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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 | |
22901c6c | 22 | * Documentation/dev-tools/kmemleak.rst. |
3c7b4e6b CM |
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> | |
3f07c014 | 76 | #include <linux/sched/signal.h> |
29930025 | 77 | #include <linux/sched/task.h> |
68db0cf1 | 78 | #include <linux/sched/task_stack.h> |
3c7b4e6b CM |
79 | #include <linux/jiffies.h> |
80 | #include <linux/delay.h> | |
b95f1b31 | 81 | #include <linux/export.h> |
3c7b4e6b | 82 | #include <linux/kthread.h> |
85d3a316 | 83 | #include <linux/rbtree.h> |
3c7b4e6b CM |
84 | #include <linux/fs.h> |
85 | #include <linux/debugfs.h> | |
86 | #include <linux/seq_file.h> | |
87 | #include <linux/cpumask.h> | |
88 | #include <linux/spinlock.h> | |
154221c3 | 89 | #include <linux/module.h> |
3c7b4e6b CM |
90 | #include <linux/mutex.h> |
91 | #include <linux/rcupdate.h> | |
92 | #include <linux/stacktrace.h> | |
93 | #include <linux/cache.h> | |
94 | #include <linux/percpu.h> | |
57c8a661 | 95 | #include <linux/memblock.h> |
9099daed | 96 | #include <linux/pfn.h> |
3c7b4e6b CM |
97 | #include <linux/mmzone.h> |
98 | #include <linux/slab.h> | |
99 | #include <linux/thread_info.h> | |
100 | #include <linux/err.h> | |
101 | #include <linux/uaccess.h> | |
102 | #include <linux/string.h> | |
103 | #include <linux/nodemask.h> | |
104 | #include <linux/mm.h> | |
179a8100 | 105 | #include <linux/workqueue.h> |
04609ccc | 106 | #include <linux/crc32.h> |
3c7b4e6b CM |
107 | |
108 | #include <asm/sections.h> | |
109 | #include <asm/processor.h> | |
60063497 | 110 | #include <linux/atomic.h> |
3c7b4e6b | 111 | |
e79ed2f1 | 112 | #include <linux/kasan.h> |
3c7b4e6b | 113 | #include <linux/kmemleak.h> |
029aeff5 | 114 | #include <linux/memory_hotplug.h> |
3c7b4e6b CM |
115 | |
116 | /* | |
117 | * Kmemleak configuration and common defines. | |
118 | */ | |
119 | #define MAX_TRACE 16 /* stack trace length */ | |
3c7b4e6b | 120 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
3c7b4e6b CM |
121 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
122 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ | |
af98603d | 123 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
3c7b4e6b CM |
124 | |
125 | #define BYTES_PER_POINTER sizeof(void *) | |
126 | ||
216c04b0 | 127 | /* GFP bitmask for kmemleak internal allocations */ |
20b5c303 | 128 | #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ |
6ae4bd1f | 129 | __GFP_NORETRY | __GFP_NOMEMALLOC | \ |
d9570ee3 | 130 | __GFP_NOWARN | __GFP_NOFAIL) |
216c04b0 | 131 | |
3c7b4e6b CM |
132 | /* scanning area inside a memory block */ |
133 | struct kmemleak_scan_area { | |
134 | struct hlist_node node; | |
c017b4be CM |
135 | unsigned long start; |
136 | size_t size; | |
3c7b4e6b CM |
137 | }; |
138 | ||
a1084c87 LR |
139 | #define KMEMLEAK_GREY 0 |
140 | #define KMEMLEAK_BLACK -1 | |
141 | ||
3c7b4e6b CM |
142 | /* |
143 | * Structure holding the metadata for each allocated memory block. | |
144 | * Modifications to such objects should be made while holding the | |
145 | * object->lock. Insertions or deletions from object_list, gray_list or | |
85d3a316 | 146 | * rb_node are already protected by the corresponding locks or mutex (see |
3c7b4e6b CM |
147 | * the notes on locking above). These objects are reference-counted |
148 | * (use_count) and freed using the RCU mechanism. | |
149 | */ | |
150 | struct kmemleak_object { | |
151 | spinlock_t lock; | |
f66abf09 | 152 | unsigned int flags; /* object status flags */ |
3c7b4e6b CM |
153 | struct list_head object_list; |
154 | struct list_head gray_list; | |
85d3a316 | 155 | struct rb_node rb_node; |
3c7b4e6b CM |
156 | struct rcu_head rcu; /* object_list lockless traversal */ |
157 | /* object usage count; object freed when use_count == 0 */ | |
158 | atomic_t use_count; | |
159 | unsigned long pointer; | |
160 | size_t size; | |
94f4a161 CM |
161 | /* pass surplus references to this pointer */ |
162 | unsigned long excess_ref; | |
3c7b4e6b CM |
163 | /* minimum number of a pointers found before it is considered leak */ |
164 | int min_count; | |
165 | /* the total number of pointers found pointing to this object */ | |
166 | int count; | |
04609ccc CM |
167 | /* checksum for detecting modified objects */ |
168 | u32 checksum; | |
3c7b4e6b CM |
169 | /* memory ranges to be scanned inside an object (empty for all) */ |
170 | struct hlist_head area_list; | |
171 | unsigned long trace[MAX_TRACE]; | |
172 | unsigned int trace_len; | |
173 | unsigned long jiffies; /* creation timestamp */ | |
174 | pid_t pid; /* pid of the current task */ | |
175 | char comm[TASK_COMM_LEN]; /* executable name */ | |
176 | }; | |
177 | ||
178 | /* flag representing the memory block allocation status */ | |
179 | #define OBJECT_ALLOCATED (1 << 0) | |
180 | /* flag set after the first reporting of an unreference object */ | |
181 | #define OBJECT_REPORTED (1 << 1) | |
182 | /* flag set to not scan the object */ | |
183 | #define OBJECT_NO_SCAN (1 << 2) | |
184 | ||
154221c3 | 185 | #define HEX_PREFIX " " |
0494e082 SS |
186 | /* number of bytes to print per line; must be 16 or 32 */ |
187 | #define HEX_ROW_SIZE 16 | |
188 | /* number of bytes to print at a time (1, 2, 4, 8) */ | |
189 | #define HEX_GROUP_SIZE 1 | |
190 | /* include ASCII after the hex output */ | |
191 | #define HEX_ASCII 1 | |
192 | /* max number of lines to be printed */ | |
193 | #define HEX_MAX_LINES 2 | |
194 | ||
3c7b4e6b CM |
195 | /* the list of all allocated objects */ |
196 | static LIST_HEAD(object_list); | |
197 | /* the list of gray-colored objects (see color_gray comment below) */ | |
198 | static LIST_HEAD(gray_list); | |
85d3a316 ML |
199 | /* search tree for object boundaries */ |
200 | static struct rb_root object_tree_root = RB_ROOT; | |
201 | /* rw_lock protecting the access to object_list and object_tree_root */ | |
3c7b4e6b CM |
202 | static DEFINE_RWLOCK(kmemleak_lock); |
203 | ||
204 | /* allocation caches for kmemleak internal data */ | |
205 | static struct kmem_cache *object_cache; | |
206 | static struct kmem_cache *scan_area_cache; | |
207 | ||
208 | /* set if tracing memory operations is enabled */ | |
8910ae89 | 209 | static int kmemleak_enabled; |
c5f3b1a5 CM |
210 | /* same as above but only for the kmemleak_free() callback */ |
211 | static int kmemleak_free_enabled; | |
3c7b4e6b | 212 | /* set in the late_initcall if there were no errors */ |
8910ae89 | 213 | static int kmemleak_initialized; |
3c7b4e6b | 214 | /* enables or disables early logging of the memory operations */ |
8910ae89 | 215 | static int kmemleak_early_log = 1; |
5f79020c | 216 | /* set if a kmemleak warning was issued */ |
8910ae89 | 217 | static int kmemleak_warning; |
5f79020c | 218 | /* set if a fatal kmemleak error has occurred */ |
8910ae89 | 219 | static int kmemleak_error; |
3c7b4e6b CM |
220 | |
221 | /* minimum and maximum address that may be valid pointers */ | |
222 | static unsigned long min_addr = ULONG_MAX; | |
223 | static unsigned long max_addr; | |
224 | ||
3c7b4e6b | 225 | static struct task_struct *scan_thread; |
acf4968e | 226 | /* used to avoid reporting of recently allocated objects */ |
3c7b4e6b | 227 | static unsigned long jiffies_min_age; |
acf4968e | 228 | static unsigned long jiffies_last_scan; |
3c7b4e6b CM |
229 | /* delay between automatic memory scannings */ |
230 | static signed long jiffies_scan_wait; | |
231 | /* enables or disables the task stacks scanning */ | |
e0a2a160 | 232 | static int kmemleak_stack_scan = 1; |
4698c1f2 | 233 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
3c7b4e6b | 234 | static DEFINE_MUTEX(scan_mutex); |
ab0155a2 JB |
235 | /* setting kmemleak=on, will set this var, skipping the disable */ |
236 | static int kmemleak_skip_disable; | |
dc9b3f42 LZ |
237 | /* If there are leaks that can be reported */ |
238 | static bool kmemleak_found_leaks; | |
3c7b4e6b | 239 | |
154221c3 VW |
240 | static bool kmemleak_verbose; |
241 | module_param_named(verbose, kmemleak_verbose, bool, 0600); | |
242 | ||
3c7b4e6b | 243 | /* |
2030117d | 244 | * Early object allocation/freeing logging. Kmemleak is initialized after the |
3c7b4e6b | 245 | * kernel allocator. However, both the kernel allocator and kmemleak may |
2030117d | 246 | * allocate memory blocks which need to be tracked. Kmemleak defines an |
3c7b4e6b CM |
247 | * arbitrary buffer to hold the allocation/freeing information before it is |
248 | * fully initialized. | |
249 | */ | |
250 | ||
251 | /* kmemleak operation type for early logging */ | |
252 | enum { | |
253 | KMEMLEAK_ALLOC, | |
f528f0b8 | 254 | KMEMLEAK_ALLOC_PERCPU, |
3c7b4e6b | 255 | KMEMLEAK_FREE, |
53238a60 | 256 | KMEMLEAK_FREE_PART, |
f528f0b8 | 257 | KMEMLEAK_FREE_PERCPU, |
3c7b4e6b CM |
258 | KMEMLEAK_NOT_LEAK, |
259 | KMEMLEAK_IGNORE, | |
260 | KMEMLEAK_SCAN_AREA, | |
94f4a161 CM |
261 | KMEMLEAK_NO_SCAN, |
262 | KMEMLEAK_SET_EXCESS_REF | |
3c7b4e6b CM |
263 | }; |
264 | ||
265 | /* | |
266 | * Structure holding the information passed to kmemleak callbacks during the | |
267 | * early logging. | |
268 | */ | |
269 | struct early_log { | |
270 | int op_type; /* kmemleak operation type */ | |
f66abf09 | 271 | int min_count; /* minimum reference count */ |
3c7b4e6b | 272 | const void *ptr; /* allocated/freed memory block */ |
94f4a161 CM |
273 | union { |
274 | size_t size; /* memory block size */ | |
275 | unsigned long excess_ref; /* surplus reference passing */ | |
276 | }; | |
fd678967 CM |
277 | unsigned long trace[MAX_TRACE]; /* stack trace */ |
278 | unsigned int trace_len; /* stack trace length */ | |
3c7b4e6b CM |
279 | }; |
280 | ||
281 | /* early logging buffer and current position */ | |
a6186d89 CM |
282 | static struct early_log |
283 | early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata; | |
284 | static int crt_early_log __initdata; | |
3c7b4e6b CM |
285 | |
286 | static void kmemleak_disable(void); | |
287 | ||
288 | /* | |
289 | * Print a warning and dump the stack trace. | |
290 | */ | |
5f79020c | 291 | #define kmemleak_warn(x...) do { \ |
598d8091 | 292 | pr_warn(x); \ |
5f79020c | 293 | dump_stack(); \ |
8910ae89 | 294 | kmemleak_warning = 1; \ |
3c7b4e6b CM |
295 | } while (0) |
296 | ||
297 | /* | |
25985edc | 298 | * Macro invoked when a serious kmemleak condition occurred and cannot be |
2030117d | 299 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
3c7b4e6b CM |
300 | * tracing no longer available. |
301 | */ | |
000814f4 | 302 | #define kmemleak_stop(x...) do { \ |
3c7b4e6b CM |
303 | kmemleak_warn(x); \ |
304 | kmemleak_disable(); \ | |
305 | } while (0) | |
306 | ||
154221c3 VW |
307 | #define warn_or_seq_printf(seq, fmt, ...) do { \ |
308 | if (seq) \ | |
309 | seq_printf(seq, fmt, ##__VA_ARGS__); \ | |
310 | else \ | |
311 | pr_warn(fmt, ##__VA_ARGS__); \ | |
312 | } while (0) | |
313 | ||
314 | static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type, | |
315 | int rowsize, int groupsize, const void *buf, | |
316 | size_t len, bool ascii) | |
317 | { | |
318 | if (seq) | |
319 | seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize, | |
320 | buf, len, ascii); | |
321 | else | |
322 | print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type, | |
323 | rowsize, groupsize, buf, len, ascii); | |
324 | } | |
325 | ||
0494e082 SS |
326 | /* |
327 | * Printing of the objects hex dump to the seq file. The number of lines to be | |
328 | * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The | |
329 | * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called | |
330 | * with the object->lock held. | |
331 | */ | |
332 | static void hex_dump_object(struct seq_file *seq, | |
333 | struct kmemleak_object *object) | |
334 | { | |
335 | const u8 *ptr = (const u8 *)object->pointer; | |
6fc37c49 | 336 | size_t len; |
0494e082 SS |
337 | |
338 | /* limit the number of lines to HEX_MAX_LINES */ | |
6fc37c49 | 339 | len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); |
0494e082 | 340 | |
154221c3 | 341 | warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len); |
5c335fe0 | 342 | kasan_disable_current(); |
154221c3 VW |
343 | warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE, |
344 | HEX_GROUP_SIZE, ptr, len, HEX_ASCII); | |
5c335fe0 | 345 | kasan_enable_current(); |
0494e082 SS |
346 | } |
347 | ||
3c7b4e6b CM |
348 | /* |
349 | * Object colors, encoded with count and min_count: | |
350 | * - white - orphan object, not enough references to it (count < min_count) | |
351 | * - gray - not orphan, not marked as false positive (min_count == 0) or | |
352 | * sufficient references to it (count >= min_count) | |
353 | * - black - ignore, it doesn't contain references (e.g. text section) | |
354 | * (min_count == -1). No function defined for this color. | |
355 | * Newly created objects don't have any color assigned (object->count == -1) | |
356 | * before the next memory scan when they become white. | |
357 | */ | |
4a558dd6 | 358 | static bool color_white(const struct kmemleak_object *object) |
3c7b4e6b | 359 | { |
a1084c87 LR |
360 | return object->count != KMEMLEAK_BLACK && |
361 | object->count < object->min_count; | |
3c7b4e6b CM |
362 | } |
363 | ||
4a558dd6 | 364 | static bool color_gray(const struct kmemleak_object *object) |
3c7b4e6b | 365 | { |
a1084c87 LR |
366 | return object->min_count != KMEMLEAK_BLACK && |
367 | object->count >= object->min_count; | |
3c7b4e6b CM |
368 | } |
369 | ||
3c7b4e6b CM |
370 | /* |
371 | * Objects are considered unreferenced only if their color is white, they have | |
372 | * not be deleted and have a minimum age to avoid false positives caused by | |
373 | * pointers temporarily stored in CPU registers. | |
374 | */ | |
4a558dd6 | 375 | static bool unreferenced_object(struct kmemleak_object *object) |
3c7b4e6b | 376 | { |
04609ccc | 377 | return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
acf4968e CM |
378 | time_before_eq(object->jiffies + jiffies_min_age, |
379 | jiffies_last_scan); | |
3c7b4e6b CM |
380 | } |
381 | ||
382 | /* | |
bab4a34a CM |
383 | * Printing of the unreferenced objects information to the seq file. The |
384 | * print_unreferenced function must be called with the object->lock held. | |
3c7b4e6b | 385 | */ |
3c7b4e6b CM |
386 | static void print_unreferenced(struct seq_file *seq, |
387 | struct kmemleak_object *object) | |
388 | { | |
389 | int i; | |
fefdd336 | 390 | unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); |
3c7b4e6b | 391 | |
154221c3 | 392 | warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
bab4a34a | 393 | object->pointer, object->size); |
154221c3 | 394 | warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", |
fefdd336 CM |
395 | object->comm, object->pid, object->jiffies, |
396 | msecs_age / 1000, msecs_age % 1000); | |
0494e082 | 397 | hex_dump_object(seq, object); |
154221c3 | 398 | warn_or_seq_printf(seq, " backtrace:\n"); |
3c7b4e6b CM |
399 | |
400 | for (i = 0; i < object->trace_len; i++) { | |
401 | void *ptr = (void *)object->trace[i]; | |
154221c3 | 402 | warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); |
3c7b4e6b CM |
403 | } |
404 | } | |
405 | ||
406 | /* | |
407 | * Print the kmemleak_object information. This function is used mainly for | |
408 | * debugging special cases when kmemleak operations. It must be called with | |
409 | * the object->lock held. | |
410 | */ | |
411 | static void dump_object_info(struct kmemleak_object *object) | |
412 | { | |
413 | struct stack_trace trace; | |
414 | ||
415 | trace.nr_entries = object->trace_len; | |
416 | trace.entries = object->trace; | |
417 | ||
ae281064 | 418 | pr_notice("Object 0x%08lx (size %zu):\n", |
85d3a316 | 419 | object->pointer, object->size); |
3c7b4e6b CM |
420 | pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", |
421 | object->comm, object->pid, object->jiffies); | |
422 | pr_notice(" min_count = %d\n", object->min_count); | |
423 | pr_notice(" count = %d\n", object->count); | |
f66abf09 | 424 | pr_notice(" flags = 0x%x\n", object->flags); |
aae0ad7a | 425 | pr_notice(" checksum = %u\n", object->checksum); |
3c7b4e6b CM |
426 | pr_notice(" backtrace:\n"); |
427 | print_stack_trace(&trace, 4); | |
428 | } | |
429 | ||
430 | /* | |
85d3a316 | 431 | * Look-up a memory block metadata (kmemleak_object) in the object search |
3c7b4e6b CM |
432 | * tree based on a pointer value. If alias is 0, only values pointing to the |
433 | * beginning of the memory block are allowed. The kmemleak_lock must be held | |
434 | * when calling this function. | |
435 | */ | |
436 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) | |
437 | { | |
85d3a316 ML |
438 | struct rb_node *rb = object_tree_root.rb_node; |
439 | ||
440 | while (rb) { | |
441 | struct kmemleak_object *object = | |
442 | rb_entry(rb, struct kmemleak_object, rb_node); | |
443 | if (ptr < object->pointer) | |
444 | rb = object->rb_node.rb_left; | |
445 | else if (object->pointer + object->size <= ptr) | |
446 | rb = object->rb_node.rb_right; | |
447 | else if (object->pointer == ptr || alias) | |
448 | return object; | |
449 | else { | |
5f79020c CM |
450 | kmemleak_warn("Found object by alias at 0x%08lx\n", |
451 | ptr); | |
a7686a45 | 452 | dump_object_info(object); |
85d3a316 | 453 | break; |
3c7b4e6b | 454 | } |
85d3a316 ML |
455 | } |
456 | return NULL; | |
3c7b4e6b CM |
457 | } |
458 | ||
459 | /* | |
460 | * Increment the object use_count. Return 1 if successful or 0 otherwise. Note | |
461 | * that once an object's use_count reached 0, the RCU freeing was already | |
462 | * registered and the object should no longer be used. This function must be | |
463 | * called under the protection of rcu_read_lock(). | |
464 | */ | |
465 | static int get_object(struct kmemleak_object *object) | |
466 | { | |
467 | return atomic_inc_not_zero(&object->use_count); | |
468 | } | |
469 | ||
470 | /* | |
471 | * RCU callback to free a kmemleak_object. | |
472 | */ | |
473 | static void free_object_rcu(struct rcu_head *rcu) | |
474 | { | |
b67bfe0d | 475 | struct hlist_node *tmp; |
3c7b4e6b CM |
476 | struct kmemleak_scan_area *area; |
477 | struct kmemleak_object *object = | |
478 | container_of(rcu, struct kmemleak_object, rcu); | |
479 | ||
480 | /* | |
481 | * Once use_count is 0 (guaranteed by put_object), there is no other | |
482 | * code accessing this object, hence no need for locking. | |
483 | */ | |
b67bfe0d SL |
484 | hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { |
485 | hlist_del(&area->node); | |
3c7b4e6b CM |
486 | kmem_cache_free(scan_area_cache, area); |
487 | } | |
488 | kmem_cache_free(object_cache, object); | |
489 | } | |
490 | ||
491 | /* | |
492 | * Decrement the object use_count. Once the count is 0, free the object using | |
493 | * an RCU callback. Since put_object() may be called via the kmemleak_free() -> | |
494 | * delete_object() path, the delayed RCU freeing ensures that there is no | |
495 | * recursive call to the kernel allocator. Lock-less RCU object_list traversal | |
496 | * is also possible. | |
497 | */ | |
498 | static void put_object(struct kmemleak_object *object) | |
499 | { | |
500 | if (!atomic_dec_and_test(&object->use_count)) | |
501 | return; | |
502 | ||
503 | /* should only get here after delete_object was called */ | |
504 | WARN_ON(object->flags & OBJECT_ALLOCATED); | |
505 | ||
506 | call_rcu(&object->rcu, free_object_rcu); | |
507 | } | |
508 | ||
509 | /* | |
85d3a316 | 510 | * Look up an object in the object search tree and increase its use_count. |
3c7b4e6b CM |
511 | */ |
512 | static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) | |
513 | { | |
514 | unsigned long flags; | |
9fbed254 | 515 | struct kmemleak_object *object; |
3c7b4e6b CM |
516 | |
517 | rcu_read_lock(); | |
518 | read_lock_irqsave(&kmemleak_lock, flags); | |
93ada579 | 519 | object = lookup_object(ptr, alias); |
3c7b4e6b CM |
520 | read_unlock_irqrestore(&kmemleak_lock, flags); |
521 | ||
522 | /* check whether the object is still available */ | |
523 | if (object && !get_object(object)) | |
524 | object = NULL; | |
525 | rcu_read_unlock(); | |
526 | ||
527 | return object; | |
528 | } | |
529 | ||
e781a9ab CM |
530 | /* |
531 | * Look up an object in the object search tree and remove it from both | |
532 | * object_tree_root and object_list. The returned object's use_count should be | |
533 | * at least 1, as initially set by create_object(). | |
534 | */ | |
535 | static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias) | |
536 | { | |
537 | unsigned long flags; | |
538 | struct kmemleak_object *object; | |
539 | ||
540 | write_lock_irqsave(&kmemleak_lock, flags); | |
541 | object = lookup_object(ptr, alias); | |
542 | if (object) { | |
543 | rb_erase(&object->rb_node, &object_tree_root); | |
544 | list_del_rcu(&object->object_list); | |
545 | } | |
546 | write_unlock_irqrestore(&kmemleak_lock, flags); | |
547 | ||
548 | return object; | |
549 | } | |
550 | ||
fd678967 CM |
551 | /* |
552 | * Save stack trace to the given array of MAX_TRACE size. | |
553 | */ | |
554 | static int __save_stack_trace(unsigned long *trace) | |
555 | { | |
556 | struct stack_trace stack_trace; | |
557 | ||
558 | stack_trace.max_entries = MAX_TRACE; | |
559 | stack_trace.nr_entries = 0; | |
560 | stack_trace.entries = trace; | |
561 | stack_trace.skip = 2; | |
562 | save_stack_trace(&stack_trace); | |
563 | ||
564 | return stack_trace.nr_entries; | |
565 | } | |
566 | ||
3c7b4e6b CM |
567 | /* |
568 | * Create the metadata (struct kmemleak_object) corresponding to an allocated | |
569 | * memory block and add it to the object_list and object_tree_root. | |
570 | */ | |
fd678967 CM |
571 | static struct kmemleak_object *create_object(unsigned long ptr, size_t size, |
572 | int min_count, gfp_t gfp) | |
3c7b4e6b CM |
573 | { |
574 | unsigned long flags; | |
85d3a316 ML |
575 | struct kmemleak_object *object, *parent; |
576 | struct rb_node **link, *rb_parent; | |
3c7b4e6b | 577 | |
6ae4bd1f | 578 | object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b | 579 | if (!object) { |
598d8091 | 580 | pr_warn("Cannot allocate a kmemleak_object structure\n"); |
6ae4bd1f | 581 | kmemleak_disable(); |
fd678967 | 582 | return NULL; |
3c7b4e6b CM |
583 | } |
584 | ||
585 | INIT_LIST_HEAD(&object->object_list); | |
586 | INIT_LIST_HEAD(&object->gray_list); | |
587 | INIT_HLIST_HEAD(&object->area_list); | |
588 | spin_lock_init(&object->lock); | |
589 | atomic_set(&object->use_count, 1); | |
04609ccc | 590 | object->flags = OBJECT_ALLOCATED; |
3c7b4e6b CM |
591 | object->pointer = ptr; |
592 | object->size = size; | |
94f4a161 | 593 | object->excess_ref = 0; |
3c7b4e6b | 594 | object->min_count = min_count; |
04609ccc | 595 | object->count = 0; /* white color initially */ |
3c7b4e6b | 596 | object->jiffies = jiffies; |
04609ccc | 597 | object->checksum = 0; |
3c7b4e6b CM |
598 | |
599 | /* task information */ | |
600 | if (in_irq()) { | |
601 | object->pid = 0; | |
602 | strncpy(object->comm, "hardirq", sizeof(object->comm)); | |
603 | } else if (in_softirq()) { | |
604 | object->pid = 0; | |
605 | strncpy(object->comm, "softirq", sizeof(object->comm)); | |
606 | } else { | |
607 | object->pid = current->pid; | |
608 | /* | |
609 | * There is a small chance of a race with set_task_comm(), | |
610 | * however using get_task_comm() here may cause locking | |
611 | * dependency issues with current->alloc_lock. In the worst | |
612 | * case, the command line is not correct. | |
613 | */ | |
614 | strncpy(object->comm, current->comm, sizeof(object->comm)); | |
615 | } | |
616 | ||
617 | /* kernel backtrace */ | |
fd678967 | 618 | object->trace_len = __save_stack_trace(object->trace); |
3c7b4e6b | 619 | |
3c7b4e6b | 620 | write_lock_irqsave(&kmemleak_lock, flags); |
0580a181 | 621 | |
3c7b4e6b CM |
622 | min_addr = min(min_addr, ptr); |
623 | max_addr = max(max_addr, ptr + size); | |
85d3a316 ML |
624 | link = &object_tree_root.rb_node; |
625 | rb_parent = NULL; | |
626 | while (*link) { | |
627 | rb_parent = *link; | |
628 | parent = rb_entry(rb_parent, struct kmemleak_object, rb_node); | |
629 | if (ptr + size <= parent->pointer) | |
630 | link = &parent->rb_node.rb_left; | |
631 | else if (parent->pointer + parent->size <= ptr) | |
632 | link = &parent->rb_node.rb_right; | |
633 | else { | |
756a025f | 634 | kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n", |
85d3a316 | 635 | ptr); |
9d5a4c73 CM |
636 | /* |
637 | * No need for parent->lock here since "parent" cannot | |
638 | * be freed while the kmemleak_lock is held. | |
639 | */ | |
640 | dump_object_info(parent); | |
85d3a316 | 641 | kmem_cache_free(object_cache, object); |
9d5a4c73 | 642 | object = NULL; |
85d3a316 ML |
643 | goto out; |
644 | } | |
3c7b4e6b | 645 | } |
85d3a316 ML |
646 | rb_link_node(&object->rb_node, rb_parent, link); |
647 | rb_insert_color(&object->rb_node, &object_tree_root); | |
648 | ||
3c7b4e6b CM |
649 | list_add_tail_rcu(&object->object_list, &object_list); |
650 | out: | |
651 | write_unlock_irqrestore(&kmemleak_lock, flags); | |
fd678967 | 652 | return object; |
3c7b4e6b CM |
653 | } |
654 | ||
655 | /* | |
e781a9ab | 656 | * Mark the object as not allocated and schedule RCU freeing via put_object(). |
3c7b4e6b | 657 | */ |
53238a60 | 658 | static void __delete_object(struct kmemleak_object *object) |
3c7b4e6b CM |
659 | { |
660 | unsigned long flags; | |
3c7b4e6b | 661 | |
3c7b4e6b | 662 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
e781a9ab | 663 | WARN_ON(atomic_read(&object->use_count) < 1); |
3c7b4e6b CM |
664 | |
665 | /* | |
666 | * Locking here also ensures that the corresponding memory block | |
667 | * cannot be freed when it is being scanned. | |
668 | */ | |
669 | spin_lock_irqsave(&object->lock, flags); | |
3c7b4e6b CM |
670 | object->flags &= ~OBJECT_ALLOCATED; |
671 | spin_unlock_irqrestore(&object->lock, flags); | |
672 | put_object(object); | |
673 | } | |
674 | ||
53238a60 CM |
675 | /* |
676 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
677 | * delete it. | |
678 | */ | |
679 | static void delete_object_full(unsigned long ptr) | |
680 | { | |
681 | struct kmemleak_object *object; | |
682 | ||
e781a9ab | 683 | object = find_and_remove_object(ptr, 0); |
53238a60 CM |
684 | if (!object) { |
685 | #ifdef DEBUG | |
686 | kmemleak_warn("Freeing unknown object at 0x%08lx\n", | |
687 | ptr); | |
688 | #endif | |
689 | return; | |
690 | } | |
691 | __delete_object(object); | |
53238a60 CM |
692 | } |
693 | ||
694 | /* | |
695 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
696 | * delete it. If the memory block is partially freed, the function may create | |
697 | * additional metadata for the remaining parts of the block. | |
698 | */ | |
699 | static void delete_object_part(unsigned long ptr, size_t size) | |
700 | { | |
701 | struct kmemleak_object *object; | |
702 | unsigned long start, end; | |
703 | ||
e781a9ab | 704 | object = find_and_remove_object(ptr, 1); |
53238a60 CM |
705 | if (!object) { |
706 | #ifdef DEBUG | |
756a025f JP |
707 | kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", |
708 | ptr, size); | |
53238a60 CM |
709 | #endif |
710 | return; | |
711 | } | |
53238a60 CM |
712 | |
713 | /* | |
714 | * Create one or two objects that may result from the memory block | |
715 | * split. Note that partial freeing is only done by free_bootmem() and | |
716 | * this happens before kmemleak_init() is called. The path below is | |
717 | * only executed during early log recording in kmemleak_init(), so | |
718 | * GFP_KERNEL is enough. | |
719 | */ | |
720 | start = object->pointer; | |
721 | end = object->pointer + object->size; | |
722 | if (ptr > start) | |
723 | create_object(start, ptr - start, object->min_count, | |
724 | GFP_KERNEL); | |
725 | if (ptr + size < end) | |
726 | create_object(ptr + size, end - ptr - size, object->min_count, | |
727 | GFP_KERNEL); | |
728 | ||
e781a9ab | 729 | __delete_object(object); |
53238a60 | 730 | } |
a1084c87 LR |
731 | |
732 | static void __paint_it(struct kmemleak_object *object, int color) | |
733 | { | |
734 | object->min_count = color; | |
735 | if (color == KMEMLEAK_BLACK) | |
736 | object->flags |= OBJECT_NO_SCAN; | |
737 | } | |
738 | ||
739 | static void paint_it(struct kmemleak_object *object, int color) | |
3c7b4e6b CM |
740 | { |
741 | unsigned long flags; | |
a1084c87 LR |
742 | |
743 | spin_lock_irqsave(&object->lock, flags); | |
744 | __paint_it(object, color); | |
745 | spin_unlock_irqrestore(&object->lock, flags); | |
746 | } | |
747 | ||
748 | static void paint_ptr(unsigned long ptr, int color) | |
749 | { | |
3c7b4e6b CM |
750 | struct kmemleak_object *object; |
751 | ||
752 | object = find_and_get_object(ptr, 0); | |
753 | if (!object) { | |
756a025f JP |
754 | kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n", |
755 | ptr, | |
a1084c87 LR |
756 | (color == KMEMLEAK_GREY) ? "Grey" : |
757 | (color == KMEMLEAK_BLACK) ? "Black" : "Unknown"); | |
3c7b4e6b CM |
758 | return; |
759 | } | |
a1084c87 | 760 | paint_it(object, color); |
3c7b4e6b CM |
761 | put_object(object); |
762 | } | |
763 | ||
a1084c87 | 764 | /* |
145b64b9 | 765 | * Mark an object permanently as gray-colored so that it can no longer be |
a1084c87 LR |
766 | * reported as a leak. This is used in general to mark a false positive. |
767 | */ | |
768 | static void make_gray_object(unsigned long ptr) | |
769 | { | |
770 | paint_ptr(ptr, KMEMLEAK_GREY); | |
771 | } | |
772 | ||
3c7b4e6b CM |
773 | /* |
774 | * Mark the object as black-colored so that it is ignored from scans and | |
775 | * reporting. | |
776 | */ | |
777 | static void make_black_object(unsigned long ptr) | |
778 | { | |
a1084c87 | 779 | paint_ptr(ptr, KMEMLEAK_BLACK); |
3c7b4e6b CM |
780 | } |
781 | ||
782 | /* | |
783 | * Add a scanning area to the object. If at least one such area is added, | |
784 | * kmemleak will only scan these ranges rather than the whole memory block. | |
785 | */ | |
c017b4be | 786 | static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
787 | { |
788 | unsigned long flags; | |
789 | struct kmemleak_object *object; | |
790 | struct kmemleak_scan_area *area; | |
791 | ||
c017b4be | 792 | object = find_and_get_object(ptr, 1); |
3c7b4e6b | 793 | if (!object) { |
ae281064 JP |
794 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
795 | ptr); | |
3c7b4e6b CM |
796 | return; |
797 | } | |
798 | ||
6ae4bd1f | 799 | area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b | 800 | if (!area) { |
598d8091 | 801 | pr_warn("Cannot allocate a scan area\n"); |
3c7b4e6b CM |
802 | goto out; |
803 | } | |
804 | ||
805 | spin_lock_irqsave(&object->lock, flags); | |
7f88f88f CM |
806 | if (size == SIZE_MAX) { |
807 | size = object->pointer + object->size - ptr; | |
808 | } else if (ptr + size > object->pointer + object->size) { | |
ae281064 | 809 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
3c7b4e6b CM |
810 | dump_object_info(object); |
811 | kmem_cache_free(scan_area_cache, area); | |
812 | goto out_unlock; | |
813 | } | |
814 | ||
815 | INIT_HLIST_NODE(&area->node); | |
c017b4be CM |
816 | area->start = ptr; |
817 | area->size = size; | |
3c7b4e6b CM |
818 | |
819 | hlist_add_head(&area->node, &object->area_list); | |
820 | out_unlock: | |
821 | spin_unlock_irqrestore(&object->lock, flags); | |
822 | out: | |
823 | put_object(object); | |
824 | } | |
825 | ||
94f4a161 CM |
826 | /* |
827 | * Any surplus references (object already gray) to 'ptr' are passed to | |
828 | * 'excess_ref'. This is used in the vmalloc() case where a pointer to | |
829 | * vm_struct may be used as an alternative reference to the vmalloc'ed object | |
830 | * (see free_thread_stack()). | |
831 | */ | |
832 | static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref) | |
833 | { | |
834 | unsigned long flags; | |
835 | struct kmemleak_object *object; | |
836 | ||
837 | object = find_and_get_object(ptr, 0); | |
838 | if (!object) { | |
839 | kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n", | |
840 | ptr); | |
841 | return; | |
842 | } | |
843 | ||
844 | spin_lock_irqsave(&object->lock, flags); | |
845 | object->excess_ref = excess_ref; | |
846 | spin_unlock_irqrestore(&object->lock, flags); | |
847 | put_object(object); | |
848 | } | |
849 | ||
3c7b4e6b CM |
850 | /* |
851 | * Set the OBJECT_NO_SCAN flag for the object corresponding to the give | |
852 | * pointer. Such object will not be scanned by kmemleak but references to it | |
853 | * are searched. | |
854 | */ | |
855 | static void object_no_scan(unsigned long ptr) | |
856 | { | |
857 | unsigned long flags; | |
858 | struct kmemleak_object *object; | |
859 | ||
860 | object = find_and_get_object(ptr, 0); | |
861 | if (!object) { | |
ae281064 | 862 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
3c7b4e6b CM |
863 | return; |
864 | } | |
865 | ||
866 | spin_lock_irqsave(&object->lock, flags); | |
867 | object->flags |= OBJECT_NO_SCAN; | |
868 | spin_unlock_irqrestore(&object->lock, flags); | |
869 | put_object(object); | |
870 | } | |
871 | ||
872 | /* | |
873 | * Log an early kmemleak_* call to the early_log buffer. These calls will be | |
874 | * processed later once kmemleak is fully initialized. | |
875 | */ | |
a6186d89 | 876 | static void __init log_early(int op_type, const void *ptr, size_t size, |
c017b4be | 877 | int min_count) |
3c7b4e6b CM |
878 | { |
879 | unsigned long flags; | |
880 | struct early_log *log; | |
881 | ||
8910ae89 | 882 | if (kmemleak_error) { |
b6693005 CM |
883 | /* kmemleak stopped recording, just count the requests */ |
884 | crt_early_log++; | |
885 | return; | |
886 | } | |
887 | ||
3c7b4e6b | 888 | if (crt_early_log >= ARRAY_SIZE(early_log)) { |
21cd3a60 | 889 | crt_early_log++; |
a9d9058a | 890 | kmemleak_disable(); |
3c7b4e6b CM |
891 | return; |
892 | } | |
893 | ||
894 | /* | |
895 | * There is no need for locking since the kernel is still in UP mode | |
896 | * at this stage. Disabling the IRQs is enough. | |
897 | */ | |
898 | local_irq_save(flags); | |
899 | log = &early_log[crt_early_log]; | |
900 | log->op_type = op_type; | |
901 | log->ptr = ptr; | |
902 | log->size = size; | |
903 | log->min_count = min_count; | |
5f79020c | 904 | log->trace_len = __save_stack_trace(log->trace); |
3c7b4e6b CM |
905 | crt_early_log++; |
906 | local_irq_restore(flags); | |
907 | } | |
908 | ||
fd678967 CM |
909 | /* |
910 | * Log an early allocated block and populate the stack trace. | |
911 | */ | |
912 | static void early_alloc(struct early_log *log) | |
913 | { | |
914 | struct kmemleak_object *object; | |
915 | unsigned long flags; | |
916 | int i; | |
917 | ||
8910ae89 | 918 | if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr)) |
fd678967 CM |
919 | return; |
920 | ||
921 | /* | |
922 | * RCU locking needed to ensure object is not freed via put_object(). | |
923 | */ | |
924 | rcu_read_lock(); | |
925 | object = create_object((unsigned long)log->ptr, log->size, | |
c1bcd6b3 | 926 | log->min_count, GFP_ATOMIC); |
0d5d1aad CM |
927 | if (!object) |
928 | goto out; | |
fd678967 CM |
929 | spin_lock_irqsave(&object->lock, flags); |
930 | for (i = 0; i < log->trace_len; i++) | |
931 | object->trace[i] = log->trace[i]; | |
932 | object->trace_len = log->trace_len; | |
933 | spin_unlock_irqrestore(&object->lock, flags); | |
0d5d1aad | 934 | out: |
fd678967 CM |
935 | rcu_read_unlock(); |
936 | } | |
937 | ||
f528f0b8 CM |
938 | /* |
939 | * Log an early allocated block and populate the stack trace. | |
940 | */ | |
941 | static void early_alloc_percpu(struct early_log *log) | |
942 | { | |
943 | unsigned int cpu; | |
944 | const void __percpu *ptr = log->ptr; | |
945 | ||
946 | for_each_possible_cpu(cpu) { | |
947 | log->ptr = per_cpu_ptr(ptr, cpu); | |
948 | early_alloc(log); | |
949 | } | |
950 | } | |
951 | ||
a2b6bf63 CM |
952 | /** |
953 | * kmemleak_alloc - register a newly allocated object | |
954 | * @ptr: pointer to beginning of the object | |
955 | * @size: size of the object | |
956 | * @min_count: minimum number of references to this object. If during memory | |
957 | * scanning a number of references less than @min_count is found, | |
958 | * the object is reported as a memory leak. If @min_count is 0, | |
959 | * the object is never reported as a leak. If @min_count is -1, | |
960 | * the object is ignored (not scanned and not reported as a leak) | |
961 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
962 | * | |
963 | * This function is called from the kernel allocators when a new object | |
94f4a161 | 964 | * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.). |
3c7b4e6b | 965 | */ |
a6186d89 CM |
966 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
967 | gfp_t gfp) | |
3c7b4e6b CM |
968 | { |
969 | pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); | |
970 | ||
8910ae89 | 971 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 972 | create_object((unsigned long)ptr, size, min_count, gfp); |
8910ae89 | 973 | else if (kmemleak_early_log) |
c017b4be | 974 | log_early(KMEMLEAK_ALLOC, ptr, size, min_count); |
3c7b4e6b CM |
975 | } |
976 | EXPORT_SYMBOL_GPL(kmemleak_alloc); | |
977 | ||
f528f0b8 CM |
978 | /** |
979 | * kmemleak_alloc_percpu - register a newly allocated __percpu object | |
980 | * @ptr: __percpu pointer to beginning of the object | |
981 | * @size: size of the object | |
8a8c35fa | 982 | * @gfp: flags used for kmemleak internal memory allocations |
f528f0b8 CM |
983 | * |
984 | * This function is called from the kernel percpu allocator when a new object | |
8a8c35fa | 985 | * (memory block) is allocated (alloc_percpu). |
f528f0b8 | 986 | */ |
8a8c35fa LF |
987 | void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, |
988 | gfp_t gfp) | |
f528f0b8 CM |
989 | { |
990 | unsigned int cpu; | |
991 | ||
992 | pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size); | |
993 | ||
994 | /* | |
995 | * Percpu allocations are only scanned and not reported as leaks | |
996 | * (min_count is set to 0). | |
997 | */ | |
8910ae89 | 998 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
999 | for_each_possible_cpu(cpu) |
1000 | create_object((unsigned long)per_cpu_ptr(ptr, cpu), | |
8a8c35fa | 1001 | size, 0, gfp); |
8910ae89 | 1002 | else if (kmemleak_early_log) |
f528f0b8 CM |
1003 | log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0); |
1004 | } | |
1005 | EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); | |
1006 | ||
94f4a161 CM |
1007 | /** |
1008 | * kmemleak_vmalloc - register a newly vmalloc'ed object | |
1009 | * @area: pointer to vm_struct | |
1010 | * @size: size of the object | |
1011 | * @gfp: __vmalloc() flags used for kmemleak internal memory allocations | |
1012 | * | |
1013 | * This function is called from the vmalloc() kernel allocator when a new | |
1014 | * object (memory block) is allocated. | |
1015 | */ | |
1016 | void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp) | |
1017 | { | |
1018 | pr_debug("%s(0x%p, %zu)\n", __func__, area, size); | |
1019 | ||
1020 | /* | |
1021 | * A min_count = 2 is needed because vm_struct contains a reference to | |
1022 | * the virtual address of the vmalloc'ed block. | |
1023 | */ | |
1024 | if (kmemleak_enabled) { | |
1025 | create_object((unsigned long)area->addr, size, 2, gfp); | |
1026 | object_set_excess_ref((unsigned long)area, | |
1027 | (unsigned long)area->addr); | |
1028 | } else if (kmemleak_early_log) { | |
1029 | log_early(KMEMLEAK_ALLOC, area->addr, size, 2); | |
1030 | /* reusing early_log.size for storing area->addr */ | |
1031 | log_early(KMEMLEAK_SET_EXCESS_REF, | |
1032 | area, (unsigned long)area->addr, 0); | |
1033 | } | |
1034 | } | |
1035 | EXPORT_SYMBOL_GPL(kmemleak_vmalloc); | |
1036 | ||
a2b6bf63 CM |
1037 | /** |
1038 | * kmemleak_free - unregister a previously registered object | |
1039 | * @ptr: pointer to beginning of the object | |
1040 | * | |
1041 | * This function is called from the kernel allocators when an object (memory | |
1042 | * block) is freed (kmem_cache_free, kfree, vfree etc.). | |
3c7b4e6b | 1043 | */ |
a6186d89 | 1044 | void __ref kmemleak_free(const void *ptr) |
3c7b4e6b CM |
1045 | { |
1046 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1047 | ||
c5f3b1a5 | 1048 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 1049 | delete_object_full((unsigned long)ptr); |
8910ae89 | 1050 | else if (kmemleak_early_log) |
c017b4be | 1051 | log_early(KMEMLEAK_FREE, ptr, 0, 0); |
3c7b4e6b CM |
1052 | } |
1053 | EXPORT_SYMBOL_GPL(kmemleak_free); | |
1054 | ||
a2b6bf63 CM |
1055 | /** |
1056 | * kmemleak_free_part - partially unregister a previously registered object | |
1057 | * @ptr: pointer to the beginning or inside the object. This also | |
1058 | * represents the start of the range to be freed | |
1059 | * @size: size to be unregistered | |
1060 | * | |
1061 | * This function is called when only a part of a memory block is freed | |
1062 | * (usually from the bootmem allocator). | |
53238a60 | 1063 | */ |
a6186d89 | 1064 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
53238a60 CM |
1065 | { |
1066 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1067 | ||
8910ae89 | 1068 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 1069 | delete_object_part((unsigned long)ptr, size); |
8910ae89 | 1070 | else if (kmemleak_early_log) |
c017b4be | 1071 | log_early(KMEMLEAK_FREE_PART, ptr, size, 0); |
53238a60 CM |
1072 | } |
1073 | EXPORT_SYMBOL_GPL(kmemleak_free_part); | |
1074 | ||
f528f0b8 CM |
1075 | /** |
1076 | * kmemleak_free_percpu - unregister a previously registered __percpu object | |
1077 | * @ptr: __percpu pointer to beginning of the object | |
1078 | * | |
1079 | * This function is called from the kernel percpu allocator when an object | |
1080 | * (memory block) is freed (free_percpu). | |
1081 | */ | |
1082 | void __ref kmemleak_free_percpu(const void __percpu *ptr) | |
1083 | { | |
1084 | unsigned int cpu; | |
1085 | ||
1086 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1087 | ||
c5f3b1a5 | 1088 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
1089 | for_each_possible_cpu(cpu) |
1090 | delete_object_full((unsigned long)per_cpu_ptr(ptr, | |
1091 | cpu)); | |
8910ae89 | 1092 | else if (kmemleak_early_log) |
f528f0b8 CM |
1093 | log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0); |
1094 | } | |
1095 | EXPORT_SYMBOL_GPL(kmemleak_free_percpu); | |
1096 | ||
ffe2c748 CM |
1097 | /** |
1098 | * kmemleak_update_trace - update object allocation stack trace | |
1099 | * @ptr: pointer to beginning of the object | |
1100 | * | |
1101 | * Override the object allocation stack trace for cases where the actual | |
1102 | * allocation place is not always useful. | |
1103 | */ | |
1104 | void __ref kmemleak_update_trace(const void *ptr) | |
1105 | { | |
1106 | struct kmemleak_object *object; | |
1107 | unsigned long flags; | |
1108 | ||
1109 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1110 | ||
1111 | if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr)) | |
1112 | return; | |
1113 | ||
1114 | object = find_and_get_object((unsigned long)ptr, 1); | |
1115 | if (!object) { | |
1116 | #ifdef DEBUG | |
1117 | kmemleak_warn("Updating stack trace for unknown object at %p\n", | |
1118 | ptr); | |
1119 | #endif | |
1120 | return; | |
1121 | } | |
1122 | ||
1123 | spin_lock_irqsave(&object->lock, flags); | |
1124 | object->trace_len = __save_stack_trace(object->trace); | |
1125 | spin_unlock_irqrestore(&object->lock, flags); | |
1126 | ||
1127 | put_object(object); | |
1128 | } | |
1129 | EXPORT_SYMBOL(kmemleak_update_trace); | |
1130 | ||
a2b6bf63 CM |
1131 | /** |
1132 | * kmemleak_not_leak - mark an allocated object as false positive | |
1133 | * @ptr: pointer to beginning of the object | |
1134 | * | |
1135 | * Calling this function on an object will cause the memory block to no longer | |
1136 | * be reported as leak and always be scanned. | |
3c7b4e6b | 1137 | */ |
a6186d89 | 1138 | void __ref kmemleak_not_leak(const void *ptr) |
3c7b4e6b CM |
1139 | { |
1140 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1141 | ||
8910ae89 | 1142 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1143 | make_gray_object((unsigned long)ptr); |
8910ae89 | 1144 | else if (kmemleak_early_log) |
c017b4be | 1145 | log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0); |
3c7b4e6b CM |
1146 | } |
1147 | EXPORT_SYMBOL(kmemleak_not_leak); | |
1148 | ||
a2b6bf63 CM |
1149 | /** |
1150 | * kmemleak_ignore - ignore an allocated object | |
1151 | * @ptr: pointer to beginning of the object | |
1152 | * | |
1153 | * Calling this function on an object will cause the memory block to be | |
1154 | * ignored (not scanned and not reported as a leak). This is usually done when | |
1155 | * it is known that the corresponding block is not a leak and does not contain | |
1156 | * any references to other allocated memory blocks. | |
3c7b4e6b | 1157 | */ |
a6186d89 | 1158 | void __ref kmemleak_ignore(const void *ptr) |
3c7b4e6b CM |
1159 | { |
1160 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1161 | ||
8910ae89 | 1162 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1163 | make_black_object((unsigned long)ptr); |
8910ae89 | 1164 | else if (kmemleak_early_log) |
c017b4be | 1165 | log_early(KMEMLEAK_IGNORE, ptr, 0, 0); |
3c7b4e6b CM |
1166 | } |
1167 | EXPORT_SYMBOL(kmemleak_ignore); | |
1168 | ||
a2b6bf63 CM |
1169 | /** |
1170 | * kmemleak_scan_area - limit the range to be scanned in an allocated object | |
1171 | * @ptr: pointer to beginning or inside the object. This also | |
1172 | * represents the start of the scan area | |
1173 | * @size: size of the scan area | |
1174 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1175 | * | |
1176 | * This function is used when it is known that only certain parts of an object | |
1177 | * contain references to other objects. Kmemleak will only scan these areas | |
1178 | * reducing the number false negatives. | |
3c7b4e6b | 1179 | */ |
c017b4be | 1180 | void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
1181 | { |
1182 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1183 | ||
8910ae89 | 1184 | if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
c017b4be | 1185 | add_scan_area((unsigned long)ptr, size, gfp); |
8910ae89 | 1186 | else if (kmemleak_early_log) |
c017b4be | 1187 | log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0); |
3c7b4e6b CM |
1188 | } |
1189 | EXPORT_SYMBOL(kmemleak_scan_area); | |
1190 | ||
a2b6bf63 CM |
1191 | /** |
1192 | * kmemleak_no_scan - do not scan an allocated object | |
1193 | * @ptr: pointer to beginning of the object | |
1194 | * | |
1195 | * This function notifies kmemleak not to scan the given memory block. Useful | |
1196 | * in situations where it is known that the given object does not contain any | |
1197 | * references to other objects. Kmemleak will not scan such objects reducing | |
1198 | * the number of false negatives. | |
3c7b4e6b | 1199 | */ |
a6186d89 | 1200 | void __ref kmemleak_no_scan(const void *ptr) |
3c7b4e6b CM |
1201 | { |
1202 | pr_debug("%s(0x%p)\n", __func__, ptr); | |
1203 | ||
8910ae89 | 1204 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1205 | object_no_scan((unsigned long)ptr); |
8910ae89 | 1206 | else if (kmemleak_early_log) |
c017b4be | 1207 | log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0); |
3c7b4e6b CM |
1208 | } |
1209 | EXPORT_SYMBOL(kmemleak_no_scan); | |
1210 | ||
9099daed CM |
1211 | /** |
1212 | * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical | |
1213 | * address argument | |
e8b098fc MR |
1214 | * @phys: physical address of the object |
1215 | * @size: size of the object | |
1216 | * @min_count: minimum number of references to this object. | |
1217 | * See kmemleak_alloc() | |
1218 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
9099daed CM |
1219 | */ |
1220 | void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count, | |
1221 | gfp_t gfp) | |
1222 | { | |
1223 | if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) | |
1224 | kmemleak_alloc(__va(phys), size, min_count, gfp); | |
1225 | } | |
1226 | EXPORT_SYMBOL(kmemleak_alloc_phys); | |
1227 | ||
1228 | /** | |
1229 | * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a | |
1230 | * physical address argument | |
e8b098fc MR |
1231 | * @phys: physical address if the beginning or inside an object. This |
1232 | * also represents the start of the range to be freed | |
1233 | * @size: size to be unregistered | |
9099daed CM |
1234 | */ |
1235 | void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size) | |
1236 | { | |
1237 | if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) | |
1238 | kmemleak_free_part(__va(phys), size); | |
1239 | } | |
1240 | EXPORT_SYMBOL(kmemleak_free_part_phys); | |
1241 | ||
1242 | /** | |
1243 | * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical | |
1244 | * address argument | |
e8b098fc | 1245 | * @phys: physical address of the object |
9099daed CM |
1246 | */ |
1247 | void __ref kmemleak_not_leak_phys(phys_addr_t phys) | |
1248 | { | |
1249 | if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) | |
1250 | kmemleak_not_leak(__va(phys)); | |
1251 | } | |
1252 | EXPORT_SYMBOL(kmemleak_not_leak_phys); | |
1253 | ||
1254 | /** | |
1255 | * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical | |
1256 | * address argument | |
e8b098fc | 1257 | * @phys: physical address of the object |
9099daed CM |
1258 | */ |
1259 | void __ref kmemleak_ignore_phys(phys_addr_t phys) | |
1260 | { | |
1261 | if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) | |
1262 | kmemleak_ignore(__va(phys)); | |
1263 | } | |
1264 | EXPORT_SYMBOL(kmemleak_ignore_phys); | |
1265 | ||
04609ccc CM |
1266 | /* |
1267 | * Update an object's checksum and return true if it was modified. | |
1268 | */ | |
1269 | static bool update_checksum(struct kmemleak_object *object) | |
1270 | { | |
1271 | u32 old_csum = object->checksum; | |
1272 | ||
e79ed2f1 | 1273 | kasan_disable_current(); |
04609ccc | 1274 | object->checksum = crc32(0, (void *)object->pointer, object->size); |
e79ed2f1 AR |
1275 | kasan_enable_current(); |
1276 | ||
04609ccc CM |
1277 | return object->checksum != old_csum; |
1278 | } | |
1279 | ||
04f70d13 CM |
1280 | /* |
1281 | * Update an object's references. object->lock must be held by the caller. | |
1282 | */ | |
1283 | static void update_refs(struct kmemleak_object *object) | |
1284 | { | |
1285 | if (!color_white(object)) { | |
1286 | /* non-orphan, ignored or new */ | |
1287 | return; | |
1288 | } | |
1289 | ||
1290 | /* | |
1291 | * Increase the object's reference count (number of pointers to the | |
1292 | * memory block). If this count reaches the required minimum, the | |
1293 | * object's color will become gray and it will be added to the | |
1294 | * gray_list. | |
1295 | */ | |
1296 | object->count++; | |
1297 | if (color_gray(object)) { | |
1298 | /* put_object() called when removing from gray_list */ | |
1299 | WARN_ON(!get_object(object)); | |
1300 | list_add_tail(&object->gray_list, &gray_list); | |
1301 | } | |
1302 | } | |
1303 | ||
3c7b4e6b CM |
1304 | /* |
1305 | * Memory scanning is a long process and it needs to be interruptable. This | |
25985edc | 1306 | * function checks whether such interrupt condition occurred. |
3c7b4e6b CM |
1307 | */ |
1308 | static int scan_should_stop(void) | |
1309 | { | |
8910ae89 | 1310 | if (!kmemleak_enabled) |
3c7b4e6b CM |
1311 | return 1; |
1312 | ||
1313 | /* | |
1314 | * This function may be called from either process or kthread context, | |
1315 | * hence the need to check for both stop conditions. | |
1316 | */ | |
1317 | if (current->mm) | |
1318 | return signal_pending(current); | |
1319 | else | |
1320 | return kthread_should_stop(); | |
1321 | ||
1322 | return 0; | |
1323 | } | |
1324 | ||
1325 | /* | |
1326 | * Scan a memory block (exclusive range) for valid pointers and add those | |
1327 | * found to the gray list. | |
1328 | */ | |
1329 | static void scan_block(void *_start, void *_end, | |
93ada579 | 1330 | struct kmemleak_object *scanned) |
3c7b4e6b CM |
1331 | { |
1332 | unsigned long *ptr; | |
1333 | unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); | |
1334 | unsigned long *end = _end - (BYTES_PER_POINTER - 1); | |
93ada579 | 1335 | unsigned long flags; |
3c7b4e6b | 1336 | |
93ada579 | 1337 | read_lock_irqsave(&kmemleak_lock, flags); |
3c7b4e6b | 1338 | for (ptr = start; ptr < end; ptr++) { |
3c7b4e6b | 1339 | struct kmemleak_object *object; |
8e019366 | 1340 | unsigned long pointer; |
94f4a161 | 1341 | unsigned long excess_ref; |
3c7b4e6b CM |
1342 | |
1343 | if (scan_should_stop()) | |
1344 | break; | |
1345 | ||
e79ed2f1 | 1346 | kasan_disable_current(); |
8e019366 | 1347 | pointer = *ptr; |
e79ed2f1 | 1348 | kasan_enable_current(); |
8e019366 | 1349 | |
93ada579 CM |
1350 | if (pointer < min_addr || pointer >= max_addr) |
1351 | continue; | |
1352 | ||
1353 | /* | |
1354 | * No need for get_object() here since we hold kmemleak_lock. | |
1355 | * object->use_count cannot be dropped to 0 while the object | |
1356 | * is still present in object_tree_root and object_list | |
1357 | * (with updates protected by kmemleak_lock). | |
1358 | */ | |
1359 | object = lookup_object(pointer, 1); | |
3c7b4e6b CM |
1360 | if (!object) |
1361 | continue; | |
93ada579 | 1362 | if (object == scanned) |
3c7b4e6b | 1363 | /* self referenced, ignore */ |
3c7b4e6b | 1364 | continue; |
3c7b4e6b CM |
1365 | |
1366 | /* | |
1367 | * Avoid the lockdep recursive warning on object->lock being | |
1368 | * previously acquired in scan_object(). These locks are | |
1369 | * enclosed by scan_mutex. | |
1370 | */ | |
93ada579 | 1371 | spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
94f4a161 CM |
1372 | /* only pass surplus references (object already gray) */ |
1373 | if (color_gray(object)) { | |
1374 | excess_ref = object->excess_ref; | |
1375 | /* no need for update_refs() if object already gray */ | |
1376 | } else { | |
1377 | excess_ref = 0; | |
1378 | update_refs(object); | |
1379 | } | |
93ada579 | 1380 | spin_unlock(&object->lock); |
94f4a161 CM |
1381 | |
1382 | if (excess_ref) { | |
1383 | object = lookup_object(excess_ref, 0); | |
1384 | if (!object) | |
1385 | continue; | |
1386 | if (object == scanned) | |
1387 | /* circular reference, ignore */ | |
1388 | continue; | |
1389 | spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); | |
1390 | update_refs(object); | |
1391 | spin_unlock(&object->lock); | |
1392 | } | |
93ada579 CM |
1393 | } |
1394 | read_unlock_irqrestore(&kmemleak_lock, flags); | |
1395 | } | |
0587da40 | 1396 | |
93ada579 CM |
1397 | /* |
1398 | * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency. | |
1399 | */ | |
1400 | static void scan_large_block(void *start, void *end) | |
1401 | { | |
1402 | void *next; | |
1403 | ||
1404 | while (start < end) { | |
1405 | next = min(start + MAX_SCAN_SIZE, end); | |
1406 | scan_block(start, next, NULL); | |
1407 | start = next; | |
1408 | cond_resched(); | |
3c7b4e6b CM |
1409 | } |
1410 | } | |
1411 | ||
1412 | /* | |
1413 | * Scan a memory block corresponding to a kmemleak_object. A condition is | |
1414 | * that object->use_count >= 1. | |
1415 | */ | |
1416 | static void scan_object(struct kmemleak_object *object) | |
1417 | { | |
1418 | struct kmemleak_scan_area *area; | |
3c7b4e6b CM |
1419 | unsigned long flags; |
1420 | ||
1421 | /* | |
21ae2956 UKK |
1422 | * Once the object->lock is acquired, the corresponding memory block |
1423 | * cannot be freed (the same lock is acquired in delete_object). | |
3c7b4e6b CM |
1424 | */ |
1425 | spin_lock_irqsave(&object->lock, flags); | |
1426 | if (object->flags & OBJECT_NO_SCAN) | |
1427 | goto out; | |
1428 | if (!(object->flags & OBJECT_ALLOCATED)) | |
1429 | /* already freed object */ | |
1430 | goto out; | |
af98603d CM |
1431 | if (hlist_empty(&object->area_list)) { |
1432 | void *start = (void *)object->pointer; | |
1433 | void *end = (void *)(object->pointer + object->size); | |
93ada579 CM |
1434 | void *next; |
1435 | ||
1436 | do { | |
1437 | next = min(start + MAX_SCAN_SIZE, end); | |
1438 | scan_block(start, next, object); | |
af98603d | 1439 | |
93ada579 CM |
1440 | start = next; |
1441 | if (start >= end) | |
1442 | break; | |
af98603d CM |
1443 | |
1444 | spin_unlock_irqrestore(&object->lock, flags); | |
1445 | cond_resched(); | |
1446 | spin_lock_irqsave(&object->lock, flags); | |
93ada579 | 1447 | } while (object->flags & OBJECT_ALLOCATED); |
af98603d | 1448 | } else |
b67bfe0d | 1449 | hlist_for_each_entry(area, &object->area_list, node) |
c017b4be CM |
1450 | scan_block((void *)area->start, |
1451 | (void *)(area->start + area->size), | |
93ada579 | 1452 | object); |
3c7b4e6b CM |
1453 | out: |
1454 | spin_unlock_irqrestore(&object->lock, flags); | |
1455 | } | |
1456 | ||
04609ccc CM |
1457 | /* |
1458 | * Scan the objects already referenced (gray objects). More objects will be | |
1459 | * referenced and, if there are no memory leaks, all the objects are scanned. | |
1460 | */ | |
1461 | static void scan_gray_list(void) | |
1462 | { | |
1463 | struct kmemleak_object *object, *tmp; | |
1464 | ||
1465 | /* | |
1466 | * The list traversal is safe for both tail additions and removals | |
1467 | * from inside the loop. The kmemleak objects cannot be freed from | |
1468 | * outside the loop because their use_count was incremented. | |
1469 | */ | |
1470 | object = list_entry(gray_list.next, typeof(*object), gray_list); | |
1471 | while (&object->gray_list != &gray_list) { | |
1472 | cond_resched(); | |
1473 | ||
1474 | /* may add new objects to the list */ | |
1475 | if (!scan_should_stop()) | |
1476 | scan_object(object); | |
1477 | ||
1478 | tmp = list_entry(object->gray_list.next, typeof(*object), | |
1479 | gray_list); | |
1480 | ||
1481 | /* remove the object from the list and release it */ | |
1482 | list_del(&object->gray_list); | |
1483 | put_object(object); | |
1484 | ||
1485 | object = tmp; | |
1486 | } | |
1487 | WARN_ON(!list_empty(&gray_list)); | |
1488 | } | |
1489 | ||
3c7b4e6b CM |
1490 | /* |
1491 | * Scan data sections and all the referenced memory blocks allocated via the | |
1492 | * kernel's standard allocators. This function must be called with the | |
1493 | * scan_mutex held. | |
1494 | */ | |
1495 | static void kmemleak_scan(void) | |
1496 | { | |
1497 | unsigned long flags; | |
04609ccc | 1498 | struct kmemleak_object *object; |
3c7b4e6b | 1499 | int i; |
4698c1f2 | 1500 | int new_leaks = 0; |
3c7b4e6b | 1501 | |
acf4968e CM |
1502 | jiffies_last_scan = jiffies; |
1503 | ||
3c7b4e6b CM |
1504 | /* prepare the kmemleak_object's */ |
1505 | rcu_read_lock(); | |
1506 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1507 | spin_lock_irqsave(&object->lock, flags); | |
1508 | #ifdef DEBUG | |
1509 | /* | |
1510 | * With a few exceptions there should be a maximum of | |
1511 | * 1 reference to any object at this point. | |
1512 | */ | |
1513 | if (atomic_read(&object->use_count) > 1) { | |
ae281064 | 1514 | pr_debug("object->use_count = %d\n", |
3c7b4e6b CM |
1515 | atomic_read(&object->use_count)); |
1516 | dump_object_info(object); | |
1517 | } | |
1518 | #endif | |
1519 | /* reset the reference count (whiten the object) */ | |
1520 | object->count = 0; | |
1521 | if (color_gray(object) && get_object(object)) | |
1522 | list_add_tail(&object->gray_list, &gray_list); | |
1523 | ||
1524 | spin_unlock_irqrestore(&object->lock, flags); | |
1525 | } | |
1526 | rcu_read_unlock(); | |
1527 | ||
1528 | /* data/bss scanning */ | |
93ada579 CM |
1529 | scan_large_block(_sdata, _edata); |
1530 | scan_large_block(__bss_start, __bss_stop); | |
906f2a51 | 1531 | scan_large_block(__start_ro_after_init, __end_ro_after_init); |
3c7b4e6b CM |
1532 | |
1533 | #ifdef CONFIG_SMP | |
1534 | /* per-cpu sections scanning */ | |
1535 | for_each_possible_cpu(i) | |
93ada579 CM |
1536 | scan_large_block(__per_cpu_start + per_cpu_offset(i), |
1537 | __per_cpu_end + per_cpu_offset(i)); | |
3c7b4e6b CM |
1538 | #endif |
1539 | ||
1540 | /* | |
029aeff5 | 1541 | * Struct page scanning for each node. |
3c7b4e6b | 1542 | */ |
bfc8c901 | 1543 | get_online_mems(); |
3c7b4e6b | 1544 | for_each_online_node(i) { |
108bcc96 CS |
1545 | unsigned long start_pfn = node_start_pfn(i); |
1546 | unsigned long end_pfn = node_end_pfn(i); | |
3c7b4e6b CM |
1547 | unsigned long pfn; |
1548 | ||
1549 | for (pfn = start_pfn; pfn < end_pfn; pfn++) { | |
9f1eb38e | 1550 | struct page *page = pfn_to_online_page(pfn); |
3c7b4e6b | 1551 | |
9f1eb38e OS |
1552 | if (!page) |
1553 | continue; | |
1554 | ||
1555 | /* only scan pages belonging to this node */ | |
1556 | if (page_to_nid(page) != i) | |
3c7b4e6b | 1557 | continue; |
3c7b4e6b CM |
1558 | /* only scan if page is in use */ |
1559 | if (page_count(page) == 0) | |
1560 | continue; | |
93ada579 | 1561 | scan_block(page, page + 1, NULL); |
13ab183d | 1562 | if (!(pfn & 63)) |
bde5f6bc | 1563 | cond_resched(); |
3c7b4e6b CM |
1564 | } |
1565 | } | |
bfc8c901 | 1566 | put_online_mems(); |
3c7b4e6b CM |
1567 | |
1568 | /* | |
43ed5d6e | 1569 | * Scanning the task stacks (may introduce false negatives). |
3c7b4e6b CM |
1570 | */ |
1571 | if (kmemleak_stack_scan) { | |
43ed5d6e CM |
1572 | struct task_struct *p, *g; |
1573 | ||
3c7b4e6b | 1574 | read_lock(&tasklist_lock); |
43ed5d6e | 1575 | do_each_thread(g, p) { |
37df49f4 CM |
1576 | void *stack = try_get_task_stack(p); |
1577 | if (stack) { | |
1578 | scan_block(stack, stack + THREAD_SIZE, NULL); | |
1579 | put_task_stack(p); | |
1580 | } | |
43ed5d6e | 1581 | } while_each_thread(g, p); |
3c7b4e6b CM |
1582 | read_unlock(&tasklist_lock); |
1583 | } | |
1584 | ||
1585 | /* | |
1586 | * Scan the objects already referenced from the sections scanned | |
04609ccc | 1587 | * above. |
3c7b4e6b | 1588 | */ |
04609ccc | 1589 | scan_gray_list(); |
2587362e CM |
1590 | |
1591 | /* | |
04609ccc CM |
1592 | * Check for new or unreferenced objects modified since the previous |
1593 | * scan and color them gray until the next scan. | |
2587362e CM |
1594 | */ |
1595 | rcu_read_lock(); | |
1596 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1597 | spin_lock_irqsave(&object->lock, flags); | |
04609ccc CM |
1598 | if (color_white(object) && (object->flags & OBJECT_ALLOCATED) |
1599 | && update_checksum(object) && get_object(object)) { | |
1600 | /* color it gray temporarily */ | |
1601 | object->count = object->min_count; | |
2587362e CM |
1602 | list_add_tail(&object->gray_list, &gray_list); |
1603 | } | |
1604 | spin_unlock_irqrestore(&object->lock, flags); | |
1605 | } | |
1606 | rcu_read_unlock(); | |
1607 | ||
04609ccc CM |
1608 | /* |
1609 | * Re-scan the gray list for modified unreferenced objects. | |
1610 | */ | |
1611 | scan_gray_list(); | |
4698c1f2 | 1612 | |
17bb9e0d | 1613 | /* |
04609ccc | 1614 | * If scanning was stopped do not report any new unreferenced objects. |
17bb9e0d | 1615 | */ |
04609ccc | 1616 | if (scan_should_stop()) |
17bb9e0d CM |
1617 | return; |
1618 | ||
4698c1f2 CM |
1619 | /* |
1620 | * Scanning result reporting. | |
1621 | */ | |
1622 | rcu_read_lock(); | |
1623 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1624 | spin_lock_irqsave(&object->lock, flags); | |
1625 | if (unreferenced_object(object) && | |
1626 | !(object->flags & OBJECT_REPORTED)) { | |
1627 | object->flags |= OBJECT_REPORTED; | |
154221c3 VW |
1628 | |
1629 | if (kmemleak_verbose) | |
1630 | print_unreferenced(NULL, object); | |
1631 | ||
4698c1f2 CM |
1632 | new_leaks++; |
1633 | } | |
1634 | spin_unlock_irqrestore(&object->lock, flags); | |
1635 | } | |
1636 | rcu_read_unlock(); | |
1637 | ||
dc9b3f42 LZ |
1638 | if (new_leaks) { |
1639 | kmemleak_found_leaks = true; | |
1640 | ||
756a025f JP |
1641 | pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n", |
1642 | new_leaks); | |
dc9b3f42 | 1643 | } |
4698c1f2 | 1644 | |
3c7b4e6b CM |
1645 | } |
1646 | ||
1647 | /* | |
1648 | * Thread function performing automatic memory scanning. Unreferenced objects | |
1649 | * at the end of a memory scan are reported but only the first time. | |
1650 | */ | |
1651 | static int kmemleak_scan_thread(void *arg) | |
1652 | { | |
d53ce042 | 1653 | static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN); |
3c7b4e6b | 1654 | |
ae281064 | 1655 | pr_info("Automatic memory scanning thread started\n"); |
bf2a76b3 | 1656 | set_user_nice(current, 10); |
3c7b4e6b CM |
1657 | |
1658 | /* | |
1659 | * Wait before the first scan to allow the system to fully initialize. | |
1660 | */ | |
1661 | if (first_run) { | |
98c42d94 | 1662 | signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000); |
3c7b4e6b | 1663 | first_run = 0; |
98c42d94 VN |
1664 | while (timeout && !kthread_should_stop()) |
1665 | timeout = schedule_timeout_interruptible(timeout); | |
3c7b4e6b CM |
1666 | } |
1667 | ||
1668 | while (!kthread_should_stop()) { | |
3c7b4e6b CM |
1669 | signed long timeout = jiffies_scan_wait; |
1670 | ||
1671 | mutex_lock(&scan_mutex); | |
3c7b4e6b | 1672 | kmemleak_scan(); |
3c7b4e6b | 1673 | mutex_unlock(&scan_mutex); |
4698c1f2 | 1674 | |
3c7b4e6b CM |
1675 | /* wait before the next scan */ |
1676 | while (timeout && !kthread_should_stop()) | |
1677 | timeout = schedule_timeout_interruptible(timeout); | |
1678 | } | |
1679 | ||
ae281064 | 1680 | pr_info("Automatic memory scanning thread ended\n"); |
3c7b4e6b CM |
1681 | |
1682 | return 0; | |
1683 | } | |
1684 | ||
1685 | /* | |
1686 | * Start the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1687 | * with the scan_mutex held. |
3c7b4e6b | 1688 | */ |
7eb0d5e5 | 1689 | static void start_scan_thread(void) |
3c7b4e6b CM |
1690 | { |
1691 | if (scan_thread) | |
1692 | return; | |
1693 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); | |
1694 | if (IS_ERR(scan_thread)) { | |
598d8091 | 1695 | pr_warn("Failed to create the scan thread\n"); |
3c7b4e6b CM |
1696 | scan_thread = NULL; |
1697 | } | |
1698 | } | |
1699 | ||
1700 | /* | |
914b6dff | 1701 | * Stop the automatic memory scanning thread. |
3c7b4e6b | 1702 | */ |
7eb0d5e5 | 1703 | static void stop_scan_thread(void) |
3c7b4e6b CM |
1704 | { |
1705 | if (scan_thread) { | |
1706 | kthread_stop(scan_thread); | |
1707 | scan_thread = NULL; | |
1708 | } | |
1709 | } | |
1710 | ||
1711 | /* | |
1712 | * Iterate over the object_list and return the first valid object at or after | |
1713 | * the required position with its use_count incremented. The function triggers | |
1714 | * a memory scanning when the pos argument points to the first position. | |
1715 | */ | |
1716 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) | |
1717 | { | |
1718 | struct kmemleak_object *object; | |
1719 | loff_t n = *pos; | |
b87324d0 CM |
1720 | int err; |
1721 | ||
1722 | err = mutex_lock_interruptible(&scan_mutex); | |
1723 | if (err < 0) | |
1724 | return ERR_PTR(err); | |
3c7b4e6b | 1725 | |
3c7b4e6b CM |
1726 | rcu_read_lock(); |
1727 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1728 | if (n-- > 0) | |
1729 | continue; | |
1730 | if (get_object(object)) | |
1731 | goto out; | |
1732 | } | |
1733 | object = NULL; | |
1734 | out: | |
3c7b4e6b CM |
1735 | return object; |
1736 | } | |
1737 | ||
1738 | /* | |
1739 | * Return the next object in the object_list. The function decrements the | |
1740 | * use_count of the previous object and increases that of the next one. | |
1741 | */ | |
1742 | static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
1743 | { | |
1744 | struct kmemleak_object *prev_obj = v; | |
1745 | struct kmemleak_object *next_obj = NULL; | |
58fac095 | 1746 | struct kmemleak_object *obj = prev_obj; |
3c7b4e6b CM |
1747 | |
1748 | ++(*pos); | |
3c7b4e6b | 1749 | |
58fac095 | 1750 | list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
52c3ce4e CM |
1751 | if (get_object(obj)) { |
1752 | next_obj = obj; | |
3c7b4e6b | 1753 | break; |
52c3ce4e | 1754 | } |
3c7b4e6b | 1755 | } |
288c857d | 1756 | |
3c7b4e6b CM |
1757 | put_object(prev_obj); |
1758 | return next_obj; | |
1759 | } | |
1760 | ||
1761 | /* | |
1762 | * Decrement the use_count of the last object required, if any. | |
1763 | */ | |
1764 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) | |
1765 | { | |
b87324d0 CM |
1766 | if (!IS_ERR(v)) { |
1767 | /* | |
1768 | * kmemleak_seq_start may return ERR_PTR if the scan_mutex | |
1769 | * waiting was interrupted, so only release it if !IS_ERR. | |
1770 | */ | |
f5886c7f | 1771 | rcu_read_unlock(); |
b87324d0 CM |
1772 | mutex_unlock(&scan_mutex); |
1773 | if (v) | |
1774 | put_object(v); | |
1775 | } | |
3c7b4e6b CM |
1776 | } |
1777 | ||
1778 | /* | |
1779 | * Print the information for an unreferenced object to the seq file. | |
1780 | */ | |
1781 | static int kmemleak_seq_show(struct seq_file *seq, void *v) | |
1782 | { | |
1783 | struct kmemleak_object *object = v; | |
1784 | unsigned long flags; | |
1785 | ||
1786 | spin_lock_irqsave(&object->lock, flags); | |
288c857d | 1787 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
17bb9e0d | 1788 | print_unreferenced(seq, object); |
3c7b4e6b CM |
1789 | spin_unlock_irqrestore(&object->lock, flags); |
1790 | return 0; | |
1791 | } | |
1792 | ||
1793 | static const struct seq_operations kmemleak_seq_ops = { | |
1794 | .start = kmemleak_seq_start, | |
1795 | .next = kmemleak_seq_next, | |
1796 | .stop = kmemleak_seq_stop, | |
1797 | .show = kmemleak_seq_show, | |
1798 | }; | |
1799 | ||
1800 | static int kmemleak_open(struct inode *inode, struct file *file) | |
1801 | { | |
b87324d0 | 1802 | return seq_open(file, &kmemleak_seq_ops); |
3c7b4e6b CM |
1803 | } |
1804 | ||
189d84ed CM |
1805 | static int dump_str_object_info(const char *str) |
1806 | { | |
1807 | unsigned long flags; | |
1808 | struct kmemleak_object *object; | |
1809 | unsigned long addr; | |
1810 | ||
dc053733 AP |
1811 | if (kstrtoul(str, 0, &addr)) |
1812 | return -EINVAL; | |
189d84ed CM |
1813 | object = find_and_get_object(addr, 0); |
1814 | if (!object) { | |
1815 | pr_info("Unknown object at 0x%08lx\n", addr); | |
1816 | return -EINVAL; | |
1817 | } | |
1818 | ||
1819 | spin_lock_irqsave(&object->lock, flags); | |
1820 | dump_object_info(object); | |
1821 | spin_unlock_irqrestore(&object->lock, flags); | |
1822 | ||
1823 | put_object(object); | |
1824 | return 0; | |
1825 | } | |
1826 | ||
30b37101 LR |
1827 | /* |
1828 | * We use grey instead of black to ensure we can do future scans on the same | |
1829 | * objects. If we did not do future scans these black objects could | |
1830 | * potentially contain references to newly allocated objects in the future and | |
1831 | * we'd end up with false positives. | |
1832 | */ | |
1833 | static void kmemleak_clear(void) | |
1834 | { | |
1835 | struct kmemleak_object *object; | |
1836 | unsigned long flags; | |
1837 | ||
1838 | rcu_read_lock(); | |
1839 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1840 | spin_lock_irqsave(&object->lock, flags); | |
1841 | if ((object->flags & OBJECT_REPORTED) && | |
1842 | unreferenced_object(object)) | |
a1084c87 | 1843 | __paint_it(object, KMEMLEAK_GREY); |
30b37101 LR |
1844 | spin_unlock_irqrestore(&object->lock, flags); |
1845 | } | |
1846 | rcu_read_unlock(); | |
dc9b3f42 LZ |
1847 | |
1848 | kmemleak_found_leaks = false; | |
30b37101 LR |
1849 | } |
1850 | ||
c89da70c LZ |
1851 | static void __kmemleak_do_cleanup(void); |
1852 | ||
3c7b4e6b CM |
1853 | /* |
1854 | * File write operation to configure kmemleak at run-time. The following | |
1855 | * commands can be written to the /sys/kernel/debug/kmemleak file: | |
1856 | * off - disable kmemleak (irreversible) | |
1857 | * stack=on - enable the task stacks scanning | |
1858 | * stack=off - disable the tasks stacks scanning | |
1859 | * scan=on - start the automatic memory scanning thread | |
1860 | * scan=off - stop the automatic memory scanning thread | |
1861 | * scan=... - set the automatic memory scanning period in seconds (0 to | |
1862 | * disable it) | |
4698c1f2 | 1863 | * scan - trigger a memory scan |
30b37101 | 1864 | * clear - mark all current reported unreferenced kmemleak objects as |
c89da70c LZ |
1865 | * grey to ignore printing them, or free all kmemleak objects |
1866 | * if kmemleak has been disabled. | |
189d84ed | 1867 | * dump=... - dump information about the object found at the given address |
3c7b4e6b CM |
1868 | */ |
1869 | static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, | |
1870 | size_t size, loff_t *ppos) | |
1871 | { | |
1872 | char buf[64]; | |
1873 | int buf_size; | |
b87324d0 | 1874 | int ret; |
3c7b4e6b CM |
1875 | |
1876 | buf_size = min(size, (sizeof(buf) - 1)); | |
1877 | if (strncpy_from_user(buf, user_buf, buf_size) < 0) | |
1878 | return -EFAULT; | |
1879 | buf[buf_size] = 0; | |
1880 | ||
b87324d0 CM |
1881 | ret = mutex_lock_interruptible(&scan_mutex); |
1882 | if (ret < 0) | |
1883 | return ret; | |
1884 | ||
c89da70c | 1885 | if (strncmp(buf, "clear", 5) == 0) { |
8910ae89 | 1886 | if (kmemleak_enabled) |
c89da70c LZ |
1887 | kmemleak_clear(); |
1888 | else | |
1889 | __kmemleak_do_cleanup(); | |
1890 | goto out; | |
1891 | } | |
1892 | ||
8910ae89 | 1893 | if (!kmemleak_enabled) { |
c89da70c LZ |
1894 | ret = -EBUSY; |
1895 | goto out; | |
1896 | } | |
1897 | ||
3c7b4e6b CM |
1898 | if (strncmp(buf, "off", 3) == 0) |
1899 | kmemleak_disable(); | |
1900 | else if (strncmp(buf, "stack=on", 8) == 0) | |
1901 | kmemleak_stack_scan = 1; | |
1902 | else if (strncmp(buf, "stack=off", 9) == 0) | |
1903 | kmemleak_stack_scan = 0; | |
1904 | else if (strncmp(buf, "scan=on", 7) == 0) | |
1905 | start_scan_thread(); | |
1906 | else if (strncmp(buf, "scan=off", 8) == 0) | |
1907 | stop_scan_thread(); | |
1908 | else if (strncmp(buf, "scan=", 5) == 0) { | |
1909 | unsigned long secs; | |
3c7b4e6b | 1910 | |
3dbb95f7 | 1911 | ret = kstrtoul(buf + 5, 0, &secs); |
b87324d0 CM |
1912 | if (ret < 0) |
1913 | goto out; | |
3c7b4e6b CM |
1914 | stop_scan_thread(); |
1915 | if (secs) { | |
1916 | jiffies_scan_wait = msecs_to_jiffies(secs * 1000); | |
1917 | start_scan_thread(); | |
1918 | } | |
4698c1f2 CM |
1919 | } else if (strncmp(buf, "scan", 4) == 0) |
1920 | kmemleak_scan(); | |
189d84ed CM |
1921 | else if (strncmp(buf, "dump=", 5) == 0) |
1922 | ret = dump_str_object_info(buf + 5); | |
4698c1f2 | 1923 | else |
b87324d0 CM |
1924 | ret = -EINVAL; |
1925 | ||
1926 | out: | |
1927 | mutex_unlock(&scan_mutex); | |
1928 | if (ret < 0) | |
1929 | return ret; | |
3c7b4e6b CM |
1930 | |
1931 | /* ignore the rest of the buffer, only one command at a time */ | |
1932 | *ppos += size; | |
1933 | return size; | |
1934 | } | |
1935 | ||
1936 | static const struct file_operations kmemleak_fops = { | |
1937 | .owner = THIS_MODULE, | |
1938 | .open = kmemleak_open, | |
1939 | .read = seq_read, | |
1940 | .write = kmemleak_write, | |
1941 | .llseek = seq_lseek, | |
5f3bf19a | 1942 | .release = seq_release, |
3c7b4e6b CM |
1943 | }; |
1944 | ||
c89da70c LZ |
1945 | static void __kmemleak_do_cleanup(void) |
1946 | { | |
1947 | struct kmemleak_object *object; | |
1948 | ||
1949 | rcu_read_lock(); | |
1950 | list_for_each_entry_rcu(object, &object_list, object_list) | |
1951 | delete_object_full(object->pointer); | |
1952 | rcu_read_unlock(); | |
1953 | } | |
1954 | ||
3c7b4e6b | 1955 | /* |
74341703 CM |
1956 | * Stop the memory scanning thread and free the kmemleak internal objects if |
1957 | * no previous scan thread (otherwise, kmemleak may still have some useful | |
1958 | * information on memory leaks). | |
3c7b4e6b | 1959 | */ |
179a8100 | 1960 | static void kmemleak_do_cleanup(struct work_struct *work) |
3c7b4e6b | 1961 | { |
3c7b4e6b | 1962 | stop_scan_thread(); |
3c7b4e6b | 1963 | |
914b6dff | 1964 | mutex_lock(&scan_mutex); |
c5f3b1a5 | 1965 | /* |
914b6dff VM |
1966 | * Once it is made sure that kmemleak_scan has stopped, it is safe to no |
1967 | * longer track object freeing. Ordering of the scan thread stopping and | |
1968 | * the memory accesses below is guaranteed by the kthread_stop() | |
1969 | * function. | |
c5f3b1a5 CM |
1970 | */ |
1971 | kmemleak_free_enabled = 0; | |
914b6dff | 1972 | mutex_unlock(&scan_mutex); |
c5f3b1a5 | 1973 | |
c89da70c LZ |
1974 | if (!kmemleak_found_leaks) |
1975 | __kmemleak_do_cleanup(); | |
1976 | else | |
756a025f | 1977 | pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n"); |
3c7b4e6b CM |
1978 | } |
1979 | ||
179a8100 | 1980 | static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
3c7b4e6b CM |
1981 | |
1982 | /* | |
1983 | * Disable kmemleak. No memory allocation/freeing will be traced once this | |
1984 | * function is called. Disabling kmemleak is an irreversible operation. | |
1985 | */ | |
1986 | static void kmemleak_disable(void) | |
1987 | { | |
1988 | /* atomically check whether it was already invoked */ | |
8910ae89 | 1989 | if (cmpxchg(&kmemleak_error, 0, 1)) |
3c7b4e6b CM |
1990 | return; |
1991 | ||
1992 | /* stop any memory operation tracing */ | |
8910ae89 | 1993 | kmemleak_enabled = 0; |
3c7b4e6b CM |
1994 | |
1995 | /* check whether it is too early for a kernel thread */ | |
8910ae89 | 1996 | if (kmemleak_initialized) |
179a8100 | 1997 | schedule_work(&cleanup_work); |
c5f3b1a5 CM |
1998 | else |
1999 | kmemleak_free_enabled = 0; | |
3c7b4e6b CM |
2000 | |
2001 | pr_info("Kernel memory leak detector disabled\n"); | |
2002 | } | |
2003 | ||
2004 | /* | |
2005 | * Allow boot-time kmemleak disabling (enabled by default). | |
2006 | */ | |
8bd30c10 | 2007 | static int __init kmemleak_boot_config(char *str) |
3c7b4e6b CM |
2008 | { |
2009 | if (!str) | |
2010 | return -EINVAL; | |
2011 | if (strcmp(str, "off") == 0) | |
2012 | kmemleak_disable(); | |
ab0155a2 JB |
2013 | else if (strcmp(str, "on") == 0) |
2014 | kmemleak_skip_disable = 1; | |
2015 | else | |
3c7b4e6b CM |
2016 | return -EINVAL; |
2017 | return 0; | |
2018 | } | |
2019 | early_param("kmemleak", kmemleak_boot_config); | |
2020 | ||
5f79020c CM |
2021 | static void __init print_log_trace(struct early_log *log) |
2022 | { | |
2023 | struct stack_trace trace; | |
2024 | ||
2025 | trace.nr_entries = log->trace_len; | |
2026 | trace.entries = log->trace; | |
2027 | ||
2028 | pr_notice("Early log backtrace:\n"); | |
2029 | print_stack_trace(&trace, 2); | |
2030 | } | |
2031 | ||
3c7b4e6b | 2032 | /* |
2030117d | 2033 | * Kmemleak initialization. |
3c7b4e6b CM |
2034 | */ |
2035 | void __init kmemleak_init(void) | |
2036 | { | |
2037 | int i; | |
2038 | unsigned long flags; | |
2039 | ||
ab0155a2 JB |
2040 | #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF |
2041 | if (!kmemleak_skip_disable) { | |
3551a928 | 2042 | kmemleak_early_log = 0; |
ab0155a2 JB |
2043 | kmemleak_disable(); |
2044 | return; | |
2045 | } | |
2046 | #endif | |
2047 | ||
3c7b4e6b CM |
2048 | jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); |
2049 | jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); | |
2050 | ||
2051 | object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); | |
2052 | scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); | |
3c7b4e6b | 2053 | |
21cd3a60 | 2054 | if (crt_early_log > ARRAY_SIZE(early_log)) |
598d8091 JP |
2055 | pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", |
2056 | crt_early_log); | |
b6693005 | 2057 | |
3c7b4e6b CM |
2058 | /* the kernel is still in UP mode, so disabling the IRQs is enough */ |
2059 | local_irq_save(flags); | |
3551a928 | 2060 | kmemleak_early_log = 0; |
8910ae89 | 2061 | if (kmemleak_error) { |
b6693005 CM |
2062 | local_irq_restore(flags); |
2063 | return; | |
c5f3b1a5 | 2064 | } else { |
8910ae89 | 2065 | kmemleak_enabled = 1; |
c5f3b1a5 CM |
2066 | kmemleak_free_enabled = 1; |
2067 | } | |
3c7b4e6b CM |
2068 | local_irq_restore(flags); |
2069 | ||
2070 | /* | |
2071 | * This is the point where tracking allocations is safe. Automatic | |
2072 | * scanning is started during the late initcall. Add the early logged | |
2073 | * callbacks to the kmemleak infrastructure. | |
2074 | */ | |
2075 | for (i = 0; i < crt_early_log; i++) { | |
2076 | struct early_log *log = &early_log[i]; | |
2077 | ||
2078 | switch (log->op_type) { | |
2079 | case KMEMLEAK_ALLOC: | |
fd678967 | 2080 | early_alloc(log); |
3c7b4e6b | 2081 | break; |
f528f0b8 CM |
2082 | case KMEMLEAK_ALLOC_PERCPU: |
2083 | early_alloc_percpu(log); | |
2084 | break; | |
3c7b4e6b CM |
2085 | case KMEMLEAK_FREE: |
2086 | kmemleak_free(log->ptr); | |
2087 | break; | |
53238a60 CM |
2088 | case KMEMLEAK_FREE_PART: |
2089 | kmemleak_free_part(log->ptr, log->size); | |
2090 | break; | |
f528f0b8 CM |
2091 | case KMEMLEAK_FREE_PERCPU: |
2092 | kmemleak_free_percpu(log->ptr); | |
2093 | break; | |
3c7b4e6b CM |
2094 | case KMEMLEAK_NOT_LEAK: |
2095 | kmemleak_not_leak(log->ptr); | |
2096 | break; | |
2097 | case KMEMLEAK_IGNORE: | |
2098 | kmemleak_ignore(log->ptr); | |
2099 | break; | |
2100 | case KMEMLEAK_SCAN_AREA: | |
c017b4be | 2101 | kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL); |
3c7b4e6b CM |
2102 | break; |
2103 | case KMEMLEAK_NO_SCAN: | |
2104 | kmemleak_no_scan(log->ptr); | |
2105 | break; | |
94f4a161 CM |
2106 | case KMEMLEAK_SET_EXCESS_REF: |
2107 | object_set_excess_ref((unsigned long)log->ptr, | |
2108 | log->excess_ref); | |
2109 | break; | |
3c7b4e6b | 2110 | default: |
5f79020c CM |
2111 | kmemleak_warn("Unknown early log operation: %d\n", |
2112 | log->op_type); | |
2113 | } | |
2114 | ||
8910ae89 | 2115 | if (kmemleak_warning) { |
5f79020c | 2116 | print_log_trace(log); |
8910ae89 | 2117 | kmemleak_warning = 0; |
3c7b4e6b CM |
2118 | } |
2119 | } | |
2120 | } | |
2121 | ||
2122 | /* | |
2123 | * Late initialization function. | |
2124 | */ | |
2125 | static int __init kmemleak_late_init(void) | |
2126 | { | |
2127 | struct dentry *dentry; | |
2128 | ||
8910ae89 | 2129 | kmemleak_initialized = 1; |
3c7b4e6b | 2130 | |
b353756b VW |
2131 | dentry = debugfs_create_file("kmemleak", 0644, NULL, NULL, |
2132 | &kmemleak_fops); | |
2133 | if (!dentry) | |
2134 | pr_warn("Failed to create the debugfs kmemleak file\n"); | |
2135 | ||
8910ae89 | 2136 | if (kmemleak_error) { |
3c7b4e6b | 2137 | /* |
25985edc | 2138 | * Some error occurred and kmemleak was disabled. There is a |
3c7b4e6b CM |
2139 | * small chance that kmemleak_disable() was called immediately |
2140 | * after setting kmemleak_initialized and we may end up with | |
2141 | * two clean-up threads but serialized by scan_mutex. | |
2142 | */ | |
179a8100 | 2143 | schedule_work(&cleanup_work); |
3c7b4e6b CM |
2144 | return -ENOMEM; |
2145 | } | |
2146 | ||
d53ce042 SK |
2147 | if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) { |
2148 | mutex_lock(&scan_mutex); | |
2149 | start_scan_thread(); | |
2150 | mutex_unlock(&scan_mutex); | |
2151 | } | |
3c7b4e6b CM |
2152 | |
2153 | pr_info("Kernel memory leak detector initialized\n"); | |
2154 | ||
2155 | return 0; | |
2156 | } | |
2157 | late_initcall(kmemleak_late_init); |