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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 | 55 | * |
93ada579 | 56 | * Locks and mutexes are acquired/nested in the following order: |
9d5a4c73 | 57 | * |
93ada579 CM |
58 | * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING) |
59 | * | |
60 | * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex | |
61 | * regions. | |
9d5a4c73 | 62 | * |
3c7b4e6b CM |
63 | * The kmemleak_object structures have a use_count incremented or decremented |
64 | * using the get_object()/put_object() functions. When the use_count becomes | |
65 | * 0, this count can no longer be incremented and put_object() schedules the | |
66 | * kmemleak_object freeing via an RCU callback. All calls to the get_object() | |
67 | * function must be protected by rcu_read_lock() to avoid accessing a freed | |
68 | * structure. | |
69 | */ | |
70 | ||
ae281064 JP |
71 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
72 | ||
3c7b4e6b CM |
73 | #include <linux/init.h> |
74 | #include <linux/kernel.h> | |
75 | #include <linux/list.h> | |
76 | #include <linux/sched.h> | |
77 | #include <linux/jiffies.h> | |
78 | #include <linux/delay.h> | |
b95f1b31 | 79 | #include <linux/export.h> |
3c7b4e6b | 80 | #include <linux/kthread.h> |
85d3a316 | 81 | #include <linux/rbtree.h> |
3c7b4e6b CM |
82 | #include <linux/fs.h> |
83 | #include <linux/debugfs.h> | |
84 | #include <linux/seq_file.h> | |
85 | #include <linux/cpumask.h> | |
86 | #include <linux/spinlock.h> | |
87 | #include <linux/mutex.h> | |
88 | #include <linux/rcupdate.h> | |
89 | #include <linux/stacktrace.h> | |
90 | #include <linux/cache.h> | |
91 | #include <linux/percpu.h> | |
92 | #include <linux/hardirq.h> | |
93 | #include <linux/mmzone.h> | |
94 | #include <linux/slab.h> | |
95 | #include <linux/thread_info.h> | |
96 | #include <linux/err.h> | |
97 | #include <linux/uaccess.h> | |
98 | #include <linux/string.h> | |
99 | #include <linux/nodemask.h> | |
100 | #include <linux/mm.h> | |
179a8100 | 101 | #include <linux/workqueue.h> |
04609ccc | 102 | #include <linux/crc32.h> |
3c7b4e6b CM |
103 | |
104 | #include <asm/sections.h> | |
105 | #include <asm/processor.h> | |
60063497 | 106 | #include <linux/atomic.h> |
3c7b4e6b | 107 | |
e79ed2f1 | 108 | #include <linux/kasan.h> |
8e019366 | 109 | #include <linux/kmemcheck.h> |
3c7b4e6b | 110 | #include <linux/kmemleak.h> |
029aeff5 | 111 | #include <linux/memory_hotplug.h> |
3c7b4e6b CM |
112 | |
113 | /* | |
114 | * Kmemleak configuration and common defines. | |
115 | */ | |
116 | #define MAX_TRACE 16 /* stack trace length */ | |
3c7b4e6b | 117 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
3c7b4e6b CM |
118 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
119 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ | |
af98603d | 120 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
3c7b4e6b CM |
121 | |
122 | #define BYTES_PER_POINTER sizeof(void *) | |
123 | ||
216c04b0 | 124 | /* GFP bitmask for kmemleak internal allocations */ |
20b5c303 | 125 | #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ |
6ae4bd1f CM |
126 | __GFP_NORETRY | __GFP_NOMEMALLOC | \ |
127 | __GFP_NOWARN) | |
216c04b0 | 128 | |
3c7b4e6b CM |
129 | /* scanning area inside a memory block */ |
130 | struct kmemleak_scan_area { | |
131 | struct hlist_node node; | |
c017b4be CM |
132 | unsigned long start; |
133 | size_t size; | |
3c7b4e6b CM |
134 | }; |
135 | ||
a1084c87 LR |
136 | #define KMEMLEAK_GREY 0 |
137 | #define KMEMLEAK_BLACK -1 | |
138 | ||
3c7b4e6b CM |
139 | /* |
140 | * Structure holding the metadata for each allocated memory block. | |
141 | * Modifications to such objects should be made while holding the | |
142 | * object->lock. Insertions or deletions from object_list, gray_list or | |
85d3a316 | 143 | * rb_node are already protected by the corresponding locks or mutex (see |
3c7b4e6b CM |
144 | * the notes on locking above). These objects are reference-counted |
145 | * (use_count) and freed using the RCU mechanism. | |
146 | */ | |
147 | struct kmemleak_object { | |
148 | spinlock_t lock; | |
149 | unsigned long flags; /* object status flags */ | |
150 | struct list_head object_list; | |
151 | struct list_head gray_list; | |
85d3a316 | 152 | struct rb_node rb_node; |
3c7b4e6b CM |
153 | struct rcu_head rcu; /* object_list lockless traversal */ |
154 | /* object usage count; object freed when use_count == 0 */ | |
155 | atomic_t use_count; | |
156 | unsigned long pointer; | |
157 | size_t size; | |
158 | /* minimum number of a pointers found before it is considered leak */ | |
159 | int min_count; | |
160 | /* the total number of pointers found pointing to this object */ | |
161 | int count; | |
04609ccc CM |
162 | /* checksum for detecting modified objects */ |
163 | u32 checksum; | |
3c7b4e6b CM |
164 | /* memory ranges to be scanned inside an object (empty for all) */ |
165 | struct hlist_head area_list; | |
166 | unsigned long trace[MAX_TRACE]; | |
167 | unsigned int trace_len; | |
168 | unsigned long jiffies; /* creation timestamp */ | |
169 | pid_t pid; /* pid of the current task */ | |
170 | char comm[TASK_COMM_LEN]; /* executable name */ | |
171 | }; | |
172 | ||
173 | /* flag representing the memory block allocation status */ | |
174 | #define OBJECT_ALLOCATED (1 << 0) | |
175 | /* flag set after the first reporting of an unreference object */ | |
176 | #define OBJECT_REPORTED (1 << 1) | |
177 | /* flag set to not scan the object */ | |
178 | #define OBJECT_NO_SCAN (1 << 2) | |
179 | ||
0494e082 SS |
180 | /* number of bytes to print per line; must be 16 or 32 */ |
181 | #define HEX_ROW_SIZE 16 | |
182 | /* number of bytes to print at a time (1, 2, 4, 8) */ | |
183 | #define HEX_GROUP_SIZE 1 | |
184 | /* include ASCII after the hex output */ | |
185 | #define HEX_ASCII 1 | |
186 | /* max number of lines to be printed */ | |
187 | #define HEX_MAX_LINES 2 | |
188 | ||
3c7b4e6b CM |
189 | /* the list of all allocated objects */ |
190 | static LIST_HEAD(object_list); | |
191 | /* the list of gray-colored objects (see color_gray comment below) */ | |
192 | static LIST_HEAD(gray_list); | |
85d3a316 ML |
193 | /* search tree for object boundaries */ |
194 | static struct rb_root object_tree_root = RB_ROOT; | |
195 | /* rw_lock protecting the access to object_list and object_tree_root */ | |
3c7b4e6b CM |
196 | static DEFINE_RWLOCK(kmemleak_lock); |
197 | ||
198 | /* allocation caches for kmemleak internal data */ | |
199 | static struct kmem_cache *object_cache; | |
200 | static struct kmem_cache *scan_area_cache; | |
201 | ||
202 | /* set if tracing memory operations is enabled */ | |
8910ae89 | 203 | static int kmemleak_enabled; |
c5f3b1a5 CM |
204 | /* same as above but only for the kmemleak_free() callback */ |
205 | static int kmemleak_free_enabled; | |
3c7b4e6b | 206 | /* set in the late_initcall if there were no errors */ |
8910ae89 | 207 | static int kmemleak_initialized; |
3c7b4e6b | 208 | /* enables or disables early logging of the memory operations */ |
8910ae89 | 209 | static int kmemleak_early_log = 1; |
5f79020c | 210 | /* set if a kmemleak warning was issued */ |
8910ae89 | 211 | static int kmemleak_warning; |
5f79020c | 212 | /* set if a fatal kmemleak error has occurred */ |
8910ae89 | 213 | static int kmemleak_error; |
3c7b4e6b CM |
214 | |
215 | /* minimum and maximum address that may be valid pointers */ | |
216 | static unsigned long min_addr = ULONG_MAX; | |
217 | static unsigned long max_addr; | |
218 | ||
3c7b4e6b | 219 | static struct task_struct *scan_thread; |
acf4968e | 220 | /* used to avoid reporting of recently allocated objects */ |
3c7b4e6b | 221 | static unsigned long jiffies_min_age; |
acf4968e | 222 | static unsigned long jiffies_last_scan; |
3c7b4e6b CM |
223 | /* delay between automatic memory scannings */ |
224 | static signed long jiffies_scan_wait; | |
225 | /* enables or disables the task stacks scanning */ | |
e0a2a160 | 226 | static int kmemleak_stack_scan = 1; |
4698c1f2 | 227 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
3c7b4e6b | 228 | static DEFINE_MUTEX(scan_mutex); |
ab0155a2 JB |
229 | /* setting kmemleak=on, will set this var, skipping the disable */ |
230 | static int kmemleak_skip_disable; | |
dc9b3f42 LZ |
231 | /* If there are leaks that can be reported */ |
232 | static bool kmemleak_found_leaks; | |
3c7b4e6b | 233 | |
3c7b4e6b | 234 | /* |
2030117d | 235 | * Early object allocation/freeing logging. Kmemleak is initialized after the |
3c7b4e6b | 236 | * kernel allocator. However, both the kernel allocator and kmemleak may |
2030117d | 237 | * allocate memory blocks which need to be tracked. Kmemleak defines an |
3c7b4e6b CM |
238 | * arbitrary buffer to hold the allocation/freeing information before it is |
239 | * fully initialized. | |
240 | */ | |
241 | ||
242 | /* kmemleak operation type for early logging */ | |
243 | enum { | |
244 | KMEMLEAK_ALLOC, | |
f528f0b8 | 245 | KMEMLEAK_ALLOC_PERCPU, |
3c7b4e6b | 246 | KMEMLEAK_FREE, |
53238a60 | 247 | KMEMLEAK_FREE_PART, |
f528f0b8 | 248 | KMEMLEAK_FREE_PERCPU, |
3c7b4e6b CM |
249 | KMEMLEAK_NOT_LEAK, |
250 | KMEMLEAK_IGNORE, | |
251 | KMEMLEAK_SCAN_AREA, | |
252 | KMEMLEAK_NO_SCAN | |
253 | }; | |
254 | ||
255 | /* | |
256 | * Structure holding the information passed to kmemleak callbacks during the | |
257 | * early logging. | |
258 | */ | |
259 | struct early_log { | |
260 | int op_type; /* kmemleak operation type */ | |
261 | const void *ptr; /* allocated/freed memory block */ | |
262 | size_t size; /* memory block size */ | |
263 | int min_count; /* minimum reference count */ | |
fd678967 CM |
264 | unsigned long trace[MAX_TRACE]; /* stack trace */ |
265 | unsigned int trace_len; /* stack trace length */ | |
3c7b4e6b CM |
266 | }; |
267 | ||
268 | /* early logging buffer and current position */ | |
a6186d89 CM |
269 | static struct early_log |
270 | early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata; | |
271 | static int crt_early_log __initdata; | |
3c7b4e6b CM |
272 | |
273 | static void kmemleak_disable(void); | |
274 | ||
275 | /* | |
276 | * Print a warning and dump the stack trace. | |
277 | */ | |
5f79020c | 278 | #define kmemleak_warn(x...) do { \ |
598d8091 | 279 | pr_warn(x); \ |
5f79020c | 280 | dump_stack(); \ |
8910ae89 | 281 | kmemleak_warning = 1; \ |
3c7b4e6b CM |
282 | } while (0) |
283 | ||
284 | /* | |
25985edc | 285 | * Macro invoked when a serious kmemleak condition occurred and cannot be |
2030117d | 286 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
3c7b4e6b CM |
287 | * tracing no longer available. |
288 | */ | |
000814f4 | 289 | #define kmemleak_stop(x...) do { \ |
3c7b4e6b CM |
290 | kmemleak_warn(x); \ |
291 | kmemleak_disable(); \ | |
292 | } while (0) | |
293 | ||
0494e082 SS |
294 | /* |
295 | * Printing of the objects hex dump to the seq file. The number of lines to be | |
296 | * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The | |
297 | * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called | |
298 | * with the object->lock held. | |
299 | */ | |
300 | static void hex_dump_object(struct seq_file *seq, | |
301 | struct kmemleak_object *object) | |
302 | { | |
303 | const u8 *ptr = (const u8 *)object->pointer; | |
6fc37c49 | 304 | size_t len; |
0494e082 SS |
305 | |
306 | /* limit the number of lines to HEX_MAX_LINES */ | |
6fc37c49 | 307 | len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); |
0494e082 | 308 | |
6fc37c49 AS |
309 | seq_printf(seq, " hex dump (first %zu bytes):\n", len); |
310 | seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE, | |
311 | HEX_GROUP_SIZE, ptr, len, HEX_ASCII); | |
0494e082 SS |
312 | } |
313 | ||
3c7b4e6b CM |
314 | /* |
315 | * Object colors, encoded with count and min_count: | |
316 | * - white - orphan object, not enough references to it (count < min_count) | |
317 | * - gray - not orphan, not marked as false positive (min_count == 0) or | |
318 | * sufficient references to it (count >= min_count) | |
319 | * - black - ignore, it doesn't contain references (e.g. text section) | |
320 | * (min_count == -1). No function defined for this color. | |
321 | * Newly created objects don't have any color assigned (object->count == -1) | |
322 | * before the next memory scan when they become white. | |
323 | */ | |
4a558dd6 | 324 | static bool color_white(const struct kmemleak_object *object) |
3c7b4e6b | 325 | { |
a1084c87 LR |
326 | return object->count != KMEMLEAK_BLACK && |
327 | object->count < object->min_count; | |
3c7b4e6b CM |
328 | } |
329 | ||
4a558dd6 | 330 | static bool color_gray(const struct kmemleak_object *object) |
3c7b4e6b | 331 | { |
a1084c87 LR |
332 | return object->min_count != KMEMLEAK_BLACK && |
333 | object->count >= object->min_count; | |
3c7b4e6b CM |
334 | } |
335 | ||
3c7b4e6b CM |
336 | /* |
337 | * Objects are considered unreferenced only if their color is white, they have | |
338 | * not be deleted and have a minimum age to avoid false positives caused by | |
339 | * pointers temporarily stored in CPU registers. | |
340 | */ | |
4a558dd6 | 341 | static bool unreferenced_object(struct kmemleak_object *object) |
3c7b4e6b | 342 | { |
04609ccc | 343 | return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
acf4968e CM |
344 | time_before_eq(object->jiffies + jiffies_min_age, |
345 | jiffies_last_scan); | |
3c7b4e6b CM |
346 | } |
347 | ||
348 | /* | |
bab4a34a CM |
349 | * Printing of the unreferenced objects information to the seq file. The |
350 | * print_unreferenced function must be called with the object->lock held. | |
3c7b4e6b | 351 | */ |
3c7b4e6b CM |
352 | static void print_unreferenced(struct seq_file *seq, |
353 | struct kmemleak_object *object) | |
354 | { | |
355 | int i; | |
fefdd336 | 356 | unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); |
3c7b4e6b | 357 | |
bab4a34a CM |
358 | seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
359 | object->pointer, object->size); | |
fefdd336 CM |
360 | seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", |
361 | object->comm, object->pid, object->jiffies, | |
362 | msecs_age / 1000, msecs_age % 1000); | |
0494e082 | 363 | hex_dump_object(seq, object); |
bab4a34a | 364 | seq_printf(seq, " backtrace:\n"); |
3c7b4e6b CM |
365 | |
366 | for (i = 0; i < object->trace_len; i++) { | |
367 | void *ptr = (void *)object->trace[i]; | |
bab4a34a | 368 | seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); |
3c7b4e6b CM |
369 | } |
370 | } | |
371 | ||
372 | /* | |
373 | * Print the kmemleak_object information. This function is used mainly for | |
374 | * debugging special cases when kmemleak operations. It must be called with | |
375 | * the object->lock held. | |
376 | */ | |
377 | static void dump_object_info(struct kmemleak_object *object) | |
378 | { | |
379 | struct stack_trace trace; | |
380 | ||
381 | trace.nr_entries = object->trace_len; | |
382 | trace.entries = object->trace; | |
383 | ||
ae281064 | 384 | pr_notice("Object 0x%08lx (size %zu):\n", |
85d3a316 | 385 | object->pointer, object->size); |
3c7b4e6b CM |
386 | pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", |
387 | object->comm, object->pid, object->jiffies); | |
388 | pr_notice(" min_count = %d\n", object->min_count); | |
389 | pr_notice(" count = %d\n", object->count); | |
189d84ed | 390 | pr_notice(" flags = 0x%lx\n", object->flags); |
aae0ad7a | 391 | pr_notice(" checksum = %u\n", object->checksum); |
3c7b4e6b CM |
392 | pr_notice(" backtrace:\n"); |
393 | print_stack_trace(&trace, 4); | |
394 | } | |
395 | ||
396 | /* | |
85d3a316 | 397 | * Look-up a memory block metadata (kmemleak_object) in the object search |
3c7b4e6b CM |
398 | * tree based on a pointer value. If alias is 0, only values pointing to the |
399 | * beginning of the memory block are allowed. The kmemleak_lock must be held | |
400 | * when calling this function. | |
401 | */ | |
402 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) | |
403 | { | |
85d3a316 ML |
404 | struct rb_node *rb = object_tree_root.rb_node; |
405 | ||
406 | while (rb) { | |
407 | struct kmemleak_object *object = | |
408 | rb_entry(rb, struct kmemleak_object, rb_node); | |
409 | if (ptr < object->pointer) | |
410 | rb = object->rb_node.rb_left; | |
411 | else if (object->pointer + object->size <= ptr) | |
412 | rb = object->rb_node.rb_right; | |
413 | else if (object->pointer == ptr || alias) | |
414 | return object; | |
415 | else { | |
5f79020c CM |
416 | kmemleak_warn("Found object by alias at 0x%08lx\n", |
417 | ptr); | |
a7686a45 | 418 | dump_object_info(object); |
85d3a316 | 419 | break; |
3c7b4e6b | 420 | } |
85d3a316 ML |
421 | } |
422 | return NULL; | |
3c7b4e6b CM |
423 | } |
424 | ||
425 | /* | |
426 | * Increment the object use_count. Return 1 if successful or 0 otherwise. Note | |
427 | * that once an object's use_count reached 0, the RCU freeing was already | |
428 | * registered and the object should no longer be used. This function must be | |
429 | * called under the protection of rcu_read_lock(). | |
430 | */ | |
431 | static int get_object(struct kmemleak_object *object) | |
432 | { | |
433 | return atomic_inc_not_zero(&object->use_count); | |
434 | } | |
435 | ||
436 | /* | |
437 | * RCU callback to free a kmemleak_object. | |
438 | */ | |
439 | static void free_object_rcu(struct rcu_head *rcu) | |
440 | { | |
b67bfe0d | 441 | struct hlist_node *tmp; |
3c7b4e6b CM |
442 | struct kmemleak_scan_area *area; |
443 | struct kmemleak_object *object = | |
444 | container_of(rcu, struct kmemleak_object, rcu); | |
445 | ||
446 | /* | |
447 | * Once use_count is 0 (guaranteed by put_object), there is no other | |
448 | * code accessing this object, hence no need for locking. | |
449 | */ | |
b67bfe0d SL |
450 | hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { |
451 | hlist_del(&area->node); | |
3c7b4e6b CM |
452 | kmem_cache_free(scan_area_cache, area); |
453 | } | |
454 | kmem_cache_free(object_cache, object); | |
455 | } | |
456 | ||
457 | /* | |
458 | * Decrement the object use_count. Once the count is 0, free the object using | |
459 | * an RCU callback. Since put_object() may be called via the kmemleak_free() -> | |
460 | * delete_object() path, the delayed RCU freeing ensures that there is no | |
461 | * recursive call to the kernel allocator. Lock-less RCU object_list traversal | |
462 | * is also possible. | |
463 | */ | |
464 | static void put_object(struct kmemleak_object *object) | |
465 | { | |
466 | if (!atomic_dec_and_test(&object->use_count)) | |
467 | return; | |
468 | ||
469 | /* should only get here after delete_object was called */ | |
470 | WARN_ON(object->flags & OBJECT_ALLOCATED); | |
471 | ||
472 | call_rcu(&object->rcu, free_object_rcu); | |
473 | } | |
474 | ||
475 | /* | |
85d3a316 | 476 | * Look up an object in the object search tree and increase its use_count. |
3c7b4e6b CM |
477 | */ |
478 | static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) | |
479 | { | |
480 | unsigned long flags; | |
9fbed254 | 481 | struct kmemleak_object *object; |
3c7b4e6b CM |
482 | |
483 | rcu_read_lock(); | |
484 | read_lock_irqsave(&kmemleak_lock, flags); | |
93ada579 | 485 | object = lookup_object(ptr, alias); |
3c7b4e6b CM |
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 | ||
e781a9ab CM |
496 | /* |
497 | * Look up an object in the object search tree and remove it from both | |
498 | * object_tree_root and object_list. The returned object's use_count should be | |
499 | * at least 1, as initially set by create_object(). | |
500 | */ | |
501 | static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias) | |
502 | { | |
503 | unsigned long flags; | |
504 | struct kmemleak_object *object; | |
505 | ||
506 | write_lock_irqsave(&kmemleak_lock, flags); | |
507 | object = lookup_object(ptr, alias); | |
508 | if (object) { | |
509 | rb_erase(&object->rb_node, &object_tree_root); | |
510 | list_del_rcu(&object->object_list); | |
511 | } | |
512 | write_unlock_irqrestore(&kmemleak_lock, flags); | |
513 | ||
514 | return object; | |
515 | } | |
516 | ||
fd678967 CM |
517 | /* |
518 | * Save stack trace to the given array of MAX_TRACE size. | |
519 | */ | |
520 | static int __save_stack_trace(unsigned long *trace) | |
521 | { | |
522 | struct stack_trace stack_trace; | |
523 | ||
524 | stack_trace.max_entries = MAX_TRACE; | |
525 | stack_trace.nr_entries = 0; | |
526 | stack_trace.entries = trace; | |
527 | stack_trace.skip = 2; | |
528 | save_stack_trace(&stack_trace); | |
529 | ||
530 | return stack_trace.nr_entries; | |
531 | } | |
532 | ||
3c7b4e6b CM |
533 | /* |
534 | * Create the metadata (struct kmemleak_object) corresponding to an allocated | |
535 | * memory block and add it to the object_list and object_tree_root. | |
536 | */ | |
fd678967 CM |
537 | static struct kmemleak_object *create_object(unsigned long ptr, size_t size, |
538 | int min_count, gfp_t gfp) | |
3c7b4e6b CM |
539 | { |
540 | unsigned long flags; | |
85d3a316 ML |
541 | struct kmemleak_object *object, *parent; |
542 | struct rb_node **link, *rb_parent; | |
3c7b4e6b | 543 | |
6ae4bd1f | 544 | object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b | 545 | if (!object) { |
598d8091 | 546 | pr_warn("Cannot allocate a kmemleak_object structure\n"); |
6ae4bd1f | 547 | kmemleak_disable(); |
fd678967 | 548 | return NULL; |
3c7b4e6b CM |
549 | } |
550 | ||
551 | INIT_LIST_HEAD(&object->object_list); | |
552 | INIT_LIST_HEAD(&object->gray_list); | |
553 | INIT_HLIST_HEAD(&object->area_list); | |
554 | spin_lock_init(&object->lock); | |
555 | atomic_set(&object->use_count, 1); | |
04609ccc | 556 | object->flags = OBJECT_ALLOCATED; |
3c7b4e6b CM |
557 | object->pointer = ptr; |
558 | object->size = size; | |
559 | object->min_count = min_count; | |
04609ccc | 560 | object->count = 0; /* white color initially */ |
3c7b4e6b | 561 | object->jiffies = jiffies; |
04609ccc | 562 | object->checksum = 0; |
3c7b4e6b CM |
563 | |
564 | /* task information */ | |
565 | if (in_irq()) { | |
566 | object->pid = 0; | |
567 | strncpy(object->comm, "hardirq", sizeof(object->comm)); | |
568 | } else if (in_softirq()) { | |
569 | object->pid = 0; | |
570 | strncpy(object->comm, "softirq", sizeof(object->comm)); | |
571 | } else { | |
572 | object->pid = current->pid; | |
573 | /* | |
574 | * There is a small chance of a race with set_task_comm(), | |
575 | * however using get_task_comm() here may cause locking | |
576 | * dependency issues with current->alloc_lock. In the worst | |
577 | * case, the command line is not correct. | |
578 | */ | |
579 | strncpy(object->comm, current->comm, sizeof(object->comm)); | |
580 | } | |
581 | ||
582 | /* kernel backtrace */ | |
fd678967 | 583 | object->trace_len = __save_stack_trace(object->trace); |
3c7b4e6b | 584 | |
3c7b4e6b | 585 | write_lock_irqsave(&kmemleak_lock, flags); |
0580a181 | 586 | |
3c7b4e6b CM |
587 | min_addr = min(min_addr, ptr); |
588 | max_addr = max(max_addr, ptr + size); | |
85d3a316 ML |
589 | link = &object_tree_root.rb_node; |
590 | rb_parent = NULL; | |
591 | while (*link) { | |
592 | rb_parent = *link; | |
593 | parent = rb_entry(rb_parent, struct kmemleak_object, rb_node); | |
594 | if (ptr + size <= parent->pointer) | |
595 | link = &parent->rb_node.rb_left; | |
596 | else if (parent->pointer + parent->size <= ptr) | |
597 | link = &parent->rb_node.rb_right; | |
598 | else { | |
756a025f | 599 | kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n", |
85d3a316 | 600 | ptr); |
9d5a4c73 CM |
601 | /* |
602 | * No need for parent->lock here since "parent" cannot | |
603 | * be freed while the kmemleak_lock is held. | |
604 | */ | |
605 | dump_object_info(parent); | |
85d3a316 | 606 | kmem_cache_free(object_cache, object); |
9d5a4c73 | 607 | object = NULL; |
85d3a316 ML |
608 | goto out; |
609 | } | |
3c7b4e6b | 610 | } |
85d3a316 ML |
611 | rb_link_node(&object->rb_node, rb_parent, link); |
612 | rb_insert_color(&object->rb_node, &object_tree_root); | |
613 | ||
3c7b4e6b CM |
614 | list_add_tail_rcu(&object->object_list, &object_list); |
615 | out: | |
616 | write_unlock_irqrestore(&kmemleak_lock, flags); | |
fd678967 | 617 | return object; |
3c7b4e6b CM |
618 | } |
619 | ||
620 | /* | |
e781a9ab | 621 | * Mark the object as not allocated and schedule RCU freeing via put_object(). |
3c7b4e6b | 622 | */ |
53238a60 | 623 | static void __delete_object(struct kmemleak_object *object) |
3c7b4e6b CM |
624 | { |
625 | unsigned long flags; | |
3c7b4e6b | 626 | |
3c7b4e6b | 627 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
e781a9ab | 628 | WARN_ON(atomic_read(&object->use_count) < 1); |
3c7b4e6b CM |
629 | |
630 | /* | |
631 | * Locking here also ensures that the corresponding memory block | |
632 | * cannot be freed when it is being scanned. | |
633 | */ | |
634 | spin_lock_irqsave(&object->lock, flags); | |
3c7b4e6b CM |
635 | object->flags &= ~OBJECT_ALLOCATED; |
636 | spin_unlock_irqrestore(&object->lock, flags); | |
637 | put_object(object); | |
638 | } | |
639 | ||
53238a60 CM |
640 | /* |
641 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
642 | * delete it. | |
643 | */ | |
644 | static void delete_object_full(unsigned long ptr) | |
645 | { | |
646 | struct kmemleak_object *object; | |
647 | ||
e781a9ab | 648 | object = find_and_remove_object(ptr, 0); |
53238a60 CM |
649 | if (!object) { |
650 | #ifdef DEBUG | |
651 | kmemleak_warn("Freeing unknown object at 0x%08lx\n", | |
652 | ptr); | |
653 | #endif | |
654 | return; | |
655 | } | |
656 | __delete_object(object); | |
53238a60 CM |
657 | } |
658 | ||
659 | /* | |
660 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
661 | * delete it. If the memory block is partially freed, the function may create | |
662 | * additional metadata for the remaining parts of the block. | |
663 | */ | |
664 | static void delete_object_part(unsigned long ptr, size_t size) | |
665 | { | |
666 | struct kmemleak_object *object; | |
667 | unsigned long start, end; | |
668 | ||
e781a9ab | 669 | object = find_and_remove_object(ptr, 1); |
53238a60 CM |
670 | if (!object) { |
671 | #ifdef DEBUG | |
756a025f JP |
672 | kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", |
673 | ptr, size); | |
53238a60 CM |
674 | #endif |
675 | return; | |
676 | } | |
53238a60 CM |
677 | |
678 | /* | |
679 | * Create one or two objects that may result from the memory block | |
680 | * split. Note that partial freeing is only done by free_bootmem() and | |
681 | * this happens before kmemleak_init() is called. The path below is | |
682 | * only executed during early log recording in kmemleak_init(), so | |
683 | * GFP_KERNEL is enough. | |
684 | */ | |
685 | start = object->pointer; | |
686 | end = object->pointer + object->size; | |
687 | if (ptr > start) | |
688 | create_object(start, ptr - start, object->min_count, | |
689 | GFP_KERNEL); | |
690 | if (ptr + size < end) | |
691 | create_object(ptr + size, end - ptr - size, object->min_count, | |
692 | GFP_KERNEL); | |
693 | ||
e781a9ab | 694 | __delete_object(object); |
53238a60 | 695 | } |
a1084c87 LR |
696 | |
697 | static void __paint_it(struct kmemleak_object *object, int color) | |
698 | { | |
699 | object->min_count = color; | |
700 | if (color == KMEMLEAK_BLACK) | |
701 | object->flags |= OBJECT_NO_SCAN; | |
702 | } | |
703 | ||
704 | static void paint_it(struct kmemleak_object *object, int color) | |
3c7b4e6b CM |
705 | { |
706 | unsigned long flags; | |
a1084c87 LR |
707 | |
708 | spin_lock_irqsave(&object->lock, flags); | |
709 | __paint_it(object, color); | |
710 | spin_unlock_irqrestore(&object->lock, flags); | |
711 | } | |
712 | ||
713 | static void paint_ptr(unsigned long ptr, int color) | |
714 | { | |
3c7b4e6b CM |
715 | struct kmemleak_object *object; |
716 | ||
717 | object = find_and_get_object(ptr, 0); | |
718 | if (!object) { | |
756a025f JP |
719 | kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n", |
720 | ptr, | |
a1084c87 LR |
721 | (color == KMEMLEAK_GREY) ? "Grey" : |
722 | (color == KMEMLEAK_BLACK) ? "Black" : "Unknown"); | |
3c7b4e6b CM |
723 | return; |
724 | } | |
a1084c87 | 725 | paint_it(object, color); |
3c7b4e6b CM |
726 | put_object(object); |
727 | } | |
728 | ||
a1084c87 | 729 | /* |
145b64b9 | 730 | * Mark an object permanently as gray-colored so that it can no longer be |
a1084c87 LR |
731 | * reported as a leak. This is used in general to mark a false positive. |
732 | */ | |
733 | static void make_gray_object(unsigned long ptr) | |
734 | { | |
735 | paint_ptr(ptr, KMEMLEAK_GREY); | |
736 | } | |
737 | ||
3c7b4e6b CM |
738 | /* |
739 | * Mark the object as black-colored so that it is ignored from scans and | |
740 | * reporting. | |
741 | */ | |
742 | static void make_black_object(unsigned long ptr) | |
743 | { | |
a1084c87 | 744 | paint_ptr(ptr, KMEMLEAK_BLACK); |
3c7b4e6b CM |
745 | } |
746 | ||
747 | /* | |
748 | * Add a scanning area to the object. If at least one such area is added, | |
749 | * kmemleak will only scan these ranges rather than the whole memory block. | |
750 | */ | |
c017b4be | 751 | static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
752 | { |
753 | unsigned long flags; | |
754 | struct kmemleak_object *object; | |
755 | struct kmemleak_scan_area *area; | |
756 | ||
c017b4be | 757 | object = find_and_get_object(ptr, 1); |
3c7b4e6b | 758 | if (!object) { |
ae281064 JP |
759 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
760 | ptr); | |
3c7b4e6b CM |
761 | return; |
762 | } | |
763 | ||
6ae4bd1f | 764 | area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b | 765 | if (!area) { |
598d8091 | 766 | pr_warn("Cannot allocate a scan area\n"); |
3c7b4e6b CM |
767 | goto out; |
768 | } | |
769 | ||
770 | spin_lock_irqsave(&object->lock, flags); | |
7f88f88f CM |
771 | if (size == SIZE_MAX) { |
772 | size = object->pointer + object->size - ptr; | |
773 | } else if (ptr + size > object->pointer + object->size) { | |
ae281064 | 774 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
3c7b4e6b CM |
775 | dump_object_info(object); |
776 | kmem_cache_free(scan_area_cache, area); | |
777 | goto out_unlock; | |
778 | } | |
779 | ||
780 | INIT_HLIST_NODE(&area->node); | |
c017b4be CM |
781 | area->start = ptr; |
782 | area->size = size; | |
3c7b4e6b CM |
783 | |
784 | hlist_add_head(&area->node, &object->area_list); | |
785 | out_unlock: | |
786 | spin_unlock_irqrestore(&object->lock, flags); | |
787 | out: | |
788 | put_object(object); | |
789 | } | |
790 | ||
791 | /* | |
792 | * Set the OBJECT_NO_SCAN flag for the object corresponding to the give | |
793 | * pointer. Such object will not be scanned by kmemleak but references to it | |
794 | * are searched. | |
795 | */ | |
796 | static void object_no_scan(unsigned long ptr) | |
797 | { | |
798 | unsigned long flags; | |
799 | struct kmemleak_object *object; | |
800 | ||
801 | object = find_and_get_object(ptr, 0); | |
802 | if (!object) { | |
ae281064 | 803 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
3c7b4e6b CM |
804 | return; |
805 | } | |
806 | ||
807 | spin_lock_irqsave(&object->lock, flags); | |
808 | object->flags |= OBJECT_NO_SCAN; | |
809 | spin_unlock_irqrestore(&object->lock, flags); | |
810 | put_object(object); | |
811 | } | |
812 | ||
813 | /* | |
814 | * Log an early kmemleak_* call to the early_log buffer. These calls will be | |
815 | * processed later once kmemleak is fully initialized. | |
816 | */ | |
a6186d89 | 817 | static void __init log_early(int op_type, const void *ptr, size_t size, |
c017b4be | 818 | int min_count) |
3c7b4e6b CM |
819 | { |
820 | unsigned long flags; | |
821 | struct early_log *log; | |
822 | ||
8910ae89 | 823 | if (kmemleak_error) { |
b6693005 CM |
824 | /* kmemleak stopped recording, just count the requests */ |
825 | crt_early_log++; | |
826 | return; | |
827 | } | |
828 | ||
3c7b4e6b | 829 | if (crt_early_log >= ARRAY_SIZE(early_log)) { |
21cd3a60 | 830 | crt_early_log++; |
a9d9058a | 831 | kmemleak_disable(); |
3c7b4e6b CM |
832 | return; |
833 | } | |
834 | ||
835 | /* | |
836 | * There is no need for locking since the kernel is still in UP mode | |
837 | * at this stage. Disabling the IRQs is enough. | |
838 | */ | |
839 | local_irq_save(flags); | |
840 | log = &early_log[crt_early_log]; | |
841 | log->op_type = op_type; | |
842 | log->ptr = ptr; | |
843 | log->size = size; | |
844 | log->min_count = min_count; | |
5f79020c | 845 | log->trace_len = __save_stack_trace(log->trace); |
3c7b4e6b CM |
846 | crt_early_log++; |
847 | local_irq_restore(flags); | |
848 | } | |
849 | ||
fd678967 CM |
850 | /* |
851 | * Log an early allocated block and populate the stack trace. | |
852 | */ | |
853 | static void early_alloc(struct early_log *log) | |
854 | { | |
855 | struct kmemleak_object *object; | |
856 | unsigned long flags; | |
857 | int i; | |
858 | ||
8910ae89 | 859 | if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr)) |
fd678967 CM |
860 | return; |
861 | ||
862 | /* | |
863 | * RCU locking needed to ensure object is not freed via put_object(). | |
864 | */ | |
865 | rcu_read_lock(); | |
866 | object = create_object((unsigned long)log->ptr, log->size, | |
c1bcd6b3 | 867 | log->min_count, GFP_ATOMIC); |
0d5d1aad CM |
868 | if (!object) |
869 | goto out; | |
fd678967 CM |
870 | spin_lock_irqsave(&object->lock, flags); |
871 | for (i = 0; i < log->trace_len; i++) | |
872 | object->trace[i] = log->trace[i]; | |
873 | object->trace_len = log->trace_len; | |
874 | spin_unlock_irqrestore(&object->lock, flags); | |
0d5d1aad | 875 | out: |
fd678967 CM |
876 | rcu_read_unlock(); |
877 | } | |
878 | ||
f528f0b8 CM |
879 | /* |
880 | * Log an early allocated block and populate the stack trace. | |
881 | */ | |
882 | static void early_alloc_percpu(struct early_log *log) | |
883 | { | |
884 | unsigned int cpu; | |
885 | const void __percpu *ptr = log->ptr; | |
886 | ||
887 | for_each_possible_cpu(cpu) { | |
888 | log->ptr = per_cpu_ptr(ptr, cpu); | |
889 | early_alloc(log); | |
890 | } | |
891 | } | |
892 | ||
a2b6bf63 CM |
893 | /** |
894 | * kmemleak_alloc - register a newly allocated object | |
895 | * @ptr: pointer to beginning of the object | |
896 | * @size: size of the object | |
897 | * @min_count: minimum number of references to this object. If during memory | |
898 | * scanning a number of references less than @min_count is found, | |
899 | * the object is reported as a memory leak. If @min_count is 0, | |
900 | * the object is never reported as a leak. If @min_count is -1, | |
901 | * the object is ignored (not scanned and not reported as a leak) | |
902 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
903 | * | |
904 | * This function is called from the kernel allocators when a new object | |
905 | * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.). | |
3c7b4e6b | 906 | */ |
a6186d89 CM |
907 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
908 | gfp_t gfp) | |
3c7b4e6b CM |
909 | { |
910 | pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); | |
911 | ||
8910ae89 | 912 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 913 | create_object((unsigned long)ptr, size, min_count, gfp); |
8910ae89 | 914 | else if (kmemleak_early_log) |
c017b4be | 915 | log_early(KMEMLEAK_ALLOC, ptr, size, min_count); |
3c7b4e6b CM |
916 | } |
917 | EXPORT_SYMBOL_GPL(kmemleak_alloc); | |
918 | ||
f528f0b8 CM |
919 | /** |
920 | * kmemleak_alloc_percpu - register a newly allocated __percpu object | |
921 | * @ptr: __percpu pointer to beginning of the object | |
922 | * @size: size of the object | |
8a8c35fa | 923 | * @gfp: flags used for kmemleak internal memory allocations |
f528f0b8 CM |
924 | * |
925 | * This function is called from the kernel percpu allocator when a new object | |
8a8c35fa | 926 | * (memory block) is allocated (alloc_percpu). |
f528f0b8 | 927 | */ |
8a8c35fa LF |
928 | void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, |
929 | gfp_t gfp) | |
f528f0b8 CM |
930 | { |
931 | unsigned int cpu; | |
932 | ||
933 | pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size); | |
934 | ||
935 | /* | |
936 | * Percpu allocations are only scanned and not reported as leaks | |
937 | * (min_count is set to 0). | |
938 | */ | |
8910ae89 | 939 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
940 | for_each_possible_cpu(cpu) |
941 | create_object((unsigned long)per_cpu_ptr(ptr, cpu), | |
8a8c35fa | 942 | size, 0, gfp); |
8910ae89 | 943 | else if (kmemleak_early_log) |
f528f0b8 CM |
944 | log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0); |
945 | } | |
946 | EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); | |
947 | ||
a2b6bf63 CM |
948 | /** |
949 | * kmemleak_free - unregister a previously registered object | |
950 | * @ptr: pointer to beginning of the object | |
951 | * | |
952 | * This function is called from the kernel allocators when an object (memory | |
953 | * block) is freed (kmem_cache_free, kfree, vfree etc.). | |
3c7b4e6b | 954 | */ |
a6186d89 | 955 | void __ref kmemleak_free(const void *ptr) |
3c7b4e6b CM |
956 | { |
957 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
958 | ||
c5f3b1a5 | 959 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 960 | delete_object_full((unsigned long)ptr); |
8910ae89 | 961 | else if (kmemleak_early_log) |
c017b4be | 962 | log_early(KMEMLEAK_FREE, ptr, 0, 0); |
3c7b4e6b CM |
963 | } |
964 | EXPORT_SYMBOL_GPL(kmemleak_free); | |
965 | ||
a2b6bf63 CM |
966 | /** |
967 | * kmemleak_free_part - partially unregister a previously registered object | |
968 | * @ptr: pointer to the beginning or inside the object. This also | |
969 | * represents the start of the range to be freed | |
970 | * @size: size to be unregistered | |
971 | * | |
972 | * This function is called when only a part of a memory block is freed | |
973 | * (usually from the bootmem allocator). | |
53238a60 | 974 | */ |
a6186d89 | 975 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
53238a60 CM |
976 | { |
977 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
978 | ||
8910ae89 | 979 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 980 | delete_object_part((unsigned long)ptr, size); |
8910ae89 | 981 | else if (kmemleak_early_log) |
c017b4be | 982 | log_early(KMEMLEAK_FREE_PART, ptr, size, 0); |
53238a60 CM |
983 | } |
984 | EXPORT_SYMBOL_GPL(kmemleak_free_part); | |
985 | ||
f528f0b8 CM |
986 | /** |
987 | * kmemleak_free_percpu - unregister a previously registered __percpu object | |
988 | * @ptr: __percpu pointer to beginning of the object | |
989 | * | |
990 | * This function is called from the kernel percpu allocator when an object | |
991 | * (memory block) is freed (free_percpu). | |
992 | */ | |
993 | void __ref kmemleak_free_percpu(const void __percpu *ptr) | |
994 | { | |
995 | unsigned int cpu; | |
996 | ||
997 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
998 | ||
c5f3b1a5 | 999 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
1000 | for_each_possible_cpu(cpu) |
1001 | delete_object_full((unsigned long)per_cpu_ptr(ptr, | |
1002 | cpu)); | |
8910ae89 | 1003 | else if (kmemleak_early_log) |
f528f0b8 CM |
1004 | log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0); |
1005 | } | |
1006 | EXPORT_SYMBOL_GPL(kmemleak_free_percpu); | |
1007 | ||
ffe2c748 CM |
1008 | /** |
1009 | * kmemleak_update_trace - update object allocation stack trace | |
1010 | * @ptr: pointer to beginning of the object | |
1011 | * | |
1012 | * Override the object allocation stack trace for cases where the actual | |
1013 | * allocation place is not always useful. | |
1014 | */ | |
1015 | void __ref kmemleak_update_trace(const void *ptr) | |
1016 | { | |
1017 | struct kmemleak_object *object; | |
1018 | unsigned long flags; | |
1019 | ||
1020 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1021 | ||
1022 | if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr)) | |
1023 | return; | |
1024 | ||
1025 | object = find_and_get_object((unsigned long)ptr, 1); | |
1026 | if (!object) { | |
1027 | #ifdef DEBUG | |
1028 | kmemleak_warn("Updating stack trace for unknown object at %p\n", | |
1029 | ptr); | |
1030 | #endif | |
1031 | return; | |
1032 | } | |
1033 | ||
1034 | spin_lock_irqsave(&object->lock, flags); | |
1035 | object->trace_len = __save_stack_trace(object->trace); | |
1036 | spin_unlock_irqrestore(&object->lock, flags); | |
1037 | ||
1038 | put_object(object); | |
1039 | } | |
1040 | EXPORT_SYMBOL(kmemleak_update_trace); | |
1041 | ||
a2b6bf63 CM |
1042 | /** |
1043 | * kmemleak_not_leak - mark an allocated object as false positive | |
1044 | * @ptr: pointer to beginning of the object | |
1045 | * | |
1046 | * Calling this function on an object will cause the memory block to no longer | |
1047 | * be reported as leak and always be scanned. | |
3c7b4e6b | 1048 | */ |
a6186d89 | 1049 | void __ref kmemleak_not_leak(const void *ptr) |
3c7b4e6b CM |
1050 | { |
1051 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1052 | ||
8910ae89 | 1053 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1054 | make_gray_object((unsigned long)ptr); |
8910ae89 | 1055 | else if (kmemleak_early_log) |
c017b4be | 1056 | log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0); |
3c7b4e6b CM |
1057 | } |
1058 | EXPORT_SYMBOL(kmemleak_not_leak); | |
1059 | ||
a2b6bf63 CM |
1060 | /** |
1061 | * kmemleak_ignore - ignore an allocated object | |
1062 | * @ptr: pointer to beginning of the object | |
1063 | * | |
1064 | * Calling this function on an object will cause the memory block to be | |
1065 | * ignored (not scanned and not reported as a leak). This is usually done when | |
1066 | * it is known that the corresponding block is not a leak and does not contain | |
1067 | * any references to other allocated memory blocks. | |
3c7b4e6b | 1068 | */ |
a6186d89 | 1069 | void __ref kmemleak_ignore(const void *ptr) |
3c7b4e6b CM |
1070 | { |
1071 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1072 | ||
8910ae89 | 1073 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1074 | make_black_object((unsigned long)ptr); |
8910ae89 | 1075 | else if (kmemleak_early_log) |
c017b4be | 1076 | log_early(KMEMLEAK_IGNORE, ptr, 0, 0); |
3c7b4e6b CM |
1077 | } |
1078 | EXPORT_SYMBOL(kmemleak_ignore); | |
1079 | ||
a2b6bf63 CM |
1080 | /** |
1081 | * kmemleak_scan_area - limit the range to be scanned in an allocated object | |
1082 | * @ptr: pointer to beginning or inside the object. This also | |
1083 | * represents the start of the scan area | |
1084 | * @size: size of the scan area | |
1085 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1086 | * | |
1087 | * This function is used when it is known that only certain parts of an object | |
1088 | * contain references to other objects. Kmemleak will only scan these areas | |
1089 | * reducing the number false negatives. | |
3c7b4e6b | 1090 | */ |
c017b4be | 1091 | void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
1092 | { |
1093 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1094 | ||
8910ae89 | 1095 | if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
c017b4be | 1096 | add_scan_area((unsigned long)ptr, size, gfp); |
8910ae89 | 1097 | else if (kmemleak_early_log) |
c017b4be | 1098 | log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0); |
3c7b4e6b CM |
1099 | } |
1100 | EXPORT_SYMBOL(kmemleak_scan_area); | |
1101 | ||
a2b6bf63 CM |
1102 | /** |
1103 | * kmemleak_no_scan - do not scan an allocated object | |
1104 | * @ptr: pointer to beginning of the object | |
1105 | * | |
1106 | * This function notifies kmemleak not to scan the given memory block. Useful | |
1107 | * in situations where it is known that the given object does not contain any | |
1108 | * references to other objects. Kmemleak will not scan such objects reducing | |
1109 | * the number of false negatives. | |
3c7b4e6b | 1110 | */ |
a6186d89 | 1111 | void __ref kmemleak_no_scan(const void *ptr) |
3c7b4e6b CM |
1112 | { |
1113 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1114 | ||
8910ae89 | 1115 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1116 | object_no_scan((unsigned long)ptr); |
8910ae89 | 1117 | else if (kmemleak_early_log) |
c017b4be | 1118 | log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0); |
3c7b4e6b CM |
1119 | } |
1120 | EXPORT_SYMBOL(kmemleak_no_scan); | |
1121 | ||
04609ccc CM |
1122 | /* |
1123 | * Update an object's checksum and return true if it was modified. | |
1124 | */ | |
1125 | static bool update_checksum(struct kmemleak_object *object) | |
1126 | { | |
1127 | u32 old_csum = object->checksum; | |
1128 | ||
1129 | if (!kmemcheck_is_obj_initialized(object->pointer, object->size)) | |
1130 | return false; | |
1131 | ||
e79ed2f1 | 1132 | kasan_disable_current(); |
04609ccc | 1133 | object->checksum = crc32(0, (void *)object->pointer, object->size); |
e79ed2f1 AR |
1134 | kasan_enable_current(); |
1135 | ||
04609ccc CM |
1136 | return object->checksum != old_csum; |
1137 | } | |
1138 | ||
3c7b4e6b CM |
1139 | /* |
1140 | * Memory scanning is a long process and it needs to be interruptable. This | |
25985edc | 1141 | * function checks whether such interrupt condition occurred. |
3c7b4e6b CM |
1142 | */ |
1143 | static int scan_should_stop(void) | |
1144 | { | |
8910ae89 | 1145 | if (!kmemleak_enabled) |
3c7b4e6b CM |
1146 | return 1; |
1147 | ||
1148 | /* | |
1149 | * This function may be called from either process or kthread context, | |
1150 | * hence the need to check for both stop conditions. | |
1151 | */ | |
1152 | if (current->mm) | |
1153 | return signal_pending(current); | |
1154 | else | |
1155 | return kthread_should_stop(); | |
1156 | ||
1157 | return 0; | |
1158 | } | |
1159 | ||
1160 | /* | |
1161 | * Scan a memory block (exclusive range) for valid pointers and add those | |
1162 | * found to the gray list. | |
1163 | */ | |
1164 | static void scan_block(void *_start, void *_end, | |
93ada579 | 1165 | struct kmemleak_object *scanned) |
3c7b4e6b CM |
1166 | { |
1167 | unsigned long *ptr; | |
1168 | unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); | |
1169 | unsigned long *end = _end - (BYTES_PER_POINTER - 1); | |
93ada579 | 1170 | unsigned long flags; |
3c7b4e6b | 1171 | |
93ada579 | 1172 | read_lock_irqsave(&kmemleak_lock, flags); |
3c7b4e6b | 1173 | for (ptr = start; ptr < end; ptr++) { |
3c7b4e6b | 1174 | struct kmemleak_object *object; |
8e019366 | 1175 | unsigned long pointer; |
3c7b4e6b CM |
1176 | |
1177 | if (scan_should_stop()) | |
1178 | break; | |
1179 | ||
8e019366 PE |
1180 | /* don't scan uninitialized memory */ |
1181 | if (!kmemcheck_is_obj_initialized((unsigned long)ptr, | |
1182 | BYTES_PER_POINTER)) | |
1183 | continue; | |
1184 | ||
e79ed2f1 | 1185 | kasan_disable_current(); |
8e019366 | 1186 | pointer = *ptr; |
e79ed2f1 | 1187 | kasan_enable_current(); |
8e019366 | 1188 | |
93ada579 CM |
1189 | if (pointer < min_addr || pointer >= max_addr) |
1190 | continue; | |
1191 | ||
1192 | /* | |
1193 | * No need for get_object() here since we hold kmemleak_lock. | |
1194 | * object->use_count cannot be dropped to 0 while the object | |
1195 | * is still present in object_tree_root and object_list | |
1196 | * (with updates protected by kmemleak_lock). | |
1197 | */ | |
1198 | object = lookup_object(pointer, 1); | |
3c7b4e6b CM |
1199 | if (!object) |
1200 | continue; | |
93ada579 | 1201 | if (object == scanned) |
3c7b4e6b | 1202 | /* self referenced, ignore */ |
3c7b4e6b | 1203 | continue; |
3c7b4e6b CM |
1204 | |
1205 | /* | |
1206 | * Avoid the lockdep recursive warning on object->lock being | |
1207 | * previously acquired in scan_object(). These locks are | |
1208 | * enclosed by scan_mutex. | |
1209 | */ | |
93ada579 | 1210 | spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
3c7b4e6b CM |
1211 | if (!color_white(object)) { |
1212 | /* non-orphan, ignored or new */ | |
93ada579 | 1213 | spin_unlock(&object->lock); |
3c7b4e6b CM |
1214 | continue; |
1215 | } | |
1216 | ||
1217 | /* | |
1218 | * Increase the object's reference count (number of pointers | |
1219 | * to the memory block). If this count reaches the required | |
1220 | * minimum, the object's color will become gray and it will be | |
1221 | * added to the gray_list. | |
1222 | */ | |
1223 | object->count++; | |
0587da40 | 1224 | if (color_gray(object)) { |
93ada579 CM |
1225 | /* put_object() called when removing from gray_list */ |
1226 | WARN_ON(!get_object(object)); | |
3c7b4e6b | 1227 | list_add_tail(&object->gray_list, &gray_list); |
0587da40 | 1228 | } |
93ada579 CM |
1229 | spin_unlock(&object->lock); |
1230 | } | |
1231 | read_unlock_irqrestore(&kmemleak_lock, flags); | |
1232 | } | |
0587da40 | 1233 | |
93ada579 CM |
1234 | /* |
1235 | * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency. | |
1236 | */ | |
1237 | static void scan_large_block(void *start, void *end) | |
1238 | { | |
1239 | void *next; | |
1240 | ||
1241 | while (start < end) { | |
1242 | next = min(start + MAX_SCAN_SIZE, end); | |
1243 | scan_block(start, next, NULL); | |
1244 | start = next; | |
1245 | cond_resched(); | |
3c7b4e6b CM |
1246 | } |
1247 | } | |
1248 | ||
1249 | /* | |
1250 | * Scan a memory block corresponding to a kmemleak_object. A condition is | |
1251 | * that object->use_count >= 1. | |
1252 | */ | |
1253 | static void scan_object(struct kmemleak_object *object) | |
1254 | { | |
1255 | struct kmemleak_scan_area *area; | |
3c7b4e6b CM |
1256 | unsigned long flags; |
1257 | ||
1258 | /* | |
21ae2956 UKK |
1259 | * Once the object->lock is acquired, the corresponding memory block |
1260 | * cannot be freed (the same lock is acquired in delete_object). | |
3c7b4e6b CM |
1261 | */ |
1262 | spin_lock_irqsave(&object->lock, flags); | |
1263 | if (object->flags & OBJECT_NO_SCAN) | |
1264 | goto out; | |
1265 | if (!(object->flags & OBJECT_ALLOCATED)) | |
1266 | /* already freed object */ | |
1267 | goto out; | |
af98603d CM |
1268 | if (hlist_empty(&object->area_list)) { |
1269 | void *start = (void *)object->pointer; | |
1270 | void *end = (void *)(object->pointer + object->size); | |
93ada579 CM |
1271 | void *next; |
1272 | ||
1273 | do { | |
1274 | next = min(start + MAX_SCAN_SIZE, end); | |
1275 | scan_block(start, next, object); | |
af98603d | 1276 | |
93ada579 CM |
1277 | start = next; |
1278 | if (start >= end) | |
1279 | break; | |
af98603d CM |
1280 | |
1281 | spin_unlock_irqrestore(&object->lock, flags); | |
1282 | cond_resched(); | |
1283 | spin_lock_irqsave(&object->lock, flags); | |
93ada579 | 1284 | } while (object->flags & OBJECT_ALLOCATED); |
af98603d | 1285 | } else |
b67bfe0d | 1286 | hlist_for_each_entry(area, &object->area_list, node) |
c017b4be CM |
1287 | scan_block((void *)area->start, |
1288 | (void *)(area->start + area->size), | |
93ada579 | 1289 | object); |
3c7b4e6b CM |
1290 | out: |
1291 | spin_unlock_irqrestore(&object->lock, flags); | |
1292 | } | |
1293 | ||
04609ccc CM |
1294 | /* |
1295 | * Scan the objects already referenced (gray objects). More objects will be | |
1296 | * referenced and, if there are no memory leaks, all the objects are scanned. | |
1297 | */ | |
1298 | static void scan_gray_list(void) | |
1299 | { | |
1300 | struct kmemleak_object *object, *tmp; | |
1301 | ||
1302 | /* | |
1303 | * The list traversal is safe for both tail additions and removals | |
1304 | * from inside the loop. The kmemleak objects cannot be freed from | |
1305 | * outside the loop because their use_count was incremented. | |
1306 | */ | |
1307 | object = list_entry(gray_list.next, typeof(*object), gray_list); | |
1308 | while (&object->gray_list != &gray_list) { | |
1309 | cond_resched(); | |
1310 | ||
1311 | /* may add new objects to the list */ | |
1312 | if (!scan_should_stop()) | |
1313 | scan_object(object); | |
1314 | ||
1315 | tmp = list_entry(object->gray_list.next, typeof(*object), | |
1316 | gray_list); | |
1317 | ||
1318 | /* remove the object from the list and release it */ | |
1319 | list_del(&object->gray_list); | |
1320 | put_object(object); | |
1321 | ||
1322 | object = tmp; | |
1323 | } | |
1324 | WARN_ON(!list_empty(&gray_list)); | |
1325 | } | |
1326 | ||
3c7b4e6b CM |
1327 | /* |
1328 | * Scan data sections and all the referenced memory blocks allocated via the | |
1329 | * kernel's standard allocators. This function must be called with the | |
1330 | * scan_mutex held. | |
1331 | */ | |
1332 | static void kmemleak_scan(void) | |
1333 | { | |
1334 | unsigned long flags; | |
04609ccc | 1335 | struct kmemleak_object *object; |
3c7b4e6b | 1336 | int i; |
4698c1f2 | 1337 | int new_leaks = 0; |
3c7b4e6b | 1338 | |
acf4968e CM |
1339 | jiffies_last_scan = jiffies; |
1340 | ||
3c7b4e6b CM |
1341 | /* prepare the kmemleak_object's */ |
1342 | rcu_read_lock(); | |
1343 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1344 | spin_lock_irqsave(&object->lock, flags); | |
1345 | #ifdef DEBUG | |
1346 | /* | |
1347 | * With a few exceptions there should be a maximum of | |
1348 | * 1 reference to any object at this point. | |
1349 | */ | |
1350 | if (atomic_read(&object->use_count) > 1) { | |
ae281064 | 1351 | pr_debug("object->use_count = %d\n", |
3c7b4e6b CM |
1352 | atomic_read(&object->use_count)); |
1353 | dump_object_info(object); | |
1354 | } | |
1355 | #endif | |
1356 | /* reset the reference count (whiten the object) */ | |
1357 | object->count = 0; | |
1358 | if (color_gray(object) && get_object(object)) | |
1359 | list_add_tail(&object->gray_list, &gray_list); | |
1360 | ||
1361 | spin_unlock_irqrestore(&object->lock, flags); | |
1362 | } | |
1363 | rcu_read_unlock(); | |
1364 | ||
1365 | /* data/bss scanning */ | |
93ada579 CM |
1366 | scan_large_block(_sdata, _edata); |
1367 | scan_large_block(__bss_start, __bss_stop); | |
3c7b4e6b CM |
1368 | |
1369 | #ifdef CONFIG_SMP | |
1370 | /* per-cpu sections scanning */ | |
1371 | for_each_possible_cpu(i) | |
93ada579 CM |
1372 | scan_large_block(__per_cpu_start + per_cpu_offset(i), |
1373 | __per_cpu_end + per_cpu_offset(i)); | |
3c7b4e6b CM |
1374 | #endif |
1375 | ||
1376 | /* | |
029aeff5 | 1377 | * Struct page scanning for each node. |
3c7b4e6b | 1378 | */ |
bfc8c901 | 1379 | get_online_mems(); |
3c7b4e6b | 1380 | for_each_online_node(i) { |
108bcc96 CS |
1381 | unsigned long start_pfn = node_start_pfn(i); |
1382 | unsigned long end_pfn = node_end_pfn(i); | |
3c7b4e6b CM |
1383 | unsigned long pfn; |
1384 | ||
1385 | for (pfn = start_pfn; pfn < end_pfn; pfn++) { | |
1386 | struct page *page; | |
1387 | ||
1388 | if (!pfn_valid(pfn)) | |
1389 | continue; | |
1390 | page = pfn_to_page(pfn); | |
1391 | /* only scan if page is in use */ | |
1392 | if (page_count(page) == 0) | |
1393 | continue; | |
93ada579 | 1394 | scan_block(page, page + 1, NULL); |
3c7b4e6b CM |
1395 | } |
1396 | } | |
bfc8c901 | 1397 | put_online_mems(); |
3c7b4e6b CM |
1398 | |
1399 | /* | |
43ed5d6e | 1400 | * Scanning the task stacks (may introduce false negatives). |
3c7b4e6b CM |
1401 | */ |
1402 | if (kmemleak_stack_scan) { | |
43ed5d6e CM |
1403 | struct task_struct *p, *g; |
1404 | ||
3c7b4e6b | 1405 | read_lock(&tasklist_lock); |
43ed5d6e CM |
1406 | do_each_thread(g, p) { |
1407 | scan_block(task_stack_page(p), task_stack_page(p) + | |
93ada579 | 1408 | THREAD_SIZE, NULL); |
43ed5d6e | 1409 | } while_each_thread(g, p); |
3c7b4e6b CM |
1410 | read_unlock(&tasklist_lock); |
1411 | } | |
1412 | ||
1413 | /* | |
1414 | * Scan the objects already referenced from the sections scanned | |
04609ccc | 1415 | * above. |
3c7b4e6b | 1416 | */ |
04609ccc | 1417 | scan_gray_list(); |
2587362e CM |
1418 | |
1419 | /* | |
04609ccc CM |
1420 | * Check for new or unreferenced objects modified since the previous |
1421 | * scan and color them gray until the next scan. | |
2587362e CM |
1422 | */ |
1423 | rcu_read_lock(); | |
1424 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1425 | spin_lock_irqsave(&object->lock, flags); | |
04609ccc CM |
1426 | if (color_white(object) && (object->flags & OBJECT_ALLOCATED) |
1427 | && update_checksum(object) && get_object(object)) { | |
1428 | /* color it gray temporarily */ | |
1429 | object->count = object->min_count; | |
2587362e CM |
1430 | list_add_tail(&object->gray_list, &gray_list); |
1431 | } | |
1432 | spin_unlock_irqrestore(&object->lock, flags); | |
1433 | } | |
1434 | rcu_read_unlock(); | |
1435 | ||
04609ccc CM |
1436 | /* |
1437 | * Re-scan the gray list for modified unreferenced objects. | |
1438 | */ | |
1439 | scan_gray_list(); | |
4698c1f2 | 1440 | |
17bb9e0d | 1441 | /* |
04609ccc | 1442 | * If scanning was stopped do not report any new unreferenced objects. |
17bb9e0d | 1443 | */ |
04609ccc | 1444 | if (scan_should_stop()) |
17bb9e0d CM |
1445 | return; |
1446 | ||
4698c1f2 CM |
1447 | /* |
1448 | * Scanning result reporting. | |
1449 | */ | |
1450 | rcu_read_lock(); | |
1451 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1452 | spin_lock_irqsave(&object->lock, flags); | |
1453 | if (unreferenced_object(object) && | |
1454 | !(object->flags & OBJECT_REPORTED)) { | |
1455 | object->flags |= OBJECT_REPORTED; | |
1456 | new_leaks++; | |
1457 | } | |
1458 | spin_unlock_irqrestore(&object->lock, flags); | |
1459 | } | |
1460 | rcu_read_unlock(); | |
1461 | ||
dc9b3f42 LZ |
1462 | if (new_leaks) { |
1463 | kmemleak_found_leaks = true; | |
1464 | ||
756a025f JP |
1465 | pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n", |
1466 | new_leaks); | |
dc9b3f42 | 1467 | } |
4698c1f2 | 1468 | |
3c7b4e6b CM |
1469 | } |
1470 | ||
1471 | /* | |
1472 | * Thread function performing automatic memory scanning. Unreferenced objects | |
1473 | * at the end of a memory scan are reported but only the first time. | |
1474 | */ | |
1475 | static int kmemleak_scan_thread(void *arg) | |
1476 | { | |
1477 | static int first_run = 1; | |
1478 | ||
ae281064 | 1479 | pr_info("Automatic memory scanning thread started\n"); |
bf2a76b3 | 1480 | set_user_nice(current, 10); |
3c7b4e6b CM |
1481 | |
1482 | /* | |
1483 | * Wait before the first scan to allow the system to fully initialize. | |
1484 | */ | |
1485 | if (first_run) { | |
1486 | first_run = 0; | |
1487 | ssleep(SECS_FIRST_SCAN); | |
1488 | } | |
1489 | ||
1490 | while (!kthread_should_stop()) { | |
3c7b4e6b CM |
1491 | signed long timeout = jiffies_scan_wait; |
1492 | ||
1493 | mutex_lock(&scan_mutex); | |
3c7b4e6b | 1494 | kmemleak_scan(); |
3c7b4e6b | 1495 | mutex_unlock(&scan_mutex); |
4698c1f2 | 1496 | |
3c7b4e6b CM |
1497 | /* wait before the next scan */ |
1498 | while (timeout && !kthread_should_stop()) | |
1499 | timeout = schedule_timeout_interruptible(timeout); | |
1500 | } | |
1501 | ||
ae281064 | 1502 | pr_info("Automatic memory scanning thread ended\n"); |
3c7b4e6b CM |
1503 | |
1504 | return 0; | |
1505 | } | |
1506 | ||
1507 | /* | |
1508 | * Start the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1509 | * with the scan_mutex held. |
3c7b4e6b | 1510 | */ |
7eb0d5e5 | 1511 | static void start_scan_thread(void) |
3c7b4e6b CM |
1512 | { |
1513 | if (scan_thread) | |
1514 | return; | |
1515 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); | |
1516 | if (IS_ERR(scan_thread)) { | |
598d8091 | 1517 | pr_warn("Failed to create the scan thread\n"); |
3c7b4e6b CM |
1518 | scan_thread = NULL; |
1519 | } | |
1520 | } | |
1521 | ||
1522 | /* | |
1523 | * Stop the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1524 | * with the scan_mutex held. |
3c7b4e6b | 1525 | */ |
7eb0d5e5 | 1526 | static void stop_scan_thread(void) |
3c7b4e6b CM |
1527 | { |
1528 | if (scan_thread) { | |
1529 | kthread_stop(scan_thread); | |
1530 | scan_thread = NULL; | |
1531 | } | |
1532 | } | |
1533 | ||
1534 | /* | |
1535 | * Iterate over the object_list and return the first valid object at or after | |
1536 | * the required position with its use_count incremented. The function triggers | |
1537 | * a memory scanning when the pos argument points to the first position. | |
1538 | */ | |
1539 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) | |
1540 | { | |
1541 | struct kmemleak_object *object; | |
1542 | loff_t n = *pos; | |
b87324d0 CM |
1543 | int err; |
1544 | ||
1545 | err = mutex_lock_interruptible(&scan_mutex); | |
1546 | if (err < 0) | |
1547 | return ERR_PTR(err); | |
3c7b4e6b | 1548 | |
3c7b4e6b CM |
1549 | rcu_read_lock(); |
1550 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1551 | if (n-- > 0) | |
1552 | continue; | |
1553 | if (get_object(object)) | |
1554 | goto out; | |
1555 | } | |
1556 | object = NULL; | |
1557 | out: | |
3c7b4e6b CM |
1558 | return object; |
1559 | } | |
1560 | ||
1561 | /* | |
1562 | * Return the next object in the object_list. The function decrements the | |
1563 | * use_count of the previous object and increases that of the next one. | |
1564 | */ | |
1565 | static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
1566 | { | |
1567 | struct kmemleak_object *prev_obj = v; | |
1568 | struct kmemleak_object *next_obj = NULL; | |
58fac095 | 1569 | struct kmemleak_object *obj = prev_obj; |
3c7b4e6b CM |
1570 | |
1571 | ++(*pos); | |
3c7b4e6b | 1572 | |
58fac095 | 1573 | list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
52c3ce4e CM |
1574 | if (get_object(obj)) { |
1575 | next_obj = obj; | |
3c7b4e6b | 1576 | break; |
52c3ce4e | 1577 | } |
3c7b4e6b | 1578 | } |
288c857d | 1579 | |
3c7b4e6b CM |
1580 | put_object(prev_obj); |
1581 | return next_obj; | |
1582 | } | |
1583 | ||
1584 | /* | |
1585 | * Decrement the use_count of the last object required, if any. | |
1586 | */ | |
1587 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) | |
1588 | { | |
b87324d0 CM |
1589 | if (!IS_ERR(v)) { |
1590 | /* | |
1591 | * kmemleak_seq_start may return ERR_PTR if the scan_mutex | |
1592 | * waiting was interrupted, so only release it if !IS_ERR. | |
1593 | */ | |
f5886c7f | 1594 | rcu_read_unlock(); |
b87324d0 CM |
1595 | mutex_unlock(&scan_mutex); |
1596 | if (v) | |
1597 | put_object(v); | |
1598 | } | |
3c7b4e6b CM |
1599 | } |
1600 | ||
1601 | /* | |
1602 | * Print the information for an unreferenced object to the seq file. | |
1603 | */ | |
1604 | static int kmemleak_seq_show(struct seq_file *seq, void *v) | |
1605 | { | |
1606 | struct kmemleak_object *object = v; | |
1607 | unsigned long flags; | |
1608 | ||
1609 | spin_lock_irqsave(&object->lock, flags); | |
288c857d | 1610 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
17bb9e0d | 1611 | print_unreferenced(seq, object); |
3c7b4e6b CM |
1612 | spin_unlock_irqrestore(&object->lock, flags); |
1613 | return 0; | |
1614 | } | |
1615 | ||
1616 | static const struct seq_operations kmemleak_seq_ops = { | |
1617 | .start = kmemleak_seq_start, | |
1618 | .next = kmemleak_seq_next, | |
1619 | .stop = kmemleak_seq_stop, | |
1620 | .show = kmemleak_seq_show, | |
1621 | }; | |
1622 | ||
1623 | static int kmemleak_open(struct inode *inode, struct file *file) | |
1624 | { | |
b87324d0 | 1625 | return seq_open(file, &kmemleak_seq_ops); |
3c7b4e6b CM |
1626 | } |
1627 | ||
189d84ed CM |
1628 | static int dump_str_object_info(const char *str) |
1629 | { | |
1630 | unsigned long flags; | |
1631 | struct kmemleak_object *object; | |
1632 | unsigned long addr; | |
1633 | ||
dc053733 AP |
1634 | if (kstrtoul(str, 0, &addr)) |
1635 | return -EINVAL; | |
189d84ed CM |
1636 | object = find_and_get_object(addr, 0); |
1637 | if (!object) { | |
1638 | pr_info("Unknown object at 0x%08lx\n", addr); | |
1639 | return -EINVAL; | |
1640 | } | |
1641 | ||
1642 | spin_lock_irqsave(&object->lock, flags); | |
1643 | dump_object_info(object); | |
1644 | spin_unlock_irqrestore(&object->lock, flags); | |
1645 | ||
1646 | put_object(object); | |
1647 | return 0; | |
1648 | } | |
1649 | ||
30b37101 LR |
1650 | /* |
1651 | * We use grey instead of black to ensure we can do future scans on the same | |
1652 | * objects. If we did not do future scans these black objects could | |
1653 | * potentially contain references to newly allocated objects in the future and | |
1654 | * we'd end up with false positives. | |
1655 | */ | |
1656 | static void kmemleak_clear(void) | |
1657 | { | |
1658 | struct kmemleak_object *object; | |
1659 | unsigned long flags; | |
1660 | ||
1661 | rcu_read_lock(); | |
1662 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1663 | spin_lock_irqsave(&object->lock, flags); | |
1664 | if ((object->flags & OBJECT_REPORTED) && | |
1665 | unreferenced_object(object)) | |
a1084c87 | 1666 | __paint_it(object, KMEMLEAK_GREY); |
30b37101 LR |
1667 | spin_unlock_irqrestore(&object->lock, flags); |
1668 | } | |
1669 | rcu_read_unlock(); | |
dc9b3f42 LZ |
1670 | |
1671 | kmemleak_found_leaks = false; | |
30b37101 LR |
1672 | } |
1673 | ||
c89da70c LZ |
1674 | static void __kmemleak_do_cleanup(void); |
1675 | ||
3c7b4e6b CM |
1676 | /* |
1677 | * File write operation to configure kmemleak at run-time. The following | |
1678 | * commands can be written to the /sys/kernel/debug/kmemleak file: | |
1679 | * off - disable kmemleak (irreversible) | |
1680 | * stack=on - enable the task stacks scanning | |
1681 | * stack=off - disable the tasks stacks scanning | |
1682 | * scan=on - start the automatic memory scanning thread | |
1683 | * scan=off - stop the automatic memory scanning thread | |
1684 | * scan=... - set the automatic memory scanning period in seconds (0 to | |
1685 | * disable it) | |
4698c1f2 | 1686 | * scan - trigger a memory scan |
30b37101 | 1687 | * clear - mark all current reported unreferenced kmemleak objects as |
c89da70c LZ |
1688 | * grey to ignore printing them, or free all kmemleak objects |
1689 | * if kmemleak has been disabled. | |
189d84ed | 1690 | * dump=... - dump information about the object found at the given address |
3c7b4e6b CM |
1691 | */ |
1692 | static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, | |
1693 | size_t size, loff_t *ppos) | |
1694 | { | |
1695 | char buf[64]; | |
1696 | int buf_size; | |
b87324d0 | 1697 | int ret; |
3c7b4e6b CM |
1698 | |
1699 | buf_size = min(size, (sizeof(buf) - 1)); | |
1700 | if (strncpy_from_user(buf, user_buf, buf_size) < 0) | |
1701 | return -EFAULT; | |
1702 | buf[buf_size] = 0; | |
1703 | ||
b87324d0 CM |
1704 | ret = mutex_lock_interruptible(&scan_mutex); |
1705 | if (ret < 0) | |
1706 | return ret; | |
1707 | ||
c89da70c | 1708 | if (strncmp(buf, "clear", 5) == 0) { |
8910ae89 | 1709 | if (kmemleak_enabled) |
c89da70c LZ |
1710 | kmemleak_clear(); |
1711 | else | |
1712 | __kmemleak_do_cleanup(); | |
1713 | goto out; | |
1714 | } | |
1715 | ||
8910ae89 | 1716 | if (!kmemleak_enabled) { |
c89da70c LZ |
1717 | ret = -EBUSY; |
1718 | goto out; | |
1719 | } | |
1720 | ||
3c7b4e6b CM |
1721 | if (strncmp(buf, "off", 3) == 0) |
1722 | kmemleak_disable(); | |
1723 | else if (strncmp(buf, "stack=on", 8) == 0) | |
1724 | kmemleak_stack_scan = 1; | |
1725 | else if (strncmp(buf, "stack=off", 9) == 0) | |
1726 | kmemleak_stack_scan = 0; | |
1727 | else if (strncmp(buf, "scan=on", 7) == 0) | |
1728 | start_scan_thread(); | |
1729 | else if (strncmp(buf, "scan=off", 8) == 0) | |
1730 | stop_scan_thread(); | |
1731 | else if (strncmp(buf, "scan=", 5) == 0) { | |
1732 | unsigned long secs; | |
3c7b4e6b | 1733 | |
3dbb95f7 | 1734 | ret = kstrtoul(buf + 5, 0, &secs); |
b87324d0 CM |
1735 | if (ret < 0) |
1736 | goto out; | |
3c7b4e6b CM |
1737 | stop_scan_thread(); |
1738 | if (secs) { | |
1739 | jiffies_scan_wait = msecs_to_jiffies(secs * 1000); | |
1740 | start_scan_thread(); | |
1741 | } | |
4698c1f2 CM |
1742 | } else if (strncmp(buf, "scan", 4) == 0) |
1743 | kmemleak_scan(); | |
189d84ed CM |
1744 | else if (strncmp(buf, "dump=", 5) == 0) |
1745 | ret = dump_str_object_info(buf + 5); | |
4698c1f2 | 1746 | else |
b87324d0 CM |
1747 | ret = -EINVAL; |
1748 | ||
1749 | out: | |
1750 | mutex_unlock(&scan_mutex); | |
1751 | if (ret < 0) | |
1752 | return ret; | |
3c7b4e6b CM |
1753 | |
1754 | /* ignore the rest of the buffer, only one command at a time */ | |
1755 | *ppos += size; | |
1756 | return size; | |
1757 | } | |
1758 | ||
1759 | static const struct file_operations kmemleak_fops = { | |
1760 | .owner = THIS_MODULE, | |
1761 | .open = kmemleak_open, | |
1762 | .read = seq_read, | |
1763 | .write = kmemleak_write, | |
1764 | .llseek = seq_lseek, | |
5f3bf19a | 1765 | .release = seq_release, |
3c7b4e6b CM |
1766 | }; |
1767 | ||
c89da70c LZ |
1768 | static void __kmemleak_do_cleanup(void) |
1769 | { | |
1770 | struct kmemleak_object *object; | |
1771 | ||
1772 | rcu_read_lock(); | |
1773 | list_for_each_entry_rcu(object, &object_list, object_list) | |
1774 | delete_object_full(object->pointer); | |
1775 | rcu_read_unlock(); | |
1776 | } | |
1777 | ||
3c7b4e6b | 1778 | /* |
74341703 CM |
1779 | * Stop the memory scanning thread and free the kmemleak internal objects if |
1780 | * no previous scan thread (otherwise, kmemleak may still have some useful | |
1781 | * information on memory leaks). | |
3c7b4e6b | 1782 | */ |
179a8100 | 1783 | static void kmemleak_do_cleanup(struct work_struct *work) |
3c7b4e6b | 1784 | { |
3c7b4e6b | 1785 | stop_scan_thread(); |
3c7b4e6b | 1786 | |
c5f3b1a5 CM |
1787 | /* |
1788 | * Once the scan thread has stopped, it is safe to no longer track | |
1789 | * object freeing. Ordering of the scan thread stopping and the memory | |
1790 | * accesses below is guaranteed by the kthread_stop() function. | |
1791 | */ | |
1792 | kmemleak_free_enabled = 0; | |
1793 | ||
c89da70c LZ |
1794 | if (!kmemleak_found_leaks) |
1795 | __kmemleak_do_cleanup(); | |
1796 | else | |
756a025f | 1797 | pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n"); |
3c7b4e6b CM |
1798 | } |
1799 | ||
179a8100 | 1800 | static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
3c7b4e6b CM |
1801 | |
1802 | /* | |
1803 | * Disable kmemleak. No memory allocation/freeing will be traced once this | |
1804 | * function is called. Disabling kmemleak is an irreversible operation. | |
1805 | */ | |
1806 | static void kmemleak_disable(void) | |
1807 | { | |
1808 | /* atomically check whether it was already invoked */ | |
8910ae89 | 1809 | if (cmpxchg(&kmemleak_error, 0, 1)) |
3c7b4e6b CM |
1810 | return; |
1811 | ||
1812 | /* stop any memory operation tracing */ | |
8910ae89 | 1813 | kmemleak_enabled = 0; |
3c7b4e6b CM |
1814 | |
1815 | /* check whether it is too early for a kernel thread */ | |
8910ae89 | 1816 | if (kmemleak_initialized) |
179a8100 | 1817 | schedule_work(&cleanup_work); |
c5f3b1a5 CM |
1818 | else |
1819 | kmemleak_free_enabled = 0; | |
3c7b4e6b CM |
1820 | |
1821 | pr_info("Kernel memory leak detector disabled\n"); | |
1822 | } | |
1823 | ||
1824 | /* | |
1825 | * Allow boot-time kmemleak disabling (enabled by default). | |
1826 | */ | |
1827 | static int kmemleak_boot_config(char *str) | |
1828 | { | |
1829 | if (!str) | |
1830 | return -EINVAL; | |
1831 | if (strcmp(str, "off") == 0) | |
1832 | kmemleak_disable(); | |
ab0155a2 JB |
1833 | else if (strcmp(str, "on") == 0) |
1834 | kmemleak_skip_disable = 1; | |
1835 | else | |
3c7b4e6b CM |
1836 | return -EINVAL; |
1837 | return 0; | |
1838 | } | |
1839 | early_param("kmemleak", kmemleak_boot_config); | |
1840 | ||
5f79020c CM |
1841 | static void __init print_log_trace(struct early_log *log) |
1842 | { | |
1843 | struct stack_trace trace; | |
1844 | ||
1845 | trace.nr_entries = log->trace_len; | |
1846 | trace.entries = log->trace; | |
1847 | ||
1848 | pr_notice("Early log backtrace:\n"); | |
1849 | print_stack_trace(&trace, 2); | |
1850 | } | |
1851 | ||
3c7b4e6b | 1852 | /* |
2030117d | 1853 | * Kmemleak initialization. |
3c7b4e6b CM |
1854 | */ |
1855 | void __init kmemleak_init(void) | |
1856 | { | |
1857 | int i; | |
1858 | unsigned long flags; | |
1859 | ||
ab0155a2 JB |
1860 | #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF |
1861 | if (!kmemleak_skip_disable) { | |
3551a928 | 1862 | kmemleak_early_log = 0; |
ab0155a2 JB |
1863 | kmemleak_disable(); |
1864 | return; | |
1865 | } | |
1866 | #endif | |
1867 | ||
3c7b4e6b CM |
1868 | jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); |
1869 | jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); | |
1870 | ||
1871 | object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); | |
1872 | scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); | |
3c7b4e6b | 1873 | |
21cd3a60 | 1874 | if (crt_early_log > ARRAY_SIZE(early_log)) |
598d8091 JP |
1875 | pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", |
1876 | crt_early_log); | |
b6693005 | 1877 | |
3c7b4e6b CM |
1878 | /* the kernel is still in UP mode, so disabling the IRQs is enough */ |
1879 | local_irq_save(flags); | |
3551a928 | 1880 | kmemleak_early_log = 0; |
8910ae89 | 1881 | if (kmemleak_error) { |
b6693005 CM |
1882 | local_irq_restore(flags); |
1883 | return; | |
c5f3b1a5 | 1884 | } else { |
8910ae89 | 1885 | kmemleak_enabled = 1; |
c5f3b1a5 CM |
1886 | kmemleak_free_enabled = 1; |
1887 | } | |
3c7b4e6b CM |
1888 | local_irq_restore(flags); |
1889 | ||
1890 | /* | |
1891 | * This is the point where tracking allocations is safe. Automatic | |
1892 | * scanning is started during the late initcall. Add the early logged | |
1893 | * callbacks to the kmemleak infrastructure. | |
1894 | */ | |
1895 | for (i = 0; i < crt_early_log; i++) { | |
1896 | struct early_log *log = &early_log[i]; | |
1897 | ||
1898 | switch (log->op_type) { | |
1899 | case KMEMLEAK_ALLOC: | |
fd678967 | 1900 | early_alloc(log); |
3c7b4e6b | 1901 | break; |
f528f0b8 CM |
1902 | case KMEMLEAK_ALLOC_PERCPU: |
1903 | early_alloc_percpu(log); | |
1904 | break; | |
3c7b4e6b CM |
1905 | case KMEMLEAK_FREE: |
1906 | kmemleak_free(log->ptr); | |
1907 | break; | |
53238a60 CM |
1908 | case KMEMLEAK_FREE_PART: |
1909 | kmemleak_free_part(log->ptr, log->size); | |
1910 | break; | |
f528f0b8 CM |
1911 | case KMEMLEAK_FREE_PERCPU: |
1912 | kmemleak_free_percpu(log->ptr); | |
1913 | break; | |
3c7b4e6b CM |
1914 | case KMEMLEAK_NOT_LEAK: |
1915 | kmemleak_not_leak(log->ptr); | |
1916 | break; | |
1917 | case KMEMLEAK_IGNORE: | |
1918 | kmemleak_ignore(log->ptr); | |
1919 | break; | |
1920 | case KMEMLEAK_SCAN_AREA: | |
c017b4be | 1921 | kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL); |
3c7b4e6b CM |
1922 | break; |
1923 | case KMEMLEAK_NO_SCAN: | |
1924 | kmemleak_no_scan(log->ptr); | |
1925 | break; | |
1926 | default: | |
5f79020c CM |
1927 | kmemleak_warn("Unknown early log operation: %d\n", |
1928 | log->op_type); | |
1929 | } | |
1930 | ||
8910ae89 | 1931 | if (kmemleak_warning) { |
5f79020c | 1932 | print_log_trace(log); |
8910ae89 | 1933 | kmemleak_warning = 0; |
3c7b4e6b CM |
1934 | } |
1935 | } | |
1936 | } | |
1937 | ||
1938 | /* | |
1939 | * Late initialization function. | |
1940 | */ | |
1941 | static int __init kmemleak_late_init(void) | |
1942 | { | |
1943 | struct dentry *dentry; | |
1944 | ||
8910ae89 | 1945 | kmemleak_initialized = 1; |
3c7b4e6b | 1946 | |
8910ae89 | 1947 | if (kmemleak_error) { |
3c7b4e6b | 1948 | /* |
25985edc | 1949 | * Some error occurred and kmemleak was disabled. There is a |
3c7b4e6b CM |
1950 | * small chance that kmemleak_disable() was called immediately |
1951 | * after setting kmemleak_initialized and we may end up with | |
1952 | * two clean-up threads but serialized by scan_mutex. | |
1953 | */ | |
179a8100 | 1954 | schedule_work(&cleanup_work); |
3c7b4e6b CM |
1955 | return -ENOMEM; |
1956 | } | |
1957 | ||
1958 | dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL, | |
1959 | &kmemleak_fops); | |
1960 | if (!dentry) | |
598d8091 | 1961 | pr_warn("Failed to create the debugfs kmemleak file\n"); |
4698c1f2 | 1962 | mutex_lock(&scan_mutex); |
3c7b4e6b | 1963 | start_scan_thread(); |
4698c1f2 | 1964 | mutex_unlock(&scan_mutex); |
3c7b4e6b CM |
1965 | |
1966 | pr_info("Kernel memory leak detector initialized\n"); | |
1967 | ||
1968 | return 0; | |
1969 | } | |
1970 | late_initcall(kmemleak_late_init); |