]>
Commit | Line | Data |
---|---|---|
3c7b4e6b CM |
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 |
3c7b4e6b CM |
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 | |
4698c1f2 CM |
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 | |
3c7b4e6b CM |
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 | ||
ae281064 JP |
64 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
65 | ||
3c7b4e6b CM |
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> |
3c7b4e6b CM |
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> |
3c7b4e6b CM |
96 | |
97 | #include <asm/sections.h> | |
98 | #include <asm/processor.h> | |
60063497 | 99 | #include <linux/atomic.h> |
3c7b4e6b | 100 | |
e79ed2f1 | 101 | #include <linux/kasan.h> |
8e019366 | 102 | #include <linux/kmemcheck.h> |
3c7b4e6b | 103 | #include <linux/kmemleak.h> |
029aeff5 | 104 | #include <linux/memory_hotplug.h> |
3c7b4e6b CM |
105 | |
106 | /* | |
107 | * Kmemleak configuration and common defines. | |
108 | */ | |
109 | #define MAX_TRACE 16 /* stack trace length */ | |
3c7b4e6b | 110 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
3c7b4e6b CM |
111 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
112 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ | |
af98603d | 113 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
3c7b4e6b CM |
114 | |
115 | #define BYTES_PER_POINTER sizeof(void *) | |
116 | ||
216c04b0 | 117 | /* GFP bitmask for kmemleak internal allocations */ |
8f4fc071 VD |
118 | #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \ |
119 | __GFP_NOACCOUNT)) | \ | |
6ae4bd1f CM |
120 | __GFP_NORETRY | __GFP_NOMEMALLOC | \ |
121 | __GFP_NOWARN) | |
216c04b0 | 122 | |
3c7b4e6b CM |
123 | /* scanning area inside a memory block */ |
124 | struct kmemleak_scan_area { | |
125 | struct hlist_node node; | |
c017b4be CM |
126 | unsigned long start; |
127 | size_t size; | |
3c7b4e6b CM |
128 | }; |
129 | ||
a1084c87 LR |
130 | #define KMEMLEAK_GREY 0 |
131 | #define KMEMLEAK_BLACK -1 | |
132 | ||
3c7b4e6b CM |
133 | /* |
134 | * Structure holding the metadata for each allocated memory block. | |
135 | * Modifications to such objects should be made while holding the | |
136 | * object->lock. Insertions or deletions from object_list, gray_list or | |
85d3a316 | 137 | * rb_node are already protected by the corresponding locks or mutex (see |
3c7b4e6b CM |
138 | * the notes on locking above). These objects are reference-counted |
139 | * (use_count) and freed using the RCU mechanism. | |
140 | */ | |
141 | struct kmemleak_object { | |
142 | spinlock_t lock; | |
143 | unsigned long flags; /* object status flags */ | |
144 | struct list_head object_list; | |
145 | struct list_head gray_list; | |
85d3a316 | 146 | struct rb_node rb_node; |
3c7b4e6b CM |
147 | struct rcu_head rcu; /* object_list lockless traversal */ |
148 | /* object usage count; object freed when use_count == 0 */ | |
149 | atomic_t use_count; | |
150 | unsigned long pointer; | |
151 | size_t size; | |
152 | /* minimum number of a pointers found before it is considered leak */ | |
153 | int min_count; | |
154 | /* the total number of pointers found pointing to this object */ | |
155 | int count; | |
04609ccc CM |
156 | /* checksum for detecting modified objects */ |
157 | u32 checksum; | |
3c7b4e6b CM |
158 | /* memory ranges to be scanned inside an object (empty for all) */ |
159 | struct hlist_head area_list; | |
160 | unsigned long trace[MAX_TRACE]; | |
161 | unsigned int trace_len; | |
162 | unsigned long jiffies; /* creation timestamp */ | |
163 | pid_t pid; /* pid of the current task */ | |
164 | char comm[TASK_COMM_LEN]; /* executable name */ | |
165 | }; | |
166 | ||
167 | /* flag representing the memory block allocation status */ | |
168 | #define OBJECT_ALLOCATED (1 << 0) | |
169 | /* flag set after the first reporting of an unreference object */ | |
170 | #define OBJECT_REPORTED (1 << 1) | |
171 | /* flag set to not scan the object */ | |
172 | #define OBJECT_NO_SCAN (1 << 2) | |
173 | ||
0494e082 SS |
174 | /* number of bytes to print per line; must be 16 or 32 */ |
175 | #define HEX_ROW_SIZE 16 | |
176 | /* number of bytes to print at a time (1, 2, 4, 8) */ | |
177 | #define HEX_GROUP_SIZE 1 | |
178 | /* include ASCII after the hex output */ | |
179 | #define HEX_ASCII 1 | |
180 | /* max number of lines to be printed */ | |
181 | #define HEX_MAX_LINES 2 | |
182 | ||
3c7b4e6b CM |
183 | /* the list of all allocated objects */ |
184 | static LIST_HEAD(object_list); | |
185 | /* the list of gray-colored objects (see color_gray comment below) */ | |
186 | static LIST_HEAD(gray_list); | |
85d3a316 ML |
187 | /* search tree for object boundaries */ |
188 | static struct rb_root object_tree_root = RB_ROOT; | |
189 | /* rw_lock protecting the access to object_list and object_tree_root */ | |
3c7b4e6b CM |
190 | static DEFINE_RWLOCK(kmemleak_lock); |
191 | ||
192 | /* allocation caches for kmemleak internal data */ | |
193 | static struct kmem_cache *object_cache; | |
194 | static struct kmem_cache *scan_area_cache; | |
195 | ||
196 | /* set if tracing memory operations is enabled */ | |
8910ae89 | 197 | static int kmemleak_enabled; |
3c7b4e6b | 198 | /* set in the late_initcall if there were no errors */ |
8910ae89 | 199 | static int kmemleak_initialized; |
3c7b4e6b | 200 | /* enables or disables early logging of the memory operations */ |
8910ae89 | 201 | static int kmemleak_early_log = 1; |
5f79020c | 202 | /* set if a kmemleak warning was issued */ |
8910ae89 | 203 | static int kmemleak_warning; |
5f79020c | 204 | /* set if a fatal kmemleak error has occurred */ |
8910ae89 | 205 | static int kmemleak_error; |
3c7b4e6b CM |
206 | |
207 | /* minimum and maximum address that may be valid pointers */ | |
208 | static unsigned long min_addr = ULONG_MAX; | |
209 | static unsigned long max_addr; | |
210 | ||
3c7b4e6b | 211 | static struct task_struct *scan_thread; |
acf4968e | 212 | /* used to avoid reporting of recently allocated objects */ |
3c7b4e6b | 213 | static unsigned long jiffies_min_age; |
acf4968e | 214 | static unsigned long jiffies_last_scan; |
3c7b4e6b CM |
215 | /* delay between automatic memory scannings */ |
216 | static signed long jiffies_scan_wait; | |
217 | /* enables or disables the task stacks scanning */ | |
e0a2a160 | 218 | static int kmemleak_stack_scan = 1; |
4698c1f2 | 219 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
3c7b4e6b | 220 | static DEFINE_MUTEX(scan_mutex); |
ab0155a2 JB |
221 | /* setting kmemleak=on, will set this var, skipping the disable */ |
222 | static int kmemleak_skip_disable; | |
dc9b3f42 LZ |
223 | /* If there are leaks that can be reported */ |
224 | static bool kmemleak_found_leaks; | |
3c7b4e6b | 225 | |
3c7b4e6b | 226 | /* |
2030117d | 227 | * Early object allocation/freeing logging. Kmemleak is initialized after the |
3c7b4e6b | 228 | * kernel allocator. However, both the kernel allocator and kmemleak may |
2030117d | 229 | * allocate memory blocks which need to be tracked. Kmemleak defines an |
3c7b4e6b CM |
230 | * arbitrary buffer to hold the allocation/freeing information before it is |
231 | * fully initialized. | |
232 | */ | |
233 | ||
234 | /* kmemleak operation type for early logging */ | |
235 | enum { | |
236 | KMEMLEAK_ALLOC, | |
f528f0b8 | 237 | KMEMLEAK_ALLOC_PERCPU, |
3c7b4e6b | 238 | KMEMLEAK_FREE, |
53238a60 | 239 | KMEMLEAK_FREE_PART, |
f528f0b8 | 240 | KMEMLEAK_FREE_PERCPU, |
3c7b4e6b CM |
241 | KMEMLEAK_NOT_LEAK, |
242 | KMEMLEAK_IGNORE, | |
243 | KMEMLEAK_SCAN_AREA, | |
244 | KMEMLEAK_NO_SCAN | |
245 | }; | |
246 | ||
247 | /* | |
248 | * Structure holding the information passed to kmemleak callbacks during the | |
249 | * early logging. | |
250 | */ | |
251 | struct early_log { | |
252 | int op_type; /* kmemleak operation type */ | |
253 | const void *ptr; /* allocated/freed memory block */ | |
254 | size_t size; /* memory block size */ | |
255 | int min_count; /* minimum reference count */ | |
fd678967 CM |
256 | unsigned long trace[MAX_TRACE]; /* stack trace */ |
257 | unsigned int trace_len; /* stack trace length */ | |
3c7b4e6b CM |
258 | }; |
259 | ||
260 | /* early logging buffer and current position */ | |
a6186d89 CM |
261 | static struct early_log |
262 | early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata; | |
263 | static int crt_early_log __initdata; | |
3c7b4e6b CM |
264 | |
265 | static void kmemleak_disable(void); | |
266 | ||
267 | /* | |
268 | * Print a warning and dump the stack trace. | |
269 | */ | |
5f79020c CM |
270 | #define kmemleak_warn(x...) do { \ |
271 | pr_warning(x); \ | |
272 | dump_stack(); \ | |
8910ae89 | 273 | kmemleak_warning = 1; \ |
3c7b4e6b CM |
274 | } while (0) |
275 | ||
276 | /* | |
25985edc | 277 | * Macro invoked when a serious kmemleak condition occurred and cannot be |
2030117d | 278 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
3c7b4e6b CM |
279 | * tracing no longer available. |
280 | */ | |
000814f4 | 281 | #define kmemleak_stop(x...) do { \ |
3c7b4e6b CM |
282 | kmemleak_warn(x); \ |
283 | kmemleak_disable(); \ | |
284 | } while (0) | |
285 | ||
0494e082 SS |
286 | /* |
287 | * Printing of the objects hex dump to the seq file. The number of lines to be | |
288 | * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The | |
289 | * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called | |
290 | * with the object->lock held. | |
291 | */ | |
292 | static void hex_dump_object(struct seq_file *seq, | |
293 | struct kmemleak_object *object) | |
294 | { | |
295 | const u8 *ptr = (const u8 *)object->pointer; | |
296 | int i, len, remaining; | |
297 | unsigned char linebuf[HEX_ROW_SIZE * 5]; | |
298 | ||
299 | /* limit the number of lines to HEX_MAX_LINES */ | |
300 | remaining = len = | |
301 | min(object->size, (size_t)(HEX_MAX_LINES * HEX_ROW_SIZE)); | |
302 | ||
303 | seq_printf(seq, " hex dump (first %d bytes):\n", len); | |
304 | for (i = 0; i < len; i += HEX_ROW_SIZE) { | |
305 | int linelen = min(remaining, HEX_ROW_SIZE); | |
306 | ||
307 | remaining -= HEX_ROW_SIZE; | |
308 | hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE, | |
309 | HEX_GROUP_SIZE, linebuf, sizeof(linebuf), | |
310 | HEX_ASCII); | |
311 | seq_printf(seq, " %s\n", linebuf); | |
312 | } | |
313 | } | |
314 | ||
3c7b4e6b CM |
315 | /* |
316 | * Object colors, encoded with count and min_count: | |
317 | * - white - orphan object, not enough references to it (count < min_count) | |
318 | * - gray - not orphan, not marked as false positive (min_count == 0) or | |
319 | * sufficient references to it (count >= min_count) | |
320 | * - black - ignore, it doesn't contain references (e.g. text section) | |
321 | * (min_count == -1). No function defined for this color. | |
322 | * Newly created objects don't have any color assigned (object->count == -1) | |
323 | * before the next memory scan when they become white. | |
324 | */ | |
4a558dd6 | 325 | static bool color_white(const struct kmemleak_object *object) |
3c7b4e6b | 326 | { |
a1084c87 LR |
327 | return object->count != KMEMLEAK_BLACK && |
328 | object->count < object->min_count; | |
3c7b4e6b CM |
329 | } |
330 | ||
4a558dd6 | 331 | static bool color_gray(const struct kmemleak_object *object) |
3c7b4e6b | 332 | { |
a1084c87 LR |
333 | return object->min_count != KMEMLEAK_BLACK && |
334 | object->count >= object->min_count; | |
3c7b4e6b CM |
335 | } |
336 | ||
3c7b4e6b CM |
337 | /* |
338 | * Objects are considered unreferenced only if their color is white, they have | |
339 | * not be deleted and have a minimum age to avoid false positives caused by | |
340 | * pointers temporarily stored in CPU registers. | |
341 | */ | |
4a558dd6 | 342 | static bool unreferenced_object(struct kmemleak_object *object) |
3c7b4e6b | 343 | { |
04609ccc | 344 | return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
acf4968e CM |
345 | time_before_eq(object->jiffies + jiffies_min_age, |
346 | jiffies_last_scan); | |
3c7b4e6b CM |
347 | } |
348 | ||
349 | /* | |
bab4a34a CM |
350 | * Printing of the unreferenced objects information to the seq file. The |
351 | * print_unreferenced function must be called with the object->lock held. | |
3c7b4e6b | 352 | */ |
3c7b4e6b CM |
353 | static void print_unreferenced(struct seq_file *seq, |
354 | struct kmemleak_object *object) | |
355 | { | |
356 | int i; | |
fefdd336 | 357 | unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); |
3c7b4e6b | 358 | |
bab4a34a CM |
359 | seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
360 | object->pointer, object->size); | |
fefdd336 CM |
361 | seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", |
362 | object->comm, object->pid, object->jiffies, | |
363 | msecs_age / 1000, msecs_age % 1000); | |
0494e082 | 364 | hex_dump_object(seq, object); |
bab4a34a | 365 | seq_printf(seq, " backtrace:\n"); |
3c7b4e6b CM |
366 | |
367 | for (i = 0; i < object->trace_len; i++) { | |
368 | void *ptr = (void *)object->trace[i]; | |
bab4a34a | 369 | seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); |
3c7b4e6b CM |
370 | } |
371 | } | |
372 | ||
373 | /* | |
374 | * Print the kmemleak_object information. This function is used mainly for | |
375 | * debugging special cases when kmemleak operations. It must be called with | |
376 | * the object->lock held. | |
377 | */ | |
378 | static void dump_object_info(struct kmemleak_object *object) | |
379 | { | |
380 | struct stack_trace trace; | |
381 | ||
382 | trace.nr_entries = object->trace_len; | |
383 | trace.entries = object->trace; | |
384 | ||
ae281064 | 385 | pr_notice("Object 0x%08lx (size %zu):\n", |
85d3a316 | 386 | object->pointer, object->size); |
3c7b4e6b CM |
387 | pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", |
388 | object->comm, object->pid, object->jiffies); | |
389 | pr_notice(" min_count = %d\n", object->min_count); | |
390 | pr_notice(" count = %d\n", object->count); | |
189d84ed | 391 | pr_notice(" flags = 0x%lx\n", object->flags); |
aae0ad7a | 392 | pr_notice(" checksum = %u\n", object->checksum); |
3c7b4e6b CM |
393 | pr_notice(" backtrace:\n"); |
394 | print_stack_trace(&trace, 4); | |
395 | } | |
396 | ||
397 | /* | |
85d3a316 | 398 | * Look-up a memory block metadata (kmemleak_object) in the object search |
3c7b4e6b CM |
399 | * tree based on a pointer value. If alias is 0, only values pointing to the |
400 | * beginning of the memory block are allowed. The kmemleak_lock must be held | |
401 | * when calling this function. | |
402 | */ | |
403 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) | |
404 | { | |
85d3a316 ML |
405 | struct rb_node *rb = object_tree_root.rb_node; |
406 | ||
407 | while (rb) { | |
408 | struct kmemleak_object *object = | |
409 | rb_entry(rb, struct kmemleak_object, rb_node); | |
410 | if (ptr < object->pointer) | |
411 | rb = object->rb_node.rb_left; | |
412 | else if (object->pointer + object->size <= ptr) | |
413 | rb = object->rb_node.rb_right; | |
414 | else if (object->pointer == ptr || alias) | |
415 | return object; | |
416 | else { | |
5f79020c CM |
417 | kmemleak_warn("Found object by alias at 0x%08lx\n", |
418 | ptr); | |
a7686a45 | 419 | dump_object_info(object); |
85d3a316 | 420 | break; |
3c7b4e6b | 421 | } |
85d3a316 ML |
422 | } |
423 | return NULL; | |
3c7b4e6b CM |
424 | } |
425 | ||
426 | /* | |
427 | * Increment the object use_count. Return 1 if successful or 0 otherwise. Note | |
428 | * that once an object's use_count reached 0, the RCU freeing was already | |
429 | * registered and the object should no longer be used. This function must be | |
430 | * called under the protection of rcu_read_lock(). | |
431 | */ | |
432 | static int get_object(struct kmemleak_object *object) | |
433 | { | |
434 | return atomic_inc_not_zero(&object->use_count); | |
435 | } | |
436 | ||
437 | /* | |
438 | * RCU callback to free a kmemleak_object. | |
439 | */ | |
440 | static void free_object_rcu(struct rcu_head *rcu) | |
441 | { | |
b67bfe0d | 442 | struct hlist_node *tmp; |
3c7b4e6b CM |
443 | struct kmemleak_scan_area *area; |
444 | struct kmemleak_object *object = | |
445 | container_of(rcu, struct kmemleak_object, rcu); | |
446 | ||
447 | /* | |
448 | * Once use_count is 0 (guaranteed by put_object), there is no other | |
449 | * code accessing this object, hence no need for locking. | |
450 | */ | |
b67bfe0d SL |
451 | hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { |
452 | hlist_del(&area->node); | |
3c7b4e6b CM |
453 | kmem_cache_free(scan_area_cache, area); |
454 | } | |
455 | kmem_cache_free(object_cache, object); | |
456 | } | |
457 | ||
458 | /* | |
459 | * Decrement the object use_count. Once the count is 0, free the object using | |
460 | * an RCU callback. Since put_object() may be called via the kmemleak_free() -> | |
461 | * delete_object() path, the delayed RCU freeing ensures that there is no | |
462 | * recursive call to the kernel allocator. Lock-less RCU object_list traversal | |
463 | * is also possible. | |
464 | */ | |
465 | static void put_object(struct kmemleak_object *object) | |
466 | { | |
467 | if (!atomic_dec_and_test(&object->use_count)) | |
468 | return; | |
469 | ||
470 | /* should only get here after delete_object was called */ | |
471 | WARN_ON(object->flags & OBJECT_ALLOCATED); | |
472 | ||
473 | call_rcu(&object->rcu, free_object_rcu); | |
474 | } | |
475 | ||
476 | /* | |
85d3a316 | 477 | * Look up an object in the object search tree and increase its use_count. |
3c7b4e6b CM |
478 | */ |
479 | static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) | |
480 | { | |
481 | unsigned long flags; | |
482 | struct kmemleak_object *object = NULL; | |
483 | ||
484 | rcu_read_lock(); | |
485 | read_lock_irqsave(&kmemleak_lock, flags); | |
486 | if (ptr >= min_addr && ptr < max_addr) | |
487 | object = lookup_object(ptr, alias); | |
488 | read_unlock_irqrestore(&kmemleak_lock, flags); | |
489 | ||
490 | /* check whether the object is still available */ | |
491 | if (object && !get_object(object)) | |
492 | object = NULL; | |
493 | rcu_read_unlock(); | |
494 | ||
495 | return object; | |
496 | } | |
497 | ||
fd678967 CM |
498 | /* |
499 | * Save stack trace to the given array of MAX_TRACE size. | |
500 | */ | |
501 | static int __save_stack_trace(unsigned long *trace) | |
502 | { | |
503 | struct stack_trace stack_trace; | |
504 | ||
505 | stack_trace.max_entries = MAX_TRACE; | |
506 | stack_trace.nr_entries = 0; | |
507 | stack_trace.entries = trace; | |
508 | stack_trace.skip = 2; | |
509 | save_stack_trace(&stack_trace); | |
510 | ||
511 | return stack_trace.nr_entries; | |
512 | } | |
513 | ||
3c7b4e6b CM |
514 | /* |
515 | * Create the metadata (struct kmemleak_object) corresponding to an allocated | |
516 | * memory block and add it to the object_list and object_tree_root. | |
517 | */ | |
fd678967 CM |
518 | static struct kmemleak_object *create_object(unsigned long ptr, size_t size, |
519 | int min_count, gfp_t gfp) | |
3c7b4e6b CM |
520 | { |
521 | unsigned long flags; | |
85d3a316 ML |
522 | struct kmemleak_object *object, *parent; |
523 | struct rb_node **link, *rb_parent; | |
3c7b4e6b | 524 | |
6ae4bd1f | 525 | object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b | 526 | if (!object) { |
6ae4bd1f CM |
527 | pr_warning("Cannot allocate a kmemleak_object structure\n"); |
528 | kmemleak_disable(); | |
fd678967 | 529 | return NULL; |
3c7b4e6b CM |
530 | } |
531 | ||
532 | INIT_LIST_HEAD(&object->object_list); | |
533 | INIT_LIST_HEAD(&object->gray_list); | |
534 | INIT_HLIST_HEAD(&object->area_list); | |
535 | spin_lock_init(&object->lock); | |
536 | atomic_set(&object->use_count, 1); | |
04609ccc | 537 | object->flags = OBJECT_ALLOCATED; |
3c7b4e6b CM |
538 | object->pointer = ptr; |
539 | object->size = size; | |
540 | object->min_count = min_count; | |
04609ccc | 541 | object->count = 0; /* white color initially */ |
3c7b4e6b | 542 | object->jiffies = jiffies; |
04609ccc | 543 | object->checksum = 0; |
3c7b4e6b CM |
544 | |
545 | /* task information */ | |
546 | if (in_irq()) { | |
547 | object->pid = 0; | |
548 | strncpy(object->comm, "hardirq", sizeof(object->comm)); | |
549 | } else if (in_softirq()) { | |
550 | object->pid = 0; | |
551 | strncpy(object->comm, "softirq", sizeof(object->comm)); | |
552 | } else { | |
553 | object->pid = current->pid; | |
554 | /* | |
555 | * There is a small chance of a race with set_task_comm(), | |
556 | * however using get_task_comm() here may cause locking | |
557 | * dependency issues with current->alloc_lock. In the worst | |
558 | * case, the command line is not correct. | |
559 | */ | |
560 | strncpy(object->comm, current->comm, sizeof(object->comm)); | |
561 | } | |
562 | ||
563 | /* kernel backtrace */ | |
fd678967 | 564 | object->trace_len = __save_stack_trace(object->trace); |
3c7b4e6b | 565 | |
3c7b4e6b | 566 | write_lock_irqsave(&kmemleak_lock, flags); |
0580a181 | 567 | |
3c7b4e6b CM |
568 | min_addr = min(min_addr, ptr); |
569 | max_addr = max(max_addr, ptr + size); | |
85d3a316 ML |
570 | link = &object_tree_root.rb_node; |
571 | rb_parent = NULL; | |
572 | while (*link) { | |
573 | rb_parent = *link; | |
574 | parent = rb_entry(rb_parent, struct kmemleak_object, rb_node); | |
575 | if (ptr + size <= parent->pointer) | |
576 | link = &parent->rb_node.rb_left; | |
577 | else if (parent->pointer + parent->size <= ptr) | |
578 | link = &parent->rb_node.rb_right; | |
579 | else { | |
580 | kmemleak_stop("Cannot insert 0x%lx into the object " | |
581 | "search tree (overlaps existing)\n", | |
582 | ptr); | |
583 | kmem_cache_free(object_cache, object); | |
584 | object = parent; | |
585 | spin_lock(&object->lock); | |
586 | dump_object_info(object); | |
587 | spin_unlock(&object->lock); | |
588 | goto out; | |
589 | } | |
3c7b4e6b | 590 | } |
85d3a316 ML |
591 | rb_link_node(&object->rb_node, rb_parent, link); |
592 | rb_insert_color(&object->rb_node, &object_tree_root); | |
593 | ||
3c7b4e6b CM |
594 | list_add_tail_rcu(&object->object_list, &object_list); |
595 | out: | |
596 | write_unlock_irqrestore(&kmemleak_lock, flags); | |
fd678967 | 597 | return object; |
3c7b4e6b CM |
598 | } |
599 | ||
600 | /* | |
601 | * Remove the metadata (struct kmemleak_object) for a memory block from the | |
602 | * object_list and object_tree_root and decrement its use_count. | |
603 | */ | |
53238a60 | 604 | static void __delete_object(struct kmemleak_object *object) |
3c7b4e6b CM |
605 | { |
606 | unsigned long flags; | |
3c7b4e6b CM |
607 | |
608 | write_lock_irqsave(&kmemleak_lock, flags); | |
85d3a316 | 609 | rb_erase(&object->rb_node, &object_tree_root); |
3c7b4e6b CM |
610 | list_del_rcu(&object->object_list); |
611 | write_unlock_irqrestore(&kmemleak_lock, flags); | |
612 | ||
613 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); | |
53238a60 | 614 | WARN_ON(atomic_read(&object->use_count) < 2); |
3c7b4e6b CM |
615 | |
616 | /* | |
617 | * Locking here also ensures that the corresponding memory block | |
618 | * cannot be freed when it is being scanned. | |
619 | */ | |
620 | spin_lock_irqsave(&object->lock, flags); | |
3c7b4e6b CM |
621 | object->flags &= ~OBJECT_ALLOCATED; |
622 | spin_unlock_irqrestore(&object->lock, flags); | |
623 | put_object(object); | |
624 | } | |
625 | ||
53238a60 CM |
626 | /* |
627 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
628 | * delete it. | |
629 | */ | |
630 | static void delete_object_full(unsigned long ptr) | |
631 | { | |
632 | struct kmemleak_object *object; | |
633 | ||
634 | object = find_and_get_object(ptr, 0); | |
635 | if (!object) { | |
636 | #ifdef DEBUG | |
637 | kmemleak_warn("Freeing unknown object at 0x%08lx\n", | |
638 | ptr); | |
639 | #endif | |
640 | return; | |
641 | } | |
642 | __delete_object(object); | |
643 | put_object(object); | |
644 | } | |
645 | ||
646 | /* | |
647 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
648 | * delete it. If the memory block is partially freed, the function may create | |
649 | * additional metadata for the remaining parts of the block. | |
650 | */ | |
651 | static void delete_object_part(unsigned long ptr, size_t size) | |
652 | { | |
653 | struct kmemleak_object *object; | |
654 | unsigned long start, end; | |
655 | ||
656 | object = find_and_get_object(ptr, 1); | |
657 | if (!object) { | |
658 | #ifdef DEBUG | |
659 | kmemleak_warn("Partially freeing unknown object at 0x%08lx " | |
660 | "(size %zu)\n", ptr, size); | |
661 | #endif | |
662 | return; | |
663 | } | |
664 | __delete_object(object); | |
665 | ||
666 | /* | |
667 | * Create one or two objects that may result from the memory block | |
668 | * split. Note that partial freeing is only done by free_bootmem() and | |
669 | * this happens before kmemleak_init() is called. The path below is | |
670 | * only executed during early log recording in kmemleak_init(), so | |
671 | * GFP_KERNEL is enough. | |
672 | */ | |
673 | start = object->pointer; | |
674 | end = object->pointer + object->size; | |
675 | if (ptr > start) | |
676 | create_object(start, ptr - start, object->min_count, | |
677 | GFP_KERNEL); | |
678 | if (ptr + size < end) | |
679 | create_object(ptr + size, end - ptr - size, object->min_count, | |
680 | GFP_KERNEL); | |
681 | ||
682 | put_object(object); | |
683 | } | |
a1084c87 LR |
684 | |
685 | static void __paint_it(struct kmemleak_object *object, int color) | |
686 | { | |
687 | object->min_count = color; | |
688 | if (color == KMEMLEAK_BLACK) | |
689 | object->flags |= OBJECT_NO_SCAN; | |
690 | } | |
691 | ||
692 | static void paint_it(struct kmemleak_object *object, int color) | |
3c7b4e6b CM |
693 | { |
694 | unsigned long flags; | |
a1084c87 LR |
695 | |
696 | spin_lock_irqsave(&object->lock, flags); | |
697 | __paint_it(object, color); | |
698 | spin_unlock_irqrestore(&object->lock, flags); | |
699 | } | |
700 | ||
701 | static void paint_ptr(unsigned long ptr, int color) | |
702 | { | |
3c7b4e6b CM |
703 | struct kmemleak_object *object; |
704 | ||
705 | object = find_and_get_object(ptr, 0); | |
706 | if (!object) { | |
a1084c87 LR |
707 | kmemleak_warn("Trying to color unknown object " |
708 | "at 0x%08lx as %s\n", ptr, | |
709 | (color == KMEMLEAK_GREY) ? "Grey" : | |
710 | (color == KMEMLEAK_BLACK) ? "Black" : "Unknown"); | |
3c7b4e6b CM |
711 | return; |
712 | } | |
a1084c87 | 713 | paint_it(object, color); |
3c7b4e6b CM |
714 | put_object(object); |
715 | } | |
716 | ||
a1084c87 | 717 | /* |
145b64b9 | 718 | * Mark an object permanently as gray-colored so that it can no longer be |
a1084c87 LR |
719 | * reported as a leak. This is used in general to mark a false positive. |
720 | */ | |
721 | static void make_gray_object(unsigned long ptr) | |
722 | { | |
723 | paint_ptr(ptr, KMEMLEAK_GREY); | |
724 | } | |
725 | ||
3c7b4e6b CM |
726 | /* |
727 | * Mark the object as black-colored so that it is ignored from scans and | |
728 | * reporting. | |
729 | */ | |
730 | static void make_black_object(unsigned long ptr) | |
731 | { | |
a1084c87 | 732 | paint_ptr(ptr, KMEMLEAK_BLACK); |
3c7b4e6b CM |
733 | } |
734 | ||
735 | /* | |
736 | * Add a scanning area to the object. If at least one such area is added, | |
737 | * kmemleak will only scan these ranges rather than the whole memory block. | |
738 | */ | |
c017b4be | 739 | static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
740 | { |
741 | unsigned long flags; | |
742 | struct kmemleak_object *object; | |
743 | struct kmemleak_scan_area *area; | |
744 | ||
c017b4be | 745 | object = find_and_get_object(ptr, 1); |
3c7b4e6b | 746 | if (!object) { |
ae281064 JP |
747 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
748 | ptr); | |
3c7b4e6b CM |
749 | return; |
750 | } | |
751 | ||
6ae4bd1f | 752 | area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b | 753 | if (!area) { |
6ae4bd1f | 754 | pr_warning("Cannot allocate a scan area\n"); |
3c7b4e6b CM |
755 | goto out; |
756 | } | |
757 | ||
758 | spin_lock_irqsave(&object->lock, flags); | |
7f88f88f CM |
759 | if (size == SIZE_MAX) { |
760 | size = object->pointer + object->size - ptr; | |
761 | } else if (ptr + size > object->pointer + object->size) { | |
ae281064 | 762 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
3c7b4e6b CM |
763 | dump_object_info(object); |
764 | kmem_cache_free(scan_area_cache, area); | |
765 | goto out_unlock; | |
766 | } | |
767 | ||
768 | INIT_HLIST_NODE(&area->node); | |
c017b4be CM |
769 | area->start = ptr; |
770 | area->size = size; | |
3c7b4e6b CM |
771 | |
772 | hlist_add_head(&area->node, &object->area_list); | |
773 | out_unlock: | |
774 | spin_unlock_irqrestore(&object->lock, flags); | |
775 | out: | |
776 | put_object(object); | |
777 | } | |
778 | ||
779 | /* | |
780 | * Set the OBJECT_NO_SCAN flag for the object corresponding to the give | |
781 | * pointer. Such object will not be scanned by kmemleak but references to it | |
782 | * are searched. | |
783 | */ | |
784 | static void object_no_scan(unsigned long ptr) | |
785 | { | |
786 | unsigned long flags; | |
787 | struct kmemleak_object *object; | |
788 | ||
789 | object = find_and_get_object(ptr, 0); | |
790 | if (!object) { | |
ae281064 | 791 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
3c7b4e6b CM |
792 | return; |
793 | } | |
794 | ||
795 | spin_lock_irqsave(&object->lock, flags); | |
796 | object->flags |= OBJECT_NO_SCAN; | |
797 | spin_unlock_irqrestore(&object->lock, flags); | |
798 | put_object(object); | |
799 | } | |
800 | ||
801 | /* | |
802 | * Log an early kmemleak_* call to the early_log buffer. These calls will be | |
803 | * processed later once kmemleak is fully initialized. | |
804 | */ | |
a6186d89 | 805 | static void __init log_early(int op_type, const void *ptr, size_t size, |
c017b4be | 806 | int min_count) |
3c7b4e6b CM |
807 | { |
808 | unsigned long flags; | |
809 | struct early_log *log; | |
810 | ||
8910ae89 | 811 | if (kmemleak_error) { |
b6693005 CM |
812 | /* kmemleak stopped recording, just count the requests */ |
813 | crt_early_log++; | |
814 | return; | |
815 | } | |
816 | ||
3c7b4e6b | 817 | if (crt_early_log >= ARRAY_SIZE(early_log)) { |
a9d9058a | 818 | kmemleak_disable(); |
3c7b4e6b CM |
819 | return; |
820 | } | |
821 | ||
822 | /* | |
823 | * There is no need for locking since the kernel is still in UP mode | |
824 | * at this stage. Disabling the IRQs is enough. | |
825 | */ | |
826 | local_irq_save(flags); | |
827 | log = &early_log[crt_early_log]; | |
828 | log->op_type = op_type; | |
829 | log->ptr = ptr; | |
830 | log->size = size; | |
831 | log->min_count = min_count; | |
5f79020c | 832 | log->trace_len = __save_stack_trace(log->trace); |
3c7b4e6b CM |
833 | crt_early_log++; |
834 | local_irq_restore(flags); | |
835 | } | |
836 | ||
fd678967 CM |
837 | /* |
838 | * Log an early allocated block and populate the stack trace. | |
839 | */ | |
840 | static void early_alloc(struct early_log *log) | |
841 | { | |
842 | struct kmemleak_object *object; | |
843 | unsigned long flags; | |
844 | int i; | |
845 | ||
8910ae89 | 846 | if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr)) |
fd678967 CM |
847 | return; |
848 | ||
849 | /* | |
850 | * RCU locking needed to ensure object is not freed via put_object(). | |
851 | */ | |
852 | rcu_read_lock(); | |
853 | object = create_object((unsigned long)log->ptr, log->size, | |
c1bcd6b3 | 854 | log->min_count, GFP_ATOMIC); |
0d5d1aad CM |
855 | if (!object) |
856 | goto out; | |
fd678967 CM |
857 | spin_lock_irqsave(&object->lock, flags); |
858 | for (i = 0; i < log->trace_len; i++) | |
859 | object->trace[i] = log->trace[i]; | |
860 | object->trace_len = log->trace_len; | |
861 | spin_unlock_irqrestore(&object->lock, flags); | |
0d5d1aad | 862 | out: |
fd678967 CM |
863 | rcu_read_unlock(); |
864 | } | |
865 | ||
f528f0b8 CM |
866 | /* |
867 | * Log an early allocated block and populate the stack trace. | |
868 | */ | |
869 | static void early_alloc_percpu(struct early_log *log) | |
870 | { | |
871 | unsigned int cpu; | |
872 | const void __percpu *ptr = log->ptr; | |
873 | ||
874 | for_each_possible_cpu(cpu) { | |
875 | log->ptr = per_cpu_ptr(ptr, cpu); | |
876 | early_alloc(log); | |
877 | } | |
878 | } | |
879 | ||
a2b6bf63 CM |
880 | /** |
881 | * kmemleak_alloc - register a newly allocated object | |
882 | * @ptr: pointer to beginning of the object | |
883 | * @size: size of the object | |
884 | * @min_count: minimum number of references to this object. If during memory | |
885 | * scanning a number of references less than @min_count is found, | |
886 | * the object is reported as a memory leak. If @min_count is 0, | |
887 | * the object is never reported as a leak. If @min_count is -1, | |
888 | * the object is ignored (not scanned and not reported as a leak) | |
889 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
890 | * | |
891 | * This function is called from the kernel allocators when a new object | |
892 | * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.). | |
3c7b4e6b | 893 | */ |
a6186d89 CM |
894 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
895 | gfp_t gfp) | |
3c7b4e6b CM |
896 | { |
897 | pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); | |
898 | ||
8910ae89 | 899 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 900 | create_object((unsigned long)ptr, size, min_count, gfp); |
8910ae89 | 901 | else if (kmemleak_early_log) |
c017b4be | 902 | log_early(KMEMLEAK_ALLOC, ptr, size, min_count); |
3c7b4e6b CM |
903 | } |
904 | EXPORT_SYMBOL_GPL(kmemleak_alloc); | |
905 | ||
f528f0b8 CM |
906 | /** |
907 | * kmemleak_alloc_percpu - register a newly allocated __percpu object | |
908 | * @ptr: __percpu pointer to beginning of the object | |
909 | * @size: size of the object | |
910 | * | |
911 | * This function is called from the kernel percpu allocator when a new object | |
912 | * (memory block) is allocated (alloc_percpu). It assumes GFP_KERNEL | |
913 | * allocation. | |
914 | */ | |
915 | void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size) | |
916 | { | |
917 | unsigned int cpu; | |
918 | ||
919 | pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size); | |
920 | ||
921 | /* | |
922 | * Percpu allocations are only scanned and not reported as leaks | |
923 | * (min_count is set to 0). | |
924 | */ | |
8910ae89 | 925 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
926 | for_each_possible_cpu(cpu) |
927 | create_object((unsigned long)per_cpu_ptr(ptr, cpu), | |
928 | size, 0, GFP_KERNEL); | |
8910ae89 | 929 | else if (kmemleak_early_log) |
f528f0b8 CM |
930 | log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0); |
931 | } | |
932 | EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); | |
933 | ||
a2b6bf63 CM |
934 | /** |
935 | * kmemleak_free - unregister a previously registered object | |
936 | * @ptr: pointer to beginning of the object | |
937 | * | |
938 | * This function is called from the kernel allocators when an object (memory | |
939 | * block) is freed (kmem_cache_free, kfree, vfree etc.). | |
3c7b4e6b | 940 | */ |
a6186d89 | 941 | void __ref kmemleak_free(const void *ptr) |
3c7b4e6b CM |
942 | { |
943 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
944 | ||
8910ae89 | 945 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 946 | delete_object_full((unsigned long)ptr); |
8910ae89 | 947 | else if (kmemleak_early_log) |
c017b4be | 948 | log_early(KMEMLEAK_FREE, ptr, 0, 0); |
3c7b4e6b CM |
949 | } |
950 | EXPORT_SYMBOL_GPL(kmemleak_free); | |
951 | ||
a2b6bf63 CM |
952 | /** |
953 | * kmemleak_free_part - partially unregister a previously registered object | |
954 | * @ptr: pointer to the beginning or inside the object. This also | |
955 | * represents the start of the range to be freed | |
956 | * @size: size to be unregistered | |
957 | * | |
958 | * This function is called when only a part of a memory block is freed | |
959 | * (usually from the bootmem allocator). | |
53238a60 | 960 | */ |
a6186d89 | 961 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
53238a60 CM |
962 | { |
963 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
964 | ||
8910ae89 | 965 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 966 | delete_object_part((unsigned long)ptr, size); |
8910ae89 | 967 | else if (kmemleak_early_log) |
c017b4be | 968 | log_early(KMEMLEAK_FREE_PART, ptr, size, 0); |
53238a60 CM |
969 | } |
970 | EXPORT_SYMBOL_GPL(kmemleak_free_part); | |
971 | ||
f528f0b8 CM |
972 | /** |
973 | * kmemleak_free_percpu - unregister a previously registered __percpu object | |
974 | * @ptr: __percpu pointer to beginning of the object | |
975 | * | |
976 | * This function is called from the kernel percpu allocator when an object | |
977 | * (memory block) is freed (free_percpu). | |
978 | */ | |
979 | void __ref kmemleak_free_percpu(const void __percpu *ptr) | |
980 | { | |
981 | unsigned int cpu; | |
982 | ||
983 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
984 | ||
8910ae89 | 985 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
986 | for_each_possible_cpu(cpu) |
987 | delete_object_full((unsigned long)per_cpu_ptr(ptr, | |
988 | cpu)); | |
8910ae89 | 989 | else if (kmemleak_early_log) |
f528f0b8 CM |
990 | log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0); |
991 | } | |
992 | EXPORT_SYMBOL_GPL(kmemleak_free_percpu); | |
993 | ||
ffe2c748 CM |
994 | /** |
995 | * kmemleak_update_trace - update object allocation stack trace | |
996 | * @ptr: pointer to beginning of the object | |
997 | * | |
998 | * Override the object allocation stack trace for cases where the actual | |
999 | * allocation place is not always useful. | |
1000 | */ | |
1001 | void __ref kmemleak_update_trace(const void *ptr) | |
1002 | { | |
1003 | struct kmemleak_object *object; | |
1004 | unsigned long flags; | |
1005 | ||
1006 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1007 | ||
1008 | if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr)) | |
1009 | return; | |
1010 | ||
1011 | object = find_and_get_object((unsigned long)ptr, 1); | |
1012 | if (!object) { | |
1013 | #ifdef DEBUG | |
1014 | kmemleak_warn("Updating stack trace for unknown object at %p\n", | |
1015 | ptr); | |
1016 | #endif | |
1017 | return; | |
1018 | } | |
1019 | ||
1020 | spin_lock_irqsave(&object->lock, flags); | |
1021 | object->trace_len = __save_stack_trace(object->trace); | |
1022 | spin_unlock_irqrestore(&object->lock, flags); | |
1023 | ||
1024 | put_object(object); | |
1025 | } | |
1026 | EXPORT_SYMBOL(kmemleak_update_trace); | |
1027 | ||
a2b6bf63 CM |
1028 | /** |
1029 | * kmemleak_not_leak - mark an allocated object as false positive | |
1030 | * @ptr: pointer to beginning of the object | |
1031 | * | |
1032 | * Calling this function on an object will cause the memory block to no longer | |
1033 | * be reported as leak and always be scanned. | |
3c7b4e6b | 1034 | */ |
a6186d89 | 1035 | void __ref kmemleak_not_leak(const void *ptr) |
3c7b4e6b CM |
1036 | { |
1037 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1038 | ||
8910ae89 | 1039 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1040 | make_gray_object((unsigned long)ptr); |
8910ae89 | 1041 | else if (kmemleak_early_log) |
c017b4be | 1042 | log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0); |
3c7b4e6b CM |
1043 | } |
1044 | EXPORT_SYMBOL(kmemleak_not_leak); | |
1045 | ||
a2b6bf63 CM |
1046 | /** |
1047 | * kmemleak_ignore - ignore an allocated object | |
1048 | * @ptr: pointer to beginning of the object | |
1049 | * | |
1050 | * Calling this function on an object will cause the memory block to be | |
1051 | * ignored (not scanned and not reported as a leak). This is usually done when | |
1052 | * it is known that the corresponding block is not a leak and does not contain | |
1053 | * any references to other allocated memory blocks. | |
3c7b4e6b | 1054 | */ |
a6186d89 | 1055 | void __ref kmemleak_ignore(const void *ptr) |
3c7b4e6b CM |
1056 | { |
1057 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1058 | ||
8910ae89 | 1059 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1060 | make_black_object((unsigned long)ptr); |
8910ae89 | 1061 | else if (kmemleak_early_log) |
c017b4be | 1062 | log_early(KMEMLEAK_IGNORE, ptr, 0, 0); |
3c7b4e6b CM |
1063 | } |
1064 | EXPORT_SYMBOL(kmemleak_ignore); | |
1065 | ||
a2b6bf63 CM |
1066 | /** |
1067 | * kmemleak_scan_area - limit the range to be scanned in an allocated object | |
1068 | * @ptr: pointer to beginning or inside the object. This also | |
1069 | * represents the start of the scan area | |
1070 | * @size: size of the scan area | |
1071 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1072 | * | |
1073 | * This function is used when it is known that only certain parts of an object | |
1074 | * contain references to other objects. Kmemleak will only scan these areas | |
1075 | * reducing the number false negatives. | |
3c7b4e6b | 1076 | */ |
c017b4be | 1077 | void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
1078 | { |
1079 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1080 | ||
8910ae89 | 1081 | if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
c017b4be | 1082 | add_scan_area((unsigned long)ptr, size, gfp); |
8910ae89 | 1083 | else if (kmemleak_early_log) |
c017b4be | 1084 | log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0); |
3c7b4e6b CM |
1085 | } |
1086 | EXPORT_SYMBOL(kmemleak_scan_area); | |
1087 | ||
a2b6bf63 CM |
1088 | /** |
1089 | * kmemleak_no_scan - do not scan an allocated object | |
1090 | * @ptr: pointer to beginning of the object | |
1091 | * | |
1092 | * This function notifies kmemleak not to scan the given memory block. Useful | |
1093 | * in situations where it is known that the given object does not contain any | |
1094 | * references to other objects. Kmemleak will not scan such objects reducing | |
1095 | * the number of false negatives. | |
3c7b4e6b | 1096 | */ |
a6186d89 | 1097 | void __ref kmemleak_no_scan(const void *ptr) |
3c7b4e6b CM |
1098 | { |
1099 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1100 | ||
8910ae89 | 1101 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1102 | object_no_scan((unsigned long)ptr); |
8910ae89 | 1103 | else if (kmemleak_early_log) |
c017b4be | 1104 | log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0); |
3c7b4e6b CM |
1105 | } |
1106 | EXPORT_SYMBOL(kmemleak_no_scan); | |
1107 | ||
04609ccc CM |
1108 | /* |
1109 | * Update an object's checksum and return true if it was modified. | |
1110 | */ | |
1111 | static bool update_checksum(struct kmemleak_object *object) | |
1112 | { | |
1113 | u32 old_csum = object->checksum; | |
1114 | ||
1115 | if (!kmemcheck_is_obj_initialized(object->pointer, object->size)) | |
1116 | return false; | |
1117 | ||
e79ed2f1 | 1118 | kasan_disable_current(); |
04609ccc | 1119 | object->checksum = crc32(0, (void *)object->pointer, object->size); |
e79ed2f1 AR |
1120 | kasan_enable_current(); |
1121 | ||
04609ccc CM |
1122 | return object->checksum != old_csum; |
1123 | } | |
1124 | ||
3c7b4e6b CM |
1125 | /* |
1126 | * Memory scanning is a long process and it needs to be interruptable. This | |
25985edc | 1127 | * function checks whether such interrupt condition occurred. |
3c7b4e6b CM |
1128 | */ |
1129 | static int scan_should_stop(void) | |
1130 | { | |
8910ae89 | 1131 | if (!kmemleak_enabled) |
3c7b4e6b CM |
1132 | return 1; |
1133 | ||
1134 | /* | |
1135 | * This function may be called from either process or kthread context, | |
1136 | * hence the need to check for both stop conditions. | |
1137 | */ | |
1138 | if (current->mm) | |
1139 | return signal_pending(current); | |
1140 | else | |
1141 | return kthread_should_stop(); | |
1142 | ||
1143 | return 0; | |
1144 | } | |
1145 | ||
1146 | /* | |
1147 | * Scan a memory block (exclusive range) for valid pointers and add those | |
1148 | * found to the gray list. | |
1149 | */ | |
1150 | static void scan_block(void *_start, void *_end, | |
4b8a9674 | 1151 | struct kmemleak_object *scanned, int allow_resched) |
3c7b4e6b CM |
1152 | { |
1153 | unsigned long *ptr; | |
1154 | unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); | |
1155 | unsigned long *end = _end - (BYTES_PER_POINTER - 1); | |
1156 | ||
1157 | for (ptr = start; ptr < end; ptr++) { | |
3c7b4e6b | 1158 | struct kmemleak_object *object; |
8e019366 PE |
1159 | unsigned long flags; |
1160 | unsigned long pointer; | |
3c7b4e6b | 1161 | |
4b8a9674 CM |
1162 | if (allow_resched) |
1163 | cond_resched(); | |
3c7b4e6b CM |
1164 | if (scan_should_stop()) |
1165 | break; | |
1166 | ||
8e019366 PE |
1167 | /* don't scan uninitialized memory */ |
1168 | if (!kmemcheck_is_obj_initialized((unsigned long)ptr, | |
1169 | BYTES_PER_POINTER)) | |
1170 | continue; | |
1171 | ||
e79ed2f1 | 1172 | kasan_disable_current(); |
8e019366 | 1173 | pointer = *ptr; |
e79ed2f1 | 1174 | kasan_enable_current(); |
8e019366 | 1175 | |
3c7b4e6b CM |
1176 | object = find_and_get_object(pointer, 1); |
1177 | if (!object) | |
1178 | continue; | |
1179 | if (object == scanned) { | |
1180 | /* self referenced, ignore */ | |
1181 | put_object(object); | |
1182 | continue; | |
1183 | } | |
1184 | ||
1185 | /* | |
1186 | * Avoid the lockdep recursive warning on object->lock being | |
1187 | * previously acquired in scan_object(). These locks are | |
1188 | * enclosed by scan_mutex. | |
1189 | */ | |
1190 | spin_lock_irqsave_nested(&object->lock, flags, | |
1191 | SINGLE_DEPTH_NESTING); | |
1192 | if (!color_white(object)) { | |
1193 | /* non-orphan, ignored or new */ | |
1194 | spin_unlock_irqrestore(&object->lock, flags); | |
1195 | put_object(object); | |
1196 | continue; | |
1197 | } | |
1198 | ||
1199 | /* | |
1200 | * Increase the object's reference count (number of pointers | |
1201 | * to the memory block). If this count reaches the required | |
1202 | * minimum, the object's color will become gray and it will be | |
1203 | * added to the gray_list. | |
1204 | */ | |
1205 | object->count++; | |
0587da40 | 1206 | if (color_gray(object)) { |
3c7b4e6b | 1207 | list_add_tail(&object->gray_list, &gray_list); |
0587da40 CM |
1208 | spin_unlock_irqrestore(&object->lock, flags); |
1209 | continue; | |
1210 | } | |
1211 | ||
3c7b4e6b | 1212 | spin_unlock_irqrestore(&object->lock, flags); |
0587da40 | 1213 | put_object(object); |
3c7b4e6b CM |
1214 | } |
1215 | } | |
1216 | ||
1217 | /* | |
1218 | * Scan a memory block corresponding to a kmemleak_object. A condition is | |
1219 | * that object->use_count >= 1. | |
1220 | */ | |
1221 | static void scan_object(struct kmemleak_object *object) | |
1222 | { | |
1223 | struct kmemleak_scan_area *area; | |
3c7b4e6b CM |
1224 | unsigned long flags; |
1225 | ||
1226 | /* | |
21ae2956 UKK |
1227 | * Once the object->lock is acquired, the corresponding memory block |
1228 | * cannot be freed (the same lock is acquired in delete_object). | |
3c7b4e6b CM |
1229 | */ |
1230 | spin_lock_irqsave(&object->lock, flags); | |
1231 | if (object->flags & OBJECT_NO_SCAN) | |
1232 | goto out; | |
1233 | if (!(object->flags & OBJECT_ALLOCATED)) | |
1234 | /* already freed object */ | |
1235 | goto out; | |
af98603d CM |
1236 | if (hlist_empty(&object->area_list)) { |
1237 | void *start = (void *)object->pointer; | |
1238 | void *end = (void *)(object->pointer + object->size); | |
1239 | ||
1240 | while (start < end && (object->flags & OBJECT_ALLOCATED) && | |
1241 | !(object->flags & OBJECT_NO_SCAN)) { | |
1242 | scan_block(start, min(start + MAX_SCAN_SIZE, end), | |
1243 | object, 0); | |
1244 | start += MAX_SCAN_SIZE; | |
1245 | ||
1246 | spin_unlock_irqrestore(&object->lock, flags); | |
1247 | cond_resched(); | |
1248 | spin_lock_irqsave(&object->lock, flags); | |
1249 | } | |
1250 | } else | |
b67bfe0d | 1251 | hlist_for_each_entry(area, &object->area_list, node) |
c017b4be CM |
1252 | scan_block((void *)area->start, |
1253 | (void *)(area->start + area->size), | |
1254 | object, 0); | |
3c7b4e6b CM |
1255 | out: |
1256 | spin_unlock_irqrestore(&object->lock, flags); | |
1257 | } | |
1258 | ||
04609ccc CM |
1259 | /* |
1260 | * Scan the objects already referenced (gray objects). More objects will be | |
1261 | * referenced and, if there are no memory leaks, all the objects are scanned. | |
1262 | */ | |
1263 | static void scan_gray_list(void) | |
1264 | { | |
1265 | struct kmemleak_object *object, *tmp; | |
1266 | ||
1267 | /* | |
1268 | * The list traversal is safe for both tail additions and removals | |
1269 | * from inside the loop. The kmemleak objects cannot be freed from | |
1270 | * outside the loop because their use_count was incremented. | |
1271 | */ | |
1272 | object = list_entry(gray_list.next, typeof(*object), gray_list); | |
1273 | while (&object->gray_list != &gray_list) { | |
1274 | cond_resched(); | |
1275 | ||
1276 | /* may add new objects to the list */ | |
1277 | if (!scan_should_stop()) | |
1278 | scan_object(object); | |
1279 | ||
1280 | tmp = list_entry(object->gray_list.next, typeof(*object), | |
1281 | gray_list); | |
1282 | ||
1283 | /* remove the object from the list and release it */ | |
1284 | list_del(&object->gray_list); | |
1285 | put_object(object); | |
1286 | ||
1287 | object = tmp; | |
1288 | } | |
1289 | WARN_ON(!list_empty(&gray_list)); | |
1290 | } | |
1291 | ||
3c7b4e6b CM |
1292 | /* |
1293 | * Scan data sections and all the referenced memory blocks allocated via the | |
1294 | * kernel's standard allocators. This function must be called with the | |
1295 | * scan_mutex held. | |
1296 | */ | |
1297 | static void kmemleak_scan(void) | |
1298 | { | |
1299 | unsigned long flags; | |
04609ccc | 1300 | struct kmemleak_object *object; |
3c7b4e6b | 1301 | int i; |
4698c1f2 | 1302 | int new_leaks = 0; |
3c7b4e6b | 1303 | |
acf4968e CM |
1304 | jiffies_last_scan = jiffies; |
1305 | ||
3c7b4e6b CM |
1306 | /* prepare the kmemleak_object's */ |
1307 | rcu_read_lock(); | |
1308 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1309 | spin_lock_irqsave(&object->lock, flags); | |
1310 | #ifdef DEBUG | |
1311 | /* | |
1312 | * With a few exceptions there should be a maximum of | |
1313 | * 1 reference to any object at this point. | |
1314 | */ | |
1315 | if (atomic_read(&object->use_count) > 1) { | |
ae281064 | 1316 | pr_debug("object->use_count = %d\n", |
3c7b4e6b CM |
1317 | atomic_read(&object->use_count)); |
1318 | dump_object_info(object); | |
1319 | } | |
1320 | #endif | |
1321 | /* reset the reference count (whiten the object) */ | |
1322 | object->count = 0; | |
1323 | if (color_gray(object) && get_object(object)) | |
1324 | list_add_tail(&object->gray_list, &gray_list); | |
1325 | ||
1326 | spin_unlock_irqrestore(&object->lock, flags); | |
1327 | } | |
1328 | rcu_read_unlock(); | |
1329 | ||
1330 | /* data/bss scanning */ | |
4b8a9674 CM |
1331 | scan_block(_sdata, _edata, NULL, 1); |
1332 | scan_block(__bss_start, __bss_stop, NULL, 1); | |
3c7b4e6b CM |
1333 | |
1334 | #ifdef CONFIG_SMP | |
1335 | /* per-cpu sections scanning */ | |
1336 | for_each_possible_cpu(i) | |
1337 | scan_block(__per_cpu_start + per_cpu_offset(i), | |
4b8a9674 | 1338 | __per_cpu_end + per_cpu_offset(i), NULL, 1); |
3c7b4e6b CM |
1339 | #endif |
1340 | ||
1341 | /* | |
029aeff5 | 1342 | * Struct page scanning for each node. |
3c7b4e6b | 1343 | */ |
bfc8c901 | 1344 | get_online_mems(); |
3c7b4e6b | 1345 | for_each_online_node(i) { |
108bcc96 CS |
1346 | unsigned long start_pfn = node_start_pfn(i); |
1347 | unsigned long end_pfn = node_end_pfn(i); | |
3c7b4e6b CM |
1348 | unsigned long pfn; |
1349 | ||
1350 | for (pfn = start_pfn; pfn < end_pfn; pfn++) { | |
1351 | struct page *page; | |
1352 | ||
1353 | if (!pfn_valid(pfn)) | |
1354 | continue; | |
1355 | page = pfn_to_page(pfn); | |
1356 | /* only scan if page is in use */ | |
1357 | if (page_count(page) == 0) | |
1358 | continue; | |
4b8a9674 | 1359 | scan_block(page, page + 1, NULL, 1); |
3c7b4e6b CM |
1360 | } |
1361 | } | |
bfc8c901 | 1362 | put_online_mems(); |
3c7b4e6b CM |
1363 | |
1364 | /* | |
43ed5d6e | 1365 | * Scanning the task stacks (may introduce false negatives). |
3c7b4e6b CM |
1366 | */ |
1367 | if (kmemleak_stack_scan) { | |
43ed5d6e CM |
1368 | struct task_struct *p, *g; |
1369 | ||
3c7b4e6b | 1370 | read_lock(&tasklist_lock); |
43ed5d6e CM |
1371 | do_each_thread(g, p) { |
1372 | scan_block(task_stack_page(p), task_stack_page(p) + | |
1373 | THREAD_SIZE, NULL, 0); | |
1374 | } while_each_thread(g, p); | |
3c7b4e6b CM |
1375 | read_unlock(&tasklist_lock); |
1376 | } | |
1377 | ||
1378 | /* | |
1379 | * Scan the objects already referenced from the sections scanned | |
04609ccc | 1380 | * above. |
3c7b4e6b | 1381 | */ |
04609ccc | 1382 | scan_gray_list(); |
2587362e CM |
1383 | |
1384 | /* | |
04609ccc CM |
1385 | * Check for new or unreferenced objects modified since the previous |
1386 | * scan and color them gray until the next scan. | |
2587362e CM |
1387 | */ |
1388 | rcu_read_lock(); | |
1389 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1390 | spin_lock_irqsave(&object->lock, flags); | |
04609ccc CM |
1391 | if (color_white(object) && (object->flags & OBJECT_ALLOCATED) |
1392 | && update_checksum(object) && get_object(object)) { | |
1393 | /* color it gray temporarily */ | |
1394 | object->count = object->min_count; | |
2587362e CM |
1395 | list_add_tail(&object->gray_list, &gray_list); |
1396 | } | |
1397 | spin_unlock_irqrestore(&object->lock, flags); | |
1398 | } | |
1399 | rcu_read_unlock(); | |
1400 | ||
04609ccc CM |
1401 | /* |
1402 | * Re-scan the gray list for modified unreferenced objects. | |
1403 | */ | |
1404 | scan_gray_list(); | |
4698c1f2 | 1405 | |
17bb9e0d | 1406 | /* |
04609ccc | 1407 | * If scanning was stopped do not report any new unreferenced objects. |
17bb9e0d | 1408 | */ |
04609ccc | 1409 | if (scan_should_stop()) |
17bb9e0d CM |
1410 | return; |
1411 | ||
4698c1f2 CM |
1412 | /* |
1413 | * Scanning result reporting. | |
1414 | */ | |
1415 | rcu_read_lock(); | |
1416 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1417 | spin_lock_irqsave(&object->lock, flags); | |
1418 | if (unreferenced_object(object) && | |
1419 | !(object->flags & OBJECT_REPORTED)) { | |
1420 | object->flags |= OBJECT_REPORTED; | |
1421 | new_leaks++; | |
1422 | } | |
1423 | spin_unlock_irqrestore(&object->lock, flags); | |
1424 | } | |
1425 | rcu_read_unlock(); | |
1426 | ||
dc9b3f42 LZ |
1427 | if (new_leaks) { |
1428 | kmemleak_found_leaks = true; | |
1429 | ||
4698c1f2 CM |
1430 | pr_info("%d new suspected memory leaks (see " |
1431 | "/sys/kernel/debug/kmemleak)\n", new_leaks); | |
dc9b3f42 | 1432 | } |
4698c1f2 | 1433 | |
3c7b4e6b CM |
1434 | } |
1435 | ||
1436 | /* | |
1437 | * Thread function performing automatic memory scanning. Unreferenced objects | |
1438 | * at the end of a memory scan are reported but only the first time. | |
1439 | */ | |
1440 | static int kmemleak_scan_thread(void *arg) | |
1441 | { | |
1442 | static int first_run = 1; | |
1443 | ||
ae281064 | 1444 | pr_info("Automatic memory scanning thread started\n"); |
bf2a76b3 | 1445 | set_user_nice(current, 10); |
3c7b4e6b CM |
1446 | |
1447 | /* | |
1448 | * Wait before the first scan to allow the system to fully initialize. | |
1449 | */ | |
1450 | if (first_run) { | |
1451 | first_run = 0; | |
1452 | ssleep(SECS_FIRST_SCAN); | |
1453 | } | |
1454 | ||
1455 | while (!kthread_should_stop()) { | |
3c7b4e6b CM |
1456 | signed long timeout = jiffies_scan_wait; |
1457 | ||
1458 | mutex_lock(&scan_mutex); | |
3c7b4e6b | 1459 | kmemleak_scan(); |
3c7b4e6b | 1460 | mutex_unlock(&scan_mutex); |
4698c1f2 | 1461 | |
3c7b4e6b CM |
1462 | /* wait before the next scan */ |
1463 | while (timeout && !kthread_should_stop()) | |
1464 | timeout = schedule_timeout_interruptible(timeout); | |
1465 | } | |
1466 | ||
ae281064 | 1467 | pr_info("Automatic memory scanning thread ended\n"); |
3c7b4e6b CM |
1468 | |
1469 | return 0; | |
1470 | } | |
1471 | ||
1472 | /* | |
1473 | * Start the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1474 | * with the scan_mutex held. |
3c7b4e6b | 1475 | */ |
7eb0d5e5 | 1476 | static void start_scan_thread(void) |
3c7b4e6b CM |
1477 | { |
1478 | if (scan_thread) | |
1479 | return; | |
1480 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); | |
1481 | if (IS_ERR(scan_thread)) { | |
ae281064 | 1482 | pr_warning("Failed to create the scan thread\n"); |
3c7b4e6b CM |
1483 | scan_thread = NULL; |
1484 | } | |
1485 | } | |
1486 | ||
1487 | /* | |
1488 | * Stop the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1489 | * with the scan_mutex held. |
3c7b4e6b | 1490 | */ |
7eb0d5e5 | 1491 | static void stop_scan_thread(void) |
3c7b4e6b CM |
1492 | { |
1493 | if (scan_thread) { | |
1494 | kthread_stop(scan_thread); | |
1495 | scan_thread = NULL; | |
1496 | } | |
1497 | } | |
1498 | ||
1499 | /* | |
1500 | * Iterate over the object_list and return the first valid object at or after | |
1501 | * the required position with its use_count incremented. The function triggers | |
1502 | * a memory scanning when the pos argument points to the first position. | |
1503 | */ | |
1504 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) | |
1505 | { | |
1506 | struct kmemleak_object *object; | |
1507 | loff_t n = *pos; | |
b87324d0 CM |
1508 | int err; |
1509 | ||
1510 | err = mutex_lock_interruptible(&scan_mutex); | |
1511 | if (err < 0) | |
1512 | return ERR_PTR(err); | |
3c7b4e6b | 1513 | |
3c7b4e6b CM |
1514 | rcu_read_lock(); |
1515 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1516 | if (n-- > 0) | |
1517 | continue; | |
1518 | if (get_object(object)) | |
1519 | goto out; | |
1520 | } | |
1521 | object = NULL; | |
1522 | out: | |
3c7b4e6b CM |
1523 | return object; |
1524 | } | |
1525 | ||
1526 | /* | |
1527 | * Return the next object in the object_list. The function decrements the | |
1528 | * use_count of the previous object and increases that of the next one. | |
1529 | */ | |
1530 | static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
1531 | { | |
1532 | struct kmemleak_object *prev_obj = v; | |
1533 | struct kmemleak_object *next_obj = NULL; | |
58fac095 | 1534 | struct kmemleak_object *obj = prev_obj; |
3c7b4e6b CM |
1535 | |
1536 | ++(*pos); | |
3c7b4e6b | 1537 | |
58fac095 | 1538 | list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
52c3ce4e CM |
1539 | if (get_object(obj)) { |
1540 | next_obj = obj; | |
3c7b4e6b | 1541 | break; |
52c3ce4e | 1542 | } |
3c7b4e6b | 1543 | } |
288c857d | 1544 | |
3c7b4e6b CM |
1545 | put_object(prev_obj); |
1546 | return next_obj; | |
1547 | } | |
1548 | ||
1549 | /* | |
1550 | * Decrement the use_count of the last object required, if any. | |
1551 | */ | |
1552 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) | |
1553 | { | |
b87324d0 CM |
1554 | if (!IS_ERR(v)) { |
1555 | /* | |
1556 | * kmemleak_seq_start may return ERR_PTR if the scan_mutex | |
1557 | * waiting was interrupted, so only release it if !IS_ERR. | |
1558 | */ | |
f5886c7f | 1559 | rcu_read_unlock(); |
b87324d0 CM |
1560 | mutex_unlock(&scan_mutex); |
1561 | if (v) | |
1562 | put_object(v); | |
1563 | } | |
3c7b4e6b CM |
1564 | } |
1565 | ||
1566 | /* | |
1567 | * Print the information for an unreferenced object to the seq file. | |
1568 | */ | |
1569 | static int kmemleak_seq_show(struct seq_file *seq, void *v) | |
1570 | { | |
1571 | struct kmemleak_object *object = v; | |
1572 | unsigned long flags; | |
1573 | ||
1574 | spin_lock_irqsave(&object->lock, flags); | |
288c857d | 1575 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
17bb9e0d | 1576 | print_unreferenced(seq, object); |
3c7b4e6b CM |
1577 | spin_unlock_irqrestore(&object->lock, flags); |
1578 | return 0; | |
1579 | } | |
1580 | ||
1581 | static const struct seq_operations kmemleak_seq_ops = { | |
1582 | .start = kmemleak_seq_start, | |
1583 | .next = kmemleak_seq_next, | |
1584 | .stop = kmemleak_seq_stop, | |
1585 | .show = kmemleak_seq_show, | |
1586 | }; | |
1587 | ||
1588 | static int kmemleak_open(struct inode *inode, struct file *file) | |
1589 | { | |
b87324d0 | 1590 | return seq_open(file, &kmemleak_seq_ops); |
3c7b4e6b CM |
1591 | } |
1592 | ||
189d84ed CM |
1593 | static int dump_str_object_info(const char *str) |
1594 | { | |
1595 | unsigned long flags; | |
1596 | struct kmemleak_object *object; | |
1597 | unsigned long addr; | |
1598 | ||
dc053733 AP |
1599 | if (kstrtoul(str, 0, &addr)) |
1600 | return -EINVAL; | |
189d84ed CM |
1601 | object = find_and_get_object(addr, 0); |
1602 | if (!object) { | |
1603 | pr_info("Unknown object at 0x%08lx\n", addr); | |
1604 | return -EINVAL; | |
1605 | } | |
1606 | ||
1607 | spin_lock_irqsave(&object->lock, flags); | |
1608 | dump_object_info(object); | |
1609 | spin_unlock_irqrestore(&object->lock, flags); | |
1610 | ||
1611 | put_object(object); | |
1612 | return 0; | |
1613 | } | |
1614 | ||
30b37101 LR |
1615 | /* |
1616 | * We use grey instead of black to ensure we can do future scans on the same | |
1617 | * objects. If we did not do future scans these black objects could | |
1618 | * potentially contain references to newly allocated objects in the future and | |
1619 | * we'd end up with false positives. | |
1620 | */ | |
1621 | static void kmemleak_clear(void) | |
1622 | { | |
1623 | struct kmemleak_object *object; | |
1624 | unsigned long flags; | |
1625 | ||
1626 | rcu_read_lock(); | |
1627 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1628 | spin_lock_irqsave(&object->lock, flags); | |
1629 | if ((object->flags & OBJECT_REPORTED) && | |
1630 | unreferenced_object(object)) | |
a1084c87 | 1631 | __paint_it(object, KMEMLEAK_GREY); |
30b37101 LR |
1632 | spin_unlock_irqrestore(&object->lock, flags); |
1633 | } | |
1634 | rcu_read_unlock(); | |
dc9b3f42 LZ |
1635 | |
1636 | kmemleak_found_leaks = false; | |
30b37101 LR |
1637 | } |
1638 | ||
c89da70c LZ |
1639 | static void __kmemleak_do_cleanup(void); |
1640 | ||
3c7b4e6b CM |
1641 | /* |
1642 | * File write operation to configure kmemleak at run-time. The following | |
1643 | * commands can be written to the /sys/kernel/debug/kmemleak file: | |
1644 | * off - disable kmemleak (irreversible) | |
1645 | * stack=on - enable the task stacks scanning | |
1646 | * stack=off - disable the tasks stacks scanning | |
1647 | * scan=on - start the automatic memory scanning thread | |
1648 | * scan=off - stop the automatic memory scanning thread | |
1649 | * scan=... - set the automatic memory scanning period in seconds (0 to | |
1650 | * disable it) | |
4698c1f2 | 1651 | * scan - trigger a memory scan |
30b37101 | 1652 | * clear - mark all current reported unreferenced kmemleak objects as |
c89da70c LZ |
1653 | * grey to ignore printing them, or free all kmemleak objects |
1654 | * if kmemleak has been disabled. | |
189d84ed | 1655 | * dump=... - dump information about the object found at the given address |
3c7b4e6b CM |
1656 | */ |
1657 | static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, | |
1658 | size_t size, loff_t *ppos) | |
1659 | { | |
1660 | char buf[64]; | |
1661 | int buf_size; | |
b87324d0 | 1662 | int ret; |
3c7b4e6b CM |
1663 | |
1664 | buf_size = min(size, (sizeof(buf) - 1)); | |
1665 | if (strncpy_from_user(buf, user_buf, buf_size) < 0) | |
1666 | return -EFAULT; | |
1667 | buf[buf_size] = 0; | |
1668 | ||
b87324d0 CM |
1669 | ret = mutex_lock_interruptible(&scan_mutex); |
1670 | if (ret < 0) | |
1671 | return ret; | |
1672 | ||
c89da70c | 1673 | if (strncmp(buf, "clear", 5) == 0) { |
8910ae89 | 1674 | if (kmemleak_enabled) |
c89da70c LZ |
1675 | kmemleak_clear(); |
1676 | else | |
1677 | __kmemleak_do_cleanup(); | |
1678 | goto out; | |
1679 | } | |
1680 | ||
8910ae89 | 1681 | if (!kmemleak_enabled) { |
c89da70c LZ |
1682 | ret = -EBUSY; |
1683 | goto out; | |
1684 | } | |
1685 | ||
3c7b4e6b CM |
1686 | if (strncmp(buf, "off", 3) == 0) |
1687 | kmemleak_disable(); | |
1688 | else if (strncmp(buf, "stack=on", 8) == 0) | |
1689 | kmemleak_stack_scan = 1; | |
1690 | else if (strncmp(buf, "stack=off", 9) == 0) | |
1691 | kmemleak_stack_scan = 0; | |
1692 | else if (strncmp(buf, "scan=on", 7) == 0) | |
1693 | start_scan_thread(); | |
1694 | else if (strncmp(buf, "scan=off", 8) == 0) | |
1695 | stop_scan_thread(); | |
1696 | else if (strncmp(buf, "scan=", 5) == 0) { | |
1697 | unsigned long secs; | |
3c7b4e6b | 1698 | |
3dbb95f7 | 1699 | ret = kstrtoul(buf + 5, 0, &secs); |
b87324d0 CM |
1700 | if (ret < 0) |
1701 | goto out; | |
3c7b4e6b CM |
1702 | stop_scan_thread(); |
1703 | if (secs) { | |
1704 | jiffies_scan_wait = msecs_to_jiffies(secs * 1000); | |
1705 | start_scan_thread(); | |
1706 | } | |
4698c1f2 CM |
1707 | } else if (strncmp(buf, "scan", 4) == 0) |
1708 | kmemleak_scan(); | |
189d84ed CM |
1709 | else if (strncmp(buf, "dump=", 5) == 0) |
1710 | ret = dump_str_object_info(buf + 5); | |
4698c1f2 | 1711 | else |
b87324d0 CM |
1712 | ret = -EINVAL; |
1713 | ||
1714 | out: | |
1715 | mutex_unlock(&scan_mutex); | |
1716 | if (ret < 0) | |
1717 | return ret; | |
3c7b4e6b CM |
1718 | |
1719 | /* ignore the rest of the buffer, only one command at a time */ | |
1720 | *ppos += size; | |
1721 | return size; | |
1722 | } | |
1723 | ||
1724 | static const struct file_operations kmemleak_fops = { | |
1725 | .owner = THIS_MODULE, | |
1726 | .open = kmemleak_open, | |
1727 | .read = seq_read, | |
1728 | .write = kmemleak_write, | |
1729 | .llseek = seq_lseek, | |
5f3bf19a | 1730 | .release = seq_release, |
3c7b4e6b CM |
1731 | }; |
1732 | ||
c89da70c LZ |
1733 | static void __kmemleak_do_cleanup(void) |
1734 | { | |
1735 | struct kmemleak_object *object; | |
1736 | ||
1737 | rcu_read_lock(); | |
1738 | list_for_each_entry_rcu(object, &object_list, object_list) | |
1739 | delete_object_full(object->pointer); | |
1740 | rcu_read_unlock(); | |
1741 | } | |
1742 | ||
3c7b4e6b | 1743 | /* |
74341703 CM |
1744 | * Stop the memory scanning thread and free the kmemleak internal objects if |
1745 | * no previous scan thread (otherwise, kmemleak may still have some useful | |
1746 | * information on memory leaks). | |
3c7b4e6b | 1747 | */ |
179a8100 | 1748 | static void kmemleak_do_cleanup(struct work_struct *work) |
3c7b4e6b | 1749 | { |
4698c1f2 | 1750 | mutex_lock(&scan_mutex); |
3c7b4e6b | 1751 | stop_scan_thread(); |
3c7b4e6b | 1752 | |
c89da70c LZ |
1753 | if (!kmemleak_found_leaks) |
1754 | __kmemleak_do_cleanup(); | |
1755 | else | |
1756 | pr_info("Kmemleak disabled without freeing internal data. " | |
1757 | "Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\"\n"); | |
3c7b4e6b | 1758 | mutex_unlock(&scan_mutex); |
3c7b4e6b CM |
1759 | } |
1760 | ||
179a8100 | 1761 | static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
3c7b4e6b CM |
1762 | |
1763 | /* | |
1764 | * Disable kmemleak. No memory allocation/freeing will be traced once this | |
1765 | * function is called. Disabling kmemleak is an irreversible operation. | |
1766 | */ | |
1767 | static void kmemleak_disable(void) | |
1768 | { | |
1769 | /* atomically check whether it was already invoked */ | |
8910ae89 | 1770 | if (cmpxchg(&kmemleak_error, 0, 1)) |
3c7b4e6b CM |
1771 | return; |
1772 | ||
1773 | /* stop any memory operation tracing */ | |
8910ae89 | 1774 | kmemleak_enabled = 0; |
3c7b4e6b CM |
1775 | |
1776 | /* check whether it is too early for a kernel thread */ | |
8910ae89 | 1777 | if (kmemleak_initialized) |
179a8100 | 1778 | schedule_work(&cleanup_work); |
3c7b4e6b CM |
1779 | |
1780 | pr_info("Kernel memory leak detector disabled\n"); | |
1781 | } | |
1782 | ||
1783 | /* | |
1784 | * Allow boot-time kmemleak disabling (enabled by default). | |
1785 | */ | |
1786 | static int kmemleak_boot_config(char *str) | |
1787 | { | |
1788 | if (!str) | |
1789 | return -EINVAL; | |
1790 | if (strcmp(str, "off") == 0) | |
1791 | kmemleak_disable(); | |
ab0155a2 JB |
1792 | else if (strcmp(str, "on") == 0) |
1793 | kmemleak_skip_disable = 1; | |
1794 | else | |
3c7b4e6b CM |
1795 | return -EINVAL; |
1796 | return 0; | |
1797 | } | |
1798 | early_param("kmemleak", kmemleak_boot_config); | |
1799 | ||
5f79020c CM |
1800 | static void __init print_log_trace(struct early_log *log) |
1801 | { | |
1802 | struct stack_trace trace; | |
1803 | ||
1804 | trace.nr_entries = log->trace_len; | |
1805 | trace.entries = log->trace; | |
1806 | ||
1807 | pr_notice("Early log backtrace:\n"); | |
1808 | print_stack_trace(&trace, 2); | |
1809 | } | |
1810 | ||
3c7b4e6b | 1811 | /* |
2030117d | 1812 | * Kmemleak initialization. |
3c7b4e6b CM |
1813 | */ |
1814 | void __init kmemleak_init(void) | |
1815 | { | |
1816 | int i; | |
1817 | unsigned long flags; | |
1818 | ||
ab0155a2 JB |
1819 | #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF |
1820 | if (!kmemleak_skip_disable) { | |
3551a928 | 1821 | kmemleak_early_log = 0; |
ab0155a2 JB |
1822 | kmemleak_disable(); |
1823 | return; | |
1824 | } | |
1825 | #endif | |
1826 | ||
3c7b4e6b CM |
1827 | jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); |
1828 | jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); | |
1829 | ||
1830 | object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); | |
1831 | scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); | |
3c7b4e6b | 1832 | |
b6693005 CM |
1833 | if (crt_early_log >= ARRAY_SIZE(early_log)) |
1834 | pr_warning("Early log buffer exceeded (%d), please increase " | |
1835 | "DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", crt_early_log); | |
1836 | ||
3c7b4e6b CM |
1837 | /* the kernel is still in UP mode, so disabling the IRQs is enough */ |
1838 | local_irq_save(flags); | |
3551a928 | 1839 | kmemleak_early_log = 0; |
8910ae89 | 1840 | if (kmemleak_error) { |
b6693005 CM |
1841 | local_irq_restore(flags); |
1842 | return; | |
1843 | } else | |
8910ae89 | 1844 | kmemleak_enabled = 1; |
3c7b4e6b CM |
1845 | local_irq_restore(flags); |
1846 | ||
1847 | /* | |
1848 | * This is the point where tracking allocations is safe. Automatic | |
1849 | * scanning is started during the late initcall. Add the early logged | |
1850 | * callbacks to the kmemleak infrastructure. | |
1851 | */ | |
1852 | for (i = 0; i < crt_early_log; i++) { | |
1853 | struct early_log *log = &early_log[i]; | |
1854 | ||
1855 | switch (log->op_type) { | |
1856 | case KMEMLEAK_ALLOC: | |
fd678967 | 1857 | early_alloc(log); |
3c7b4e6b | 1858 | break; |
f528f0b8 CM |
1859 | case KMEMLEAK_ALLOC_PERCPU: |
1860 | early_alloc_percpu(log); | |
1861 | break; | |
3c7b4e6b CM |
1862 | case KMEMLEAK_FREE: |
1863 | kmemleak_free(log->ptr); | |
1864 | break; | |
53238a60 CM |
1865 | case KMEMLEAK_FREE_PART: |
1866 | kmemleak_free_part(log->ptr, log->size); | |
1867 | break; | |
f528f0b8 CM |
1868 | case KMEMLEAK_FREE_PERCPU: |
1869 | kmemleak_free_percpu(log->ptr); | |
1870 | break; | |
3c7b4e6b CM |
1871 | case KMEMLEAK_NOT_LEAK: |
1872 | kmemleak_not_leak(log->ptr); | |
1873 | break; | |
1874 | case KMEMLEAK_IGNORE: | |
1875 | kmemleak_ignore(log->ptr); | |
1876 | break; | |
1877 | case KMEMLEAK_SCAN_AREA: | |
c017b4be | 1878 | kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL); |
3c7b4e6b CM |
1879 | break; |
1880 | case KMEMLEAK_NO_SCAN: | |
1881 | kmemleak_no_scan(log->ptr); | |
1882 | break; | |
1883 | default: | |
5f79020c CM |
1884 | kmemleak_warn("Unknown early log operation: %d\n", |
1885 | log->op_type); | |
1886 | } | |
1887 | ||
8910ae89 | 1888 | if (kmemleak_warning) { |
5f79020c | 1889 | print_log_trace(log); |
8910ae89 | 1890 | kmemleak_warning = 0; |
3c7b4e6b CM |
1891 | } |
1892 | } | |
1893 | } | |
1894 | ||
1895 | /* | |
1896 | * Late initialization function. | |
1897 | */ | |
1898 | static int __init kmemleak_late_init(void) | |
1899 | { | |
1900 | struct dentry *dentry; | |
1901 | ||
8910ae89 | 1902 | kmemleak_initialized = 1; |
3c7b4e6b | 1903 | |
8910ae89 | 1904 | if (kmemleak_error) { |
3c7b4e6b | 1905 | /* |
25985edc | 1906 | * Some error occurred and kmemleak was disabled. There is a |
3c7b4e6b CM |
1907 | * small chance that kmemleak_disable() was called immediately |
1908 | * after setting kmemleak_initialized and we may end up with | |
1909 | * two clean-up threads but serialized by scan_mutex. | |
1910 | */ | |
179a8100 | 1911 | schedule_work(&cleanup_work); |
3c7b4e6b CM |
1912 | return -ENOMEM; |
1913 | } | |
1914 | ||
1915 | dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL, | |
1916 | &kmemleak_fops); | |
1917 | if (!dentry) | |
ae281064 | 1918 | pr_warning("Failed to create the debugfs kmemleak file\n"); |
4698c1f2 | 1919 | mutex_lock(&scan_mutex); |
3c7b4e6b | 1920 | start_scan_thread(); |
4698c1f2 | 1921 | mutex_unlock(&scan_mutex); |
3c7b4e6b CM |
1922 | |
1923 | pr_info("Kernel memory leak detector initialized\n"); | |
1924 | ||
1925 | return 0; | |
1926 | } | |
1927 | late_initcall(kmemleak_late_init); |