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1/*
2 * mm/kmemleak.c
3 *
4 * Copyright (C) 2008 ARM Limited
5 * Written by Catalin Marinas <catalin.marinas@arm.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 *
21 * For more information on the algorithm and kmemleak usage, please see
22 * Documentation/kmemleak.txt.
23 *
24 * Notes on locking
25 * ----------------
26 *
27 * The following locks and mutexes are used by kmemleak:
28 *
29 * - kmemleak_lock (rwlock): protects the object_list modifications and
30 * accesses to the object_tree_root. The object_list is the main list
31 * holding the metadata (struct kmemleak_object) for the allocated memory
85d3a316 32 * blocks. The object_tree_root is a red black tree used to look-up
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33 * metadata based on a pointer to the corresponding memory block. The
34 * kmemleak_object structures are added to the object_list and
35 * object_tree_root in the create_object() function called from the
36 * kmemleak_alloc() callback and removed in delete_object() called from the
37 * kmemleak_free() callback
38 * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
39 * the metadata (e.g. count) are protected by this lock. Note that some
40 * members of this structure may be protected by other means (atomic or
41 * kmemleak_lock). This lock is also held when scanning the corresponding
42 * memory block to avoid the kernel freeing it via the kmemleak_free()
43 * callback. This is less heavyweight than holding a global lock like
44 * kmemleak_lock during scanning
45 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
46 * unreferenced objects at a time. The gray_list contains the objects which
47 * are already referenced or marked as false positives and need to be
48 * scanned. This list is only modified during a scanning episode when the
49 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
50 * Note that the kmemleak_object.use_count is incremented when an object is
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51 * added to the gray_list and therefore cannot be freed. This mutex also
52 * prevents multiple users of the "kmemleak" debugfs file together with
53 * modifications to the memory scanning parameters including the scan_thread
54 * pointer
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55 *
56 * The kmemleak_object structures have a use_count incremented or decremented
57 * using the get_object()/put_object() functions. When the use_count becomes
58 * 0, this count can no longer be incremented and put_object() schedules the
59 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
60 * function must be protected by rcu_read_lock() to avoid accessing a freed
61 * structure.
62 */
63
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64#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
65
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66#include <linux/init.h>
67#include <linux/kernel.h>
68#include <linux/list.h>
69#include <linux/sched.h>
70#include <linux/jiffies.h>
71#include <linux/delay.h>
b95f1b31 72#include <linux/export.h>
3c7b4e6b 73#include <linux/kthread.h>
85d3a316 74#include <linux/rbtree.h>
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75#include <linux/fs.h>
76#include <linux/debugfs.h>
77#include <linux/seq_file.h>
78#include <linux/cpumask.h>
79#include <linux/spinlock.h>
80#include <linux/mutex.h>
81#include <linux/rcupdate.h>
82#include <linux/stacktrace.h>
83#include <linux/cache.h>
84#include <linux/percpu.h>
85#include <linux/hardirq.h>
86#include <linux/mmzone.h>
87#include <linux/slab.h>
88#include <linux/thread_info.h>
89#include <linux/err.h>
90#include <linux/uaccess.h>
91#include <linux/string.h>
92#include <linux/nodemask.h>
93#include <linux/mm.h>
179a8100 94#include <linux/workqueue.h>
04609ccc 95#include <linux/crc32.h>
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96
97#include <asm/sections.h>
98#include <asm/processor.h>
60063497 99#include <linux/atomic.h>
3c7b4e6b 100
8e019366 101#include <linux/kmemcheck.h>
3c7b4e6b 102#include <linux/kmemleak.h>
029aeff5 103#include <linux/memory_hotplug.h>
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104
105/*
106 * Kmemleak configuration and common defines.
107 */
108#define MAX_TRACE 16 /* stack trace length */
3c7b4e6b 109#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
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110#define SECS_FIRST_SCAN 60 /* delay before the first scan */
111#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
af98603d 112#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
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113
114#define BYTES_PER_POINTER sizeof(void *)
115
216c04b0 116/* GFP bitmask for kmemleak internal allocations */
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117#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
118 __GFP_NORETRY | __GFP_NOMEMALLOC | \
119 __GFP_NOWARN)
216c04b0 120
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121/* scanning area inside a memory block */
122struct kmemleak_scan_area {
123 struct hlist_node node;
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124 unsigned long start;
125 size_t size;
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126};
127
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128#define KMEMLEAK_GREY 0
129#define KMEMLEAK_BLACK -1
130
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131/*
132 * Structure holding the metadata for each allocated memory block.
133 * Modifications to such objects should be made while holding the
134 * object->lock. Insertions or deletions from object_list, gray_list or
85d3a316 135 * rb_node are already protected by the corresponding locks or mutex (see
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136 * the notes on locking above). These objects are reference-counted
137 * (use_count) and freed using the RCU mechanism.
138 */
139struct kmemleak_object {
140 spinlock_t lock;
141 unsigned long flags; /* object status flags */
142 struct list_head object_list;
143 struct list_head gray_list;
85d3a316 144 struct rb_node rb_node;
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145 struct rcu_head rcu; /* object_list lockless traversal */
146 /* object usage count; object freed when use_count == 0 */
147 atomic_t use_count;
148 unsigned long pointer;
149 size_t size;
150 /* minimum number of a pointers found before it is considered leak */
151 int min_count;
152 /* the total number of pointers found pointing to this object */
153 int count;
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154 /* checksum for detecting modified objects */
155 u32 checksum;
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156 /* memory ranges to be scanned inside an object (empty for all) */
157 struct hlist_head area_list;
158 unsigned long trace[MAX_TRACE];
159 unsigned int trace_len;
160 unsigned long jiffies; /* creation timestamp */
161 pid_t pid; /* pid of the current task */
162 char comm[TASK_COMM_LEN]; /* executable name */
163};
164
165/* flag representing the memory block allocation status */
166#define OBJECT_ALLOCATED (1 << 0)
167/* flag set after the first reporting of an unreference object */
168#define OBJECT_REPORTED (1 << 1)
169/* flag set to not scan the object */
170#define OBJECT_NO_SCAN (1 << 2)
171
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172/* number of bytes to print per line; must be 16 or 32 */
173#define HEX_ROW_SIZE 16
174/* number of bytes to print at a time (1, 2, 4, 8) */
175#define HEX_GROUP_SIZE 1
176/* include ASCII after the hex output */
177#define HEX_ASCII 1
178/* max number of lines to be printed */
179#define HEX_MAX_LINES 2
180
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181/* the list of all allocated objects */
182static LIST_HEAD(object_list);
183/* the list of gray-colored objects (see color_gray comment below) */
184static LIST_HEAD(gray_list);
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185/* search tree for object boundaries */
186static struct rb_root object_tree_root = RB_ROOT;
187/* rw_lock protecting the access to object_list and object_tree_root */
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188static DEFINE_RWLOCK(kmemleak_lock);
189
190/* allocation caches for kmemleak internal data */
191static struct kmem_cache *object_cache;
192static struct kmem_cache *scan_area_cache;
193
194/* set if tracing memory operations is enabled */
8910ae89 195static int kmemleak_enabled;
3c7b4e6b 196/* set in the late_initcall if there were no errors */
8910ae89 197static int kmemleak_initialized;
3c7b4e6b 198/* enables or disables early logging of the memory operations */
8910ae89 199static int kmemleak_early_log = 1;
5f79020c 200/* set if a kmemleak warning was issued */
8910ae89 201static int kmemleak_warning;
5f79020c 202/* set if a fatal kmemleak error has occurred */
8910ae89 203static int kmemleak_error;
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204
205/* minimum and maximum address that may be valid pointers */
206static unsigned long min_addr = ULONG_MAX;
207static unsigned long max_addr;
208
3c7b4e6b 209static struct task_struct *scan_thread;
acf4968e 210/* used to avoid reporting of recently allocated objects */
3c7b4e6b 211static unsigned long jiffies_min_age;
acf4968e 212static unsigned long jiffies_last_scan;
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213/* delay between automatic memory scannings */
214static signed long jiffies_scan_wait;
215/* enables or disables the task stacks scanning */
e0a2a160 216static int kmemleak_stack_scan = 1;
4698c1f2 217/* protects the memory scanning, parameters and debug/kmemleak file access */
3c7b4e6b 218static DEFINE_MUTEX(scan_mutex);
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219/* setting kmemleak=on, will set this var, skipping the disable */
220static int kmemleak_skip_disable;
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221/* If there are leaks that can be reported */
222static bool kmemleak_found_leaks;
3c7b4e6b 223
3c7b4e6b 224/*
2030117d 225 * Early object allocation/freeing logging. Kmemleak is initialized after the
3c7b4e6b 226 * kernel allocator. However, both the kernel allocator and kmemleak may
2030117d 227 * allocate memory blocks which need to be tracked. Kmemleak defines an
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228 * arbitrary buffer to hold the allocation/freeing information before it is
229 * fully initialized.
230 */
231
232/* kmemleak operation type for early logging */
233enum {
234 KMEMLEAK_ALLOC,
f528f0b8 235 KMEMLEAK_ALLOC_PERCPU,
3c7b4e6b 236 KMEMLEAK_FREE,
53238a60 237 KMEMLEAK_FREE_PART,
f528f0b8 238 KMEMLEAK_FREE_PERCPU,
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239 KMEMLEAK_NOT_LEAK,
240 KMEMLEAK_IGNORE,
241 KMEMLEAK_SCAN_AREA,
242 KMEMLEAK_NO_SCAN
243};
244
245/*
246 * Structure holding the information passed to kmemleak callbacks during the
247 * early logging.
248 */
249struct early_log {
250 int op_type; /* kmemleak operation type */
251 const void *ptr; /* allocated/freed memory block */
252 size_t size; /* memory block size */
253 int min_count; /* minimum reference count */
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254 unsigned long trace[MAX_TRACE]; /* stack trace */
255 unsigned int trace_len; /* stack trace length */
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256};
257
258/* early logging buffer and current position */
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259static struct early_log
260 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
261static int crt_early_log __initdata;
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262
263static void kmemleak_disable(void);
264
265/*
266 * Print a warning and dump the stack trace.
267 */
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268#define kmemleak_warn(x...) do { \
269 pr_warning(x); \
270 dump_stack(); \
8910ae89 271 kmemleak_warning = 1; \
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272} while (0)
273
274/*
25985edc 275 * Macro invoked when a serious kmemleak condition occurred and cannot be
2030117d 276 * recovered from. Kmemleak will be disabled and further allocation/freeing
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277 * tracing no longer available.
278 */
000814f4 279#define kmemleak_stop(x...) do { \
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280 kmemleak_warn(x); \
281 kmemleak_disable(); \
282} while (0)
283
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284/*
285 * Printing of the objects hex dump to the seq file. The number of lines to be
286 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
287 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
288 * with the object->lock held.
289 */
290static void hex_dump_object(struct seq_file *seq,
291 struct kmemleak_object *object)
292{
293 const u8 *ptr = (const u8 *)object->pointer;
294 int i, len, remaining;
295 unsigned char linebuf[HEX_ROW_SIZE * 5];
296
297 /* limit the number of lines to HEX_MAX_LINES */
298 remaining = len =
299 min(object->size, (size_t)(HEX_MAX_LINES * HEX_ROW_SIZE));
300
301 seq_printf(seq, " hex dump (first %d bytes):\n", len);
302 for (i = 0; i < len; i += HEX_ROW_SIZE) {
303 int linelen = min(remaining, HEX_ROW_SIZE);
304
305 remaining -= HEX_ROW_SIZE;
306 hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE,
307 HEX_GROUP_SIZE, linebuf, sizeof(linebuf),
308 HEX_ASCII);
309 seq_printf(seq, " %s\n", linebuf);
310 }
311}
312
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313/*
314 * Object colors, encoded with count and min_count:
315 * - white - orphan object, not enough references to it (count < min_count)
316 * - gray - not orphan, not marked as false positive (min_count == 0) or
317 * sufficient references to it (count >= min_count)
318 * - black - ignore, it doesn't contain references (e.g. text section)
319 * (min_count == -1). No function defined for this color.
320 * Newly created objects don't have any color assigned (object->count == -1)
321 * before the next memory scan when they become white.
322 */
4a558dd6 323static bool color_white(const struct kmemleak_object *object)
3c7b4e6b 324{
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325 return object->count != KMEMLEAK_BLACK &&
326 object->count < object->min_count;
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327}
328
4a558dd6 329static bool color_gray(const struct kmemleak_object *object)
3c7b4e6b 330{
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331 return object->min_count != KMEMLEAK_BLACK &&
332 object->count >= object->min_count;
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333}
334
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335/*
336 * Objects are considered unreferenced only if their color is white, they have
337 * not be deleted and have a minimum age to avoid false positives caused by
338 * pointers temporarily stored in CPU registers.
339 */
4a558dd6 340static bool unreferenced_object(struct kmemleak_object *object)
3c7b4e6b 341{
04609ccc 342 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
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343 time_before_eq(object->jiffies + jiffies_min_age,
344 jiffies_last_scan);
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345}
346
347/*
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348 * Printing of the unreferenced objects information to the seq file. The
349 * print_unreferenced function must be called with the object->lock held.
3c7b4e6b 350 */
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351static void print_unreferenced(struct seq_file *seq,
352 struct kmemleak_object *object)
353{
354 int i;
fefdd336 355 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
3c7b4e6b 356
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357 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
358 object->pointer, object->size);
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359 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
360 object->comm, object->pid, object->jiffies,
361 msecs_age / 1000, msecs_age % 1000);
0494e082 362 hex_dump_object(seq, object);
bab4a34a 363 seq_printf(seq, " backtrace:\n");
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364
365 for (i = 0; i < object->trace_len; i++) {
366 void *ptr = (void *)object->trace[i];
bab4a34a 367 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
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368 }
369}
370
371/*
372 * Print the kmemleak_object information. This function is used mainly for
373 * debugging special cases when kmemleak operations. It must be called with
374 * the object->lock held.
375 */
376static void dump_object_info(struct kmemleak_object *object)
377{
378 struct stack_trace trace;
379
380 trace.nr_entries = object->trace_len;
381 trace.entries = object->trace;
382
ae281064 383 pr_notice("Object 0x%08lx (size %zu):\n",
85d3a316 384 object->pointer, object->size);
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385 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
386 object->comm, object->pid, object->jiffies);
387 pr_notice(" min_count = %d\n", object->min_count);
388 pr_notice(" count = %d\n", object->count);
189d84ed 389 pr_notice(" flags = 0x%lx\n", object->flags);
aae0ad7a 390 pr_notice(" checksum = %u\n", object->checksum);
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391 pr_notice(" backtrace:\n");
392 print_stack_trace(&trace, 4);
393}
394
395/*
85d3a316 396 * Look-up a memory block metadata (kmemleak_object) in the object search
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397 * tree based on a pointer value. If alias is 0, only values pointing to the
398 * beginning of the memory block are allowed. The kmemleak_lock must be held
399 * when calling this function.
400 */
401static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
402{
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403 struct rb_node *rb = object_tree_root.rb_node;
404
405 while (rb) {
406 struct kmemleak_object *object =
407 rb_entry(rb, struct kmemleak_object, rb_node);
408 if (ptr < object->pointer)
409 rb = object->rb_node.rb_left;
410 else if (object->pointer + object->size <= ptr)
411 rb = object->rb_node.rb_right;
412 else if (object->pointer == ptr || alias)
413 return object;
414 else {
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415 kmemleak_warn("Found object by alias at 0x%08lx\n",
416 ptr);
a7686a45 417 dump_object_info(object);
85d3a316 418 break;
3c7b4e6b 419 }
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420 }
421 return NULL;
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422}
423
424/*
425 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
426 * that once an object's use_count reached 0, the RCU freeing was already
427 * registered and the object should no longer be used. This function must be
428 * called under the protection of rcu_read_lock().
429 */
430static int get_object(struct kmemleak_object *object)
431{
432 return atomic_inc_not_zero(&object->use_count);
433}
434
435/*
436 * RCU callback to free a kmemleak_object.
437 */
438static void free_object_rcu(struct rcu_head *rcu)
439{
b67bfe0d 440 struct hlist_node *tmp;
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441 struct kmemleak_scan_area *area;
442 struct kmemleak_object *object =
443 container_of(rcu, struct kmemleak_object, rcu);
444
445 /*
446 * Once use_count is 0 (guaranteed by put_object), there is no other
447 * code accessing this object, hence no need for locking.
448 */
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449 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
450 hlist_del(&area->node);
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451 kmem_cache_free(scan_area_cache, area);
452 }
453 kmem_cache_free(object_cache, object);
454}
455
456/*
457 * Decrement the object use_count. Once the count is 0, free the object using
458 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
459 * delete_object() path, the delayed RCU freeing ensures that there is no
460 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
461 * is also possible.
462 */
463static void put_object(struct kmemleak_object *object)
464{
465 if (!atomic_dec_and_test(&object->use_count))
466 return;
467
468 /* should only get here after delete_object was called */
469 WARN_ON(object->flags & OBJECT_ALLOCATED);
470
471 call_rcu(&object->rcu, free_object_rcu);
472}
473
474/*
85d3a316 475 * Look up an object in the object search tree and increase its use_count.
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476 */
477static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
478{
479 unsigned long flags;
480 struct kmemleak_object *object = NULL;
481
482 rcu_read_lock();
483 read_lock_irqsave(&kmemleak_lock, flags);
484 if (ptr >= min_addr && ptr < max_addr)
485 object = lookup_object(ptr, alias);
486 read_unlock_irqrestore(&kmemleak_lock, flags);
487
488 /* check whether the object is still available */
489 if (object && !get_object(object))
490 object = NULL;
491 rcu_read_unlock();
492
493 return object;
494}
495
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496/*
497 * Save stack trace to the given array of MAX_TRACE size.
498 */
499static int __save_stack_trace(unsigned long *trace)
500{
501 struct stack_trace stack_trace;
502
503 stack_trace.max_entries = MAX_TRACE;
504 stack_trace.nr_entries = 0;
505 stack_trace.entries = trace;
506 stack_trace.skip = 2;
507 save_stack_trace(&stack_trace);
508
509 return stack_trace.nr_entries;
510}
511
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512/*
513 * Create the metadata (struct kmemleak_object) corresponding to an allocated
514 * memory block and add it to the object_list and object_tree_root.
515 */
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516static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
517 int min_count, gfp_t gfp)
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518{
519 unsigned long flags;
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520 struct kmemleak_object *object, *parent;
521 struct rb_node **link, *rb_parent;
3c7b4e6b 522
6ae4bd1f 523 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
3c7b4e6b 524 if (!object) {
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525 pr_warning("Cannot allocate a kmemleak_object structure\n");
526 kmemleak_disable();
fd678967 527 return NULL;
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528 }
529
530 INIT_LIST_HEAD(&object->object_list);
531 INIT_LIST_HEAD(&object->gray_list);
532 INIT_HLIST_HEAD(&object->area_list);
533 spin_lock_init(&object->lock);
534 atomic_set(&object->use_count, 1);
04609ccc 535 object->flags = OBJECT_ALLOCATED;
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536 object->pointer = ptr;
537 object->size = size;
538 object->min_count = min_count;
04609ccc 539 object->count = 0; /* white color initially */
3c7b4e6b 540 object->jiffies = jiffies;
04609ccc 541 object->checksum = 0;
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542
543 /* task information */
544 if (in_irq()) {
545 object->pid = 0;
546 strncpy(object->comm, "hardirq", sizeof(object->comm));
547 } else if (in_softirq()) {
548 object->pid = 0;
549 strncpy(object->comm, "softirq", sizeof(object->comm));
550 } else {
551 object->pid = current->pid;
552 /*
553 * There is a small chance of a race with set_task_comm(),
554 * however using get_task_comm() here may cause locking
555 * dependency issues with current->alloc_lock. In the worst
556 * case, the command line is not correct.
557 */
558 strncpy(object->comm, current->comm, sizeof(object->comm));
559 }
560
561 /* kernel backtrace */
fd678967 562 object->trace_len = __save_stack_trace(object->trace);
3c7b4e6b 563
3c7b4e6b 564 write_lock_irqsave(&kmemleak_lock, flags);
0580a181 565
3c7b4e6b
CM
566 min_addr = min(min_addr, ptr);
567 max_addr = max(max_addr, ptr + size);
85d3a316
ML
568 link = &object_tree_root.rb_node;
569 rb_parent = NULL;
570 while (*link) {
571 rb_parent = *link;
572 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
573 if (ptr + size <= parent->pointer)
574 link = &parent->rb_node.rb_left;
575 else if (parent->pointer + parent->size <= ptr)
576 link = &parent->rb_node.rb_right;
577 else {
578 kmemleak_stop("Cannot insert 0x%lx into the object "
579 "search tree (overlaps existing)\n",
580 ptr);
581 kmem_cache_free(object_cache, object);
582 object = parent;
583 spin_lock(&object->lock);
584 dump_object_info(object);
585 spin_unlock(&object->lock);
586 goto out;
587 }
3c7b4e6b 588 }
85d3a316
ML
589 rb_link_node(&object->rb_node, rb_parent, link);
590 rb_insert_color(&object->rb_node, &object_tree_root);
591
3c7b4e6b
CM
592 list_add_tail_rcu(&object->object_list, &object_list);
593out:
594 write_unlock_irqrestore(&kmemleak_lock, flags);
fd678967 595 return object;
3c7b4e6b
CM
596}
597
598/*
599 * Remove the metadata (struct kmemleak_object) for a memory block from the
600 * object_list and object_tree_root and decrement its use_count.
601 */
53238a60 602static void __delete_object(struct kmemleak_object *object)
3c7b4e6b
CM
603{
604 unsigned long flags;
3c7b4e6b
CM
605
606 write_lock_irqsave(&kmemleak_lock, flags);
85d3a316 607 rb_erase(&object->rb_node, &object_tree_root);
3c7b4e6b
CM
608 list_del_rcu(&object->object_list);
609 write_unlock_irqrestore(&kmemleak_lock, flags);
610
611 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
53238a60 612 WARN_ON(atomic_read(&object->use_count) < 2);
3c7b4e6b
CM
613
614 /*
615 * Locking here also ensures that the corresponding memory block
616 * cannot be freed when it is being scanned.
617 */
618 spin_lock_irqsave(&object->lock, flags);
3c7b4e6b
CM
619 object->flags &= ~OBJECT_ALLOCATED;
620 spin_unlock_irqrestore(&object->lock, flags);
621 put_object(object);
622}
623
53238a60
CM
624/*
625 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
626 * delete it.
627 */
628static void delete_object_full(unsigned long ptr)
629{
630 struct kmemleak_object *object;
631
632 object = find_and_get_object(ptr, 0);
633 if (!object) {
634#ifdef DEBUG
635 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
636 ptr);
637#endif
638 return;
639 }
640 __delete_object(object);
641 put_object(object);
642}
643
644/*
645 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
646 * delete it. If the memory block is partially freed, the function may create
647 * additional metadata for the remaining parts of the block.
648 */
649static void delete_object_part(unsigned long ptr, size_t size)
650{
651 struct kmemleak_object *object;
652 unsigned long start, end;
653
654 object = find_and_get_object(ptr, 1);
655 if (!object) {
656#ifdef DEBUG
657 kmemleak_warn("Partially freeing unknown object at 0x%08lx "
658 "(size %zu)\n", ptr, size);
659#endif
660 return;
661 }
662 __delete_object(object);
663
664 /*
665 * Create one or two objects that may result from the memory block
666 * split. Note that partial freeing is only done by free_bootmem() and
667 * this happens before kmemleak_init() is called. The path below is
668 * only executed during early log recording in kmemleak_init(), so
669 * GFP_KERNEL is enough.
670 */
671 start = object->pointer;
672 end = object->pointer + object->size;
673 if (ptr > start)
674 create_object(start, ptr - start, object->min_count,
675 GFP_KERNEL);
676 if (ptr + size < end)
677 create_object(ptr + size, end - ptr - size, object->min_count,
678 GFP_KERNEL);
679
680 put_object(object);
681}
a1084c87
LR
682
683static void __paint_it(struct kmemleak_object *object, int color)
684{
685 object->min_count = color;
686 if (color == KMEMLEAK_BLACK)
687 object->flags |= OBJECT_NO_SCAN;
688}
689
690static void paint_it(struct kmemleak_object *object, int color)
3c7b4e6b
CM
691{
692 unsigned long flags;
a1084c87
LR
693
694 spin_lock_irqsave(&object->lock, flags);
695 __paint_it(object, color);
696 spin_unlock_irqrestore(&object->lock, flags);
697}
698
699static void paint_ptr(unsigned long ptr, int color)
700{
3c7b4e6b
CM
701 struct kmemleak_object *object;
702
703 object = find_and_get_object(ptr, 0);
704 if (!object) {
a1084c87
LR
705 kmemleak_warn("Trying to color unknown object "
706 "at 0x%08lx as %s\n", ptr,
707 (color == KMEMLEAK_GREY) ? "Grey" :
708 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
3c7b4e6b
CM
709 return;
710 }
a1084c87 711 paint_it(object, color);
3c7b4e6b
CM
712 put_object(object);
713}
714
a1084c87 715/*
145b64b9 716 * Mark an object permanently as gray-colored so that it can no longer be
a1084c87
LR
717 * reported as a leak. This is used in general to mark a false positive.
718 */
719static void make_gray_object(unsigned long ptr)
720{
721 paint_ptr(ptr, KMEMLEAK_GREY);
722}
723
3c7b4e6b
CM
724/*
725 * Mark the object as black-colored so that it is ignored from scans and
726 * reporting.
727 */
728static void make_black_object(unsigned long ptr)
729{
a1084c87 730 paint_ptr(ptr, KMEMLEAK_BLACK);
3c7b4e6b
CM
731}
732
733/*
734 * Add a scanning area to the object. If at least one such area is added,
735 * kmemleak will only scan these ranges rather than the whole memory block.
736 */
c017b4be 737static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
3c7b4e6b
CM
738{
739 unsigned long flags;
740 struct kmemleak_object *object;
741 struct kmemleak_scan_area *area;
742
c017b4be 743 object = find_and_get_object(ptr, 1);
3c7b4e6b 744 if (!object) {
ae281064
JP
745 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
746 ptr);
3c7b4e6b
CM
747 return;
748 }
749
6ae4bd1f 750 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
3c7b4e6b 751 if (!area) {
6ae4bd1f 752 pr_warning("Cannot allocate a scan area\n");
3c7b4e6b
CM
753 goto out;
754 }
755
756 spin_lock_irqsave(&object->lock, flags);
7f88f88f
CM
757 if (size == SIZE_MAX) {
758 size = object->pointer + object->size - ptr;
759 } else if (ptr + size > object->pointer + object->size) {
ae281064 760 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
3c7b4e6b
CM
761 dump_object_info(object);
762 kmem_cache_free(scan_area_cache, area);
763 goto out_unlock;
764 }
765
766 INIT_HLIST_NODE(&area->node);
c017b4be
CM
767 area->start = ptr;
768 area->size = size;
3c7b4e6b
CM
769
770 hlist_add_head(&area->node, &object->area_list);
771out_unlock:
772 spin_unlock_irqrestore(&object->lock, flags);
773out:
774 put_object(object);
775}
776
777/*
778 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
779 * pointer. Such object will not be scanned by kmemleak but references to it
780 * are searched.
781 */
782static void object_no_scan(unsigned long ptr)
783{
784 unsigned long flags;
785 struct kmemleak_object *object;
786
787 object = find_and_get_object(ptr, 0);
788 if (!object) {
ae281064 789 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
3c7b4e6b
CM
790 return;
791 }
792
793 spin_lock_irqsave(&object->lock, flags);
794 object->flags |= OBJECT_NO_SCAN;
795 spin_unlock_irqrestore(&object->lock, flags);
796 put_object(object);
797}
798
799/*
800 * Log an early kmemleak_* call to the early_log buffer. These calls will be
801 * processed later once kmemleak is fully initialized.
802 */
a6186d89 803static void __init log_early(int op_type, const void *ptr, size_t size,
c017b4be 804 int min_count)
3c7b4e6b
CM
805{
806 unsigned long flags;
807 struct early_log *log;
808
8910ae89 809 if (kmemleak_error) {
b6693005
CM
810 /* kmemleak stopped recording, just count the requests */
811 crt_early_log++;
812 return;
813 }
814
3c7b4e6b 815 if (crt_early_log >= ARRAY_SIZE(early_log)) {
a9d9058a 816 kmemleak_disable();
3c7b4e6b
CM
817 return;
818 }
819
820 /*
821 * There is no need for locking since the kernel is still in UP mode
822 * at this stage. Disabling the IRQs is enough.
823 */
824 local_irq_save(flags);
825 log = &early_log[crt_early_log];
826 log->op_type = op_type;
827 log->ptr = ptr;
828 log->size = size;
829 log->min_count = min_count;
5f79020c 830 log->trace_len = __save_stack_trace(log->trace);
3c7b4e6b
CM
831 crt_early_log++;
832 local_irq_restore(flags);
833}
834
fd678967
CM
835/*
836 * Log an early allocated block and populate the stack trace.
837 */
838static void early_alloc(struct early_log *log)
839{
840 struct kmemleak_object *object;
841 unsigned long flags;
842 int i;
843
8910ae89 844 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
fd678967
CM
845 return;
846
847 /*
848 * RCU locking needed to ensure object is not freed via put_object().
849 */
850 rcu_read_lock();
851 object = create_object((unsigned long)log->ptr, log->size,
c1bcd6b3 852 log->min_count, GFP_ATOMIC);
0d5d1aad
CM
853 if (!object)
854 goto out;
fd678967
CM
855 spin_lock_irqsave(&object->lock, flags);
856 for (i = 0; i < log->trace_len; i++)
857 object->trace[i] = log->trace[i];
858 object->trace_len = log->trace_len;
859 spin_unlock_irqrestore(&object->lock, flags);
0d5d1aad 860out:
fd678967
CM
861 rcu_read_unlock();
862}
863
f528f0b8
CM
864/*
865 * Log an early allocated block and populate the stack trace.
866 */
867static void early_alloc_percpu(struct early_log *log)
868{
869 unsigned int cpu;
870 const void __percpu *ptr = log->ptr;
871
872 for_each_possible_cpu(cpu) {
873 log->ptr = per_cpu_ptr(ptr, cpu);
874 early_alloc(log);
875 }
876}
877
a2b6bf63
CM
878/**
879 * kmemleak_alloc - register a newly allocated object
880 * @ptr: pointer to beginning of the object
881 * @size: size of the object
882 * @min_count: minimum number of references to this object. If during memory
883 * scanning a number of references less than @min_count is found,
884 * the object is reported as a memory leak. If @min_count is 0,
885 * the object is never reported as a leak. If @min_count is -1,
886 * the object is ignored (not scanned and not reported as a leak)
887 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
888 *
889 * This function is called from the kernel allocators when a new object
890 * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
3c7b4e6b 891 */
a6186d89
CM
892void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
893 gfp_t gfp)
3c7b4e6b
CM
894{
895 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
896
8910ae89 897 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
3c7b4e6b 898 create_object((unsigned long)ptr, size, min_count, gfp);
8910ae89 899 else if (kmemleak_early_log)
c017b4be 900 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
3c7b4e6b
CM
901}
902EXPORT_SYMBOL_GPL(kmemleak_alloc);
903
f528f0b8
CM
904/**
905 * kmemleak_alloc_percpu - register a newly allocated __percpu object
906 * @ptr: __percpu pointer to beginning of the object
907 * @size: size of the object
908 *
909 * This function is called from the kernel percpu allocator when a new object
910 * (memory block) is allocated (alloc_percpu). It assumes GFP_KERNEL
911 * allocation.
912 */
913void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size)
914{
915 unsigned int cpu;
916
917 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
918
919 /*
920 * Percpu allocations are only scanned and not reported as leaks
921 * (min_count is set to 0).
922 */
8910ae89 923 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
f528f0b8
CM
924 for_each_possible_cpu(cpu)
925 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
926 size, 0, GFP_KERNEL);
8910ae89 927 else if (kmemleak_early_log)
f528f0b8
CM
928 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
929}
930EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
931
a2b6bf63
CM
932/**
933 * kmemleak_free - unregister a previously registered object
934 * @ptr: pointer to beginning of the object
935 *
936 * This function is called from the kernel allocators when an object (memory
937 * block) is freed (kmem_cache_free, kfree, vfree etc.).
3c7b4e6b 938 */
a6186d89 939void __ref kmemleak_free(const void *ptr)
3c7b4e6b
CM
940{
941 pr_debug("%s(0x%p)\n", __func__, ptr);
942
8910ae89 943 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
53238a60 944 delete_object_full((unsigned long)ptr);
8910ae89 945 else if (kmemleak_early_log)
c017b4be 946 log_early(KMEMLEAK_FREE, ptr, 0, 0);
3c7b4e6b
CM
947}
948EXPORT_SYMBOL_GPL(kmemleak_free);
949
a2b6bf63
CM
950/**
951 * kmemleak_free_part - partially unregister a previously registered object
952 * @ptr: pointer to the beginning or inside the object. This also
953 * represents the start of the range to be freed
954 * @size: size to be unregistered
955 *
956 * This function is called when only a part of a memory block is freed
957 * (usually from the bootmem allocator).
53238a60 958 */
a6186d89 959void __ref kmemleak_free_part(const void *ptr, size_t size)
53238a60
CM
960{
961 pr_debug("%s(0x%p)\n", __func__, ptr);
962
8910ae89 963 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
53238a60 964 delete_object_part((unsigned long)ptr, size);
8910ae89 965 else if (kmemleak_early_log)
c017b4be 966 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
53238a60
CM
967}
968EXPORT_SYMBOL_GPL(kmemleak_free_part);
969
f528f0b8
CM
970/**
971 * kmemleak_free_percpu - unregister a previously registered __percpu object
972 * @ptr: __percpu pointer to beginning of the object
973 *
974 * This function is called from the kernel percpu allocator when an object
975 * (memory block) is freed (free_percpu).
976 */
977void __ref kmemleak_free_percpu(const void __percpu *ptr)
978{
979 unsigned int cpu;
980
981 pr_debug("%s(0x%p)\n", __func__, ptr);
982
8910ae89 983 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
f528f0b8
CM
984 for_each_possible_cpu(cpu)
985 delete_object_full((unsigned long)per_cpu_ptr(ptr,
986 cpu));
8910ae89 987 else if (kmemleak_early_log)
f528f0b8
CM
988 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
989}
990EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
991
ffe2c748
CM
992/**
993 * kmemleak_update_trace - update object allocation stack trace
994 * @ptr: pointer to beginning of the object
995 *
996 * Override the object allocation stack trace for cases where the actual
997 * allocation place is not always useful.
998 */
999void __ref kmemleak_update_trace(const void *ptr)
1000{
1001 struct kmemleak_object *object;
1002 unsigned long flags;
1003
1004 pr_debug("%s(0x%p)\n", __func__, ptr);
1005
1006 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1007 return;
1008
1009 object = find_and_get_object((unsigned long)ptr, 1);
1010 if (!object) {
1011#ifdef DEBUG
1012 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1013 ptr);
1014#endif
1015 return;
1016 }
1017
1018 spin_lock_irqsave(&object->lock, flags);
1019 object->trace_len = __save_stack_trace(object->trace);
1020 spin_unlock_irqrestore(&object->lock, flags);
1021
1022 put_object(object);
1023}
1024EXPORT_SYMBOL(kmemleak_update_trace);
1025
a2b6bf63
CM
1026/**
1027 * kmemleak_not_leak - mark an allocated object as false positive
1028 * @ptr: pointer to beginning of the object
1029 *
1030 * Calling this function on an object will cause the memory block to no longer
1031 * be reported as leak and always be scanned.
3c7b4e6b 1032 */
a6186d89 1033void __ref kmemleak_not_leak(const void *ptr)
3c7b4e6b
CM
1034{
1035 pr_debug("%s(0x%p)\n", __func__, ptr);
1036
8910ae89 1037 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
3c7b4e6b 1038 make_gray_object((unsigned long)ptr);
8910ae89 1039 else if (kmemleak_early_log)
c017b4be 1040 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
3c7b4e6b
CM
1041}
1042EXPORT_SYMBOL(kmemleak_not_leak);
1043
a2b6bf63
CM
1044/**
1045 * kmemleak_ignore - ignore an allocated object
1046 * @ptr: pointer to beginning of the object
1047 *
1048 * Calling this function on an object will cause the memory block to be
1049 * ignored (not scanned and not reported as a leak). This is usually done when
1050 * it is known that the corresponding block is not a leak and does not contain
1051 * any references to other allocated memory blocks.
3c7b4e6b 1052 */
a6186d89 1053void __ref kmemleak_ignore(const void *ptr)
3c7b4e6b
CM
1054{
1055 pr_debug("%s(0x%p)\n", __func__, ptr);
1056
8910ae89 1057 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
3c7b4e6b 1058 make_black_object((unsigned long)ptr);
8910ae89 1059 else if (kmemleak_early_log)
c017b4be 1060 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
3c7b4e6b
CM
1061}
1062EXPORT_SYMBOL(kmemleak_ignore);
1063
a2b6bf63
CM
1064/**
1065 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1066 * @ptr: pointer to beginning or inside the object. This also
1067 * represents the start of the scan area
1068 * @size: size of the scan area
1069 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1070 *
1071 * This function is used when it is known that only certain parts of an object
1072 * contain references to other objects. Kmemleak will only scan these areas
1073 * reducing the number false negatives.
3c7b4e6b 1074 */
c017b4be 1075void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
3c7b4e6b
CM
1076{
1077 pr_debug("%s(0x%p)\n", __func__, ptr);
1078
8910ae89 1079 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
c017b4be 1080 add_scan_area((unsigned long)ptr, size, gfp);
8910ae89 1081 else if (kmemleak_early_log)
c017b4be 1082 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
3c7b4e6b
CM
1083}
1084EXPORT_SYMBOL(kmemleak_scan_area);
1085
a2b6bf63
CM
1086/**
1087 * kmemleak_no_scan - do not scan an allocated object
1088 * @ptr: pointer to beginning of the object
1089 *
1090 * This function notifies kmemleak not to scan the given memory block. Useful
1091 * in situations where it is known that the given object does not contain any
1092 * references to other objects. Kmemleak will not scan such objects reducing
1093 * the number of false negatives.
3c7b4e6b 1094 */
a6186d89 1095void __ref kmemleak_no_scan(const void *ptr)
3c7b4e6b
CM
1096{
1097 pr_debug("%s(0x%p)\n", __func__, ptr);
1098
8910ae89 1099 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
3c7b4e6b 1100 object_no_scan((unsigned long)ptr);
8910ae89 1101 else if (kmemleak_early_log)
c017b4be 1102 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
3c7b4e6b
CM
1103}
1104EXPORT_SYMBOL(kmemleak_no_scan);
1105
04609ccc
CM
1106/*
1107 * Update an object's checksum and return true if it was modified.
1108 */
1109static bool update_checksum(struct kmemleak_object *object)
1110{
1111 u32 old_csum = object->checksum;
1112
1113 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1114 return false;
1115
1116 object->checksum = crc32(0, (void *)object->pointer, object->size);
1117 return object->checksum != old_csum;
1118}
1119
3c7b4e6b
CM
1120/*
1121 * Memory scanning is a long process and it needs to be interruptable. This
25985edc 1122 * function checks whether such interrupt condition occurred.
3c7b4e6b
CM
1123 */
1124static int scan_should_stop(void)
1125{
8910ae89 1126 if (!kmemleak_enabled)
3c7b4e6b
CM
1127 return 1;
1128
1129 /*
1130 * This function may be called from either process or kthread context,
1131 * hence the need to check for both stop conditions.
1132 */
1133 if (current->mm)
1134 return signal_pending(current);
1135 else
1136 return kthread_should_stop();
1137
1138 return 0;
1139}
1140
1141/*
1142 * Scan a memory block (exclusive range) for valid pointers and add those
1143 * found to the gray list.
1144 */
1145static void scan_block(void *_start, void *_end,
4b8a9674 1146 struct kmemleak_object *scanned, int allow_resched)
3c7b4e6b
CM
1147{
1148 unsigned long *ptr;
1149 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1150 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
1151
1152 for (ptr = start; ptr < end; ptr++) {
3c7b4e6b 1153 struct kmemleak_object *object;
8e019366
PE
1154 unsigned long flags;
1155 unsigned long pointer;
3c7b4e6b 1156
4b8a9674
CM
1157 if (allow_resched)
1158 cond_resched();
3c7b4e6b
CM
1159 if (scan_should_stop())
1160 break;
1161
8e019366
PE
1162 /* don't scan uninitialized memory */
1163 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1164 BYTES_PER_POINTER))
1165 continue;
1166
1167 pointer = *ptr;
1168
3c7b4e6b
CM
1169 object = find_and_get_object(pointer, 1);
1170 if (!object)
1171 continue;
1172 if (object == scanned) {
1173 /* self referenced, ignore */
1174 put_object(object);
1175 continue;
1176 }
1177
1178 /*
1179 * Avoid the lockdep recursive warning on object->lock being
1180 * previously acquired in scan_object(). These locks are
1181 * enclosed by scan_mutex.
1182 */
1183 spin_lock_irqsave_nested(&object->lock, flags,
1184 SINGLE_DEPTH_NESTING);
1185 if (!color_white(object)) {
1186 /* non-orphan, ignored or new */
1187 spin_unlock_irqrestore(&object->lock, flags);
1188 put_object(object);
1189 continue;
1190 }
1191
1192 /*
1193 * Increase the object's reference count (number of pointers
1194 * to the memory block). If this count reaches the required
1195 * minimum, the object's color will become gray and it will be
1196 * added to the gray_list.
1197 */
1198 object->count++;
0587da40 1199 if (color_gray(object)) {
3c7b4e6b 1200 list_add_tail(&object->gray_list, &gray_list);
0587da40
CM
1201 spin_unlock_irqrestore(&object->lock, flags);
1202 continue;
1203 }
1204
3c7b4e6b 1205 spin_unlock_irqrestore(&object->lock, flags);
0587da40 1206 put_object(object);
3c7b4e6b
CM
1207 }
1208}
1209
1210/*
1211 * Scan a memory block corresponding to a kmemleak_object. A condition is
1212 * that object->use_count >= 1.
1213 */
1214static void scan_object(struct kmemleak_object *object)
1215{
1216 struct kmemleak_scan_area *area;
3c7b4e6b
CM
1217 unsigned long flags;
1218
1219 /*
21ae2956
UKK
1220 * Once the object->lock is acquired, the corresponding memory block
1221 * cannot be freed (the same lock is acquired in delete_object).
3c7b4e6b
CM
1222 */
1223 spin_lock_irqsave(&object->lock, flags);
1224 if (object->flags & OBJECT_NO_SCAN)
1225 goto out;
1226 if (!(object->flags & OBJECT_ALLOCATED))
1227 /* already freed object */
1228 goto out;
af98603d
CM
1229 if (hlist_empty(&object->area_list)) {
1230 void *start = (void *)object->pointer;
1231 void *end = (void *)(object->pointer + object->size);
1232
1233 while (start < end && (object->flags & OBJECT_ALLOCATED) &&
1234 !(object->flags & OBJECT_NO_SCAN)) {
1235 scan_block(start, min(start + MAX_SCAN_SIZE, end),
1236 object, 0);
1237 start += MAX_SCAN_SIZE;
1238
1239 spin_unlock_irqrestore(&object->lock, flags);
1240 cond_resched();
1241 spin_lock_irqsave(&object->lock, flags);
1242 }
1243 } else
b67bfe0d 1244 hlist_for_each_entry(area, &object->area_list, node)
c017b4be
CM
1245 scan_block((void *)area->start,
1246 (void *)(area->start + area->size),
1247 object, 0);
3c7b4e6b
CM
1248out:
1249 spin_unlock_irqrestore(&object->lock, flags);
1250}
1251
04609ccc
CM
1252/*
1253 * Scan the objects already referenced (gray objects). More objects will be
1254 * referenced and, if there are no memory leaks, all the objects are scanned.
1255 */
1256static void scan_gray_list(void)
1257{
1258 struct kmemleak_object *object, *tmp;
1259
1260 /*
1261 * The list traversal is safe for both tail additions and removals
1262 * from inside the loop. The kmemleak objects cannot be freed from
1263 * outside the loop because their use_count was incremented.
1264 */
1265 object = list_entry(gray_list.next, typeof(*object), gray_list);
1266 while (&object->gray_list != &gray_list) {
1267 cond_resched();
1268
1269 /* may add new objects to the list */
1270 if (!scan_should_stop())
1271 scan_object(object);
1272
1273 tmp = list_entry(object->gray_list.next, typeof(*object),
1274 gray_list);
1275
1276 /* remove the object from the list and release it */
1277 list_del(&object->gray_list);
1278 put_object(object);
1279
1280 object = tmp;
1281 }
1282 WARN_ON(!list_empty(&gray_list));
1283}
1284
3c7b4e6b
CM
1285/*
1286 * Scan data sections and all the referenced memory blocks allocated via the
1287 * kernel's standard allocators. This function must be called with the
1288 * scan_mutex held.
1289 */
1290static void kmemleak_scan(void)
1291{
1292 unsigned long flags;
04609ccc 1293 struct kmemleak_object *object;
3c7b4e6b 1294 int i;
4698c1f2 1295 int new_leaks = 0;
3c7b4e6b 1296
acf4968e
CM
1297 jiffies_last_scan = jiffies;
1298
3c7b4e6b
CM
1299 /* prepare the kmemleak_object's */
1300 rcu_read_lock();
1301 list_for_each_entry_rcu(object, &object_list, object_list) {
1302 spin_lock_irqsave(&object->lock, flags);
1303#ifdef DEBUG
1304 /*
1305 * With a few exceptions there should be a maximum of
1306 * 1 reference to any object at this point.
1307 */
1308 if (atomic_read(&object->use_count) > 1) {
ae281064 1309 pr_debug("object->use_count = %d\n",
3c7b4e6b
CM
1310 atomic_read(&object->use_count));
1311 dump_object_info(object);
1312 }
1313#endif
1314 /* reset the reference count (whiten the object) */
1315 object->count = 0;
1316 if (color_gray(object) && get_object(object))
1317 list_add_tail(&object->gray_list, &gray_list);
1318
1319 spin_unlock_irqrestore(&object->lock, flags);
1320 }
1321 rcu_read_unlock();
1322
1323 /* data/bss scanning */
4b8a9674
CM
1324 scan_block(_sdata, _edata, NULL, 1);
1325 scan_block(__bss_start, __bss_stop, NULL, 1);
3c7b4e6b
CM
1326
1327#ifdef CONFIG_SMP
1328 /* per-cpu sections scanning */
1329 for_each_possible_cpu(i)
1330 scan_block(__per_cpu_start + per_cpu_offset(i),
4b8a9674 1331 __per_cpu_end + per_cpu_offset(i), NULL, 1);
3c7b4e6b
CM
1332#endif
1333
1334 /*
029aeff5 1335 * Struct page scanning for each node.
3c7b4e6b 1336 */
bfc8c901 1337 get_online_mems();
3c7b4e6b 1338 for_each_online_node(i) {
108bcc96
CS
1339 unsigned long start_pfn = node_start_pfn(i);
1340 unsigned long end_pfn = node_end_pfn(i);
3c7b4e6b
CM
1341 unsigned long pfn;
1342
1343 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1344 struct page *page;
1345
1346 if (!pfn_valid(pfn))
1347 continue;
1348 page = pfn_to_page(pfn);
1349 /* only scan if page is in use */
1350 if (page_count(page) == 0)
1351 continue;
4b8a9674 1352 scan_block(page, page + 1, NULL, 1);
3c7b4e6b
CM
1353 }
1354 }
bfc8c901 1355 put_online_mems();
3c7b4e6b
CM
1356
1357 /*
43ed5d6e 1358 * Scanning the task stacks (may introduce false negatives).
3c7b4e6b
CM
1359 */
1360 if (kmemleak_stack_scan) {
43ed5d6e
CM
1361 struct task_struct *p, *g;
1362
3c7b4e6b 1363 read_lock(&tasklist_lock);
43ed5d6e
CM
1364 do_each_thread(g, p) {
1365 scan_block(task_stack_page(p), task_stack_page(p) +
1366 THREAD_SIZE, NULL, 0);
1367 } while_each_thread(g, p);
3c7b4e6b
CM
1368 read_unlock(&tasklist_lock);
1369 }
1370
1371 /*
1372 * Scan the objects already referenced from the sections scanned
04609ccc 1373 * above.
3c7b4e6b 1374 */
04609ccc 1375 scan_gray_list();
2587362e
CM
1376
1377 /*
04609ccc
CM
1378 * Check for new or unreferenced objects modified since the previous
1379 * scan and color them gray until the next scan.
2587362e
CM
1380 */
1381 rcu_read_lock();
1382 list_for_each_entry_rcu(object, &object_list, object_list) {
1383 spin_lock_irqsave(&object->lock, flags);
04609ccc
CM
1384 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1385 && update_checksum(object) && get_object(object)) {
1386 /* color it gray temporarily */
1387 object->count = object->min_count;
2587362e
CM
1388 list_add_tail(&object->gray_list, &gray_list);
1389 }
1390 spin_unlock_irqrestore(&object->lock, flags);
1391 }
1392 rcu_read_unlock();
1393
04609ccc
CM
1394 /*
1395 * Re-scan the gray list for modified unreferenced objects.
1396 */
1397 scan_gray_list();
4698c1f2 1398
17bb9e0d 1399 /*
04609ccc 1400 * If scanning was stopped do not report any new unreferenced objects.
17bb9e0d 1401 */
04609ccc 1402 if (scan_should_stop())
17bb9e0d
CM
1403 return;
1404
4698c1f2
CM
1405 /*
1406 * Scanning result reporting.
1407 */
1408 rcu_read_lock();
1409 list_for_each_entry_rcu(object, &object_list, object_list) {
1410 spin_lock_irqsave(&object->lock, flags);
1411 if (unreferenced_object(object) &&
1412 !(object->flags & OBJECT_REPORTED)) {
1413 object->flags |= OBJECT_REPORTED;
1414 new_leaks++;
1415 }
1416 spin_unlock_irqrestore(&object->lock, flags);
1417 }
1418 rcu_read_unlock();
1419
dc9b3f42
LZ
1420 if (new_leaks) {
1421 kmemleak_found_leaks = true;
1422
4698c1f2
CM
1423 pr_info("%d new suspected memory leaks (see "
1424 "/sys/kernel/debug/kmemleak)\n", new_leaks);
dc9b3f42 1425 }
4698c1f2 1426
3c7b4e6b
CM
1427}
1428
1429/*
1430 * Thread function performing automatic memory scanning. Unreferenced objects
1431 * at the end of a memory scan are reported but only the first time.
1432 */
1433static int kmemleak_scan_thread(void *arg)
1434{
1435 static int first_run = 1;
1436
ae281064 1437 pr_info("Automatic memory scanning thread started\n");
bf2a76b3 1438 set_user_nice(current, 10);
3c7b4e6b
CM
1439
1440 /*
1441 * Wait before the first scan to allow the system to fully initialize.
1442 */
1443 if (first_run) {
1444 first_run = 0;
1445 ssleep(SECS_FIRST_SCAN);
1446 }
1447
1448 while (!kthread_should_stop()) {
3c7b4e6b
CM
1449 signed long timeout = jiffies_scan_wait;
1450
1451 mutex_lock(&scan_mutex);
3c7b4e6b 1452 kmemleak_scan();
3c7b4e6b 1453 mutex_unlock(&scan_mutex);
4698c1f2 1454
3c7b4e6b
CM
1455 /* wait before the next scan */
1456 while (timeout && !kthread_should_stop())
1457 timeout = schedule_timeout_interruptible(timeout);
1458 }
1459
ae281064 1460 pr_info("Automatic memory scanning thread ended\n");
3c7b4e6b
CM
1461
1462 return 0;
1463}
1464
1465/*
1466 * Start the automatic memory scanning thread. This function must be called
4698c1f2 1467 * with the scan_mutex held.
3c7b4e6b 1468 */
7eb0d5e5 1469static void start_scan_thread(void)
3c7b4e6b
CM
1470{
1471 if (scan_thread)
1472 return;
1473 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1474 if (IS_ERR(scan_thread)) {
ae281064 1475 pr_warning("Failed to create the scan thread\n");
3c7b4e6b
CM
1476 scan_thread = NULL;
1477 }
1478}
1479
1480/*
1481 * Stop the automatic memory scanning thread. This function must be called
4698c1f2 1482 * with the scan_mutex held.
3c7b4e6b 1483 */
7eb0d5e5 1484static void stop_scan_thread(void)
3c7b4e6b
CM
1485{
1486 if (scan_thread) {
1487 kthread_stop(scan_thread);
1488 scan_thread = NULL;
1489 }
1490}
1491
1492/*
1493 * Iterate over the object_list and return the first valid object at or after
1494 * the required position with its use_count incremented. The function triggers
1495 * a memory scanning when the pos argument points to the first position.
1496 */
1497static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1498{
1499 struct kmemleak_object *object;
1500 loff_t n = *pos;
b87324d0
CM
1501 int err;
1502
1503 err = mutex_lock_interruptible(&scan_mutex);
1504 if (err < 0)
1505 return ERR_PTR(err);
3c7b4e6b 1506
3c7b4e6b
CM
1507 rcu_read_lock();
1508 list_for_each_entry_rcu(object, &object_list, object_list) {
1509 if (n-- > 0)
1510 continue;
1511 if (get_object(object))
1512 goto out;
1513 }
1514 object = NULL;
1515out:
3c7b4e6b
CM
1516 return object;
1517}
1518
1519/*
1520 * Return the next object in the object_list. The function decrements the
1521 * use_count of the previous object and increases that of the next one.
1522 */
1523static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1524{
1525 struct kmemleak_object *prev_obj = v;
1526 struct kmemleak_object *next_obj = NULL;
58fac095 1527 struct kmemleak_object *obj = prev_obj;
3c7b4e6b
CM
1528
1529 ++(*pos);
3c7b4e6b 1530
58fac095 1531 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
52c3ce4e
CM
1532 if (get_object(obj)) {
1533 next_obj = obj;
3c7b4e6b 1534 break;
52c3ce4e 1535 }
3c7b4e6b 1536 }
288c857d 1537
3c7b4e6b
CM
1538 put_object(prev_obj);
1539 return next_obj;
1540}
1541
1542/*
1543 * Decrement the use_count of the last object required, if any.
1544 */
1545static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1546{
b87324d0
CM
1547 if (!IS_ERR(v)) {
1548 /*
1549 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1550 * waiting was interrupted, so only release it if !IS_ERR.
1551 */
f5886c7f 1552 rcu_read_unlock();
b87324d0
CM
1553 mutex_unlock(&scan_mutex);
1554 if (v)
1555 put_object(v);
1556 }
3c7b4e6b
CM
1557}
1558
1559/*
1560 * Print the information for an unreferenced object to the seq file.
1561 */
1562static int kmemleak_seq_show(struct seq_file *seq, void *v)
1563{
1564 struct kmemleak_object *object = v;
1565 unsigned long flags;
1566
1567 spin_lock_irqsave(&object->lock, flags);
288c857d 1568 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
17bb9e0d 1569 print_unreferenced(seq, object);
3c7b4e6b
CM
1570 spin_unlock_irqrestore(&object->lock, flags);
1571 return 0;
1572}
1573
1574static const struct seq_operations kmemleak_seq_ops = {
1575 .start = kmemleak_seq_start,
1576 .next = kmemleak_seq_next,
1577 .stop = kmemleak_seq_stop,
1578 .show = kmemleak_seq_show,
1579};
1580
1581static int kmemleak_open(struct inode *inode, struct file *file)
1582{
b87324d0 1583 return seq_open(file, &kmemleak_seq_ops);
3c7b4e6b
CM
1584}
1585
189d84ed
CM
1586static int dump_str_object_info(const char *str)
1587{
1588 unsigned long flags;
1589 struct kmemleak_object *object;
1590 unsigned long addr;
1591
dc053733
AP
1592 if (kstrtoul(str, 0, &addr))
1593 return -EINVAL;
189d84ed
CM
1594 object = find_and_get_object(addr, 0);
1595 if (!object) {
1596 pr_info("Unknown object at 0x%08lx\n", addr);
1597 return -EINVAL;
1598 }
1599
1600 spin_lock_irqsave(&object->lock, flags);
1601 dump_object_info(object);
1602 spin_unlock_irqrestore(&object->lock, flags);
1603
1604 put_object(object);
1605 return 0;
1606}
1607
30b37101
LR
1608/*
1609 * We use grey instead of black to ensure we can do future scans on the same
1610 * objects. If we did not do future scans these black objects could
1611 * potentially contain references to newly allocated objects in the future and
1612 * we'd end up with false positives.
1613 */
1614static void kmemleak_clear(void)
1615{
1616 struct kmemleak_object *object;
1617 unsigned long flags;
1618
1619 rcu_read_lock();
1620 list_for_each_entry_rcu(object, &object_list, object_list) {
1621 spin_lock_irqsave(&object->lock, flags);
1622 if ((object->flags & OBJECT_REPORTED) &&
1623 unreferenced_object(object))
a1084c87 1624 __paint_it(object, KMEMLEAK_GREY);
30b37101
LR
1625 spin_unlock_irqrestore(&object->lock, flags);
1626 }
1627 rcu_read_unlock();
dc9b3f42
LZ
1628
1629 kmemleak_found_leaks = false;
30b37101
LR
1630}
1631
c89da70c
LZ
1632static void __kmemleak_do_cleanup(void);
1633
3c7b4e6b
CM
1634/*
1635 * File write operation to configure kmemleak at run-time. The following
1636 * commands can be written to the /sys/kernel/debug/kmemleak file:
1637 * off - disable kmemleak (irreversible)
1638 * stack=on - enable the task stacks scanning
1639 * stack=off - disable the tasks stacks scanning
1640 * scan=on - start the automatic memory scanning thread
1641 * scan=off - stop the automatic memory scanning thread
1642 * scan=... - set the automatic memory scanning period in seconds (0 to
1643 * disable it)
4698c1f2 1644 * scan - trigger a memory scan
30b37101 1645 * clear - mark all current reported unreferenced kmemleak objects as
c89da70c
LZ
1646 * grey to ignore printing them, or free all kmemleak objects
1647 * if kmemleak has been disabled.
189d84ed 1648 * dump=... - dump information about the object found at the given address
3c7b4e6b
CM
1649 */
1650static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1651 size_t size, loff_t *ppos)
1652{
1653 char buf[64];
1654 int buf_size;
b87324d0 1655 int ret;
3c7b4e6b
CM
1656
1657 buf_size = min(size, (sizeof(buf) - 1));
1658 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1659 return -EFAULT;
1660 buf[buf_size] = 0;
1661
b87324d0
CM
1662 ret = mutex_lock_interruptible(&scan_mutex);
1663 if (ret < 0)
1664 return ret;
1665
c89da70c 1666 if (strncmp(buf, "clear", 5) == 0) {
8910ae89 1667 if (kmemleak_enabled)
c89da70c
LZ
1668 kmemleak_clear();
1669 else
1670 __kmemleak_do_cleanup();
1671 goto out;
1672 }
1673
8910ae89 1674 if (!kmemleak_enabled) {
c89da70c
LZ
1675 ret = -EBUSY;
1676 goto out;
1677 }
1678
3c7b4e6b
CM
1679 if (strncmp(buf, "off", 3) == 0)
1680 kmemleak_disable();
1681 else if (strncmp(buf, "stack=on", 8) == 0)
1682 kmemleak_stack_scan = 1;
1683 else if (strncmp(buf, "stack=off", 9) == 0)
1684 kmemleak_stack_scan = 0;
1685 else if (strncmp(buf, "scan=on", 7) == 0)
1686 start_scan_thread();
1687 else if (strncmp(buf, "scan=off", 8) == 0)
1688 stop_scan_thread();
1689 else if (strncmp(buf, "scan=", 5) == 0) {
1690 unsigned long secs;
3c7b4e6b 1691
3dbb95f7 1692 ret = kstrtoul(buf + 5, 0, &secs);
b87324d0
CM
1693 if (ret < 0)
1694 goto out;
3c7b4e6b
CM
1695 stop_scan_thread();
1696 if (secs) {
1697 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1698 start_scan_thread();
1699 }
4698c1f2
CM
1700 } else if (strncmp(buf, "scan", 4) == 0)
1701 kmemleak_scan();
189d84ed
CM
1702 else if (strncmp(buf, "dump=", 5) == 0)
1703 ret = dump_str_object_info(buf + 5);
4698c1f2 1704 else
b87324d0
CM
1705 ret = -EINVAL;
1706
1707out:
1708 mutex_unlock(&scan_mutex);
1709 if (ret < 0)
1710 return ret;
3c7b4e6b
CM
1711
1712 /* ignore the rest of the buffer, only one command at a time */
1713 *ppos += size;
1714 return size;
1715}
1716
1717static const struct file_operations kmemleak_fops = {
1718 .owner = THIS_MODULE,
1719 .open = kmemleak_open,
1720 .read = seq_read,
1721 .write = kmemleak_write,
1722 .llseek = seq_lseek,
5f3bf19a 1723 .release = seq_release,
3c7b4e6b
CM
1724};
1725
c89da70c
LZ
1726static void __kmemleak_do_cleanup(void)
1727{
1728 struct kmemleak_object *object;
1729
1730 rcu_read_lock();
1731 list_for_each_entry_rcu(object, &object_list, object_list)
1732 delete_object_full(object->pointer);
1733 rcu_read_unlock();
1734}
1735
3c7b4e6b 1736/*
74341703
CM
1737 * Stop the memory scanning thread and free the kmemleak internal objects if
1738 * no previous scan thread (otherwise, kmemleak may still have some useful
1739 * information on memory leaks).
3c7b4e6b 1740 */
179a8100 1741static void kmemleak_do_cleanup(struct work_struct *work)
3c7b4e6b 1742{
4698c1f2 1743 mutex_lock(&scan_mutex);
3c7b4e6b 1744 stop_scan_thread();
3c7b4e6b 1745
c89da70c
LZ
1746 if (!kmemleak_found_leaks)
1747 __kmemleak_do_cleanup();
1748 else
1749 pr_info("Kmemleak disabled without freeing internal data. "
1750 "Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\"\n");
3c7b4e6b 1751 mutex_unlock(&scan_mutex);
3c7b4e6b
CM
1752}
1753
179a8100 1754static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
3c7b4e6b
CM
1755
1756/*
1757 * Disable kmemleak. No memory allocation/freeing will be traced once this
1758 * function is called. Disabling kmemleak is an irreversible operation.
1759 */
1760static void kmemleak_disable(void)
1761{
1762 /* atomically check whether it was already invoked */
8910ae89 1763 if (cmpxchg(&kmemleak_error, 0, 1))
3c7b4e6b
CM
1764 return;
1765
1766 /* stop any memory operation tracing */
8910ae89 1767 kmemleak_enabled = 0;
3c7b4e6b
CM
1768
1769 /* check whether it is too early for a kernel thread */
8910ae89 1770 if (kmemleak_initialized)
179a8100 1771 schedule_work(&cleanup_work);
3c7b4e6b
CM
1772
1773 pr_info("Kernel memory leak detector disabled\n");
1774}
1775
1776/*
1777 * Allow boot-time kmemleak disabling (enabled by default).
1778 */
1779static int kmemleak_boot_config(char *str)
1780{
1781 if (!str)
1782 return -EINVAL;
1783 if (strcmp(str, "off") == 0)
1784 kmemleak_disable();
ab0155a2
JB
1785 else if (strcmp(str, "on") == 0)
1786 kmemleak_skip_disable = 1;
1787 else
3c7b4e6b
CM
1788 return -EINVAL;
1789 return 0;
1790}
1791early_param("kmemleak", kmemleak_boot_config);
1792
5f79020c
CM
1793static void __init print_log_trace(struct early_log *log)
1794{
1795 struct stack_trace trace;
1796
1797 trace.nr_entries = log->trace_len;
1798 trace.entries = log->trace;
1799
1800 pr_notice("Early log backtrace:\n");
1801 print_stack_trace(&trace, 2);
1802}
1803
3c7b4e6b 1804/*
2030117d 1805 * Kmemleak initialization.
3c7b4e6b
CM
1806 */
1807void __init kmemleak_init(void)
1808{
1809 int i;
1810 unsigned long flags;
1811
ab0155a2
JB
1812#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1813 if (!kmemleak_skip_disable) {
3551a928 1814 kmemleak_early_log = 0;
ab0155a2
JB
1815 kmemleak_disable();
1816 return;
1817 }
1818#endif
1819
3c7b4e6b
CM
1820 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1821 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1822
1823 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1824 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
3c7b4e6b 1825
b6693005
CM
1826 if (crt_early_log >= ARRAY_SIZE(early_log))
1827 pr_warning("Early log buffer exceeded (%d), please increase "
1828 "DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", crt_early_log);
1829
3c7b4e6b
CM
1830 /* the kernel is still in UP mode, so disabling the IRQs is enough */
1831 local_irq_save(flags);
3551a928 1832 kmemleak_early_log = 0;
8910ae89 1833 if (kmemleak_error) {
b6693005
CM
1834 local_irq_restore(flags);
1835 return;
1836 } else
8910ae89 1837 kmemleak_enabled = 1;
3c7b4e6b
CM
1838 local_irq_restore(flags);
1839
1840 /*
1841 * This is the point where tracking allocations is safe. Automatic
1842 * scanning is started during the late initcall. Add the early logged
1843 * callbacks to the kmemleak infrastructure.
1844 */
1845 for (i = 0; i < crt_early_log; i++) {
1846 struct early_log *log = &early_log[i];
1847
1848 switch (log->op_type) {
1849 case KMEMLEAK_ALLOC:
fd678967 1850 early_alloc(log);
3c7b4e6b 1851 break;
f528f0b8
CM
1852 case KMEMLEAK_ALLOC_PERCPU:
1853 early_alloc_percpu(log);
1854 break;
3c7b4e6b
CM
1855 case KMEMLEAK_FREE:
1856 kmemleak_free(log->ptr);
1857 break;
53238a60
CM
1858 case KMEMLEAK_FREE_PART:
1859 kmemleak_free_part(log->ptr, log->size);
1860 break;
f528f0b8
CM
1861 case KMEMLEAK_FREE_PERCPU:
1862 kmemleak_free_percpu(log->ptr);
1863 break;
3c7b4e6b
CM
1864 case KMEMLEAK_NOT_LEAK:
1865 kmemleak_not_leak(log->ptr);
1866 break;
1867 case KMEMLEAK_IGNORE:
1868 kmemleak_ignore(log->ptr);
1869 break;
1870 case KMEMLEAK_SCAN_AREA:
c017b4be 1871 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
3c7b4e6b
CM
1872 break;
1873 case KMEMLEAK_NO_SCAN:
1874 kmemleak_no_scan(log->ptr);
1875 break;
1876 default:
5f79020c
CM
1877 kmemleak_warn("Unknown early log operation: %d\n",
1878 log->op_type);
1879 }
1880
8910ae89 1881 if (kmemleak_warning) {
5f79020c 1882 print_log_trace(log);
8910ae89 1883 kmemleak_warning = 0;
3c7b4e6b
CM
1884 }
1885 }
1886}
1887
1888/*
1889 * Late initialization function.
1890 */
1891static int __init kmemleak_late_init(void)
1892{
1893 struct dentry *dentry;
1894
8910ae89 1895 kmemleak_initialized = 1;
3c7b4e6b 1896
8910ae89 1897 if (kmemleak_error) {
3c7b4e6b 1898 /*
25985edc 1899 * Some error occurred and kmemleak was disabled. There is a
3c7b4e6b
CM
1900 * small chance that kmemleak_disable() was called immediately
1901 * after setting kmemleak_initialized and we may end up with
1902 * two clean-up threads but serialized by scan_mutex.
1903 */
179a8100 1904 schedule_work(&cleanup_work);
3c7b4e6b
CM
1905 return -ENOMEM;
1906 }
1907
1908 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
1909 &kmemleak_fops);
1910 if (!dentry)
ae281064 1911 pr_warning("Failed to create the debugfs kmemleak file\n");
4698c1f2 1912 mutex_lock(&scan_mutex);
3c7b4e6b 1913 start_scan_thread();
4698c1f2 1914 mutex_unlock(&scan_mutex);
3c7b4e6b
CM
1915
1916 pr_info("Kernel memory leak detector initialized\n");
1917
1918 return 0;
1919}
1920late_initcall(kmemleak_late_init);