. */
4130 s = page->slab_cache;
4131
4132 /* Reject impossible pointers. */
4133 if (ptr < page_address(page))
4134 usercopy_abort("SLUB object not in SLUB page?!", NULL,
4135 to_user, 0, n);
4136
4137 /* Find offset within object. */
4138 if (is_kfence)
4139 offset = ptr - kfence_object_start(ptr);
4140 else
4141 offset = (ptr - page_address(page)) % s->size;
4142
4143 /* Adjust for redzone and reject if within the redzone. */
4144 if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
4145 if (offset < s->red_left_pad)
4146 usercopy_abort("SLUB object in left red zone",
4147 s->name, to_user, offset, n);
4148 offset -= s->red_left_pad;
4149 }
4150
4151 /* Allow address range falling entirely within usercopy region. */
4152 if (offset >= s->useroffset &&
4153 offset - s->useroffset <= s->usersize &&
4154 n <= s->useroffset - offset + s->usersize)
4155 return;
4156
4157 /*
4158 * If the copy is still within the allocated object, produce
4159 * a warning instead of rejecting the copy. This is intended
4160 * to be a temporary method to find any missing usercopy
4161 * whitelists.
4162 */
4163 object_size = slab_ksize(s);
4164 if (usercopy_fallback &&
4165 offset <= object_size && n <= object_size - offset) {
4166 usercopy_warn("SLUB object", s->name, to_user, offset, n);
4167 return;
4168 }
4169
4170 usercopy_abort("SLUB object", s->name, to_user, offset, n);
4171 }
4172 #endif /* CONFIG_HARDENED_USERCOPY */
4173
4174 size_t __ksize(const void *object)
4175 {
4176 struct page *page;
4177
4178 if (unlikely(object == ZERO_SIZE_PTR))
4179 return 0;
4180
4181 page = virt_to_head_page(object);
4182
4183 if (unlikely(!PageSlab(page))) {
4184 WARN_ON(!PageCompound(page));
4185 return page_size(page);
4186 }
4187
4188 return slab_ksize(page->slab_cache);
4189 }
4190 EXPORT_SYMBOL(__ksize);
4191
4192 void kfree(const void *x)
4193 {
4194 struct page *page;
4195 void *object = (void *)x;
4196
4197 trace_kfree(_RET_IP_, x);
4198
4199 if (unlikely(ZERO_OR_NULL_PTR(x)))
4200 return;
4201
4202 page = virt_to_head_page(x);
4203 if (unlikely(!PageSlab(page))) {
4204 unsigned int order = compound_order(page);
4205
4206 BUG_ON(!PageCompound(page));
4207 kfree_hook(object);
4208 mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
4209 -(PAGE_SIZE << order));
4210 __free_pages(page, order);
4211 return;
4212 }
4213 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
4214 }
4215 EXPORT_SYMBOL(kfree);
4216
4217 #define SHRINK_PROMOTE_MAX 32
4218
4219 /*
4220 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
4221 * up most to the head of the partial lists. New allocations will then
4222 * fill those up and thus they can be removed from the partial lists.
4223 *
4224 * The slabs with the least items are placed last. This results in them
4225 * being allocated from last increasing the chance that the last objects
4226 * are freed in them.
4227 */
4228 int __kmem_cache_shrink(struct kmem_cache *s)
4229 {
4230 int node;
4231 int i;
4232 struct kmem_cache_node *n;
4233 struct page *page;
4234 struct page *t;
4235 struct list_head discard;
4236 struct list_head promote[SHRINK_PROMOTE_MAX];
4237 unsigned long flags;
4238 int ret = 0;
4239
4240 flush_all(s);
4241 for_each_kmem_cache_node(s, node, n) {
4242 INIT_LIST_HEAD(&discard);
4243 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
4244 INIT_LIST_HEAD(promote + i);
4245
4246 spin_lock_irqsave(&n->list_lock, flags);
4247
4248 /*
4249 * Build lists of slabs to discard or promote.
4250 *
4251 * Note that concurrent frees may occur while we hold the
4252 * list_lock. page->inuse here is the upper limit.
4253 */
4254 list_for_each_entry_safe(page, t, &n->partial, slab_list) {
4255 int free = page->objects - page->inuse;
4256
4257 /* Do not reread page->inuse */
4258 barrier();
4259
4260 /* We do not keep full slabs on the list */
4261 BUG_ON(free <= 0);
4262
4263 if (free == page->objects) {
4264 list_move(&page->slab_list, &discard);
4265 n->nr_partial--;
4266 } else if (free <= SHRINK_PROMOTE_MAX)
4267 list_move(&page->slab_list, promote + free - 1);
4268 }
4269
4270 /*
4271 * Promote the slabs filled up most to the head of the
4272 * partial list.
4273 */
4274 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4275 list_splice(promote + i, &n->partial);
4276
4277 spin_unlock_irqrestore(&n->list_lock, flags);
4278
4279 /* Release empty slabs */
4280 list_for_each_entry_safe(page, t, &discard, slab_list)
4281 discard_slab(s, page);
4282
4283 if (slabs_node(s, node))
4284 ret = 1;
4285 }
4286
4287 return ret;
4288 }
4289
4290 static int slab_mem_going_offline_callback(void *arg)
4291 {
4292 struct kmem_cache *s;
4293
4294 mutex_lock(&slab_mutex);
4295 list_for_each_entry(s, &slab_caches, list)
4296 __kmem_cache_shrink(s);
4297 mutex_unlock(&slab_mutex);
4298
4299 return 0;
4300 }
4301
4302 static void slab_mem_offline_callback(void *arg)
4303 {
4304 struct memory_notify *marg = arg;
4305 int offline_node;
4306
4307 offline_node = marg->status_change_nid_normal;
4308
4309 /*
4310 * If the node still has available memory. we need kmem_cache_node
4311 * for it yet.
4312 */
4313 if (offline_node < 0)
4314 return;
4315
4316 mutex_lock(&slab_mutex);
4317 node_clear(offline_node, slab_nodes);
4318 /*
4319 * We no longer free kmem_cache_node structures here, as it would be
4320 * racy with all get_node() users, and infeasible to protect them with
4321 * slab_mutex.
4322 */
4323 mutex_unlock(&slab_mutex);
4324 }
4325
4326 static int slab_mem_going_online_callback(void *arg)
4327 {
4328 struct kmem_cache_node *n;
4329 struct kmem_cache *s;
4330 struct memory_notify *marg = arg;
4331 int nid = marg->status_change_nid_normal;
4332 int ret = 0;
4333
4334 /*
4335 * If the node's memory is already available, then kmem_cache_node is
4336 * already created. Nothing to do.
4337 */
4338 if (nid < 0)
4339 return 0;
4340
4341 /*
4342 * We are bringing a node online. No memory is available yet. We must
4343 * allocate a kmem_cache_node structure in order to bring the node
4344 * online.
4345 */
4346 mutex_lock(&slab_mutex);
4347 list_for_each_entry(s, &slab_caches, list) {
4348 /*
4349 * The structure may already exist if the node was previously
4350 * onlined and offlined.
4351 */
4352 if (get_node(s, nid))
4353 continue;
4354 /*
4355 * XXX: kmem_cache_alloc_node will fallback to other nodes
4356 * since memory is not yet available from the node that
4357 * is brought up.
4358 */
4359 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4360 if (!n) {
4361 ret = -ENOMEM;
4362 goto out;
4363 }
4364 init_kmem_cache_node(n);
4365 s->node[nid] = n;
4366 }
4367 /*
4368 * Any cache created after this point will also have kmem_cache_node
4369 * initialized for the new node.
4370 */
4371 node_set(nid, slab_nodes);
4372 out:
4373 mutex_unlock(&slab_mutex);
4374 return ret;
4375 }
4376
4377 static int slab_memory_callback(struct notifier_block *self,
4378 unsigned long action, void *arg)
4379 {
4380 int ret = 0;
4381
4382 switch (action) {
4383 case MEM_GOING_ONLINE:
4384 ret = slab_mem_going_online_callback(arg);
4385 break;
4386 case MEM_GOING_OFFLINE:
4387 ret = slab_mem_going_offline_callback(arg);
4388 break;
4389 case MEM_OFFLINE:
4390 case MEM_CANCEL_ONLINE:
4391 slab_mem_offline_callback(arg);
4392 break;
4393 case MEM_ONLINE:
4394 case MEM_CANCEL_OFFLINE:
4395 break;
4396 }
4397 if (ret)
4398 ret = notifier_from_errno(ret);
4399 else
4400 ret = NOTIFY_OK;
4401 return ret;
4402 }
4403
4404 static struct notifier_block slab_memory_callback_nb = {
4405 .notifier_call = slab_memory_callback,
4406 .priority = SLAB_CALLBACK_PRI,
4407 };
4408
4409 /********************************************************************
4410 * Basic setup of slabs
4411 *******************************************************************/
4412
4413 /*
4414 * Used for early kmem_cache structures that were allocated using
4415 * the page allocator. Allocate them properly then fix up the pointers
4416 * that may be pointing to the wrong kmem_cache structure.
4417 */
4418
4419 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4420 {
4421 int node;
4422 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4423 struct kmem_cache_node *n;
4424
4425 memcpy(s, static_cache, kmem_cache->object_size);
4426
4427 /*
4428 * This runs very early, and only the boot processor is supposed to be
4429 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4430 * IPIs around.
4431 */
4432 __flush_cpu_slab(s, smp_processor_id());
4433 for_each_kmem_cache_node(s, node, n) {
4434 struct page *p;
4435
4436 list_for_each_entry(p, &n->partial, slab_list)
4437 p->slab_cache = s;
4438
4439 #ifdef CONFIG_SLUB_DEBUG
4440 list_for_each_entry(p, &n->full, slab_list)
4441 p->slab_cache = s;
4442 #endif
4443 }
4444 list_add(&s->list, &slab_caches);
4445 return s;
4446 }
4447
4448 void __init kmem_cache_init(void)
4449 {
4450 static __initdata struct kmem_cache boot_kmem_cache,
4451 boot_kmem_cache_node;
4452 int node;
4453
4454 if (debug_guardpage_minorder())
4455 slub_max_order = 0;
4456
4457 kmem_cache_node = &boot_kmem_cache_node;
4458 kmem_cache = &boot_kmem_cache;
4459
4460 /*
4461 * Initialize the nodemask for which we will allocate per node
4462 * structures. Here we don't need taking slab_mutex yet.
4463 */
4464 for_each_node_state(node, N_NORMAL_MEMORY)
4465 node_set(node, slab_nodes);
4466
4467 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4468 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4469
4470 register_hotmemory_notifier(&slab_memory_callback_nb);
4471
4472 /* Able to allocate the per node structures */
4473 slab_state = PARTIAL;
4474
4475 create_boot_cache(kmem_cache, "kmem_cache",
4476 offsetof(struct kmem_cache, node) +
4477 nr_node_ids * sizeof(struct kmem_cache_node *),
4478 SLAB_HWCACHE_ALIGN, 0, 0);
4479
4480 kmem_cache = bootstrap(&boot_kmem_cache);
4481 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4482
4483 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4484 setup_kmalloc_cache_index_table();
4485 create_kmalloc_caches(0);
4486
4487 /* Setup random freelists for each cache */
4488 init_freelist_randomization();
4489
4490 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4491 slub_cpu_dead);
4492
4493 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
4494 cache_line_size(),
4495 slub_min_order, slub_max_order, slub_min_objects,
4496 nr_cpu_ids, nr_node_ids);
4497 }
4498
4499 void __init kmem_cache_init_late(void)
4500 {
4501 }
4502
4503 struct kmem_cache *
4504 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4505 slab_flags_t flags, void (*ctor)(void *))
4506 {
4507 struct kmem_cache *s;
4508
4509 s = find_mergeable(size, align, flags, name, ctor);
4510 if (s) {
4511 s->refcount++;
4512
4513 /*
4514 * Adjust the object sizes so that we clear
4515 * the complete object on kzalloc.
4516 */
4517 s->object_size = max(s->object_size, size);
4518 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4519
4520 if (sysfs_slab_alias(s, name)) {
4521 s->refcount--;
4522 s = NULL;
4523 }
4524 }
4525
4526 return s;
4527 }
4528
4529 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4530 {
4531 int err;
4532
4533 err = kmem_cache_open(s, flags);
4534 if (err)
4535 return err;
4536
4537 /* Mutex is not taken during early boot */
4538 if (slab_state <= UP)
4539 return 0;
4540
4541 err = sysfs_slab_add(s);
4542 if (err)
4543 __kmem_cache_release(s);
4544
4545 return err;
4546 }
4547
4548 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4549 {
4550 struct kmem_cache *s;
4551 void *ret;
4552
4553 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4554 return kmalloc_large(size, gfpflags);
4555
4556 s = kmalloc_slab(size, gfpflags);
4557
4558 if (unlikely(ZERO_OR_NULL_PTR(s)))
4559 return s;
4560
4561 ret = slab_alloc(s, gfpflags, caller, size);
4562
4563 /* Honor the call site pointer we received. */
4564 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4565
4566 return ret;
4567 }
4568 EXPORT_SYMBOL(__kmalloc_track_caller);
4569
4570 #ifdef CONFIG_NUMA
4571 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4572 int node, unsigned long caller)
4573 {
4574 struct kmem_cache *s;
4575 void *ret;
4576
4577 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4578 ret = kmalloc_large_node(size, gfpflags, node);
4579
4580 trace_kmalloc_node(caller, ret,
4581 size, PAGE_SIZE << get_order(size),
4582 gfpflags, node);
4583
4584 return ret;
4585 }
4586
4587 s = kmalloc_slab(size, gfpflags);
4588
4589 if (unlikely(ZERO_OR_NULL_PTR(s)))
4590 return s;
4591
4592 ret = slab_alloc_node(s, gfpflags, node, caller, size);
4593
4594 /* Honor the call site pointer we received. */
4595 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4596
4597 return ret;
4598 }
4599 EXPORT_SYMBOL(__kmalloc_node_track_caller);
4600 #endif
4601
4602 #ifdef CONFIG_SYSFS
4603 static int count_inuse(struct page *page)
4604 {
4605 return page->inuse;
4606 }
4607
4608 static int count_total(struct page *page)
4609 {
4610 return page->objects;
4611 }
4612 #endif
4613
4614 #ifdef CONFIG_SLUB_DEBUG
4615 static void validate_slab(struct kmem_cache *s, struct page *page)
4616 {
4617 void *p;
4618 void *addr = page_address(page);
4619 unsigned long *map;
4620
4621 slab_lock(page);
4622
4623 if (!check_slab(s, page) || !on_freelist(s, page, NULL))
4624 goto unlock;
4625
4626 /* Now we know that a valid freelist exists */
4627 map = get_map(s, page);
4628 for_each_object(p, s, addr, page->objects) {
4629 u8 val = test_bit(__obj_to_index(s, addr, p), map) ?
4630 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
4631
4632 if (!check_object(s, page, p, val))
4633 break;
4634 }
4635 put_map(map);
4636 unlock:
4637 slab_unlock(page);
4638 }
4639
4640 static int validate_slab_node(struct kmem_cache *s,
4641 struct kmem_cache_node *n)
4642 {
4643 unsigned long count = 0;
4644 struct page *page;
4645 unsigned long flags;
4646
4647 spin_lock_irqsave(&n->list_lock, flags);
4648
4649 list_for_each_entry(page, &n->partial, slab_list) {
4650 validate_slab(s, page);
4651 count++;
4652 }
4653 if (count != n->nr_partial)
4654 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4655 s->name, count, n->nr_partial);
4656
4657 if (!(s->flags & SLAB_STORE_USER))
4658 goto out;
4659
4660 list_for_each_entry(page, &n->full, slab_list) {
4661 validate_slab(s, page);
4662 count++;
4663 }
4664 if (count != atomic_long_read(&n->nr_slabs))
4665 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4666 s->name, count, atomic_long_read(&n->nr_slabs));
4667
4668 out:
4669 spin_unlock_irqrestore(&n->list_lock, flags);
4670 return count;
4671 }
4672
4673 static long validate_slab_cache(struct kmem_cache *s)
4674 {
4675 int node;
4676 unsigned long count = 0;
4677 struct kmem_cache_node *n;
4678
4679 flush_all(s);
4680 for_each_kmem_cache_node(s, node, n)
4681 count += validate_slab_node(s, n);
4682
4683 return count;
4684 }
4685 /*
4686 * Generate lists of code addresses where slabcache objects are allocated
4687 * and freed.
4688 */
4689
4690 struct location {
4691 unsigned long count;
4692 unsigned long addr;
4693 long long sum_time;
4694 long min_time;
4695 long max_time;
4696 long min_pid;
4697 long max_pid;
4698 DECLARE_BITMAP(cpus, NR_CPUS);
4699 nodemask_t nodes;
4700 };
4701
4702 struct loc_track {
4703 unsigned long max;
4704 unsigned long count;
4705 struct location *loc;
4706 };
4707
4708 static void free_loc_track(struct loc_track *t)
4709 {
4710 if (t->max)
4711 free_pages((unsigned long)t->loc,
4712 get_order(sizeof(struct location) * t->max));
4713 }
4714
4715 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4716 {
4717 struct location *l;
4718 int order;
4719
4720 order = get_order(sizeof(struct location) * max);
4721
4722 l = (void *)__get_free_pages(flags, order);
4723 if (!l)
4724 return 0;
4725
4726 if (t->count) {
4727 memcpy(l, t->loc, sizeof(struct location) * t->count);
4728 free_loc_track(t);
4729 }
4730 t->max = max;
4731 t->loc = l;
4732 return 1;
4733 }
4734
4735 static int add_location(struct loc_track *t, struct kmem_cache *s,
4736 const struct track *track)
4737 {
4738 long start, end, pos;
4739 struct location *l;
4740 unsigned long caddr;
4741 unsigned long age = jiffies - track->when;
4742
4743 start = -1;
4744 end = t->count;
4745
4746 for ( ; ; ) {
4747 pos = start + (end - start + 1) / 2;
4748
4749 /*
4750 * There is nothing at "end". If we end up there
4751 * we need to add something to before end.
4752 */
4753 if (pos == end)
4754 break;
4755
4756 caddr = t->loc[pos].addr;
4757 if (track->addr == caddr) {
4758
4759 l = &t->loc[pos];
4760 l->count++;
4761 if (track->when) {
4762 l->sum_time += age;
4763 if (age < l->min_time)
4764 l->min_time = age;
4765 if (age > l->max_time)
4766 l->max_time = age;
4767
4768 if (track->pid < l->min_pid)
4769 l->min_pid = track->pid;
4770 if (track->pid > l->max_pid)
4771 l->max_pid = track->pid;
4772
4773 cpumask_set_cpu(track->cpu,
4774 to_cpumask(l->cpus));
4775 }
4776 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4777 return 1;
4778 }
4779
4780 if (track->addr < caddr)
4781 end = pos;
4782 else
4783 start = pos;
4784 }
4785
4786 /*
4787 * Not found. Insert new tracking element.
4788 */
4789 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4790 return 0;
4791
4792 l = t->loc + pos;
4793 if (pos < t->count)
4794 memmove(l + 1, l,
4795 (t->count - pos) * sizeof(struct location));
4796 t->count++;
4797 l->count = 1;
4798 l->addr = track->addr;
4799 l->sum_time = age;
4800 l->min_time = age;
4801 l->max_time = age;
4802 l->min_pid = track->pid;
4803 l->max_pid = track->pid;
4804 cpumask_clear(to_cpumask(l->cpus));
4805 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4806 nodes_clear(l->nodes);
4807 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4808 return 1;
4809 }
4810
4811 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4812 struct page *page, enum track_item alloc)
4813 {
4814 void *addr = page_address(page);
4815 void *p;
4816 unsigned long *map;
4817
4818 map = get_map(s, page);
4819 for_each_object(p, s, addr, page->objects)
4820 if (!test_bit(__obj_to_index(s, addr, p), map))
4821 add_location(t, s, get_track(s, p, alloc));
4822 put_map(map);
4823 }
4824
4825 static int list_locations(struct kmem_cache *s, char *buf,
4826 enum track_item alloc)
4827 {
4828 int len = 0;
4829 unsigned long i;
4830 struct loc_track t = { 0, 0, NULL };
4831 int node;
4832 struct kmem_cache_node *n;
4833
4834 if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4835 GFP_KERNEL)) {
4836 return sysfs_emit(buf, "Out of memory\n");
4837 }
4838 /* Push back cpu slabs */
4839 flush_all(s);
4840
4841 for_each_kmem_cache_node(s, node, n) {
4842 unsigned long flags;
4843 struct page *page;
4844
4845 if (!atomic_long_read(&n->nr_slabs))
4846 continue;
4847
4848 spin_lock_irqsave(&n->list_lock, flags);
4849 list_for_each_entry(page, &n->partial, slab_list)
4850 process_slab(&t, s, page, alloc);
4851 list_for_each_entry(page, &n->full, slab_list)
4852 process_slab(&t, s, page, alloc);
4853 spin_unlock_irqrestore(&n->list_lock, flags);
4854 }
4855
4856 for (i = 0; i < t.count; i++) {
4857 struct location *l = &t.loc[i];
4858
4859 len += sysfs_emit_at(buf, len, "%7ld ", l->count);
4860
4861 if (l->addr)
4862 len += sysfs_emit_at(buf, len, "%pS", (void *)l->addr);
4863 else
4864 len += sysfs_emit_at(buf, len, "<not-available>");
4865
4866 if (l->sum_time != l->min_time)
4867 len += sysfs_emit_at(buf, len, " age=%ld/%ld/%ld",
4868 l->min_time,
4869 (long)div_u64(l->sum_time,
4870 l->count),
4871 l->max_time);
4872 else
4873 len += sysfs_emit_at(buf, len, " age=%ld", l->min_time);
4874
4875 if (l->min_pid != l->max_pid)
4876 len += sysfs_emit_at(buf, len, " pid=%ld-%ld",
4877 l->min_pid, l->max_pid);
4878 else
4879 len += sysfs_emit_at(buf, len, " pid=%ld",
4880 l->min_pid);
4881
4882 if (num_online_cpus() > 1 &&
4883 !cpumask_empty(to_cpumask(l->cpus)))
4884 len += sysfs_emit_at(buf, len, " cpus=%*pbl",
4885 cpumask_pr_args(to_cpumask(l->cpus)));
4886
4887 if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
4888 len += sysfs_emit_at(buf, len, " nodes=%*pbl",
4889 nodemask_pr_args(&l->nodes));
4890
4891 len += sysfs_emit_at(buf, len, "\n");
4892 }
4893
4894 free_loc_track(&t);
4895 if (!t.count)
4896 len += sysfs_emit_at(buf, len, "No data\n");
4897
4898 return len;
4899 }
4900 #endif /* CONFIG_SLUB_DEBUG */
4901
4902 #ifdef SLUB_RESILIENCY_TEST
4903 static void __init resiliency_test(void)
4904 {
4905 u8 *p;
4906 int type = KMALLOC_NORMAL;
4907
4908 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4909
4910 pr_err("SLUB resiliency testing\n");
4911 pr_err("-----------------------\n");
4912 pr_err("A. Corruption after allocation\n");
4913
4914 p = kzalloc(16, GFP_KERNEL);
4915 p[16] = 0x12;
4916 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4917 p + 16);
4918
4919 validate_slab_cache(kmalloc_caches[type][4]);
4920
4921 /* Hmmm... The next two are dangerous */
4922 p = kzalloc(32, GFP_KERNEL);
4923 p[32 + sizeof(void *)] = 0x34;
4924 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4925 p);
4926 pr_err("If allocated object is overwritten then not detectable\n\n");
4927
4928 validate_slab_cache(kmalloc_caches[type][5]);
4929 p = kzalloc(64, GFP_KERNEL);
4930 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4931 *p = 0x56;
4932 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4933 p);
4934 pr_err("If allocated object is overwritten then not detectable\n\n");
4935 validate_slab_cache(kmalloc_caches[type][6]);
4936
4937 pr_err("\nB. Corruption after free\n");
4938 p = kzalloc(128, GFP_KERNEL);
4939 kfree(p);
4940 *p = 0x78;
4941 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4942 validate_slab_cache(kmalloc_caches[type][7]);
4943
4944 p = kzalloc(256, GFP_KERNEL);
4945 kfree(p);
4946 p[50] = 0x9a;
4947 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4948 validate_slab_cache(kmalloc_caches[type][8]);
4949
4950 p = kzalloc(512, GFP_KERNEL);
4951 kfree(p);
4952 p[512] = 0xab;
4953 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4954 validate_slab_cache(kmalloc_caches[type][9]);
4955 }
4956 #else
4957 #ifdef CONFIG_SYSFS
4958 static void resiliency_test(void) {};
4959 #endif
4960 #endif /* SLUB_RESILIENCY_TEST */
4961
4962 #ifdef CONFIG_SYSFS
4963 enum slab_stat_type {
4964 SL_ALL, /* All slabs */
4965 SL_PARTIAL, /* Only partially allocated slabs */
4966 SL_CPU, /* Only slabs used for cpu caches */
4967 SL_OBJECTS, /* Determine allocated objects not slabs */
4968 SL_TOTAL /* Determine object capacity not slabs */
4969 };
4970
4971 #define SO_ALL (1 << SL_ALL)
4972 #define SO_PARTIAL (1 << SL_PARTIAL)
4973 #define SO_CPU (1 << SL_CPU)
4974 #define SO_OBJECTS (1 << SL_OBJECTS)
4975 #define SO_TOTAL (1 << SL_TOTAL)
4976
4977 static ssize_t show_slab_objects(struct kmem_cache *s,
4978 char *buf, unsigned long flags)
4979 {
4980 unsigned long total = 0;
4981 int node;
4982 int x;
4983 unsigned long *nodes;
4984 int len = 0;
4985
4986 nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
4987 if (!nodes)
4988 return -ENOMEM;
4989
4990 if (flags & SO_CPU) {
4991 int cpu;
4992
4993 for_each_possible_cpu(cpu) {
4994 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4995 cpu);
4996 int node;
4997 struct page *page;
4998
4999 page = READ_ONCE(c->page);
5000 if (!page)
5001 continue;
5002
5003 node = page_to_nid(page);
5004 if (flags & SO_TOTAL)
5005 x = page->objects;
5006 else if (flags & SO_OBJECTS)
5007 x = page->inuse;
5008 else
5009 x = 1;
5010
5011 total += x;
5012 nodes[node] += x;
5013
5014 page = slub_percpu_partial_read_once(c);
5015 if (page) {
5016 node = page_to_nid(page);
5017 if (flags & SO_TOTAL)
5018 WARN_ON_ONCE(1);
5019 else if (flags & SO_OBJECTS)
5020 WARN_ON_ONCE(1);
5021 else
5022 x = page->pages;
5023 total += x;
5024 nodes[node] += x;
5025 }
5026 }
5027 }
5028
5029 /*
5030 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
5031 * already held which will conflict with an existing lock order:
5032 *
5033 * mem_hotplug_lock->slab_mutex->kernfs_mutex
5034 *
5035 * We don't really need mem_hotplug_lock (to hold off
5036 * slab_mem_going_offline_callback) here because slab's memory hot
5037 * unplug code doesn't destroy the kmem_cache->node[] data.
5038 */
5039
5040 #ifdef CONFIG_SLUB_DEBUG
5041 if (flags & SO_ALL) {
5042 struct kmem_cache_node *n;
5043
5044 for_each_kmem_cache_node(s, node, n) {
5045
5046 if (flags & SO_TOTAL)
5047 x = atomic_long_read(&n->total_objects);
5048 else if (flags & SO_OBJECTS)
5049 x = atomic_long_read(&n->total_objects) -
5050 count_partial(n, count_free);
5051 else
5052 x = atomic_long_read(&n->nr_slabs);
5053 total += x;
5054 nodes[node] += x;
5055 }
5056
5057 } else
5058 #endif
5059 if (flags & SO_PARTIAL) {
5060 struct kmem_cache_node *n;
5061
5062 for_each_kmem_cache_node(s, node, n) {
5063 if (flags & SO_TOTAL)
5064 x = count_partial(n, count_total);
5065 else if (flags & SO_OBJECTS)
5066 x = count_partial(n, count_inuse);
5067 else
5068 x = n->nr_partial;
5069 total += x;
5070 nodes[node] += x;
5071 }
5072 }
5073
5074 len += sysfs_emit_at(buf, len, "%lu", total);
5075 #ifdef CONFIG_NUMA
5076 for (node = 0; node < nr_node_ids; node++) {
5077 if (nodes[node])
5078 len += sysfs_emit_at(buf, len, " N%d=%lu",
5079 node, nodes[node]);
5080 }
5081 #endif
5082 len += sysfs_emit_at(buf, len, "\n");
5083 kfree(nodes);
5084
5085 return len;
5086 }
5087
5088 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
5089 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
5090
5091 struct slab_attribute {
5092 struct attribute attr;
5093 ssize_t (*show)(struct kmem_cache *s, char *buf);
5094 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
5095 };
5096
5097 #define SLAB_ATTR_RO(_name) \
5098 static struct slab_attribute _name##_attr = \
5099 __ATTR(_name, 0400, _name##_show, NULL)
5100
5101 #define SLAB_ATTR(_name) \
5102 static struct slab_attribute _name##_attr = \
5103 __ATTR(_name, 0600, _name##_show, _name##_store)
5104
5105 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
5106 {
5107 return sysfs_emit(buf, "%u\n", s->size);
5108 }
5109 SLAB_ATTR_RO(slab_size);
5110
5111 static ssize_t align_show(struct kmem_cache *s, char *buf)
5112 {
5113 return sysfs_emit(buf, "%u\n", s->align);
5114 }
5115 SLAB_ATTR_RO(align);
5116
5117 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
5118 {
5119 return sysfs_emit(buf, "%u\n", s->object_size);
5120 }
5121 SLAB_ATTR_RO(object_size);
5122
5123 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
5124 {
5125 return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
5126 }
5127 SLAB_ATTR_RO(objs_per_slab);
5128
5129 static ssize_t order_show(struct kmem_cache *s, char *buf)
5130 {
5131 return sysfs_emit(buf, "%u\n", oo_order(s->oo));
5132 }
5133 SLAB_ATTR_RO(order);
5134
5135 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
5136 {
5137 return sysfs_emit(buf, "%lu\n", s->min_partial);
5138 }
5139
5140 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
5141 size_t length)
5142 {
5143 unsigned long min;
5144 int err;
5145
5146 err = kstrtoul(buf, 10, &min);
5147 if (err)
5148 return err;
5149
5150 set_min_partial(s, min);
5151 return length;
5152 }
5153 SLAB_ATTR(min_partial);
5154
5155 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
5156 {
5157 return sysfs_emit(buf, "%u\n", slub_cpu_partial(s));
5158 }
5159
5160 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
5161 size_t length)
5162 {
5163 unsigned int objects;
5164 int err;
5165
5166 err = kstrtouint(buf, 10, &objects);
5167 if (err)
5168 return err;
5169 if (objects && !kmem_cache_has_cpu_partial(s))
5170 return -EINVAL;
5171
5172 slub_set_cpu_partial(s, objects);
5173 flush_all(s);
5174 return length;
5175 }
5176 SLAB_ATTR(cpu_partial);
5177
5178 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5179 {
5180 if (!s->ctor)
5181 return 0;
5182 return sysfs_emit(buf, "%pS\n", s->ctor);
5183 }
5184 SLAB_ATTR_RO(ctor);
5185
5186 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5187 {
5188 return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5189 }
5190 SLAB_ATTR_RO(aliases);
5191
5192 static ssize_t partial_show(struct kmem_cache *s, char *buf)
5193 {
5194 return show_slab_objects(s, buf, SO_PARTIAL);
5195 }
5196 SLAB_ATTR_RO(partial);
5197
5198 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5199 {
5200 return show_slab_objects(s, buf, SO_CPU);
5201 }
5202 SLAB_ATTR_RO(cpu_slabs);
5203
5204 static ssize_t objects_show(struct kmem_cache *s, char *buf)
5205 {
5206 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5207 }
5208 SLAB_ATTR_RO(objects);
5209
5210 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5211 {
5212 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5213 }
5214 SLAB_ATTR_RO(objects_partial);
5215
5216 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5217 {
5218 int objects = 0;
5219 int pages = 0;
5220 int cpu;
5221 int len = 0;
5222
5223 for_each_online_cpu(cpu) {
5224 struct page *page;
5225
5226 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5227
5228 if (page) {
5229 pages += page->pages;
5230 objects += page->pobjects;
5231 }
5232 }
5233
5234 len += sysfs_emit_at(buf, len, "%d(%d)", objects, pages);
5235
5236 #ifdef CONFIG_SMP
5237 for_each_online_cpu(cpu) {
5238 struct page *page;
5239
5240 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5241 if (page)
5242 len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
5243 cpu, page->pobjects, page->pages);
5244 }
5245 #endif
5246 len += sysfs_emit_at(buf, len, "\n");
5247
5248 return len;
5249 }
5250 SLAB_ATTR_RO(slabs_cpu_partial);
5251
5252 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5253 {
5254 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5255 }
5256 SLAB_ATTR_RO(reclaim_account);
5257
5258 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5259 {
5260 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5261 }
5262 SLAB_ATTR_RO(hwcache_align);
5263
5264 #ifdef CONFIG_ZONE_DMA
5265 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5266 {
5267 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5268 }
5269 SLAB_ATTR_RO(cache_dma);
5270 #endif
5271
5272 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5273 {
5274 return sysfs_emit(buf, "%u\n", s->usersize);
5275 }
5276 SLAB_ATTR_RO(usersize);
5277
5278 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5279 {
5280 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5281 }
5282 SLAB_ATTR_RO(destroy_by_rcu);
5283
5284 #ifdef CONFIG_SLUB_DEBUG
5285 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5286 {
5287 return show_slab_objects(s, buf, SO_ALL);
5288 }
5289 SLAB_ATTR_RO(slabs);
5290
5291 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5292 {
5293 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5294 }
5295 SLAB_ATTR_RO(total_objects);
5296
5297 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5298 {
5299 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5300 }
5301 SLAB_ATTR_RO(sanity_checks);
5302
5303 static ssize_t trace_show(struct kmem_cache *s, char *buf)
5304 {
5305 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5306 }
5307 SLAB_ATTR_RO(trace);
5308
5309 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5310 {
5311 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5312 }
5313
5314 SLAB_ATTR_RO(red_zone);
5315
5316 static ssize_t poison_show(struct kmem_cache *s, char *buf)
5317 {
5318 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
5319 }
5320
5321 SLAB_ATTR_RO(poison);
5322
5323 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5324 {
5325 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5326 }
5327
5328 SLAB_ATTR_RO(store_user);
5329
5330 static ssize_t validate_show(struct kmem_cache *s, char *buf)
5331 {
5332 return 0;
5333 }
5334
5335 static ssize_t validate_store(struct kmem_cache *s,
5336 const char *buf, size_t length)
5337 {
5338 int ret = -EINVAL;
5339
5340 if (buf[0] == '1') {
5341 ret = validate_slab_cache(s);
5342 if (ret >= 0)
5343 ret = length;
5344 }
5345 return ret;
5346 }
5347 SLAB_ATTR(validate);
5348
5349 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5350 {
5351 if (!(s->flags & SLAB_STORE_USER))
5352 return -ENOSYS;
5353 return list_locations(s, buf, TRACK_ALLOC);
5354 }
5355 SLAB_ATTR_RO(alloc_calls);
5356
5357 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5358 {
5359 if (!(s->flags & SLAB_STORE_USER))
5360 return -ENOSYS;
5361 return list_locations(s, buf, TRACK_FREE);
5362 }
5363 SLAB_ATTR_RO(free_calls);
5364 #endif /* CONFIG_SLUB_DEBUG */
5365
5366 #ifdef CONFIG_FAILSLAB
5367 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5368 {
5369 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5370 }
5371 SLAB_ATTR_RO(failslab);
5372 #endif
5373
5374 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5375 {
5376 return 0;
5377 }
5378
5379 static ssize_t shrink_store(struct kmem_cache *s,
5380 const char *buf, size_t length)
5381 {
5382 if (buf[0] == '1')
5383 kmem_cache_shrink(s);
5384 else
5385 return -EINVAL;
5386 return length;
5387 }
5388 SLAB_ATTR(shrink);
5389
5390 #ifdef CONFIG_NUMA
5391 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5392 {
5393 return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5394 }
5395
5396 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5397 const char *buf, size_t length)
5398 {
5399 unsigned int ratio;
5400 int err;
5401
5402 err = kstrtouint(buf, 10, &ratio);
5403 if (err)
5404 return err;
5405 if (ratio > 100)
5406 return -ERANGE;
5407
5408 s->remote_node_defrag_ratio = ratio * 10;
5409
5410 return length;
5411 }
5412 SLAB_ATTR(remote_node_defrag_ratio);
5413 #endif
5414
5415 #ifdef CONFIG_SLUB_STATS
5416 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5417 {
5418 unsigned long sum = 0;
5419 int cpu;
5420 int len = 0;
5421 int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
5422
5423 if (!data)
5424 return -ENOMEM;
5425
5426 for_each_online_cpu(cpu) {
5427 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5428
5429 data[cpu] = x;
5430 sum += x;
5431 }
5432
5433 len += sysfs_emit_at(buf, len, "%lu", sum);
5434
5435 #ifdef CONFIG_SMP
5436 for_each_online_cpu(cpu) {
5437 if (data[cpu])
5438 len += sysfs_emit_at(buf, len, " C%d=%u",
5439 cpu, data[cpu]);
5440 }
5441 #endif
5442 kfree(data);
5443 len += sysfs_emit_at(buf, len, "\n");
5444
5445 return len;
5446 }
5447
5448 static void clear_stat(struct kmem_cache *s, enum stat_item si)
5449 {
5450 int cpu;
5451
5452 for_each_online_cpu(cpu)
5453 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5454 }
5455
5456 #define STAT_ATTR(si, text) \
5457 static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5458 { \
5459 return show_stat(s, buf, si); \
5460 } \
5461 static ssize_t text##_store(struct kmem_cache *s, \
5462 const char *buf, size_t length) \
5463 { \
5464 if (buf[0] != '0') \
5465 return -EINVAL; \
5466 clear_stat(s, si); \
5467 return length; \
5468 } \
5469 SLAB_ATTR(text); \
5470
5471 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5472 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5473 STAT_ATTR(FREE_FASTPATH, free_fastpath);
5474 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5475 STAT_ATTR(FREE_FROZEN, free_frozen);
5476 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5477 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5478 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5479 STAT_ATTR(ALLOC_SLAB, alloc_slab);
5480 STAT_ATTR(ALLOC_REFILL, alloc_refill);
5481 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5482 STAT_ATTR(FREE_SLAB, free_slab);
5483 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5484 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5485 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5486 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5487 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5488 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5489 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5490 STAT_ATTR(ORDER_FALLBACK, order_fallback);
5491 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5492 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5493 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5494 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5495 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5496 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5497 #endif /* CONFIG_SLUB_STATS */
5498
5499 static struct attribute *slab_attrs[] = {
5500 &slab_size_attr.attr,
5501 &object_size_attr.attr,
5502 &objs_per_slab_attr.attr,
5503 &order_attr.attr,
5504 &min_partial_attr.attr,
5505 &cpu_partial_attr.attr,
5506 &objects_attr.attr,
5507 &objects_partial_attr.attr,
5508 &partial_attr.attr,
5509 &cpu_slabs_attr.attr,
5510 &ctor_attr.attr,
5511 &aliases_attr.attr,
5512 &align_attr.attr,
5513 &hwcache_align_attr.attr,
5514 &reclaim_account_attr.attr,
5515 &destroy_by_rcu_attr.attr,
5516 &shrink_attr.attr,
5517 &slabs_cpu_partial_attr.attr,
5518 #ifdef CONFIG_SLUB_DEBUG
5519 &total_objects_attr.attr,
5520 &slabs_attr.attr,
5521 &sanity_checks_attr.attr,
5522 &trace_attr.attr,
5523 &red_zone_attr.attr,
5524 &poison_attr.attr,
5525 &store_user_attr.attr,
5526 &validate_attr.attr,
5527 &alloc_calls_attr.attr,
5528 &free_calls_attr.attr,
5529 #endif
5530 #ifdef CONFIG_ZONE_DMA
5531 &cache_dma_attr.attr,
5532 #endif
5533 #ifdef CONFIG_NUMA
5534 &remote_node_defrag_ratio_attr.attr,
5535 #endif
5536 #ifdef CONFIG_SLUB_STATS
5537 &alloc_fastpath_attr.attr,
5538 &alloc_slowpath_attr.attr,
5539 &free_fastpath_attr.attr,
5540 &free_slowpath_attr.attr,
5541 &free_frozen_attr.attr,
5542 &free_add_partial_attr.attr,
5543 &free_remove_partial_attr.attr,
5544 &alloc_from_partial_attr.attr,
5545 &alloc_slab_attr.attr,
5546 &alloc_refill_attr.attr,
5547 &alloc_node_mismatch_attr.attr,
5548 &free_slab_attr.attr,
5549 &cpuslab_flush_attr.attr,
5550 &deactivate_full_attr.attr,
5551 &deactivate_empty_attr.attr,
5552 &deactivate_to_head_attr.attr,
5553 &deactivate_to_tail_attr.attr,
5554 &deactivate_remote_frees_attr.attr,
5555 &deactivate_bypass_attr.attr,
5556 &order_fallback_attr.attr,
5557 &cmpxchg_double_fail_attr.attr,
5558 &cmpxchg_double_cpu_fail_attr.attr,
5559 &cpu_partial_alloc_attr.attr,
5560 &cpu_partial_free_attr.attr,
5561 &cpu_partial_node_attr.attr,
5562 &cpu_partial_drain_attr.attr,
5563 #endif
5564 #ifdef CONFIG_FAILSLAB
5565 &failslab_attr.attr,
5566 #endif
5567 &usersize_attr.attr,
5568
5569 NULL
5570 };
5571
5572 static const struct attribute_group slab_attr_group = {
5573 .attrs = slab_attrs,
5574 };
5575
5576 static ssize_t slab_attr_show(struct kobject *kobj,
5577 struct attribute *attr,
5578 char *buf)
5579 {
5580 struct slab_attribute *attribute;
5581 struct kmem_cache *s;
5582 int err;
5583
5584 attribute = to_slab_attr(attr);
5585 s = to_slab(kobj);
5586
5587 if (!attribute->show)
5588 return -EIO;
5589
5590 err = attribute->show(s, buf);
5591
5592 return err;
5593 }
5594
5595 static ssize_t slab_attr_store(struct kobject *kobj,
5596 struct attribute *attr,
5597 const char *buf, size_t len)
5598 {
5599 struct slab_attribute *attribute;
5600 struct kmem_cache *s;
5601 int err;
5602
5603 attribute = to_slab_attr(attr);
5604 s = to_slab(kobj);
5605
5606 if (!attribute->store)
5607 return -EIO;
5608
5609 err = attribute->store(s, buf, len);
5610 return err;
5611 }
5612
5613 static void kmem_cache_release(struct kobject *k)
5614 {
5615 slab_kmem_cache_release(to_slab(k));
5616 }
5617
5618 static const struct sysfs_ops slab_sysfs_ops = {
5619 .show = slab_attr_show,
5620 .store = slab_attr_store,
5621 };
5622
5623 static struct kobj_type slab_ktype = {
5624 .sysfs_ops = &slab_sysfs_ops,
5625 .release = kmem_cache_release,
5626 };
5627
5628 static struct kset *slab_kset;
5629
5630 static inline struct kset *cache_kset(struct kmem_cache *s)
5631 {
5632 return slab_kset;
5633 }
5634
5635 #define ID_STR_LENGTH 64
5636
5637 /* Create a unique string id for a slab cache:
5638 *
5639 * Format :[flags-]size
5640 */
5641 static char *create_unique_id(struct kmem_cache *s)
5642 {
5643 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5644 char *p = name;
5645
5646 BUG_ON(!name);
5647
5648 *p++ = ':';
5649 /*
5650 * First flags affecting slabcache operations. We will only
5651 * get here for aliasable slabs so we do not need to support
5652 * too many flags. The flags here must cover all flags that
5653 * are matched during merging to guarantee that the id is
5654 * unique.
5655 */
5656 if (s->flags & SLAB_CACHE_DMA)
5657 *p++ = 'd';
5658 if (s->flags & SLAB_CACHE_DMA32)
5659 *p++ = 'D';
5660 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5661 *p++ = 'a';
5662 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5663 *p++ = 'F';
5664 if (s->flags & SLAB_ACCOUNT)
5665 *p++ = 'A';
5666 if (p != name + 1)
5667 *p++ = '-';
5668 p += sprintf(p, "%07u", s->size);
5669
5670 BUG_ON(p > name + ID_STR_LENGTH - 1);
5671 return name;
5672 }
5673
5674 static int sysfs_slab_add(struct kmem_cache *s)
5675 {
5676 int err;
5677 const char *name;
5678 struct kset *kset = cache_kset(s);
5679 int unmergeable = slab_unmergeable(s);
5680
5681 if (!kset) {
5682 kobject_init(&s->kobj, &slab_ktype);
5683 return 0;
5684 }
5685
5686 if (!unmergeable && disable_higher_order_debug &&
5687 (slub_debug & DEBUG_METADATA_FLAGS))
5688 unmergeable = 1;
5689
5690 if (unmergeable) {
5691 /*
5692 * Slabcache can never be merged so we can use the name proper.
5693 * This is typically the case for debug situations. In that
5694 * case we can catch duplicate names easily.
5695 */
5696 sysfs_remove_link(&slab_kset->kobj, s->name);
5697 name = s->name;
5698 } else {
5699 /*
5700 * Create a unique name for the slab as a target
5701 * for the symlinks.
5702 */
5703 name = create_unique_id(s);
5704 }
5705
5706 s->kobj.kset = kset;
5707 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5708 if (err)
5709 goto out;
5710
5711 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5712 if (err)
5713 goto out_del_kobj;
5714
5715 if (!unmergeable) {
5716 /* Setup first alias */
5717 sysfs_slab_alias(s, s->name);
5718 }
5719 out:
5720 if (!unmergeable)
5721 kfree(name);
5722 return err;
5723 out_del_kobj:
5724 kobject_del(&s->kobj);
5725 goto out;
5726 }
5727
5728 void sysfs_slab_unlink(struct kmem_cache *s)
5729 {
5730 if (slab_state >= FULL)
5731 kobject_del(&s->kobj);
5732 }
5733
5734 void sysfs_slab_release(struct kmem_cache *s)
5735 {
5736 if (slab_state >= FULL)
5737 kobject_put(&s->kobj);
5738 }
5739
5740 /*
5741 * Need to buffer aliases during bootup until sysfs becomes
5742 * available lest we lose that information.
5743 */
5744 struct saved_alias {
5745 struct kmem_cache *s;
5746 const char *name;
5747 struct saved_alias *next;
5748 };
5749
5750 static struct saved_alias *alias_list;
5751
5752 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5753 {
5754 struct saved_alias *al;
5755
5756 if (slab_state == FULL) {
5757 /*
5758 * If we have a leftover link then remove it.
5759 */
5760 sysfs_remove_link(&slab_kset->kobj, name);
5761 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5762 }
5763
5764 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5765 if (!al)
5766 return -ENOMEM;
5767
5768 al->s = s;
5769 al->name = name;
5770 al->next = alias_list;
5771 alias_list = al;
5772 return 0;
5773 }
5774
5775 static int __init slab_sysfs_init(void)
5776 {
5777 struct kmem_cache *s;
5778 int err;
5779
5780 mutex_lock(&slab_mutex);
5781
5782 slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
5783 if (!slab_kset) {
5784 mutex_unlock(&slab_mutex);
5785 pr_err("Cannot register slab subsystem.\n");
5786 return -ENOSYS;
5787 }
5788
5789 slab_state = FULL;
5790
5791 list_for_each_entry(s, &slab_caches, list) {
5792 err = sysfs_slab_add(s);
5793 if (err)
5794 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5795 s->name);
5796 }
5797
5798 while (alias_list) {
5799 struct saved_alias *al = alias_list;
5800
5801 alias_list = alias_list->next;
5802 err = sysfs_slab_alias(al->s, al->name);
5803 if (err)
5804 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5805 al->name);
5806 kfree(al);
5807 }
5808
5809 mutex_unlock(&slab_mutex);
5810 resiliency_test();
5811 return 0;
5812 }
5813
5814 __initcall(slab_sysfs_init);
5815 #endif /* CONFIG_SYSFS */
5816
5817 /*
5818 * The /proc/slabinfo ABI
5819 */
5820 #ifdef CONFIG_SLUB_DEBUG
5821 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5822 {
5823 unsigned long nr_slabs = 0;
5824 unsigned long nr_objs = 0;
5825 unsigned long nr_free = 0;
5826 int node;
5827 struct kmem_cache_node *n;
5828
5829 for_each_kmem_cache_node(s, node, n) {
5830 nr_slabs += node_nr_slabs(n);
5831 nr_objs += node_nr_objs(n);
5832 nr_free += count_partial(n, count_free);
5833 }
5834
5835 sinfo->active_objs = nr_objs - nr_free;
5836 sinfo->num_objs = nr_objs;
5837 sinfo->active_slabs = nr_slabs;
5838 sinfo->num_slabs = nr_slabs;
5839 sinfo->objects_per_slab = oo_objects(s->oo);
5840 sinfo->cache_order = oo_order(s->oo);
5841 }
5842
5843 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5844 {
5845 }
5846
5847 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5848 size_t count, loff_t *ppos)
5849 {
5850 return -EIO;
5851 }
5852 #endif /* CONFIG_SLUB_DEBUG */