Root/
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 |
32 | * blocks. The object_tree_root is a red black tree used to look-up |
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 |
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 |
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 | |
64 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
65 | |
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> |
72 | #include <linux/export.h> |
73 | #include <linux/kthread.h> |
74 | #include <linux/rbtree.h> |
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> |
94 | #include <linux/workqueue.h> |
95 | #include <linux/crc32.h> |
96 | |
97 | #include <asm/sections.h> |
98 | #include <asm/processor.h> |
99 | #include <linux/atomic.h> |
100 | |
101 | #include <linux/kmemcheck.h> |
102 | #include <linux/kmemleak.h> |
103 | #include <linux/memory_hotplug.h> |
104 | |
105 | /* |
106 | * Kmemleak configuration and common defines. |
107 | */ |
108 | #define MAX_TRACE 16 /* stack trace length */ |
109 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
110 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
111 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ |
112 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
113 | |
114 | #define BYTES_PER_POINTER sizeof(void *) |
115 | |
116 | /* GFP bitmask for kmemleak internal allocations */ |
117 | #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ |
118 | __GFP_NORETRY | __GFP_NOMEMALLOC | \ |
119 | __GFP_NOWARN) |
120 | |
121 | /* scanning area inside a memory block */ |
122 | struct kmemleak_scan_area { |
123 | struct hlist_node node; |
124 | unsigned long start; |
125 | size_t size; |
126 | }; |
127 | |
128 | #define KMEMLEAK_GREY 0 |
129 | #define KMEMLEAK_BLACK -1 |
130 | |
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 |
135 | * rb_node are already protected by the corresponding locks or mutex (see |
136 | * the notes on locking above). These objects are reference-counted |
137 | * (use_count) and freed using the RCU mechanism. |
138 | */ |
139 | struct 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; |
144 | struct rb_node rb_node; |
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; |
154 | /* checksum for detecting modified objects */ |
155 | u32 checksum; |
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 | |
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 | |
181 | /* the list of all allocated objects */ |
182 | static LIST_HEAD(object_list); |
183 | /* the list of gray-colored objects (see color_gray comment below) */ |
184 | static LIST_HEAD(gray_list); |
185 | /* search tree for object boundaries */ |
186 | static struct rb_root object_tree_root = RB_ROOT; |
187 | /* rw_lock protecting the access to object_list and object_tree_root */ |
188 | static DEFINE_RWLOCK(kmemleak_lock); |
189 | |
190 | /* allocation caches for kmemleak internal data */ |
191 | static struct kmem_cache *object_cache; |
192 | static struct kmem_cache *scan_area_cache; |
193 | |
194 | /* set if tracing memory operations is enabled */ |
195 | static int kmemleak_enabled; |
196 | /* set in the late_initcall if there were no errors */ |
197 | static int kmemleak_initialized; |
198 | /* enables or disables early logging of the memory operations */ |
199 | static int kmemleak_early_log = 1; |
200 | /* set if a kmemleak warning was issued */ |
201 | static int kmemleak_warning; |
202 | /* set if a fatal kmemleak error has occurred */ |
203 | static int kmemleak_error; |
204 | |
205 | /* minimum and maximum address that may be valid pointers */ |
206 | static unsigned long min_addr = ULONG_MAX; |
207 | static unsigned long max_addr; |
208 | |
209 | static struct task_struct *scan_thread; |
210 | /* used to avoid reporting of recently allocated objects */ |
211 | static unsigned long jiffies_min_age; |
212 | static unsigned long jiffies_last_scan; |
213 | /* delay between automatic memory scannings */ |
214 | static signed long jiffies_scan_wait; |
215 | /* enables or disables the task stacks scanning */ |
216 | static int kmemleak_stack_scan = 1; |
217 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
218 | static DEFINE_MUTEX(scan_mutex); |
219 | /* setting kmemleak=on, will set this var, skipping the disable */ |
220 | static int kmemleak_skip_disable; |
221 | /* If there are leaks that can be reported */ |
222 | static bool kmemleak_found_leaks; |
223 | |
224 | /* |
225 | * Early object allocation/freeing logging. Kmemleak is initialized after the |
226 | * kernel allocator. However, both the kernel allocator and kmemleak may |
227 | * allocate memory blocks which need to be tracked. Kmemleak defines an |
228 | * arbitrary buffer to hold the allocation/freeing information before it is |
229 | * fully initialized. |
230 | */ |
231 | |
232 | /* kmemleak operation type for early logging */ |
233 | enum { |
234 | KMEMLEAK_ALLOC, |
235 | KMEMLEAK_ALLOC_PERCPU, |
236 | KMEMLEAK_FREE, |
237 | KMEMLEAK_FREE_PART, |
238 | KMEMLEAK_FREE_PERCPU, |
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 | */ |
249 | struct 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 */ |
254 | unsigned long trace[MAX_TRACE]; /* stack trace */ |
255 | unsigned int trace_len; /* stack trace length */ |
256 | }; |
257 | |
258 | /* early logging buffer and current position */ |
259 | static struct early_log |
260 | early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata; |
261 | static int crt_early_log __initdata; |
262 | |
263 | static void kmemleak_disable(void); |
264 | |
265 | /* |
266 | * Print a warning and dump the stack trace. |
267 | */ |
268 | #define kmemleak_warn(x...) do { \ |
269 | pr_warning(x); \ |
270 | dump_stack(); \ |
271 | kmemleak_warning = 1; \ |
272 | } while (0) |
273 | |
274 | /* |
275 | * Macro invoked when a serious kmemleak condition occurred and cannot be |
276 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
277 | * tracing no longer available. |
278 | */ |
279 | #define kmemleak_stop(x...) do { \ |
280 | kmemleak_warn(x); \ |
281 | kmemleak_disable(); \ |
282 | } while (0) |
283 | |
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 | */ |
290 | static 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 | |
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 | */ |
323 | static bool color_white(const struct kmemleak_object *object) |
324 | { |
325 | return object->count != KMEMLEAK_BLACK && |
326 | object->count < object->min_count; |
327 | } |
328 | |
329 | static bool color_gray(const struct kmemleak_object *object) |
330 | { |
331 | return object->min_count != KMEMLEAK_BLACK && |
332 | object->count >= object->min_count; |
333 | } |
334 | |
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 | */ |
340 | static bool unreferenced_object(struct kmemleak_object *object) |
341 | { |
342 | return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
343 | time_before_eq(object->jiffies + jiffies_min_age, |
344 | jiffies_last_scan); |
345 | } |
346 | |
347 | /* |
348 | * Printing of the unreferenced objects information to the seq file. The |
349 | * print_unreferenced function must be called with the object->lock held. |
350 | */ |
351 | static void print_unreferenced(struct seq_file *seq, |
352 | struct kmemleak_object *object) |
353 | { |
354 | int i; |
355 | unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); |
356 | |
357 | seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
358 | object->pointer, object->size); |
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); |
362 | hex_dump_object(seq, object); |
363 | seq_printf(seq, " backtrace:\n"); |
364 | |
365 | for (i = 0; i < object->trace_len; i++) { |
366 | void *ptr = (void *)object->trace[i]; |
367 | seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); |
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 | */ |
376 | static 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 | |
383 | pr_notice("Object 0x%08lx (size %zu):\n", |
384 | object->pointer, object->size); |
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); |
389 | pr_notice(" flags = 0x%lx\n", object->flags); |
390 | pr_notice(" checksum = %u\n", object->checksum); |
391 | pr_notice(" backtrace:\n"); |
392 | print_stack_trace(&trace, 4); |
393 | } |
394 | |
395 | /* |
396 | * Look-up a memory block metadata (kmemleak_object) in the object search |
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 | */ |
401 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) |
402 | { |
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 { |
415 | kmemleak_warn("Found object by alias at 0x%08lx\n", |
416 | ptr); |
417 | dump_object_info(object); |
418 | break; |
419 | } |
420 | } |
421 | return NULL; |
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 | */ |
430 | static 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 | */ |
438 | static void free_object_rcu(struct rcu_head *rcu) |
439 | { |
440 | struct hlist_node *tmp; |
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 | */ |
449 | hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { |
450 | hlist_del(&area->node); |
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 | */ |
463 | static 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 | /* |
475 | * Look up an object in the object search tree and increase its use_count. |
476 | */ |
477 | static 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 | |
496 | /* |
497 | * Save stack trace to the given array of MAX_TRACE size. |
498 | */ |
499 | static 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 | |
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 | */ |
516 | static struct kmemleak_object *create_object(unsigned long ptr, size_t size, |
517 | int min_count, gfp_t gfp) |
518 | { |
519 | unsigned long flags; |
520 | struct kmemleak_object *object, *parent; |
521 | struct rb_node **link, *rb_parent; |
522 | |
523 | object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); |
524 | if (!object) { |
525 | pr_warning("Cannot allocate a kmemleak_object structure\n"); |
526 | kmemleak_disable(); |
527 | return NULL; |
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); |
535 | object->flags = OBJECT_ALLOCATED; |
536 | object->pointer = ptr; |
537 | object->size = size; |
538 | object->min_count = min_count; |
539 | object->count = 0; /* white color initially */ |
540 | object->jiffies = jiffies; |
541 | object->checksum = 0; |
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 */ |
562 | object->trace_len = __save_stack_trace(object->trace); |
563 | |
564 | write_lock_irqsave(&kmemleak_lock, flags); |
565 | |
566 | min_addr = min(min_addr, ptr); |
567 | max_addr = max(max_addr, ptr + size); |
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 | } |
588 | } |
589 | rb_link_node(&object->rb_node, rb_parent, link); |
590 | rb_insert_color(&object->rb_node, &object_tree_root); |
591 | |
592 | list_add_tail_rcu(&object->object_list, &object_list); |
593 | out: |
594 | write_unlock_irqrestore(&kmemleak_lock, flags); |
595 | return object; |
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 | */ |
602 | static void __delete_object(struct kmemleak_object *object) |
603 | { |
604 | unsigned long flags; |
605 | |
606 | write_lock_irqsave(&kmemleak_lock, flags); |
607 | rb_erase(&object->rb_node, &object_tree_root); |
608 | list_del_rcu(&object->object_list); |
609 | write_unlock_irqrestore(&kmemleak_lock, flags); |
610 | |
611 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
612 | WARN_ON(atomic_read(&object->use_count) < 2); |
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); |
619 | object->flags &= ~OBJECT_ALLOCATED; |
620 | spin_unlock_irqrestore(&object->lock, flags); |
621 | put_object(object); |
622 | } |
623 | |
624 | /* |
625 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and |
626 | * delete it. |
627 | */ |
628 | static 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 | */ |
649 | static 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 | } |
682 | |
683 | static 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 | |
690 | static void paint_it(struct kmemleak_object *object, int color) |
691 | { |
692 | unsigned long flags; |
693 | |
694 | spin_lock_irqsave(&object->lock, flags); |
695 | __paint_it(object, color); |
696 | spin_unlock_irqrestore(&object->lock, flags); |
697 | } |
698 | |
699 | static void paint_ptr(unsigned long ptr, int color) |
700 | { |
701 | struct kmemleak_object *object; |
702 | |
703 | object = find_and_get_object(ptr, 0); |
704 | if (!object) { |
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"); |
709 | return; |
710 | } |
711 | paint_it(object, color); |
712 | put_object(object); |
713 | } |
714 | |
715 | /* |
716 | * Mark an object permanently as gray-colored so that it can no longer be |
717 | * reported as a leak. This is used in general to mark a false positive. |
718 | */ |
719 | static void make_gray_object(unsigned long ptr) |
720 | { |
721 | paint_ptr(ptr, KMEMLEAK_GREY); |
722 | } |
723 | |
724 | /* |
725 | * Mark the object as black-colored so that it is ignored from scans and |
726 | * reporting. |
727 | */ |
728 | static void make_black_object(unsigned long ptr) |
729 | { |
730 | paint_ptr(ptr, KMEMLEAK_BLACK); |
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 | */ |
737 | static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
738 | { |
739 | unsigned long flags; |
740 | struct kmemleak_object *object; |
741 | struct kmemleak_scan_area *area; |
742 | |
743 | object = find_and_get_object(ptr, 1); |
744 | if (!object) { |
745 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
746 | ptr); |
747 | return; |
748 | } |
749 | |
750 | area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); |
751 | if (!area) { |
752 | pr_warning("Cannot allocate a scan area\n"); |
753 | goto out; |
754 | } |
755 | |
756 | spin_lock_irqsave(&object->lock, flags); |
757 | if (size == SIZE_MAX) { |
758 | size = object->pointer + object->size - ptr; |
759 | } else if (ptr + size > object->pointer + object->size) { |
760 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
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); |
767 | area->start = ptr; |
768 | area->size = size; |
769 | |
770 | hlist_add_head(&area->node, &object->area_list); |
771 | out_unlock: |
772 | spin_unlock_irqrestore(&object->lock, flags); |
773 | out: |
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 | */ |
782 | static 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) { |
789 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
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 | */ |
803 | static void __init log_early(int op_type, const void *ptr, size_t size, |
804 | int min_count) |
805 | { |
806 | unsigned long flags; |
807 | struct early_log *log; |
808 | |
809 | if (kmemleak_error) { |
810 | /* kmemleak stopped recording, just count the requests */ |
811 | crt_early_log++; |
812 | return; |
813 | } |
814 | |
815 | if (crt_early_log >= ARRAY_SIZE(early_log)) { |
816 | kmemleak_disable(); |
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; |
830 | log->trace_len = __save_stack_trace(log->trace); |
831 | crt_early_log++; |
832 | local_irq_restore(flags); |
833 | } |
834 | |
835 | /* |
836 | * Log an early allocated block and populate the stack trace. |
837 | */ |
838 | static void early_alloc(struct early_log *log) |
839 | { |
840 | struct kmemleak_object *object; |
841 | unsigned long flags; |
842 | int i; |
843 | |
844 | if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr)) |
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, |
852 | log->min_count, GFP_ATOMIC); |
853 | if (!object) |
854 | goto out; |
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); |
860 | out: |
861 | rcu_read_unlock(); |
862 | } |
863 | |
864 | /* |
865 | * Log an early allocated block and populate the stack trace. |
866 | */ |
867 | static 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 | |
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.). |
891 | */ |
892 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
893 | gfp_t gfp) |
894 | { |
895 | pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); |
896 | |
897 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
898 | create_object((unsigned long)ptr, size, min_count, gfp); |
899 | else if (kmemleak_early_log) |
900 | log_early(KMEMLEAK_ALLOC, ptr, size, min_count); |
901 | } |
902 | EXPORT_SYMBOL_GPL(kmemleak_alloc); |
903 | |
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 | */ |
913 | void __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 | */ |
923 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
924 | for_each_possible_cpu(cpu) |
925 | create_object((unsigned long)per_cpu_ptr(ptr, cpu), |
926 | size, 0, GFP_KERNEL); |
927 | else if (kmemleak_early_log) |
928 | log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0); |
929 | } |
930 | EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); |
931 | |
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.). |
938 | */ |
939 | void __ref kmemleak_free(const void *ptr) |
940 | { |
941 | pr_debug("%s(0x%p)\n", __func__, ptr); |
942 | |
943 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
944 | delete_object_full((unsigned long)ptr); |
945 | else if (kmemleak_early_log) |
946 | log_early(KMEMLEAK_FREE, ptr, 0, 0); |
947 | } |
948 | EXPORT_SYMBOL_GPL(kmemleak_free); |
949 | |
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). |
958 | */ |
959 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
960 | { |
961 | pr_debug("%s(0x%p)\n", __func__, ptr); |
962 | |
963 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
964 | delete_object_part((unsigned long)ptr, size); |
965 | else if (kmemleak_early_log) |
966 | log_early(KMEMLEAK_FREE_PART, ptr, size, 0); |
967 | } |
968 | EXPORT_SYMBOL_GPL(kmemleak_free_part); |
969 | |
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 | */ |
977 | void __ref kmemleak_free_percpu(const void __percpu *ptr) |
978 | { |
979 | unsigned int cpu; |
980 | |
981 | pr_debug("%s(0x%p)\n", __func__, ptr); |
982 | |
983 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
984 | for_each_possible_cpu(cpu) |
985 | delete_object_full((unsigned long)per_cpu_ptr(ptr, |
986 | cpu)); |
987 | else if (kmemleak_early_log) |
988 | log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0); |
989 | } |
990 | EXPORT_SYMBOL_GPL(kmemleak_free_percpu); |
991 | |
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 | */ |
999 | void __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 | } |
1024 | EXPORT_SYMBOL(kmemleak_update_trace); |
1025 | |
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. |
1032 | */ |
1033 | void __ref kmemleak_not_leak(const void *ptr) |
1034 | { |
1035 | pr_debug("%s(0x%p)\n", __func__, ptr); |
1036 | |
1037 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
1038 | make_gray_object((unsigned long)ptr); |
1039 | else if (kmemleak_early_log) |
1040 | log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0); |
1041 | } |
1042 | EXPORT_SYMBOL(kmemleak_not_leak); |
1043 | |
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. |
1052 | */ |
1053 | void __ref kmemleak_ignore(const void *ptr) |
1054 | { |
1055 | pr_debug("%s(0x%p)\n", __func__, ptr); |
1056 | |
1057 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
1058 | make_black_object((unsigned long)ptr); |
1059 | else if (kmemleak_early_log) |
1060 | log_early(KMEMLEAK_IGNORE, ptr, 0, 0); |
1061 | } |
1062 | EXPORT_SYMBOL(kmemleak_ignore); |
1063 | |
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. |
1074 | */ |
1075 | void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
1076 | { |
1077 | pr_debug("%s(0x%p)\n", __func__, ptr); |
1078 | |
1079 | if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
1080 | add_scan_area((unsigned long)ptr, size, gfp); |
1081 | else if (kmemleak_early_log) |
1082 | log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0); |
1083 | } |
1084 | EXPORT_SYMBOL(kmemleak_scan_area); |
1085 | |
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. |
1094 | */ |
1095 | void __ref kmemleak_no_scan(const void *ptr) |
1096 | { |
1097 | pr_debug("%s(0x%p)\n", __func__, ptr); |
1098 | |
1099 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
1100 | object_no_scan((unsigned long)ptr); |
1101 | else if (kmemleak_early_log) |
1102 | log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0); |
1103 | } |
1104 | EXPORT_SYMBOL(kmemleak_no_scan); |
1105 | |
1106 | /* |
1107 | * Update an object's checksum and return true if it was modified. |
1108 | */ |
1109 | static 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 | |
1120 | /* |
1121 | * Memory scanning is a long process and it needs to be interruptable. This |
1122 | * function checks whether such interrupt condition occurred. |
1123 | */ |
1124 | static int scan_should_stop(void) |
1125 | { |
1126 | if (!kmemleak_enabled) |
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 | */ |
1145 | static void scan_block(void *_start, void *_end, |
1146 | struct kmemleak_object *scanned, int allow_resched) |
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++) { |
1153 | struct kmemleak_object *object; |
1154 | unsigned long flags; |
1155 | unsigned long pointer; |
1156 | |
1157 | if (allow_resched) |
1158 | cond_resched(); |
1159 | if (scan_should_stop()) |
1160 | break; |
1161 | |
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 | |
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++; |
1199 | if (color_gray(object)) { |
1200 | list_add_tail(&object->gray_list, &gray_list); |
1201 | spin_unlock_irqrestore(&object->lock, flags); |
1202 | continue; |
1203 | } |
1204 | |
1205 | spin_unlock_irqrestore(&object->lock, flags); |
1206 | put_object(object); |
1207 | } |
1208 | } |
1209 | |
1210 | /* |
1211 | * Scan a memory block corresponding to a kmemleak_object. A condition is |
1212 | * that object->use_count >= 1. |
1213 | */ |
1214 | static void scan_object(struct kmemleak_object *object) |
1215 | { |
1216 | struct kmemleak_scan_area *area; |
1217 | unsigned long flags; |
1218 | |
1219 | /* |
1220 | * Once the object->lock is acquired, the corresponding memory block |
1221 | * cannot be freed (the same lock is acquired in delete_object). |
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; |
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 |
1244 | hlist_for_each_entry(area, &object->area_list, node) |
1245 | scan_block((void *)area->start, |
1246 | (void *)(area->start + area->size), |
1247 | object, 0); |
1248 | out: |
1249 | spin_unlock_irqrestore(&object->lock, flags); |
1250 | } |
1251 | |
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 | */ |
1256 | static 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 | |
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 | */ |
1290 | static void kmemleak_scan(void) |
1291 | { |
1292 | unsigned long flags; |
1293 | struct kmemleak_object *object; |
1294 | int i; |
1295 | int new_leaks = 0; |
1296 | |
1297 | jiffies_last_scan = jiffies; |
1298 | |
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) { |
1309 | pr_debug("object->use_count = %d\n", |
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 */ |
1324 | scan_block(_sdata, _edata, NULL, 1); |
1325 | scan_block(__bss_start, __bss_stop, NULL, 1); |
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), |
1331 | __per_cpu_end + per_cpu_offset(i), NULL, 1); |
1332 | #endif |
1333 | |
1334 | /* |
1335 | * Struct page scanning for each node. |
1336 | */ |
1337 | get_online_mems(); |
1338 | for_each_online_node(i) { |
1339 | unsigned long start_pfn = node_start_pfn(i); |
1340 | unsigned long end_pfn = node_end_pfn(i); |
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; |
1352 | scan_block(page, page + 1, NULL, 1); |
1353 | } |
1354 | } |
1355 | put_online_mems(); |
1356 | |
1357 | /* |
1358 | * Scanning the task stacks (may introduce false negatives). |
1359 | */ |
1360 | if (kmemleak_stack_scan) { |
1361 | struct task_struct *p, *g; |
1362 | |
1363 | read_lock(&tasklist_lock); |
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); |
1368 | read_unlock(&tasklist_lock); |
1369 | } |
1370 | |
1371 | /* |
1372 | * Scan the objects already referenced from the sections scanned |
1373 | * above. |
1374 | */ |
1375 | scan_gray_list(); |
1376 | |
1377 | /* |
1378 | * Check for new or unreferenced objects modified since the previous |
1379 | * scan and color them gray until the next scan. |
1380 | */ |
1381 | rcu_read_lock(); |
1382 | list_for_each_entry_rcu(object, &object_list, object_list) { |
1383 | spin_lock_irqsave(&object->lock, flags); |
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; |
1388 | list_add_tail(&object->gray_list, &gray_list); |
1389 | } |
1390 | spin_unlock_irqrestore(&object->lock, flags); |
1391 | } |
1392 | rcu_read_unlock(); |
1393 | |
1394 | /* |
1395 | * Re-scan the gray list for modified unreferenced objects. |
1396 | */ |
1397 | scan_gray_list(); |
1398 | |
1399 | /* |
1400 | * If scanning was stopped do not report any new unreferenced objects. |
1401 | */ |
1402 | if (scan_should_stop()) |
1403 | return; |
1404 | |
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 | |
1420 | if (new_leaks) { |
1421 | kmemleak_found_leaks = true; |
1422 | |
1423 | pr_info("%d new suspected memory leaks (see " |
1424 | "/sys/kernel/debug/kmemleak)\n", new_leaks); |
1425 | } |
1426 | |
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 | */ |
1433 | static int kmemleak_scan_thread(void *arg) |
1434 | { |
1435 | static int first_run = 1; |
1436 | |
1437 | pr_info("Automatic memory scanning thread started\n"); |
1438 | set_user_nice(current, 10); |
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()) { |
1449 | signed long timeout = jiffies_scan_wait; |
1450 | |
1451 | mutex_lock(&scan_mutex); |
1452 | kmemleak_scan(); |
1453 | mutex_unlock(&scan_mutex); |
1454 | |
1455 | /* wait before the next scan */ |
1456 | while (timeout && !kthread_should_stop()) |
1457 | timeout = schedule_timeout_interruptible(timeout); |
1458 | } |
1459 | |
1460 | pr_info("Automatic memory scanning thread ended\n"); |
1461 | |
1462 | return 0; |
1463 | } |
1464 | |
1465 | /* |
1466 | * Start the automatic memory scanning thread. This function must be called |
1467 | * with the scan_mutex held. |
1468 | */ |
1469 | static void start_scan_thread(void) |
1470 | { |
1471 | if (scan_thread) |
1472 | return; |
1473 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); |
1474 | if (IS_ERR(scan_thread)) { |
1475 | pr_warning("Failed to create the scan thread\n"); |
1476 | scan_thread = NULL; |
1477 | } |
1478 | } |
1479 | |
1480 | /* |
1481 | * Stop the automatic memory scanning thread. This function must be called |
1482 | * with the scan_mutex held. |
1483 | */ |
1484 | static void stop_scan_thread(void) |
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 | */ |
1497 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) |
1498 | { |
1499 | struct kmemleak_object *object; |
1500 | loff_t n = *pos; |
1501 | int err; |
1502 | |
1503 | err = mutex_lock_interruptible(&scan_mutex); |
1504 | if (err < 0) |
1505 | return ERR_PTR(err); |
1506 | |
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; |
1515 | out: |
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 | */ |
1523 | static 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; |
1527 | struct kmemleak_object *obj = prev_obj; |
1528 | |
1529 | ++(*pos); |
1530 | |
1531 | list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
1532 | if (get_object(obj)) { |
1533 | next_obj = obj; |
1534 | break; |
1535 | } |
1536 | } |
1537 | |
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 | */ |
1545 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) |
1546 | { |
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 | */ |
1552 | rcu_read_unlock(); |
1553 | mutex_unlock(&scan_mutex); |
1554 | if (v) |
1555 | put_object(v); |
1556 | } |
1557 | } |
1558 | |
1559 | /* |
1560 | * Print the information for an unreferenced object to the seq file. |
1561 | */ |
1562 | static 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); |
1568 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
1569 | print_unreferenced(seq, object); |
1570 | spin_unlock_irqrestore(&object->lock, flags); |
1571 | return 0; |
1572 | } |
1573 | |
1574 | static 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 | |
1581 | static int kmemleak_open(struct inode *inode, struct file *file) |
1582 | { |
1583 | return seq_open(file, &kmemleak_seq_ops); |
1584 | } |
1585 | |
1586 | static int dump_str_object_info(const char *str) |
1587 | { |
1588 | unsigned long flags; |
1589 | struct kmemleak_object *object; |
1590 | unsigned long addr; |
1591 | |
1592 | if (kstrtoul(str, 0, &addr)) |
1593 | return -EINVAL; |
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 | |
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 | */ |
1614 | static 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)) |
1624 | __paint_it(object, KMEMLEAK_GREY); |
1625 | spin_unlock_irqrestore(&object->lock, flags); |
1626 | } |
1627 | rcu_read_unlock(); |
1628 | |
1629 | kmemleak_found_leaks = false; |
1630 | } |
1631 | |
1632 | static void __kmemleak_do_cleanup(void); |
1633 | |
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) |
1644 | * scan - trigger a memory scan |
1645 | * clear - mark all current reported unreferenced kmemleak objects as |
1646 | * grey to ignore printing them, or free all kmemleak objects |
1647 | * if kmemleak has been disabled. |
1648 | * dump=... - dump information about the object found at the given address |
1649 | */ |
1650 | static 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; |
1655 | int ret; |
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 | |
1662 | ret = mutex_lock_interruptible(&scan_mutex); |
1663 | if (ret < 0) |
1664 | return ret; |
1665 | |
1666 | if (strncmp(buf, "clear", 5) == 0) { |
1667 | if (kmemleak_enabled) |
1668 | kmemleak_clear(); |
1669 | else |
1670 | __kmemleak_do_cleanup(); |
1671 | goto out; |
1672 | } |
1673 | |
1674 | if (!kmemleak_enabled) { |
1675 | ret = -EBUSY; |
1676 | goto out; |
1677 | } |
1678 | |
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; |
1691 | |
1692 | ret = kstrtoul(buf + 5, 0, &secs); |
1693 | if (ret < 0) |
1694 | goto out; |
1695 | stop_scan_thread(); |
1696 | if (secs) { |
1697 | jiffies_scan_wait = msecs_to_jiffies(secs * 1000); |
1698 | start_scan_thread(); |
1699 | } |
1700 | } else if (strncmp(buf, "scan", 4) == 0) |
1701 | kmemleak_scan(); |
1702 | else if (strncmp(buf, "dump=", 5) == 0) |
1703 | ret = dump_str_object_info(buf + 5); |
1704 | else |
1705 | ret = -EINVAL; |
1706 | |
1707 | out: |
1708 | mutex_unlock(&scan_mutex); |
1709 | if (ret < 0) |
1710 | return ret; |
1711 | |
1712 | /* ignore the rest of the buffer, only one command at a time */ |
1713 | *ppos += size; |
1714 | return size; |
1715 | } |
1716 | |
1717 | static 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, |
1723 | .release = seq_release, |
1724 | }; |
1725 | |
1726 | static 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 | |
1736 | /* |
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). |
1740 | */ |
1741 | static void kmemleak_do_cleanup(struct work_struct *work) |
1742 | { |
1743 | mutex_lock(&scan_mutex); |
1744 | stop_scan_thread(); |
1745 | |
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"); |
1751 | mutex_unlock(&scan_mutex); |
1752 | } |
1753 | |
1754 | static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
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 | */ |
1760 | static void kmemleak_disable(void) |
1761 | { |
1762 | /* atomically check whether it was already invoked */ |
1763 | if (cmpxchg(&kmemleak_error, 0, 1)) |
1764 | return; |
1765 | |
1766 | /* stop any memory operation tracing */ |
1767 | kmemleak_enabled = 0; |
1768 | |
1769 | /* check whether it is too early for a kernel thread */ |
1770 | if (kmemleak_initialized) |
1771 | schedule_work(&cleanup_work); |
1772 | |
1773 | pr_info("Kernel memory leak detector disabled\n"); |
1774 | } |
1775 | |
1776 | /* |
1777 | * Allow boot-time kmemleak disabling (enabled by default). |
1778 | */ |
1779 | static int kmemleak_boot_config(char *str) |
1780 | { |
1781 | if (!str) |
1782 | return -EINVAL; |
1783 | if (strcmp(str, "off") == 0) |
1784 | kmemleak_disable(); |
1785 | else if (strcmp(str, "on") == 0) |
1786 | kmemleak_skip_disable = 1; |
1787 | else |
1788 | return -EINVAL; |
1789 | return 0; |
1790 | } |
1791 | early_param("kmemleak", kmemleak_boot_config); |
1792 | |
1793 | static 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 | |
1804 | /* |
1805 | * Kmemleak initialization. |
1806 | */ |
1807 | void __init kmemleak_init(void) |
1808 | { |
1809 | int i; |
1810 | unsigned long flags; |
1811 | |
1812 | #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF |
1813 | if (!kmemleak_skip_disable) { |
1814 | kmemleak_early_log = 0; |
1815 | kmemleak_disable(); |
1816 | return; |
1817 | } |
1818 | #endif |
1819 | |
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); |
1825 | |
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 | |
1830 | /* the kernel is still in UP mode, so disabling the IRQs is enough */ |
1831 | local_irq_save(flags); |
1832 | kmemleak_early_log = 0; |
1833 | if (kmemleak_error) { |
1834 | local_irq_restore(flags); |
1835 | return; |
1836 | } else |
1837 | kmemleak_enabled = 1; |
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: |
1850 | early_alloc(log); |
1851 | break; |
1852 | case KMEMLEAK_ALLOC_PERCPU: |
1853 | early_alloc_percpu(log); |
1854 | break; |
1855 | case KMEMLEAK_FREE: |
1856 | kmemleak_free(log->ptr); |
1857 | break; |
1858 | case KMEMLEAK_FREE_PART: |
1859 | kmemleak_free_part(log->ptr, log->size); |
1860 | break; |
1861 | case KMEMLEAK_FREE_PERCPU: |
1862 | kmemleak_free_percpu(log->ptr); |
1863 | break; |
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: |
1871 | kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL); |
1872 | break; |
1873 | case KMEMLEAK_NO_SCAN: |
1874 | kmemleak_no_scan(log->ptr); |
1875 | break; |
1876 | default: |
1877 | kmemleak_warn("Unknown early log operation: %d\n", |
1878 | log->op_type); |
1879 | } |
1880 | |
1881 | if (kmemleak_warning) { |
1882 | print_log_trace(log); |
1883 | kmemleak_warning = 0; |
1884 | } |
1885 | } |
1886 | } |
1887 | |
1888 | /* |
1889 | * Late initialization function. |
1890 | */ |
1891 | static int __init kmemleak_late_init(void) |
1892 | { |
1893 | struct dentry *dentry; |
1894 | |
1895 | kmemleak_initialized = 1; |
1896 | |
1897 | if (kmemleak_error) { |
1898 | /* |
1899 | * Some error occurred and kmemleak was disabled. There is a |
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 | */ |
1904 | schedule_work(&cleanup_work); |
1905 | return -ENOMEM; |
1906 | } |
1907 | |
1908 | dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL, |
1909 | &kmemleak_fops); |
1910 | if (!dentry) |
1911 | pr_warning("Failed to create the debugfs kmemleak file\n"); |
1912 | mutex_lock(&scan_mutex); |
1913 | start_scan_thread(); |
1914 | mutex_unlock(&scan_mutex); |
1915 | |
1916 | pr_info("Kernel memory leak detector initialized\n"); |
1917 | |
1918 | return 0; |
1919 | } |
1920 | late_initcall(kmemleak_late_init); |
1921 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9