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45051539 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3c7b4e6b CM |
2 | /* |
3 | * mm/kmemleak.c | |
4 | * | |
5 | * Copyright (C) 2008 ARM Limited | |
6 | * Written by Catalin Marinas <catalin.marinas@arm.com> | |
7 | * | |
3c7b4e6b | 8 | * For more information on the algorithm and kmemleak usage, please see |
22901c6c | 9 | * Documentation/dev-tools/kmemleak.rst. |
3c7b4e6b CM |
10 | * |
11 | * Notes on locking | |
12 | * ---------------- | |
13 | * | |
14 | * The following locks and mutexes are used by kmemleak: | |
15 | * | |
782e4179 | 16 | * - kmemleak_lock (raw_spinlock_t): protects the object_list as well as |
39042079 CM |
17 | * del_state modifications and accesses to the object trees |
18 | * (object_tree_root, object_phys_tree_root, object_percpu_tree_root). The | |
19 | * object_list is the main list holding the metadata (struct | |
20 | * kmemleak_object) for the allocated memory blocks. The object trees are | |
21 | * red black trees used to look-up metadata based on a pointer to the | |
22 | * corresponding memory block. The kmemleak_object structures are added to | |
23 | * the object_list and the object tree root in the create_object() function | |
24 | * called from the kmemleak_alloc{,_phys,_percpu}() callback and removed in | |
25 | * delete_object() called from the kmemleak_free{,_phys,_percpu}() callback | |
8c96f1bc HZ |
26 | * - kmemleak_object.lock (raw_spinlock_t): protects a kmemleak_object. |
27 | * Accesses to the metadata (e.g. count) are protected by this lock. Note | |
28 | * that some members of this structure may be protected by other means | |
29 | * (atomic or kmemleak_lock). This lock is also held when scanning the | |
30 | * corresponding memory block to avoid the kernel freeing it via the | |
31 | * kmemleak_free() callback. This is less heavyweight than holding a global | |
32 | * lock like kmemleak_lock during scanning. | |
3c7b4e6b CM |
33 | * - scan_mutex (mutex): ensures that only one thread may scan the memory for |
34 | * unreferenced objects at a time. The gray_list contains the objects which | |
35 | * are already referenced or marked as false positives and need to be | |
36 | * scanned. This list is only modified during a scanning episode when the | |
37 | * scan_mutex is held. At the end of a scan, the gray_list is always empty. | |
38 | * Note that the kmemleak_object.use_count is incremented when an object is | |
4698c1f2 CM |
39 | * added to the gray_list and therefore cannot be freed. This mutex also |
40 | * prevents multiple users of the "kmemleak" debugfs file together with | |
41 | * modifications to the memory scanning parameters including the scan_thread | |
42 | * pointer | |
3c7b4e6b | 43 | * |
93ada579 | 44 | * Locks and mutexes are acquired/nested in the following order: |
9d5a4c73 | 45 | * |
93ada579 CM |
46 | * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING) |
47 | * | |
48 | * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex | |
49 | * regions. | |
9d5a4c73 | 50 | * |
3c7b4e6b CM |
51 | * The kmemleak_object structures have a use_count incremented or decremented |
52 | * using the get_object()/put_object() functions. When the use_count becomes | |
53 | * 0, this count can no longer be incremented and put_object() schedules the | |
54 | * kmemleak_object freeing via an RCU callback. All calls to the get_object() | |
55 | * function must be protected by rcu_read_lock() to avoid accessing a freed | |
56 | * structure. | |
57 | */ | |
58 | ||
ae281064 JP |
59 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
60 | ||
3c7b4e6b CM |
61 | #include <linux/init.h> |
62 | #include <linux/kernel.h> | |
63 | #include <linux/list.h> | |
3f07c014 | 64 | #include <linux/sched/signal.h> |
29930025 | 65 | #include <linux/sched/task.h> |
68db0cf1 | 66 | #include <linux/sched/task_stack.h> |
3c7b4e6b CM |
67 | #include <linux/jiffies.h> |
68 | #include <linux/delay.h> | |
b95f1b31 | 69 | #include <linux/export.h> |
3c7b4e6b | 70 | #include <linux/kthread.h> |
85d3a316 | 71 | #include <linux/rbtree.h> |
3c7b4e6b CM |
72 | #include <linux/fs.h> |
73 | #include <linux/debugfs.h> | |
74 | #include <linux/seq_file.h> | |
75 | #include <linux/cpumask.h> | |
76 | #include <linux/spinlock.h> | |
154221c3 | 77 | #include <linux/module.h> |
3c7b4e6b CM |
78 | #include <linux/mutex.h> |
79 | #include <linux/rcupdate.h> | |
80 | #include <linux/stacktrace.h> | |
56a61617 | 81 | #include <linux/stackdepot.h> |
3c7b4e6b CM |
82 | #include <linux/cache.h> |
83 | #include <linux/percpu.h> | |
57c8a661 | 84 | #include <linux/memblock.h> |
9099daed | 85 | #include <linux/pfn.h> |
3c7b4e6b CM |
86 | #include <linux/mmzone.h> |
87 | #include <linux/slab.h> | |
88 | #include <linux/thread_info.h> | |
89 | #include <linux/err.h> | |
90 | #include <linux/uaccess.h> | |
91 | #include <linux/string.h> | |
92 | #include <linux/nodemask.h> | |
93 | #include <linux/mm.h> | |
179a8100 | 94 | #include <linux/workqueue.h> |
04609ccc | 95 | #include <linux/crc32.h> |
3c7b4e6b CM |
96 | |
97 | #include <asm/sections.h> | |
98 | #include <asm/processor.h> | |
60063497 | 99 | #include <linux/atomic.h> |
3c7b4e6b | 100 | |
e79ed2f1 | 101 | #include <linux/kasan.h> |
95511580 | 102 | #include <linux/kfence.h> |
3c7b4e6b | 103 | #include <linux/kmemleak.h> |
029aeff5 | 104 | #include <linux/memory_hotplug.h> |
3c7b4e6b CM |
105 | |
106 | /* | |
107 | * Kmemleak configuration and common defines. | |
108 | */ | |
109 | #define MAX_TRACE 16 /* stack trace length */ | |
3c7b4e6b | 110 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
3c7b4e6b CM |
111 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
112 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ | |
af98603d | 113 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
3c7b4e6b CM |
114 | |
115 | #define BYTES_PER_POINTER sizeof(void *) | |
116 | ||
117 | /* scanning area inside a memory block */ | |
118 | struct kmemleak_scan_area { | |
119 | struct hlist_node node; | |
c017b4be CM |
120 | unsigned long start; |
121 | size_t size; | |
3c7b4e6b CM |
122 | }; |
123 | ||
a1084c87 LR |
124 | #define KMEMLEAK_GREY 0 |
125 | #define KMEMLEAK_BLACK -1 | |
126 | ||
3c7b4e6b CM |
127 | /* |
128 | * Structure holding the metadata for each allocated memory block. | |
129 | * Modifications to such objects should be made while holding the | |
130 | * object->lock. Insertions or deletions from object_list, gray_list or | |
85d3a316 | 131 | * rb_node are already protected by the corresponding locks or mutex (see |
3c7b4e6b CM |
132 | * the notes on locking above). These objects are reference-counted |
133 | * (use_count) and freed using the RCU mechanism. | |
134 | */ | |
135 | struct kmemleak_object { | |
8c96f1bc | 136 | raw_spinlock_t lock; |
f66abf09 | 137 | unsigned int flags; /* object status flags */ |
3c7b4e6b CM |
138 | struct list_head object_list; |
139 | struct list_head gray_list; | |
85d3a316 | 140 | struct rb_node rb_node; |
3c7b4e6b CM |
141 | struct rcu_head rcu; /* object_list lockless traversal */ |
142 | /* object usage count; object freed when use_count == 0 */ | |
143 | atomic_t use_count; | |
782e4179 | 144 | unsigned int del_state; /* deletion state */ |
3c7b4e6b CM |
145 | unsigned long pointer; |
146 | size_t size; | |
94f4a161 CM |
147 | /* pass surplus references to this pointer */ |
148 | unsigned long excess_ref; | |
3c7b4e6b CM |
149 | /* minimum number of a pointers found before it is considered leak */ |
150 | int min_count; | |
151 | /* the total number of pointers found pointing to this object */ | |
152 | int count; | |
04609ccc CM |
153 | /* checksum for detecting modified objects */ |
154 | u32 checksum; | |
b04da042 | 155 | depot_stack_handle_t trace_handle; |
3c7b4e6b CM |
156 | /* memory ranges to be scanned inside an object (empty for all) */ |
157 | struct hlist_head area_list; | |
3c7b4e6b CM |
158 | unsigned long jiffies; /* creation timestamp */ |
159 | pid_t pid; /* pid of the current task */ | |
160 | char comm[TASK_COMM_LEN]; /* executable name */ | |
161 | }; | |
162 | ||
163 | /* flag representing the memory block allocation status */ | |
164 | #define OBJECT_ALLOCATED (1 << 0) | |
165 | /* flag set after the first reporting of an unreference object */ | |
166 | #define OBJECT_REPORTED (1 << 1) | |
167 | /* flag set to not scan the object */ | |
168 | #define OBJECT_NO_SCAN (1 << 2) | |
dba82d94 CM |
169 | /* flag set to fully scan the object when scan_area allocation failed */ |
170 | #define OBJECT_FULL_SCAN (1 << 3) | |
8e0c4ab3 PW |
171 | /* flag set for object allocated with physical address */ |
172 | #define OBJECT_PHYS (1 << 4) | |
39042079 CM |
173 | /* flag set for per-CPU pointers */ |
174 | #define OBJECT_PERCPU (1 << 5) | |
3c7b4e6b | 175 | |
782e4179 WL |
176 | /* set when __remove_object() called */ |
177 | #define DELSTATE_REMOVED (1 << 0) | |
178 | /* set to temporarily prevent deletion from object_list */ | |
179 | #define DELSTATE_NO_DELETE (1 << 1) | |
180 | ||
154221c3 | 181 | #define HEX_PREFIX " " |
0494e082 SS |
182 | /* number of bytes to print per line; must be 16 or 32 */ |
183 | #define HEX_ROW_SIZE 16 | |
184 | /* number of bytes to print at a time (1, 2, 4, 8) */ | |
185 | #define HEX_GROUP_SIZE 1 | |
186 | /* include ASCII after the hex output */ | |
187 | #define HEX_ASCII 1 | |
188 | /* max number of lines to be printed */ | |
189 | #define HEX_MAX_LINES 2 | |
190 | ||
3c7b4e6b CM |
191 | /* the list of all allocated objects */ |
192 | static LIST_HEAD(object_list); | |
193 | /* the list of gray-colored objects (see color_gray comment below) */ | |
194 | static LIST_HEAD(gray_list); | |
0647398a | 195 | /* memory pool allocation */ |
c5665868 | 196 | static struct kmemleak_object mem_pool[CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE]; |
0647398a CM |
197 | static int mem_pool_free_count = ARRAY_SIZE(mem_pool); |
198 | static LIST_HEAD(mem_pool_free_list); | |
85d3a316 ML |
199 | /* search tree for object boundaries */ |
200 | static struct rb_root object_tree_root = RB_ROOT; | |
0c24e061 PW |
201 | /* search tree for object (with OBJECT_PHYS flag) boundaries */ |
202 | static struct rb_root object_phys_tree_root = RB_ROOT; | |
39042079 CM |
203 | /* search tree for object (with OBJECT_PERCPU flag) boundaries */ |
204 | static struct rb_root object_percpu_tree_root = RB_ROOT; | |
0c24e061 | 205 | /* protecting the access to object_list, object_tree_root (or object_phys_tree_root) */ |
8c96f1bc | 206 | static DEFINE_RAW_SPINLOCK(kmemleak_lock); |
3c7b4e6b CM |
207 | |
208 | /* allocation caches for kmemleak internal data */ | |
209 | static struct kmem_cache *object_cache; | |
210 | static struct kmem_cache *scan_area_cache; | |
211 | ||
212 | /* set if tracing memory operations is enabled */ | |
c5665868 | 213 | static int kmemleak_enabled = 1; |
c5f3b1a5 | 214 | /* same as above but only for the kmemleak_free() callback */ |
c5665868 | 215 | static int kmemleak_free_enabled = 1; |
3c7b4e6b | 216 | /* set in the late_initcall if there were no errors */ |
d160ef71 | 217 | static int kmemleak_late_initialized; |
5f79020c | 218 | /* set if a kmemleak warning was issued */ |
8910ae89 | 219 | static int kmemleak_warning; |
5f79020c | 220 | /* set if a fatal kmemleak error has occurred */ |
8910ae89 | 221 | static int kmemleak_error; |
3c7b4e6b CM |
222 | |
223 | /* minimum and maximum address that may be valid pointers */ | |
224 | static unsigned long min_addr = ULONG_MAX; | |
225 | static unsigned long max_addr; | |
226 | ||
3c7b4e6b | 227 | static struct task_struct *scan_thread; |
acf4968e | 228 | /* used to avoid reporting of recently allocated objects */ |
3c7b4e6b | 229 | static unsigned long jiffies_min_age; |
acf4968e | 230 | static unsigned long jiffies_last_scan; |
3c7b4e6b | 231 | /* delay between automatic memory scannings */ |
54dd200c | 232 | static unsigned long jiffies_scan_wait; |
3c7b4e6b | 233 | /* enables or disables the task stacks scanning */ |
e0a2a160 | 234 | static int kmemleak_stack_scan = 1; |
4698c1f2 | 235 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
3c7b4e6b | 236 | static DEFINE_MUTEX(scan_mutex); |
ab0155a2 JB |
237 | /* setting kmemleak=on, will set this var, skipping the disable */ |
238 | static int kmemleak_skip_disable; | |
dc9b3f42 LZ |
239 | /* If there are leaks that can be reported */ |
240 | static bool kmemleak_found_leaks; | |
3c7b4e6b | 241 | |
154221c3 VW |
242 | static bool kmemleak_verbose; |
243 | module_param_named(verbose, kmemleak_verbose, bool, 0600); | |
244 | ||
3c7b4e6b CM |
245 | static void kmemleak_disable(void); |
246 | ||
247 | /* | |
248 | * Print a warning and dump the stack trace. | |
249 | */ | |
5f79020c | 250 | #define kmemleak_warn(x...) do { \ |
598d8091 | 251 | pr_warn(x); \ |
5f79020c | 252 | dump_stack(); \ |
8910ae89 | 253 | kmemleak_warning = 1; \ |
3c7b4e6b CM |
254 | } while (0) |
255 | ||
256 | /* | |
25985edc | 257 | * Macro invoked when a serious kmemleak condition occurred and cannot be |
2030117d | 258 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
3c7b4e6b CM |
259 | * tracing no longer available. |
260 | */ | |
000814f4 | 261 | #define kmemleak_stop(x...) do { \ |
3c7b4e6b CM |
262 | kmemleak_warn(x); \ |
263 | kmemleak_disable(); \ | |
264 | } while (0) | |
265 | ||
154221c3 VW |
266 | #define warn_or_seq_printf(seq, fmt, ...) do { \ |
267 | if (seq) \ | |
268 | seq_printf(seq, fmt, ##__VA_ARGS__); \ | |
269 | else \ | |
270 | pr_warn(fmt, ##__VA_ARGS__); \ | |
271 | } while (0) | |
272 | ||
273 | static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type, | |
274 | int rowsize, int groupsize, const void *buf, | |
275 | size_t len, bool ascii) | |
276 | { | |
277 | if (seq) | |
278 | seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize, | |
279 | buf, len, ascii); | |
280 | else | |
281 | print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type, | |
282 | rowsize, groupsize, buf, len, ascii); | |
283 | } | |
284 | ||
0494e082 SS |
285 | /* |
286 | * Printing of the objects hex dump to the seq file. The number of lines to be | |
287 | * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The | |
288 | * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called | |
289 | * with the object->lock held. | |
290 | */ | |
291 | static void hex_dump_object(struct seq_file *seq, | |
292 | struct kmemleak_object *object) | |
293 | { | |
294 | const u8 *ptr = (const u8 *)object->pointer; | |
6fc37c49 | 295 | size_t len; |
0494e082 | 296 | |
39042079 | 297 | if (WARN_ON_ONCE(object->flags & (OBJECT_PHYS | OBJECT_PERCPU))) |
0c24e061 PW |
298 | return; |
299 | ||
0494e082 | 300 | /* limit the number of lines to HEX_MAX_LINES */ |
6fc37c49 | 301 | len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); |
0494e082 | 302 | |
154221c3 | 303 | warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len); |
5c335fe0 | 304 | kasan_disable_current(); |
154221c3 | 305 | warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE, |
6c7a00b8 | 306 | HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII); |
5c335fe0 | 307 | kasan_enable_current(); |
0494e082 SS |
308 | } |
309 | ||
3c7b4e6b CM |
310 | /* |
311 | * Object colors, encoded with count and min_count: | |
312 | * - white - orphan object, not enough references to it (count < min_count) | |
313 | * - gray - not orphan, not marked as false positive (min_count == 0) or | |
314 | * sufficient references to it (count >= min_count) | |
315 | * - black - ignore, it doesn't contain references (e.g. text section) | |
316 | * (min_count == -1). No function defined for this color. | |
317 | * Newly created objects don't have any color assigned (object->count == -1) | |
318 | * before the next memory scan when they become white. | |
319 | */ | |
4a558dd6 | 320 | static bool color_white(const struct kmemleak_object *object) |
3c7b4e6b | 321 | { |
a1084c87 LR |
322 | return object->count != KMEMLEAK_BLACK && |
323 | object->count < object->min_count; | |
3c7b4e6b CM |
324 | } |
325 | ||
4a558dd6 | 326 | static bool color_gray(const struct kmemleak_object *object) |
3c7b4e6b | 327 | { |
a1084c87 LR |
328 | return object->min_count != KMEMLEAK_BLACK && |
329 | object->count >= object->min_count; | |
3c7b4e6b CM |
330 | } |
331 | ||
3c7b4e6b CM |
332 | /* |
333 | * Objects are considered unreferenced only if their color is white, they have | |
334 | * not be deleted and have a minimum age to avoid false positives caused by | |
335 | * pointers temporarily stored in CPU registers. | |
336 | */ | |
4a558dd6 | 337 | static bool unreferenced_object(struct kmemleak_object *object) |
3c7b4e6b | 338 | { |
04609ccc | 339 | return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
acf4968e CM |
340 | time_before_eq(object->jiffies + jiffies_min_age, |
341 | jiffies_last_scan); | |
3c7b4e6b CM |
342 | } |
343 | ||
344 | /* | |
bab4a34a CM |
345 | * Printing of the unreferenced objects information to the seq file. The |
346 | * print_unreferenced function must be called with the object->lock held. | |
3c7b4e6b | 347 | */ |
3c7b4e6b CM |
348 | static void print_unreferenced(struct seq_file *seq, |
349 | struct kmemleak_object *object) | |
350 | { | |
351 | int i; | |
56a61617 ZH |
352 | unsigned long *entries; |
353 | unsigned int nr_entries; | |
3c7b4e6b | 354 | |
56a61617 | 355 | nr_entries = stack_depot_fetch(object->trace_handle, &entries); |
154221c3 | 356 | warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
56a61617 | 357 | object->pointer, object->size); |
88f9ee2b JC |
358 | warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", |
359 | object->comm, object->pid, object->jiffies); | |
0494e082 | 360 | hex_dump_object(seq, object); |
52c5d2bc | 361 | warn_or_seq_printf(seq, " backtrace (crc %x):\n", object->checksum); |
3c7b4e6b | 362 | |
56a61617 ZH |
363 | for (i = 0; i < nr_entries; i++) { |
364 | void *ptr = (void *)entries[i]; | |
3a6f33d8 | 365 | warn_or_seq_printf(seq, " [<%pK>] %pS\n", ptr, ptr); |
3c7b4e6b CM |
366 | } |
367 | } | |
368 | ||
369 | /* | |
370 | * Print the kmemleak_object information. This function is used mainly for | |
371 | * debugging special cases when kmemleak operations. It must be called with | |
372 | * the object->lock held. | |
373 | */ | |
374 | static void dump_object_info(struct kmemleak_object *object) | |
375 | { | |
ae281064 | 376 | pr_notice("Object 0x%08lx (size %zu):\n", |
56a61617 | 377 | object->pointer, object->size); |
3c7b4e6b | 378 | pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", |
56a61617 | 379 | object->comm, object->pid, object->jiffies); |
3c7b4e6b CM |
380 | pr_notice(" min_count = %d\n", object->min_count); |
381 | pr_notice(" count = %d\n", object->count); | |
f66abf09 | 382 | pr_notice(" flags = 0x%x\n", object->flags); |
aae0ad7a | 383 | pr_notice(" checksum = %u\n", object->checksum); |
3c7b4e6b | 384 | pr_notice(" backtrace:\n"); |
56a61617 ZH |
385 | if (object->trace_handle) |
386 | stack_depot_print(object->trace_handle); | |
3c7b4e6b CM |
387 | } |
388 | ||
39042079 CM |
389 | static struct rb_root *object_tree(unsigned long objflags) |
390 | { | |
391 | if (objflags & OBJECT_PHYS) | |
392 | return &object_phys_tree_root; | |
393 | if (objflags & OBJECT_PERCPU) | |
394 | return &object_percpu_tree_root; | |
395 | return &object_tree_root; | |
396 | } | |
397 | ||
3c7b4e6b | 398 | /* |
85d3a316 | 399 | * Look-up a memory block metadata (kmemleak_object) in the object search |
3c7b4e6b CM |
400 | * tree based on a pointer value. If alias is 0, only values pointing to the |
401 | * beginning of the memory block are allowed. The kmemleak_lock must be held | |
402 | * when calling this function. | |
403 | */ | |
0c24e061 | 404 | static struct kmemleak_object *__lookup_object(unsigned long ptr, int alias, |
39042079 | 405 | unsigned int objflags) |
3c7b4e6b | 406 | { |
39042079 | 407 | struct rb_node *rb = object_tree(objflags)->rb_node; |
ad1a3e15 | 408 | unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); |
85d3a316 ML |
409 | |
410 | while (rb) { | |
ad1a3e15 KYL |
411 | struct kmemleak_object *object; |
412 | unsigned long untagged_objp; | |
413 | ||
414 | object = rb_entry(rb, struct kmemleak_object, rb_node); | |
415 | untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); | |
416 | ||
417 | if (untagged_ptr < untagged_objp) | |
85d3a316 | 418 | rb = object->rb_node.rb_left; |
ad1a3e15 | 419 | else if (untagged_objp + object->size <= untagged_ptr) |
85d3a316 | 420 | rb = object->rb_node.rb_right; |
ad1a3e15 | 421 | else if (untagged_objp == untagged_ptr || alias) |
85d3a316 ML |
422 | return object; |
423 | else { | |
5f79020c CM |
424 | kmemleak_warn("Found object by alias at 0x%08lx\n", |
425 | ptr); | |
a7686a45 | 426 | dump_object_info(object); |
85d3a316 | 427 | break; |
3c7b4e6b | 428 | } |
85d3a316 ML |
429 | } |
430 | return NULL; | |
3c7b4e6b CM |
431 | } |
432 | ||
0c24e061 PW |
433 | /* Look-up a kmemleak object which allocated with virtual address. */ |
434 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) | |
435 | { | |
39042079 | 436 | return __lookup_object(ptr, alias, 0); |
0c24e061 PW |
437 | } |
438 | ||
3c7b4e6b CM |
439 | /* |
440 | * Increment the object use_count. Return 1 if successful or 0 otherwise. Note | |
441 | * that once an object's use_count reached 0, the RCU freeing was already | |
442 | * registered and the object should no longer be used. This function must be | |
443 | * called under the protection of rcu_read_lock(). | |
444 | */ | |
445 | static int get_object(struct kmemleak_object *object) | |
446 | { | |
447 | return atomic_inc_not_zero(&object->use_count); | |
448 | } | |
449 | ||
0647398a CM |
450 | /* |
451 | * Memory pool allocation and freeing. kmemleak_lock must not be held. | |
452 | */ | |
453 | static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) | |
454 | { | |
455 | unsigned long flags; | |
456 | struct kmemleak_object *object; | |
457 | ||
458 | /* try the slab allocator first */ | |
c5665868 | 459 | if (object_cache) { |
1c00f936 DC |
460 | object = kmem_cache_alloc_noprof(object_cache, |
461 | gfp_nested_mask(gfp)); | |
c5665868 CM |
462 | if (object) |
463 | return object; | |
464 | } | |
0647398a CM |
465 | |
466 | /* slab allocation failed, try the memory pool */ | |
8c96f1bc | 467 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
0647398a CM |
468 | object = list_first_entry_or_null(&mem_pool_free_list, |
469 | typeof(*object), object_list); | |
470 | if (object) | |
471 | list_del(&object->object_list); | |
472 | else if (mem_pool_free_count) | |
473 | object = &mem_pool[--mem_pool_free_count]; | |
c5665868 CM |
474 | else |
475 | pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n"); | |
8c96f1bc | 476 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
0647398a CM |
477 | |
478 | return object; | |
479 | } | |
480 | ||
481 | /* | |
482 | * Return the object to either the slab allocator or the memory pool. | |
483 | */ | |
484 | static void mem_pool_free(struct kmemleak_object *object) | |
485 | { | |
486 | unsigned long flags; | |
487 | ||
488 | if (object < mem_pool || object >= mem_pool + ARRAY_SIZE(mem_pool)) { | |
489 | kmem_cache_free(object_cache, object); | |
490 | return; | |
491 | } | |
492 | ||
493 | /* add the object to the memory pool free list */ | |
8c96f1bc | 494 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
0647398a | 495 | list_add(&object->object_list, &mem_pool_free_list); |
8c96f1bc | 496 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
0647398a CM |
497 | } |
498 | ||
3c7b4e6b CM |
499 | /* |
500 | * RCU callback to free a kmemleak_object. | |
501 | */ | |
502 | static void free_object_rcu(struct rcu_head *rcu) | |
503 | { | |
b67bfe0d | 504 | struct hlist_node *tmp; |
3c7b4e6b CM |
505 | struct kmemleak_scan_area *area; |
506 | struct kmemleak_object *object = | |
507 | container_of(rcu, struct kmemleak_object, rcu); | |
508 | ||
509 | /* | |
510 | * Once use_count is 0 (guaranteed by put_object), there is no other | |
511 | * code accessing this object, hence no need for locking. | |
512 | */ | |
b67bfe0d SL |
513 | hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { |
514 | hlist_del(&area->node); | |
3c7b4e6b CM |
515 | kmem_cache_free(scan_area_cache, area); |
516 | } | |
0647398a | 517 | mem_pool_free(object); |
3c7b4e6b CM |
518 | } |
519 | ||
520 | /* | |
521 | * Decrement the object use_count. Once the count is 0, free the object using | |
522 | * an RCU callback. Since put_object() may be called via the kmemleak_free() -> | |
523 | * delete_object() path, the delayed RCU freeing ensures that there is no | |
524 | * recursive call to the kernel allocator. Lock-less RCU object_list traversal | |
525 | * is also possible. | |
526 | */ | |
527 | static void put_object(struct kmemleak_object *object) | |
528 | { | |
529 | if (!atomic_dec_and_test(&object->use_count)) | |
530 | return; | |
531 | ||
532 | /* should only get here after delete_object was called */ | |
533 | WARN_ON(object->flags & OBJECT_ALLOCATED); | |
534 | ||
c5665868 CM |
535 | /* |
536 | * It may be too early for the RCU callbacks, however, there is no | |
537 | * concurrent object_list traversal when !object_cache and all objects | |
538 | * came from the memory pool. Free the object directly. | |
539 | */ | |
540 | if (object_cache) | |
541 | call_rcu(&object->rcu, free_object_rcu); | |
542 | else | |
543 | free_object_rcu(&object->rcu); | |
3c7b4e6b CM |
544 | } |
545 | ||
546 | /* | |
85d3a316 | 547 | * Look up an object in the object search tree and increase its use_count. |
3c7b4e6b | 548 | */ |
0c24e061 | 549 | static struct kmemleak_object *__find_and_get_object(unsigned long ptr, int alias, |
39042079 | 550 | unsigned int objflags) |
3c7b4e6b CM |
551 | { |
552 | unsigned long flags; | |
9fbed254 | 553 | struct kmemleak_object *object; |
3c7b4e6b CM |
554 | |
555 | rcu_read_lock(); | |
8c96f1bc | 556 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
39042079 | 557 | object = __lookup_object(ptr, alias, objflags); |
8c96f1bc | 558 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
3c7b4e6b CM |
559 | |
560 | /* check whether the object is still available */ | |
561 | if (object && !get_object(object)) | |
562 | object = NULL; | |
563 | rcu_read_unlock(); | |
564 | ||
565 | return object; | |
566 | } | |
567 | ||
0c24e061 PW |
568 | /* Look up and get an object which allocated with virtual address. */ |
569 | static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) | |
570 | { | |
39042079 | 571 | return __find_and_get_object(ptr, alias, 0); |
0c24e061 PW |
572 | } |
573 | ||
2abd839a | 574 | /* |
39042079 CM |
575 | * Remove an object from its object tree and object_list. Must be called with |
576 | * the kmemleak_lock held _if_ kmemleak is still enabled. | |
2abd839a CM |
577 | */ |
578 | static void __remove_object(struct kmemleak_object *object) | |
579 | { | |
39042079 | 580 | rb_erase(&object->rb_node, object_tree(object->flags)); |
782e4179 WL |
581 | if (!(object->del_state & DELSTATE_NO_DELETE)) |
582 | list_del_rcu(&object->object_list); | |
583 | object->del_state |= DELSTATE_REMOVED; | |
2abd839a CM |
584 | } |
585 | ||
858a195b LS |
586 | static struct kmemleak_object *__find_and_remove_object(unsigned long ptr, |
587 | int alias, | |
39042079 | 588 | unsigned int objflags) |
858a195b LS |
589 | { |
590 | struct kmemleak_object *object; | |
591 | ||
39042079 | 592 | object = __lookup_object(ptr, alias, objflags); |
858a195b LS |
593 | if (object) |
594 | __remove_object(object); | |
595 | ||
596 | return object; | |
597 | } | |
598 | ||
e781a9ab | 599 | /* |
39042079 CM |
600 | * Look up an object in the object search tree and remove it from both object |
601 | * tree root and object_list. The returned object's use_count should be at | |
602 | * least 1, as initially set by create_object(). | |
e781a9ab | 603 | */ |
0c24e061 | 604 | static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias, |
39042079 | 605 | unsigned int objflags) |
e781a9ab CM |
606 | { |
607 | unsigned long flags; | |
608 | struct kmemleak_object *object; | |
609 | ||
8c96f1bc | 610 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
39042079 | 611 | object = __find_and_remove_object(ptr, alias, objflags); |
8c96f1bc | 612 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
e781a9ab CM |
613 | |
614 | return object; | |
615 | } | |
616 | ||
56a61617 | 617 | static noinline depot_stack_handle_t set_track_prepare(void) |
fd678967 | 618 | { |
56a61617 ZH |
619 | depot_stack_handle_t trace_handle; |
620 | unsigned long entries[MAX_TRACE]; | |
621 | unsigned int nr_entries; | |
622 | ||
835bc157 XW |
623 | /* |
624 | * Use object_cache to determine whether kmemleak_init() has | |
625 | * been invoked. stack_depot_early_init() is called before | |
626 | * kmemleak_init() in mm_core_init(). | |
627 | */ | |
628 | if (!object_cache) | |
56a61617 ZH |
629 | return 0; |
630 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); | |
631 | trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); | |
632 | ||
633 | return trace_handle; | |
fd678967 CM |
634 | } |
635 | ||
0edd7b58 | 636 | static struct kmemleak_object *__alloc_object(gfp_t gfp) |
3c7b4e6b | 637 | { |
0edd7b58 | 638 | struct kmemleak_object *object; |
3c7b4e6b | 639 | |
0647398a | 640 | object = mem_pool_alloc(gfp); |
3c7b4e6b | 641 | if (!object) { |
598d8091 | 642 | pr_warn("Cannot allocate a kmemleak_object structure\n"); |
6ae4bd1f | 643 | kmemleak_disable(); |
4eff7d62 | 644 | return NULL; |
3c7b4e6b CM |
645 | } |
646 | ||
647 | INIT_LIST_HEAD(&object->object_list); | |
648 | INIT_LIST_HEAD(&object->gray_list); | |
649 | INIT_HLIST_HEAD(&object->area_list); | |
8c96f1bc | 650 | raw_spin_lock_init(&object->lock); |
3c7b4e6b | 651 | atomic_set(&object->use_count, 1); |
94f4a161 | 652 | object->excess_ref = 0; |
04609ccc | 653 | object->count = 0; /* white color initially */ |
04609ccc | 654 | object->checksum = 0; |
782e4179 | 655 | object->del_state = 0; |
3c7b4e6b CM |
656 | |
657 | /* task information */ | |
ea0eafea | 658 | if (in_hardirq()) { |
3c7b4e6b CM |
659 | object->pid = 0; |
660 | strncpy(object->comm, "hardirq", sizeof(object->comm)); | |
6ef90569 | 661 | } else if (in_serving_softirq()) { |
3c7b4e6b CM |
662 | object->pid = 0; |
663 | strncpy(object->comm, "softirq", sizeof(object->comm)); | |
664 | } else { | |
665 | object->pid = current->pid; | |
666 | /* | |
667 | * There is a small chance of a race with set_task_comm(), | |
668 | * however using get_task_comm() here may cause locking | |
669 | * dependency issues with current->alloc_lock. In the worst | |
670 | * case, the command line is not correct. | |
671 | */ | |
672 | strncpy(object->comm, current->comm, sizeof(object->comm)); | |
673 | } | |
674 | ||
675 | /* kernel backtrace */ | |
56a61617 | 676 | object->trace_handle = set_track_prepare(); |
3c7b4e6b | 677 | |
4eff7d62 LS |
678 | return object; |
679 | } | |
680 | ||
681 | static int __link_object(struct kmemleak_object *object, unsigned long ptr, | |
39042079 | 682 | size_t size, int min_count, unsigned int objflags) |
4eff7d62 LS |
683 | { |
684 | ||
685 | struct kmemleak_object *parent; | |
686 | struct rb_node **link, *rb_parent; | |
687 | unsigned long untagged_ptr; | |
688 | unsigned long untagged_objp; | |
689 | ||
39042079 | 690 | object->flags = OBJECT_ALLOCATED | objflags; |
4eff7d62 LS |
691 | object->pointer = ptr; |
692 | object->size = kfence_ksize((void *)ptr) ?: size; | |
693 | object->min_count = min_count; | |
694 | object->jiffies = jiffies; | |
695 | ||
a2f77575 | 696 | untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); |
0c24e061 PW |
697 | /* |
698 | * Only update min_addr and max_addr with object | |
699 | * storing virtual address. | |
700 | */ | |
39042079 | 701 | if (!(objflags & (OBJECT_PHYS | OBJECT_PERCPU))) { |
0c24e061 PW |
702 | min_addr = min(min_addr, untagged_ptr); |
703 | max_addr = max(max_addr, untagged_ptr + size); | |
704 | } | |
39042079 | 705 | link = &object_tree(objflags)->rb_node; |
85d3a316 ML |
706 | rb_parent = NULL; |
707 | while (*link) { | |
708 | rb_parent = *link; | |
709 | parent = rb_entry(rb_parent, struct kmemleak_object, rb_node); | |
ad1a3e15 KYL |
710 | untagged_objp = (unsigned long)kasan_reset_tag((void *)parent->pointer); |
711 | if (untagged_ptr + size <= untagged_objp) | |
85d3a316 | 712 | link = &parent->rb_node.rb_left; |
ad1a3e15 | 713 | else if (untagged_objp + parent->size <= untagged_ptr) |
85d3a316 ML |
714 | link = &parent->rb_node.rb_right; |
715 | else { | |
756a025f | 716 | kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n", |
85d3a316 | 717 | ptr); |
9d5a4c73 CM |
718 | /* |
719 | * No need for parent->lock here since "parent" cannot | |
720 | * be freed while the kmemleak_lock is held. | |
721 | */ | |
722 | dump_object_info(parent); | |
2e1d4738 | 723 | return -EEXIST; |
85d3a316 | 724 | } |
3c7b4e6b | 725 | } |
85d3a316 | 726 | rb_link_node(&object->rb_node, rb_parent, link); |
39042079 | 727 | rb_insert_color(&object->rb_node, object_tree(objflags)); |
3c7b4e6b | 728 | list_add_tail_rcu(&object->object_list, &object_list); |
2e1d4738 LS |
729 | |
730 | return 0; | |
0edd7b58 LS |
731 | } |
732 | ||
733 | /* | |
734 | * Create the metadata (struct kmemleak_object) corresponding to an allocated | |
39042079 | 735 | * memory block and add it to the object_list and object tree. |
0edd7b58 LS |
736 | */ |
737 | static void __create_object(unsigned long ptr, size_t size, | |
39042079 | 738 | int min_count, gfp_t gfp, unsigned int objflags) |
0edd7b58 LS |
739 | { |
740 | struct kmemleak_object *object; | |
741 | unsigned long flags; | |
2e1d4738 | 742 | int ret; |
0edd7b58 LS |
743 | |
744 | object = __alloc_object(gfp); | |
745 | if (!object) | |
746 | return; | |
747 | ||
748 | raw_spin_lock_irqsave(&kmemleak_lock, flags); | |
39042079 | 749 | ret = __link_object(object, ptr, size, min_count, objflags); |
8c96f1bc | 750 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
2e1d4738 LS |
751 | if (ret) |
752 | mem_pool_free(object); | |
3c7b4e6b CM |
753 | } |
754 | ||
8e0c4ab3 | 755 | /* Create kmemleak object which allocated with virtual address. */ |
b955aa70 LS |
756 | static void create_object(unsigned long ptr, size_t size, |
757 | int min_count, gfp_t gfp) | |
8e0c4ab3 | 758 | { |
39042079 | 759 | __create_object(ptr, size, min_count, gfp, 0); |
8e0c4ab3 PW |
760 | } |
761 | ||
762 | /* Create kmemleak object which allocated with physical address. */ | |
b955aa70 LS |
763 | static void create_object_phys(unsigned long ptr, size_t size, |
764 | int min_count, gfp_t gfp) | |
8e0c4ab3 | 765 | { |
39042079 CM |
766 | __create_object(ptr, size, min_count, gfp, OBJECT_PHYS); |
767 | } | |
768 | ||
769 | /* Create kmemleak object corresponding to a per-CPU allocation. */ | |
770 | static void create_object_percpu(unsigned long ptr, size_t size, | |
771 | int min_count, gfp_t gfp) | |
772 | { | |
773 | __create_object(ptr, size, min_count, gfp, OBJECT_PERCPU); | |
8e0c4ab3 PW |
774 | } |
775 | ||
3c7b4e6b | 776 | /* |
e781a9ab | 777 | * Mark the object as not allocated and schedule RCU freeing via put_object(). |
3c7b4e6b | 778 | */ |
53238a60 | 779 | static void __delete_object(struct kmemleak_object *object) |
3c7b4e6b CM |
780 | { |
781 | unsigned long flags; | |
3c7b4e6b | 782 | |
3c7b4e6b | 783 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
e781a9ab | 784 | WARN_ON(atomic_read(&object->use_count) < 1); |
3c7b4e6b CM |
785 | |
786 | /* | |
787 | * Locking here also ensures that the corresponding memory block | |
788 | * cannot be freed when it is being scanned. | |
789 | */ | |
8c96f1bc | 790 | raw_spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b | 791 | object->flags &= ~OBJECT_ALLOCATED; |
8c96f1bc | 792 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
793 | put_object(object); |
794 | } | |
795 | ||
53238a60 CM |
796 | /* |
797 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
798 | * delete it. | |
799 | */ | |
39042079 | 800 | static void delete_object_full(unsigned long ptr, unsigned int objflags) |
53238a60 CM |
801 | { |
802 | struct kmemleak_object *object; | |
803 | ||
39042079 | 804 | object = find_and_remove_object(ptr, 0, objflags); |
53238a60 CM |
805 | if (!object) { |
806 | #ifdef DEBUG | |
807 | kmemleak_warn("Freeing unknown object at 0x%08lx\n", | |
808 | ptr); | |
809 | #endif | |
810 | return; | |
811 | } | |
812 | __delete_object(object); | |
53238a60 CM |
813 | } |
814 | ||
815 | /* | |
816 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
817 | * delete it. If the memory block is partially freed, the function may create | |
818 | * additional metadata for the remaining parts of the block. | |
819 | */ | |
39042079 CM |
820 | static void delete_object_part(unsigned long ptr, size_t size, |
821 | unsigned int objflags) | |
53238a60 | 822 | { |
5e4fc577 LS |
823 | struct kmemleak_object *object, *object_l, *object_r; |
824 | unsigned long start, end, flags; | |
825 | ||
826 | object_l = __alloc_object(GFP_KERNEL); | |
827 | if (!object_l) | |
828 | return; | |
53238a60 | 829 | |
5e4fc577 LS |
830 | object_r = __alloc_object(GFP_KERNEL); |
831 | if (!object_r) | |
832 | goto out; | |
833 | ||
834 | raw_spin_lock_irqsave(&kmemleak_lock, flags); | |
39042079 | 835 | object = __find_and_remove_object(ptr, 1, objflags); |
53238a60 CM |
836 | if (!object) { |
837 | #ifdef DEBUG | |
756a025f JP |
838 | kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", |
839 | ptr, size); | |
53238a60 | 840 | #endif |
5e4fc577 | 841 | goto unlock; |
53238a60 | 842 | } |
53238a60 CM |
843 | |
844 | /* | |
845 | * Create one or two objects that may result from the memory block | |
846 | * split. Note that partial freeing is only done by free_bootmem() and | |
c5665868 | 847 | * this happens before kmemleak_init() is called. |
53238a60 CM |
848 | */ |
849 | start = object->pointer; | |
850 | end = object->pointer + object->size; | |
5e4fc577 LS |
851 | if ((ptr > start) && |
852 | !__link_object(object_l, start, ptr - start, | |
39042079 | 853 | object->min_count, objflags)) |
5e4fc577 LS |
854 | object_l = NULL; |
855 | if ((ptr + size < end) && | |
856 | !__link_object(object_r, ptr + size, end - ptr - size, | |
39042079 | 857 | object->min_count, objflags)) |
5e4fc577 LS |
858 | object_r = NULL; |
859 | ||
860 | unlock: | |
861 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); | |
862 | if (object) | |
863 | __delete_object(object); | |
53238a60 | 864 | |
5e4fc577 LS |
865 | out: |
866 | if (object_l) | |
867 | mem_pool_free(object_l); | |
868 | if (object_r) | |
869 | mem_pool_free(object_r); | |
53238a60 | 870 | } |
a1084c87 LR |
871 | |
872 | static void __paint_it(struct kmemleak_object *object, int color) | |
873 | { | |
874 | object->min_count = color; | |
875 | if (color == KMEMLEAK_BLACK) | |
876 | object->flags |= OBJECT_NO_SCAN; | |
877 | } | |
878 | ||
879 | static void paint_it(struct kmemleak_object *object, int color) | |
3c7b4e6b CM |
880 | { |
881 | unsigned long flags; | |
a1084c87 | 882 | |
8c96f1bc | 883 | raw_spin_lock_irqsave(&object->lock, flags); |
a1084c87 | 884 | __paint_it(object, color); |
8c96f1bc | 885 | raw_spin_unlock_irqrestore(&object->lock, flags); |
a1084c87 LR |
886 | } |
887 | ||
39042079 | 888 | static void paint_ptr(unsigned long ptr, int color, unsigned int objflags) |
a1084c87 | 889 | { |
3c7b4e6b CM |
890 | struct kmemleak_object *object; |
891 | ||
39042079 | 892 | object = __find_and_get_object(ptr, 0, objflags); |
3c7b4e6b | 893 | if (!object) { |
756a025f JP |
894 | kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n", |
895 | ptr, | |
a1084c87 LR |
896 | (color == KMEMLEAK_GREY) ? "Grey" : |
897 | (color == KMEMLEAK_BLACK) ? "Black" : "Unknown"); | |
3c7b4e6b CM |
898 | return; |
899 | } | |
a1084c87 | 900 | paint_it(object, color); |
3c7b4e6b CM |
901 | put_object(object); |
902 | } | |
903 | ||
a1084c87 | 904 | /* |
145b64b9 | 905 | * Mark an object permanently as gray-colored so that it can no longer be |
a1084c87 LR |
906 | * reported as a leak. This is used in general to mark a false positive. |
907 | */ | |
908 | static void make_gray_object(unsigned long ptr) | |
909 | { | |
39042079 | 910 | paint_ptr(ptr, KMEMLEAK_GREY, 0); |
a1084c87 LR |
911 | } |
912 | ||
3c7b4e6b CM |
913 | /* |
914 | * Mark the object as black-colored so that it is ignored from scans and | |
915 | * reporting. | |
916 | */ | |
39042079 | 917 | static void make_black_object(unsigned long ptr, unsigned int objflags) |
3c7b4e6b | 918 | { |
39042079 | 919 | paint_ptr(ptr, KMEMLEAK_BLACK, objflags); |
3c7b4e6b CM |
920 | } |
921 | ||
922 | /* | |
923 | * Add a scanning area to the object. If at least one such area is added, | |
924 | * kmemleak will only scan these ranges rather than the whole memory block. | |
925 | */ | |
c017b4be | 926 | static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
927 | { |
928 | unsigned long flags; | |
929 | struct kmemleak_object *object; | |
c5665868 | 930 | struct kmemleak_scan_area *area = NULL; |
bfc8089f KYL |
931 | unsigned long untagged_ptr; |
932 | unsigned long untagged_objp; | |
3c7b4e6b | 933 | |
c017b4be | 934 | object = find_and_get_object(ptr, 1); |
3c7b4e6b | 935 | if (!object) { |
ae281064 JP |
936 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
937 | ptr); | |
3c7b4e6b CM |
938 | return; |
939 | } | |
940 | ||
bfc8089f KYL |
941 | untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); |
942 | untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); | |
943 | ||
c5665868 | 944 | if (scan_area_cache) |
1c00f936 DC |
945 | area = kmem_cache_alloc_noprof(scan_area_cache, |
946 | gfp_nested_mask(gfp)); | |
3c7b4e6b | 947 | |
8c96f1bc | 948 | raw_spin_lock_irqsave(&object->lock, flags); |
dba82d94 CM |
949 | if (!area) { |
950 | pr_warn_once("Cannot allocate a scan area, scanning the full object\n"); | |
951 | /* mark the object for full scan to avoid false positives */ | |
952 | object->flags |= OBJECT_FULL_SCAN; | |
953 | goto out_unlock; | |
954 | } | |
7f88f88f | 955 | if (size == SIZE_MAX) { |
bfc8089f KYL |
956 | size = untagged_objp + object->size - untagged_ptr; |
957 | } else if (untagged_ptr + size > untagged_objp + object->size) { | |
ae281064 | 958 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
3c7b4e6b CM |
959 | dump_object_info(object); |
960 | kmem_cache_free(scan_area_cache, area); | |
961 | goto out_unlock; | |
962 | } | |
963 | ||
964 | INIT_HLIST_NODE(&area->node); | |
c017b4be CM |
965 | area->start = ptr; |
966 | area->size = size; | |
3c7b4e6b CM |
967 | |
968 | hlist_add_head(&area->node, &object->area_list); | |
969 | out_unlock: | |
8c96f1bc | 970 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
971 | put_object(object); |
972 | } | |
973 | ||
94f4a161 CM |
974 | /* |
975 | * Any surplus references (object already gray) to 'ptr' are passed to | |
976 | * 'excess_ref'. This is used in the vmalloc() case where a pointer to | |
977 | * vm_struct may be used as an alternative reference to the vmalloc'ed object | |
978 | * (see free_thread_stack()). | |
979 | */ | |
980 | static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref) | |
981 | { | |
982 | unsigned long flags; | |
983 | struct kmemleak_object *object; | |
984 | ||
985 | object = find_and_get_object(ptr, 0); | |
986 | if (!object) { | |
987 | kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n", | |
988 | ptr); | |
989 | return; | |
990 | } | |
991 | ||
8c96f1bc | 992 | raw_spin_lock_irqsave(&object->lock, flags); |
94f4a161 | 993 | object->excess_ref = excess_ref; |
8c96f1bc | 994 | raw_spin_unlock_irqrestore(&object->lock, flags); |
94f4a161 CM |
995 | put_object(object); |
996 | } | |
997 | ||
3c7b4e6b CM |
998 | /* |
999 | * Set the OBJECT_NO_SCAN flag for the object corresponding to the give | |
1000 | * pointer. Such object will not be scanned by kmemleak but references to it | |
1001 | * are searched. | |
1002 | */ | |
1003 | static void object_no_scan(unsigned long ptr) | |
1004 | { | |
1005 | unsigned long flags; | |
1006 | struct kmemleak_object *object; | |
1007 | ||
1008 | object = find_and_get_object(ptr, 0); | |
1009 | if (!object) { | |
ae281064 | 1010 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
3c7b4e6b CM |
1011 | return; |
1012 | } | |
1013 | ||
8c96f1bc | 1014 | raw_spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b | 1015 | object->flags |= OBJECT_NO_SCAN; |
8c96f1bc | 1016 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
1017 | put_object(object); |
1018 | } | |
1019 | ||
a2b6bf63 CM |
1020 | /** |
1021 | * kmemleak_alloc - register a newly allocated object | |
1022 | * @ptr: pointer to beginning of the object | |
1023 | * @size: size of the object | |
1024 | * @min_count: minimum number of references to this object. If during memory | |
1025 | * scanning a number of references less than @min_count is found, | |
1026 | * the object is reported as a memory leak. If @min_count is 0, | |
1027 | * the object is never reported as a leak. If @min_count is -1, | |
1028 | * the object is ignored (not scanned and not reported as a leak) | |
1029 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1030 | * | |
1031 | * This function is called from the kernel allocators when a new object | |
94f4a161 | 1032 | * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.). |
3c7b4e6b | 1033 | */ |
a6186d89 CM |
1034 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
1035 | gfp_t gfp) | |
3c7b4e6b | 1036 | { |
62047e0f | 1037 | pr_debug("%s(0x%px, %zu, %d)\n", __func__, ptr, size, min_count); |
3c7b4e6b | 1038 | |
8910ae89 | 1039 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1040 | create_object((unsigned long)ptr, size, min_count, gfp); |
3c7b4e6b CM |
1041 | } |
1042 | EXPORT_SYMBOL_GPL(kmemleak_alloc); | |
1043 | ||
f528f0b8 CM |
1044 | /** |
1045 | * kmemleak_alloc_percpu - register a newly allocated __percpu object | |
1046 | * @ptr: __percpu pointer to beginning of the object | |
1047 | * @size: size of the object | |
8a8c35fa | 1048 | * @gfp: flags used for kmemleak internal memory allocations |
f528f0b8 CM |
1049 | * |
1050 | * This function is called from the kernel percpu allocator when a new object | |
8a8c35fa | 1051 | * (memory block) is allocated (alloc_percpu). |
f528f0b8 | 1052 | */ |
8a8c35fa LF |
1053 | void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, |
1054 | gfp_t gfp) | |
f528f0b8 | 1055 | { |
62047e0f | 1056 | pr_debug("%s(0x%px, %zu)\n", __func__, ptr, size); |
f528f0b8 CM |
1057 | |
1058 | /* | |
1059 | * Percpu allocations are only scanned and not reported as leaks | |
1060 | * (min_count is set to 0). | |
1061 | */ | |
8910ae89 | 1062 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
39042079 | 1063 | create_object_percpu((unsigned long)ptr, size, 0, gfp); |
f528f0b8 CM |
1064 | } |
1065 | EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); | |
1066 | ||
94f4a161 CM |
1067 | /** |
1068 | * kmemleak_vmalloc - register a newly vmalloc'ed object | |
1069 | * @area: pointer to vm_struct | |
1070 | * @size: size of the object | |
1071 | * @gfp: __vmalloc() flags used for kmemleak internal memory allocations | |
1072 | * | |
1073 | * This function is called from the vmalloc() kernel allocator when a new | |
1074 | * object (memory block) is allocated. | |
1075 | */ | |
1076 | void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp) | |
1077 | { | |
62047e0f | 1078 | pr_debug("%s(0x%px, %zu)\n", __func__, area, size); |
94f4a161 CM |
1079 | |
1080 | /* | |
1081 | * A min_count = 2 is needed because vm_struct contains a reference to | |
1082 | * the virtual address of the vmalloc'ed block. | |
1083 | */ | |
1084 | if (kmemleak_enabled) { | |
1085 | create_object((unsigned long)area->addr, size, 2, gfp); | |
1086 | object_set_excess_ref((unsigned long)area, | |
1087 | (unsigned long)area->addr); | |
94f4a161 CM |
1088 | } |
1089 | } | |
1090 | EXPORT_SYMBOL_GPL(kmemleak_vmalloc); | |
1091 | ||
a2b6bf63 CM |
1092 | /** |
1093 | * kmemleak_free - unregister a previously registered object | |
1094 | * @ptr: pointer to beginning of the object | |
1095 | * | |
1096 | * This function is called from the kernel allocators when an object (memory | |
1097 | * block) is freed (kmem_cache_free, kfree, vfree etc.). | |
3c7b4e6b | 1098 | */ |
a6186d89 | 1099 | void __ref kmemleak_free(const void *ptr) |
3c7b4e6b | 1100 | { |
62047e0f | 1101 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1102 | |
c5f3b1a5 | 1103 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
39042079 | 1104 | delete_object_full((unsigned long)ptr, 0); |
3c7b4e6b CM |
1105 | } |
1106 | EXPORT_SYMBOL_GPL(kmemleak_free); | |
1107 | ||
a2b6bf63 CM |
1108 | /** |
1109 | * kmemleak_free_part - partially unregister a previously registered object | |
1110 | * @ptr: pointer to the beginning or inside the object. This also | |
1111 | * represents the start of the range to be freed | |
1112 | * @size: size to be unregistered | |
1113 | * | |
1114 | * This function is called when only a part of a memory block is freed | |
1115 | * (usually from the bootmem allocator). | |
53238a60 | 1116 | */ |
a6186d89 | 1117 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
53238a60 | 1118 | { |
62047e0f | 1119 | pr_debug("%s(0x%px)\n", __func__, ptr); |
53238a60 | 1120 | |
8910ae89 | 1121 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
39042079 | 1122 | delete_object_part((unsigned long)ptr, size, 0); |
53238a60 CM |
1123 | } |
1124 | EXPORT_SYMBOL_GPL(kmemleak_free_part); | |
1125 | ||
f528f0b8 CM |
1126 | /** |
1127 | * kmemleak_free_percpu - unregister a previously registered __percpu object | |
1128 | * @ptr: __percpu pointer to beginning of the object | |
1129 | * | |
1130 | * This function is called from the kernel percpu allocator when an object | |
1131 | * (memory block) is freed (free_percpu). | |
1132 | */ | |
1133 | void __ref kmemleak_free_percpu(const void __percpu *ptr) | |
1134 | { | |
62047e0f | 1135 | pr_debug("%s(0x%px)\n", __func__, ptr); |
f528f0b8 | 1136 | |
c5f3b1a5 | 1137 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
39042079 | 1138 | delete_object_full((unsigned long)ptr, OBJECT_PERCPU); |
f528f0b8 CM |
1139 | } |
1140 | EXPORT_SYMBOL_GPL(kmemleak_free_percpu); | |
1141 | ||
ffe2c748 CM |
1142 | /** |
1143 | * kmemleak_update_trace - update object allocation stack trace | |
1144 | * @ptr: pointer to beginning of the object | |
1145 | * | |
1146 | * Override the object allocation stack trace for cases where the actual | |
1147 | * allocation place is not always useful. | |
1148 | */ | |
1149 | void __ref kmemleak_update_trace(const void *ptr) | |
1150 | { | |
1151 | struct kmemleak_object *object; | |
d63385a7 | 1152 | depot_stack_handle_t trace_handle; |
ffe2c748 CM |
1153 | unsigned long flags; |
1154 | ||
62047e0f | 1155 | pr_debug("%s(0x%px)\n", __func__, ptr); |
ffe2c748 CM |
1156 | |
1157 | if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr)) | |
1158 | return; | |
1159 | ||
1160 | object = find_and_get_object((unsigned long)ptr, 1); | |
1161 | if (!object) { | |
1162 | #ifdef DEBUG | |
1163 | kmemleak_warn("Updating stack trace for unknown object at %p\n", | |
1164 | ptr); | |
1165 | #endif | |
1166 | return; | |
1167 | } | |
1168 | ||
d63385a7 | 1169 | trace_handle = set_track_prepare(); |
8c96f1bc | 1170 | raw_spin_lock_irqsave(&object->lock, flags); |
d63385a7 | 1171 | object->trace_handle = trace_handle; |
8c96f1bc | 1172 | raw_spin_unlock_irqrestore(&object->lock, flags); |
ffe2c748 CM |
1173 | |
1174 | put_object(object); | |
1175 | } | |
1176 | EXPORT_SYMBOL(kmemleak_update_trace); | |
1177 | ||
a2b6bf63 CM |
1178 | /** |
1179 | * kmemleak_not_leak - mark an allocated object as false positive | |
1180 | * @ptr: pointer to beginning of the object | |
1181 | * | |
1182 | * Calling this function on an object will cause the memory block to no longer | |
1183 | * be reported as leak and always be scanned. | |
3c7b4e6b | 1184 | */ |
a6186d89 | 1185 | void __ref kmemleak_not_leak(const void *ptr) |
3c7b4e6b | 1186 | { |
62047e0f | 1187 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1188 | |
8910ae89 | 1189 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1190 | make_gray_object((unsigned long)ptr); |
3c7b4e6b CM |
1191 | } |
1192 | EXPORT_SYMBOL(kmemleak_not_leak); | |
1193 | ||
a2b6bf63 CM |
1194 | /** |
1195 | * kmemleak_ignore - ignore an allocated object | |
1196 | * @ptr: pointer to beginning of the object | |
1197 | * | |
1198 | * Calling this function on an object will cause the memory block to be | |
1199 | * ignored (not scanned and not reported as a leak). This is usually done when | |
1200 | * it is known that the corresponding block is not a leak and does not contain | |
1201 | * any references to other allocated memory blocks. | |
3c7b4e6b | 1202 | */ |
a6186d89 | 1203 | void __ref kmemleak_ignore(const void *ptr) |
3c7b4e6b | 1204 | { |
62047e0f | 1205 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1206 | |
8910ae89 | 1207 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
39042079 | 1208 | make_black_object((unsigned long)ptr, 0); |
3c7b4e6b CM |
1209 | } |
1210 | EXPORT_SYMBOL(kmemleak_ignore); | |
1211 | ||
a2b6bf63 CM |
1212 | /** |
1213 | * kmemleak_scan_area - limit the range to be scanned in an allocated object | |
1214 | * @ptr: pointer to beginning or inside the object. This also | |
1215 | * represents the start of the scan area | |
1216 | * @size: size of the scan area | |
1217 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1218 | * | |
1219 | * This function is used when it is known that only certain parts of an object | |
1220 | * contain references to other objects. Kmemleak will only scan these areas | |
1221 | * reducing the number false negatives. | |
3c7b4e6b | 1222 | */ |
c017b4be | 1223 | void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
3c7b4e6b | 1224 | { |
62047e0f | 1225 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1226 | |
8910ae89 | 1227 | if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
c017b4be | 1228 | add_scan_area((unsigned long)ptr, size, gfp); |
3c7b4e6b CM |
1229 | } |
1230 | EXPORT_SYMBOL(kmemleak_scan_area); | |
1231 | ||
a2b6bf63 CM |
1232 | /** |
1233 | * kmemleak_no_scan - do not scan an allocated object | |
1234 | * @ptr: pointer to beginning of the object | |
1235 | * | |
1236 | * This function notifies kmemleak not to scan the given memory block. Useful | |
1237 | * in situations where it is known that the given object does not contain any | |
1238 | * references to other objects. Kmemleak will not scan such objects reducing | |
1239 | * the number of false negatives. | |
3c7b4e6b | 1240 | */ |
a6186d89 | 1241 | void __ref kmemleak_no_scan(const void *ptr) |
3c7b4e6b | 1242 | { |
62047e0f | 1243 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1244 | |
8910ae89 | 1245 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1246 | object_no_scan((unsigned long)ptr); |
3c7b4e6b CM |
1247 | } |
1248 | EXPORT_SYMBOL(kmemleak_no_scan); | |
1249 | ||
9099daed CM |
1250 | /** |
1251 | * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical | |
1252 | * address argument | |
e8b098fc MR |
1253 | * @phys: physical address of the object |
1254 | * @size: size of the object | |
e8b098fc | 1255 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations |
9099daed | 1256 | */ |
c200d900 | 1257 | void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp) |
9099daed | 1258 | { |
62047e0f | 1259 | pr_debug("%s(0x%px, %zu)\n", __func__, &phys, size); |
8e0c4ab3 | 1260 | |
84c32629 | 1261 | if (kmemleak_enabled) |
8e0c4ab3 PW |
1262 | /* |
1263 | * Create object with OBJECT_PHYS flag and | |
1264 | * assume min_count 0. | |
1265 | */ | |
0c24e061 | 1266 | create_object_phys((unsigned long)phys, size, 0, gfp); |
9099daed CM |
1267 | } |
1268 | EXPORT_SYMBOL(kmemleak_alloc_phys); | |
1269 | ||
1270 | /** | |
1271 | * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a | |
1272 | * physical address argument | |
e8b098fc MR |
1273 | * @phys: physical address if the beginning or inside an object. This |
1274 | * also represents the start of the range to be freed | |
1275 | * @size: size to be unregistered | |
9099daed CM |
1276 | */ |
1277 | void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size) | |
1278 | { | |
62047e0f | 1279 | pr_debug("%s(0x%px)\n", __func__, &phys); |
0c24e061 | 1280 | |
84c32629 | 1281 | if (kmemleak_enabled) |
39042079 | 1282 | delete_object_part((unsigned long)phys, size, OBJECT_PHYS); |
9099daed CM |
1283 | } |
1284 | EXPORT_SYMBOL(kmemleak_free_part_phys); | |
1285 | ||
9099daed CM |
1286 | /** |
1287 | * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical | |
1288 | * address argument | |
e8b098fc | 1289 | * @phys: physical address of the object |
9099daed CM |
1290 | */ |
1291 | void __ref kmemleak_ignore_phys(phys_addr_t phys) | |
1292 | { | |
62047e0f | 1293 | pr_debug("%s(0x%px)\n", __func__, &phys); |
0c24e061 | 1294 | |
84c32629 | 1295 | if (kmemleak_enabled) |
39042079 | 1296 | make_black_object((unsigned long)phys, OBJECT_PHYS); |
9099daed CM |
1297 | } |
1298 | EXPORT_SYMBOL(kmemleak_ignore_phys); | |
1299 | ||
04609ccc CM |
1300 | /* |
1301 | * Update an object's checksum and return true if it was modified. | |
1302 | */ | |
1303 | static bool update_checksum(struct kmemleak_object *object) | |
1304 | { | |
1305 | u32 old_csum = object->checksum; | |
1306 | ||
39042079 | 1307 | if (WARN_ON_ONCE(object->flags & (OBJECT_PHYS | OBJECT_PERCPU))) |
0c24e061 PW |
1308 | return false; |
1309 | ||
e79ed2f1 | 1310 | kasan_disable_current(); |
69d0b54d | 1311 | kcsan_disable_current(); |
6c7a00b8 | 1312 | object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size); |
e79ed2f1 | 1313 | kasan_enable_current(); |
69d0b54d | 1314 | kcsan_enable_current(); |
e79ed2f1 | 1315 | |
04609ccc CM |
1316 | return object->checksum != old_csum; |
1317 | } | |
1318 | ||
04f70d13 CM |
1319 | /* |
1320 | * Update an object's references. object->lock must be held by the caller. | |
1321 | */ | |
1322 | static void update_refs(struct kmemleak_object *object) | |
1323 | { | |
1324 | if (!color_white(object)) { | |
1325 | /* non-orphan, ignored or new */ | |
1326 | return; | |
1327 | } | |
1328 | ||
1329 | /* | |
1330 | * Increase the object's reference count (number of pointers to the | |
1331 | * memory block). If this count reaches the required minimum, the | |
1332 | * object's color will become gray and it will be added to the | |
1333 | * gray_list. | |
1334 | */ | |
1335 | object->count++; | |
1336 | if (color_gray(object)) { | |
1337 | /* put_object() called when removing from gray_list */ | |
1338 | WARN_ON(!get_object(object)); | |
1339 | list_add_tail(&object->gray_list, &gray_list); | |
1340 | } | |
1341 | } | |
1342 | ||
3c7b4e6b | 1343 | /* |
0b5121ef | 1344 | * Memory scanning is a long process and it needs to be interruptible. This |
25985edc | 1345 | * function checks whether such interrupt condition occurred. |
3c7b4e6b CM |
1346 | */ |
1347 | static int scan_should_stop(void) | |
1348 | { | |
8910ae89 | 1349 | if (!kmemleak_enabled) |
3c7b4e6b CM |
1350 | return 1; |
1351 | ||
1352 | /* | |
1353 | * This function may be called from either process or kthread context, | |
1354 | * hence the need to check for both stop conditions. | |
1355 | */ | |
1356 | if (current->mm) | |
1357 | return signal_pending(current); | |
1358 | else | |
1359 | return kthread_should_stop(); | |
1360 | ||
1361 | return 0; | |
1362 | } | |
1363 | ||
1364 | /* | |
1365 | * Scan a memory block (exclusive range) for valid pointers and add those | |
1366 | * found to the gray list. | |
1367 | */ | |
1368 | static void scan_block(void *_start, void *_end, | |
93ada579 | 1369 | struct kmemleak_object *scanned) |
3c7b4e6b CM |
1370 | { |
1371 | unsigned long *ptr; | |
1372 | unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); | |
1373 | unsigned long *end = _end - (BYTES_PER_POINTER - 1); | |
93ada579 | 1374 | unsigned long flags; |
a2f77575 | 1375 | unsigned long untagged_ptr; |
3c7b4e6b | 1376 | |
8c96f1bc | 1377 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
3c7b4e6b | 1378 | for (ptr = start; ptr < end; ptr++) { |
3c7b4e6b | 1379 | struct kmemleak_object *object; |
8e019366 | 1380 | unsigned long pointer; |
94f4a161 | 1381 | unsigned long excess_ref; |
3c7b4e6b CM |
1382 | |
1383 | if (scan_should_stop()) | |
1384 | break; | |
1385 | ||
e79ed2f1 | 1386 | kasan_disable_current(); |
6c7a00b8 | 1387 | pointer = *(unsigned long *)kasan_reset_tag((void *)ptr); |
e79ed2f1 | 1388 | kasan_enable_current(); |
8e019366 | 1389 | |
a2f77575 AK |
1390 | untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer); |
1391 | if (untagged_ptr < min_addr || untagged_ptr >= max_addr) | |
93ada579 CM |
1392 | continue; |
1393 | ||
1394 | /* | |
1395 | * No need for get_object() here since we hold kmemleak_lock. | |
1396 | * object->use_count cannot be dropped to 0 while the object | |
1397 | * is still present in object_tree_root and object_list | |
1398 | * (with updates protected by kmemleak_lock). | |
1399 | */ | |
1400 | object = lookup_object(pointer, 1); | |
3c7b4e6b CM |
1401 | if (!object) |
1402 | continue; | |
93ada579 | 1403 | if (object == scanned) |
3c7b4e6b | 1404 | /* self referenced, ignore */ |
3c7b4e6b | 1405 | continue; |
3c7b4e6b CM |
1406 | |
1407 | /* | |
1408 | * Avoid the lockdep recursive warning on object->lock being | |
1409 | * previously acquired in scan_object(). These locks are | |
1410 | * enclosed by scan_mutex. | |
1411 | */ | |
8c96f1bc | 1412 | raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
94f4a161 CM |
1413 | /* only pass surplus references (object already gray) */ |
1414 | if (color_gray(object)) { | |
1415 | excess_ref = object->excess_ref; | |
1416 | /* no need for update_refs() if object already gray */ | |
1417 | } else { | |
1418 | excess_ref = 0; | |
1419 | update_refs(object); | |
1420 | } | |
8c96f1bc | 1421 | raw_spin_unlock(&object->lock); |
94f4a161 CM |
1422 | |
1423 | if (excess_ref) { | |
1424 | object = lookup_object(excess_ref, 0); | |
1425 | if (!object) | |
1426 | continue; | |
1427 | if (object == scanned) | |
1428 | /* circular reference, ignore */ | |
1429 | continue; | |
8c96f1bc | 1430 | raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
94f4a161 | 1431 | update_refs(object); |
8c96f1bc | 1432 | raw_spin_unlock(&object->lock); |
94f4a161 | 1433 | } |
93ada579 | 1434 | } |
8c96f1bc | 1435 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
93ada579 | 1436 | } |
0587da40 | 1437 | |
93ada579 CM |
1438 | /* |
1439 | * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency. | |
1440 | */ | |
dce5b0bd | 1441 | #ifdef CONFIG_SMP |
93ada579 CM |
1442 | static void scan_large_block(void *start, void *end) |
1443 | { | |
1444 | void *next; | |
1445 | ||
1446 | while (start < end) { | |
1447 | next = min(start + MAX_SCAN_SIZE, end); | |
1448 | scan_block(start, next, NULL); | |
1449 | start = next; | |
1450 | cond_resched(); | |
3c7b4e6b CM |
1451 | } |
1452 | } | |
dce5b0bd | 1453 | #endif |
3c7b4e6b CM |
1454 | |
1455 | /* | |
1456 | * Scan a memory block corresponding to a kmemleak_object. A condition is | |
1457 | * that object->use_count >= 1. | |
1458 | */ | |
1459 | static void scan_object(struct kmemleak_object *object) | |
1460 | { | |
1461 | struct kmemleak_scan_area *area; | |
3c7b4e6b CM |
1462 | unsigned long flags; |
1463 | ||
1464 | /* | |
21ae2956 UKK |
1465 | * Once the object->lock is acquired, the corresponding memory block |
1466 | * cannot be freed (the same lock is acquired in delete_object). | |
3c7b4e6b | 1467 | */ |
8c96f1bc | 1468 | raw_spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b CM |
1469 | if (object->flags & OBJECT_NO_SCAN) |
1470 | goto out; | |
1471 | if (!(object->flags & OBJECT_ALLOCATED)) | |
1472 | /* already freed object */ | |
1473 | goto out; | |
0c24e061 | 1474 | |
39042079 CM |
1475 | if (object->flags & OBJECT_PERCPU) { |
1476 | unsigned int cpu; | |
1477 | ||
1478 | for_each_possible_cpu(cpu) { | |
1479 | void *start = per_cpu_ptr((void __percpu *)object->pointer, cpu); | |
1480 | void *end = start + object->size; | |
0c24e061 | 1481 | |
39042079 CM |
1482 | scan_block(start, end, object); |
1483 | ||
1484 | raw_spin_unlock_irqrestore(&object->lock, flags); | |
1485 | cond_resched(); | |
1486 | raw_spin_lock_irqsave(&object->lock, flags); | |
1487 | if (!(object->flags & OBJECT_ALLOCATED)) | |
1488 | break; | |
1489 | } | |
1490 | } else if (hlist_empty(&object->area_list) || | |
dba82d94 | 1491 | object->flags & OBJECT_FULL_SCAN) { |
39042079 CM |
1492 | void *start = object->flags & OBJECT_PHYS ? |
1493 | __va((phys_addr_t)object->pointer) : | |
1494 | (void *)object->pointer; | |
1495 | void *end = start + object->size; | |
93ada579 CM |
1496 | void *next; |
1497 | ||
1498 | do { | |
1499 | next = min(start + MAX_SCAN_SIZE, end); | |
1500 | scan_block(start, next, object); | |
af98603d | 1501 | |
93ada579 CM |
1502 | start = next; |
1503 | if (start >= end) | |
1504 | break; | |
af98603d | 1505 | |
8c96f1bc | 1506 | raw_spin_unlock_irqrestore(&object->lock, flags); |
af98603d | 1507 | cond_resched(); |
8c96f1bc | 1508 | raw_spin_lock_irqsave(&object->lock, flags); |
93ada579 | 1509 | } while (object->flags & OBJECT_ALLOCATED); |
39042079 | 1510 | } else { |
b67bfe0d | 1511 | hlist_for_each_entry(area, &object->area_list, node) |
c017b4be CM |
1512 | scan_block((void *)area->start, |
1513 | (void *)(area->start + area->size), | |
93ada579 | 1514 | object); |
39042079 | 1515 | } |
3c7b4e6b | 1516 | out: |
8c96f1bc | 1517 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
1518 | } |
1519 | ||
04609ccc CM |
1520 | /* |
1521 | * Scan the objects already referenced (gray objects). More objects will be | |
1522 | * referenced and, if there are no memory leaks, all the objects are scanned. | |
1523 | */ | |
1524 | static void scan_gray_list(void) | |
1525 | { | |
1526 | struct kmemleak_object *object, *tmp; | |
1527 | ||
1528 | /* | |
1529 | * The list traversal is safe for both tail additions and removals | |
1530 | * from inside the loop. The kmemleak objects cannot be freed from | |
1531 | * outside the loop because their use_count was incremented. | |
1532 | */ | |
1533 | object = list_entry(gray_list.next, typeof(*object), gray_list); | |
1534 | while (&object->gray_list != &gray_list) { | |
1535 | cond_resched(); | |
1536 | ||
1537 | /* may add new objects to the list */ | |
1538 | if (!scan_should_stop()) | |
1539 | scan_object(object); | |
1540 | ||
1541 | tmp = list_entry(object->gray_list.next, typeof(*object), | |
1542 | gray_list); | |
1543 | ||
1544 | /* remove the object from the list and release it */ | |
1545 | list_del(&object->gray_list); | |
1546 | put_object(object); | |
1547 | ||
1548 | object = tmp; | |
1549 | } | |
1550 | WARN_ON(!list_empty(&gray_list)); | |
1551 | } | |
1552 | ||
984a6083 | 1553 | /* |
25e9fa22 | 1554 | * Conditionally call resched() in an object iteration loop while making sure |
984a6083 | 1555 | * that the given object won't go away without RCU read lock by performing a |
6061e740 | 1556 | * get_object() if necessaary. |
984a6083 | 1557 | */ |
6061e740 | 1558 | static void kmemleak_cond_resched(struct kmemleak_object *object) |
984a6083 | 1559 | { |
6061e740 WL |
1560 | if (!get_object(object)) |
1561 | return; /* Try next object */ | |
984a6083 | 1562 | |
782e4179 WL |
1563 | raw_spin_lock_irq(&kmemleak_lock); |
1564 | if (object->del_state & DELSTATE_REMOVED) | |
1565 | goto unlock_put; /* Object removed */ | |
1566 | object->del_state |= DELSTATE_NO_DELETE; | |
1567 | raw_spin_unlock_irq(&kmemleak_lock); | |
1568 | ||
984a6083 WL |
1569 | rcu_read_unlock(); |
1570 | cond_resched(); | |
1571 | rcu_read_lock(); | |
782e4179 WL |
1572 | |
1573 | raw_spin_lock_irq(&kmemleak_lock); | |
1574 | if (object->del_state & DELSTATE_REMOVED) | |
1575 | list_del_rcu(&object->object_list); | |
1576 | object->del_state &= ~DELSTATE_NO_DELETE; | |
1577 | unlock_put: | |
1578 | raw_spin_unlock_irq(&kmemleak_lock); | |
6061e740 | 1579 | put_object(object); |
984a6083 WL |
1580 | } |
1581 | ||
3c7b4e6b CM |
1582 | /* |
1583 | * Scan data sections and all the referenced memory blocks allocated via the | |
1584 | * kernel's standard allocators. This function must be called with the | |
1585 | * scan_mutex held. | |
1586 | */ | |
1587 | static void kmemleak_scan(void) | |
1588 | { | |
04609ccc | 1589 | struct kmemleak_object *object; |
c10a0f87 LY |
1590 | struct zone *zone; |
1591 | int __maybe_unused i; | |
4698c1f2 | 1592 | int new_leaks = 0; |
3c7b4e6b | 1593 | |
acf4968e CM |
1594 | jiffies_last_scan = jiffies; |
1595 | ||
3c7b4e6b CM |
1596 | /* prepare the kmemleak_object's */ |
1597 | rcu_read_lock(); | |
1598 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
00c15506 | 1599 | raw_spin_lock_irq(&object->lock); |
3c7b4e6b CM |
1600 | #ifdef DEBUG |
1601 | /* | |
1602 | * With a few exceptions there should be a maximum of | |
1603 | * 1 reference to any object at this point. | |
1604 | */ | |
1605 | if (atomic_read(&object->use_count) > 1) { | |
ae281064 | 1606 | pr_debug("object->use_count = %d\n", |
3c7b4e6b CM |
1607 | atomic_read(&object->use_count)); |
1608 | dump_object_info(object); | |
1609 | } | |
1610 | #endif | |
84c32629 PW |
1611 | |
1612 | /* ignore objects outside lowmem (paint them black) */ | |
1613 | if ((object->flags & OBJECT_PHYS) && | |
1614 | !(object->flags & OBJECT_NO_SCAN)) { | |
1615 | unsigned long phys = object->pointer; | |
1616 | ||
1617 | if (PHYS_PFN(phys) < min_low_pfn || | |
1618 | PHYS_PFN(phys + object->size) >= max_low_pfn) | |
1619 | __paint_it(object, KMEMLEAK_BLACK); | |
1620 | } | |
1621 | ||
3c7b4e6b CM |
1622 | /* reset the reference count (whiten the object) */ |
1623 | object->count = 0; | |
6061e740 | 1624 | if (color_gray(object) && get_object(object)) |
3c7b4e6b CM |
1625 | list_add_tail(&object->gray_list, &gray_list); |
1626 | ||
00c15506 | 1627 | raw_spin_unlock_irq(&object->lock); |
6edda04c | 1628 | |
6061e740 WL |
1629 | if (need_resched()) |
1630 | kmemleak_cond_resched(object); | |
3c7b4e6b CM |
1631 | } |
1632 | rcu_read_unlock(); | |
1633 | ||
3c7b4e6b CM |
1634 | #ifdef CONFIG_SMP |
1635 | /* per-cpu sections scanning */ | |
1636 | for_each_possible_cpu(i) | |
93ada579 CM |
1637 | scan_large_block(__per_cpu_start + per_cpu_offset(i), |
1638 | __per_cpu_end + per_cpu_offset(i)); | |
3c7b4e6b CM |
1639 | #endif |
1640 | ||
1641 | /* | |
029aeff5 | 1642 | * Struct page scanning for each node. |
3c7b4e6b | 1643 | */ |
bfc8c901 | 1644 | get_online_mems(); |
c10a0f87 LY |
1645 | for_each_populated_zone(zone) { |
1646 | unsigned long start_pfn = zone->zone_start_pfn; | |
1647 | unsigned long end_pfn = zone_end_pfn(zone); | |
3c7b4e6b CM |
1648 | unsigned long pfn; |
1649 | ||
1650 | for (pfn = start_pfn; pfn < end_pfn; pfn++) { | |
9f1eb38e | 1651 | struct page *page = pfn_to_online_page(pfn); |
3c7b4e6b | 1652 | |
e68d343d WL |
1653 | if (!(pfn & 63)) |
1654 | cond_resched(); | |
1655 | ||
9f1eb38e OS |
1656 | if (!page) |
1657 | continue; | |
1658 | ||
c10a0f87 LY |
1659 | /* only scan pages belonging to this zone */ |
1660 | if (page_zone(page) != zone) | |
3c7b4e6b | 1661 | continue; |
3c7b4e6b CM |
1662 | /* only scan if page is in use */ |
1663 | if (page_count(page) == 0) | |
1664 | continue; | |
93ada579 | 1665 | scan_block(page, page + 1, NULL); |
3c7b4e6b CM |
1666 | } |
1667 | } | |
bfc8c901 | 1668 | put_online_mems(); |
3c7b4e6b CM |
1669 | |
1670 | /* | |
43ed5d6e | 1671 | * Scanning the task stacks (may introduce false negatives). |
3c7b4e6b CM |
1672 | */ |
1673 | if (kmemleak_stack_scan) { | |
43ed5d6e CM |
1674 | struct task_struct *p, *g; |
1675 | ||
c4b28963 DB |
1676 | rcu_read_lock(); |
1677 | for_each_process_thread(g, p) { | |
37df49f4 CM |
1678 | void *stack = try_get_task_stack(p); |
1679 | if (stack) { | |
1680 | scan_block(stack, stack + THREAD_SIZE, NULL); | |
1681 | put_task_stack(p); | |
1682 | } | |
c4b28963 DB |
1683 | } |
1684 | rcu_read_unlock(); | |
3c7b4e6b CM |
1685 | } |
1686 | ||
1687 | /* | |
1688 | * Scan the objects already referenced from the sections scanned | |
04609ccc | 1689 | * above. |
3c7b4e6b | 1690 | */ |
04609ccc | 1691 | scan_gray_list(); |
2587362e CM |
1692 | |
1693 | /* | |
04609ccc CM |
1694 | * Check for new or unreferenced objects modified since the previous |
1695 | * scan and color them gray until the next scan. | |
2587362e CM |
1696 | */ |
1697 | rcu_read_lock(); | |
1698 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
6061e740 WL |
1699 | if (need_resched()) |
1700 | kmemleak_cond_resched(object); | |
984a6083 | 1701 | |
64977918 WL |
1702 | /* |
1703 | * This is racy but we can save the overhead of lock/unlock | |
1704 | * calls. The missed objects, if any, should be caught in | |
1705 | * the next scan. | |
1706 | */ | |
1707 | if (!color_white(object)) | |
1708 | continue; | |
00c15506 | 1709 | raw_spin_lock_irq(&object->lock); |
04609ccc CM |
1710 | if (color_white(object) && (object->flags & OBJECT_ALLOCATED) |
1711 | && update_checksum(object) && get_object(object)) { | |
1712 | /* color it gray temporarily */ | |
1713 | object->count = object->min_count; | |
2587362e CM |
1714 | list_add_tail(&object->gray_list, &gray_list); |
1715 | } | |
00c15506 | 1716 | raw_spin_unlock_irq(&object->lock); |
2587362e CM |
1717 | } |
1718 | rcu_read_unlock(); | |
1719 | ||
04609ccc CM |
1720 | /* |
1721 | * Re-scan the gray list for modified unreferenced objects. | |
1722 | */ | |
1723 | scan_gray_list(); | |
4698c1f2 | 1724 | |
17bb9e0d | 1725 | /* |
04609ccc | 1726 | * If scanning was stopped do not report any new unreferenced objects. |
17bb9e0d | 1727 | */ |
04609ccc | 1728 | if (scan_should_stop()) |
17bb9e0d CM |
1729 | return; |
1730 | ||
4698c1f2 CM |
1731 | /* |
1732 | * Scanning result reporting. | |
1733 | */ | |
1734 | rcu_read_lock(); | |
1735 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
6061e740 WL |
1736 | if (need_resched()) |
1737 | kmemleak_cond_resched(object); | |
984a6083 | 1738 | |
64977918 WL |
1739 | /* |
1740 | * This is racy but we can save the overhead of lock/unlock | |
1741 | * calls. The missed objects, if any, should be caught in | |
1742 | * the next scan. | |
1743 | */ | |
1744 | if (!color_white(object)) | |
1745 | continue; | |
00c15506 | 1746 | raw_spin_lock_irq(&object->lock); |
4698c1f2 CM |
1747 | if (unreferenced_object(object) && |
1748 | !(object->flags & OBJECT_REPORTED)) { | |
1749 | object->flags |= OBJECT_REPORTED; | |
154221c3 VW |
1750 | |
1751 | if (kmemleak_verbose) | |
1752 | print_unreferenced(NULL, object); | |
1753 | ||
4698c1f2 CM |
1754 | new_leaks++; |
1755 | } | |
00c15506 | 1756 | raw_spin_unlock_irq(&object->lock); |
4698c1f2 CM |
1757 | } |
1758 | rcu_read_unlock(); | |
1759 | ||
dc9b3f42 LZ |
1760 | if (new_leaks) { |
1761 | kmemleak_found_leaks = true; | |
1762 | ||
756a025f JP |
1763 | pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n", |
1764 | new_leaks); | |
dc9b3f42 | 1765 | } |
4698c1f2 | 1766 | |
3c7b4e6b CM |
1767 | } |
1768 | ||
1769 | /* | |
1770 | * Thread function performing automatic memory scanning. Unreferenced objects | |
1771 | * at the end of a memory scan are reported but only the first time. | |
1772 | */ | |
1773 | static int kmemleak_scan_thread(void *arg) | |
1774 | { | |
d53ce042 | 1775 | static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN); |
3c7b4e6b | 1776 | |
ae281064 | 1777 | pr_info("Automatic memory scanning thread started\n"); |
bf2a76b3 | 1778 | set_user_nice(current, 10); |
3c7b4e6b CM |
1779 | |
1780 | /* | |
1781 | * Wait before the first scan to allow the system to fully initialize. | |
1782 | */ | |
1783 | if (first_run) { | |
98c42d94 | 1784 | signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000); |
3c7b4e6b | 1785 | first_run = 0; |
98c42d94 VN |
1786 | while (timeout && !kthread_should_stop()) |
1787 | timeout = schedule_timeout_interruptible(timeout); | |
3c7b4e6b CM |
1788 | } |
1789 | ||
1790 | while (!kthread_should_stop()) { | |
54dd200c | 1791 | signed long timeout = READ_ONCE(jiffies_scan_wait); |
3c7b4e6b CM |
1792 | |
1793 | mutex_lock(&scan_mutex); | |
3c7b4e6b | 1794 | kmemleak_scan(); |
3c7b4e6b | 1795 | mutex_unlock(&scan_mutex); |
4698c1f2 | 1796 | |
3c7b4e6b CM |
1797 | /* wait before the next scan */ |
1798 | while (timeout && !kthread_should_stop()) | |
1799 | timeout = schedule_timeout_interruptible(timeout); | |
1800 | } | |
1801 | ||
ae281064 | 1802 | pr_info("Automatic memory scanning thread ended\n"); |
3c7b4e6b CM |
1803 | |
1804 | return 0; | |
1805 | } | |
1806 | ||
1807 | /* | |
1808 | * Start the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1809 | * with the scan_mutex held. |
3c7b4e6b | 1810 | */ |
7eb0d5e5 | 1811 | static void start_scan_thread(void) |
3c7b4e6b CM |
1812 | { |
1813 | if (scan_thread) | |
1814 | return; | |
1815 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); | |
1816 | if (IS_ERR(scan_thread)) { | |
598d8091 | 1817 | pr_warn("Failed to create the scan thread\n"); |
3c7b4e6b CM |
1818 | scan_thread = NULL; |
1819 | } | |
1820 | } | |
1821 | ||
1822 | /* | |
914b6dff | 1823 | * Stop the automatic memory scanning thread. |
3c7b4e6b | 1824 | */ |
7eb0d5e5 | 1825 | static void stop_scan_thread(void) |
3c7b4e6b CM |
1826 | { |
1827 | if (scan_thread) { | |
1828 | kthread_stop(scan_thread); | |
1829 | scan_thread = NULL; | |
1830 | } | |
1831 | } | |
1832 | ||
1833 | /* | |
1834 | * Iterate over the object_list and return the first valid object at or after | |
1835 | * the required position with its use_count incremented. The function triggers | |
1836 | * a memory scanning when the pos argument points to the first position. | |
1837 | */ | |
1838 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) | |
1839 | { | |
1840 | struct kmemleak_object *object; | |
1841 | loff_t n = *pos; | |
b87324d0 CM |
1842 | int err; |
1843 | ||
1844 | err = mutex_lock_interruptible(&scan_mutex); | |
1845 | if (err < 0) | |
1846 | return ERR_PTR(err); | |
3c7b4e6b | 1847 | |
3c7b4e6b CM |
1848 | rcu_read_lock(); |
1849 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1850 | if (n-- > 0) | |
1851 | continue; | |
1852 | if (get_object(object)) | |
1853 | goto out; | |
1854 | } | |
1855 | object = NULL; | |
1856 | out: | |
3c7b4e6b CM |
1857 | return object; |
1858 | } | |
1859 | ||
1860 | /* | |
1861 | * Return the next object in the object_list. The function decrements the | |
1862 | * use_count of the previous object and increases that of the next one. | |
1863 | */ | |
1864 | static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
1865 | { | |
1866 | struct kmemleak_object *prev_obj = v; | |
1867 | struct kmemleak_object *next_obj = NULL; | |
58fac095 | 1868 | struct kmemleak_object *obj = prev_obj; |
3c7b4e6b CM |
1869 | |
1870 | ++(*pos); | |
3c7b4e6b | 1871 | |
58fac095 | 1872 | list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
52c3ce4e CM |
1873 | if (get_object(obj)) { |
1874 | next_obj = obj; | |
3c7b4e6b | 1875 | break; |
52c3ce4e | 1876 | } |
3c7b4e6b | 1877 | } |
288c857d | 1878 | |
3c7b4e6b CM |
1879 | put_object(prev_obj); |
1880 | return next_obj; | |
1881 | } | |
1882 | ||
1883 | /* | |
1884 | * Decrement the use_count of the last object required, if any. | |
1885 | */ | |
1886 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) | |
1887 | { | |
b87324d0 CM |
1888 | if (!IS_ERR(v)) { |
1889 | /* | |
1890 | * kmemleak_seq_start may return ERR_PTR if the scan_mutex | |
1891 | * waiting was interrupted, so only release it if !IS_ERR. | |
1892 | */ | |
f5886c7f | 1893 | rcu_read_unlock(); |
b87324d0 CM |
1894 | mutex_unlock(&scan_mutex); |
1895 | if (v) | |
1896 | put_object(v); | |
1897 | } | |
3c7b4e6b CM |
1898 | } |
1899 | ||
1900 | /* | |
1901 | * Print the information for an unreferenced object to the seq file. | |
1902 | */ | |
1903 | static int kmemleak_seq_show(struct seq_file *seq, void *v) | |
1904 | { | |
1905 | struct kmemleak_object *object = v; | |
1906 | unsigned long flags; | |
1907 | ||
8c96f1bc | 1908 | raw_spin_lock_irqsave(&object->lock, flags); |
288c857d | 1909 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
17bb9e0d | 1910 | print_unreferenced(seq, object); |
8c96f1bc | 1911 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
1912 | return 0; |
1913 | } | |
1914 | ||
1915 | static const struct seq_operations kmemleak_seq_ops = { | |
1916 | .start = kmemleak_seq_start, | |
1917 | .next = kmemleak_seq_next, | |
1918 | .stop = kmemleak_seq_stop, | |
1919 | .show = kmemleak_seq_show, | |
1920 | }; | |
1921 | ||
1922 | static int kmemleak_open(struct inode *inode, struct file *file) | |
1923 | { | |
b87324d0 | 1924 | return seq_open(file, &kmemleak_seq_ops); |
3c7b4e6b CM |
1925 | } |
1926 | ||
189d84ed CM |
1927 | static int dump_str_object_info(const char *str) |
1928 | { | |
1929 | unsigned long flags; | |
1930 | struct kmemleak_object *object; | |
1931 | unsigned long addr; | |
1932 | ||
dc053733 AP |
1933 | if (kstrtoul(str, 0, &addr)) |
1934 | return -EINVAL; | |
189d84ed CM |
1935 | object = find_and_get_object(addr, 0); |
1936 | if (!object) { | |
1937 | pr_info("Unknown object at 0x%08lx\n", addr); | |
1938 | return -EINVAL; | |
1939 | } | |
1940 | ||
8c96f1bc | 1941 | raw_spin_lock_irqsave(&object->lock, flags); |
189d84ed | 1942 | dump_object_info(object); |
8c96f1bc | 1943 | raw_spin_unlock_irqrestore(&object->lock, flags); |
189d84ed CM |
1944 | |
1945 | put_object(object); | |
1946 | return 0; | |
1947 | } | |
1948 | ||
30b37101 LR |
1949 | /* |
1950 | * We use grey instead of black to ensure we can do future scans on the same | |
1951 | * objects. If we did not do future scans these black objects could | |
1952 | * potentially contain references to newly allocated objects in the future and | |
1953 | * we'd end up with false positives. | |
1954 | */ | |
1955 | static void kmemleak_clear(void) | |
1956 | { | |
1957 | struct kmemleak_object *object; | |
30b37101 LR |
1958 | |
1959 | rcu_read_lock(); | |
1960 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
00c15506 | 1961 | raw_spin_lock_irq(&object->lock); |
30b37101 LR |
1962 | if ((object->flags & OBJECT_REPORTED) && |
1963 | unreferenced_object(object)) | |
a1084c87 | 1964 | __paint_it(object, KMEMLEAK_GREY); |
00c15506 | 1965 | raw_spin_unlock_irq(&object->lock); |
30b37101 LR |
1966 | } |
1967 | rcu_read_unlock(); | |
dc9b3f42 LZ |
1968 | |
1969 | kmemleak_found_leaks = false; | |
30b37101 LR |
1970 | } |
1971 | ||
c89da70c LZ |
1972 | static void __kmemleak_do_cleanup(void); |
1973 | ||
3c7b4e6b CM |
1974 | /* |
1975 | * File write operation to configure kmemleak at run-time. The following | |
1976 | * commands can be written to the /sys/kernel/debug/kmemleak file: | |
1977 | * off - disable kmemleak (irreversible) | |
1978 | * stack=on - enable the task stacks scanning | |
1979 | * stack=off - disable the tasks stacks scanning | |
1980 | * scan=on - start the automatic memory scanning thread | |
1981 | * scan=off - stop the automatic memory scanning thread | |
1982 | * scan=... - set the automatic memory scanning period in seconds (0 to | |
1983 | * disable it) | |
4698c1f2 | 1984 | * scan - trigger a memory scan |
30b37101 | 1985 | * clear - mark all current reported unreferenced kmemleak objects as |
c89da70c LZ |
1986 | * grey to ignore printing them, or free all kmemleak objects |
1987 | * if kmemleak has been disabled. | |
189d84ed | 1988 | * dump=... - dump information about the object found at the given address |
3c7b4e6b CM |
1989 | */ |
1990 | static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, | |
1991 | size_t size, loff_t *ppos) | |
1992 | { | |
1993 | char buf[64]; | |
1994 | int buf_size; | |
b87324d0 | 1995 | int ret; |
3c7b4e6b CM |
1996 | |
1997 | buf_size = min(size, (sizeof(buf) - 1)); | |
1998 | if (strncpy_from_user(buf, user_buf, buf_size) < 0) | |
1999 | return -EFAULT; | |
2000 | buf[buf_size] = 0; | |
2001 | ||
b87324d0 CM |
2002 | ret = mutex_lock_interruptible(&scan_mutex); |
2003 | if (ret < 0) | |
2004 | return ret; | |
2005 | ||
c89da70c | 2006 | if (strncmp(buf, "clear", 5) == 0) { |
8910ae89 | 2007 | if (kmemleak_enabled) |
c89da70c LZ |
2008 | kmemleak_clear(); |
2009 | else | |
2010 | __kmemleak_do_cleanup(); | |
2011 | goto out; | |
2012 | } | |
2013 | ||
8910ae89 | 2014 | if (!kmemleak_enabled) { |
4e4dfce2 | 2015 | ret = -EPERM; |
c89da70c LZ |
2016 | goto out; |
2017 | } | |
2018 | ||
3c7b4e6b CM |
2019 | if (strncmp(buf, "off", 3) == 0) |
2020 | kmemleak_disable(); | |
2021 | else if (strncmp(buf, "stack=on", 8) == 0) | |
2022 | kmemleak_stack_scan = 1; | |
2023 | else if (strncmp(buf, "stack=off", 9) == 0) | |
2024 | kmemleak_stack_scan = 0; | |
2025 | else if (strncmp(buf, "scan=on", 7) == 0) | |
2026 | start_scan_thread(); | |
2027 | else if (strncmp(buf, "scan=off", 8) == 0) | |
2028 | stop_scan_thread(); | |
2029 | else if (strncmp(buf, "scan=", 5) == 0) { | |
54dd200c YX |
2030 | unsigned secs; |
2031 | unsigned long msecs; | |
3c7b4e6b | 2032 | |
54dd200c | 2033 | ret = kstrtouint(buf + 5, 0, &secs); |
b87324d0 CM |
2034 | if (ret < 0) |
2035 | goto out; | |
54dd200c YX |
2036 | |
2037 | msecs = secs * MSEC_PER_SEC; | |
2038 | if (msecs > UINT_MAX) | |
2039 | msecs = UINT_MAX; | |
2040 | ||
3c7b4e6b | 2041 | stop_scan_thread(); |
54dd200c YX |
2042 | if (msecs) { |
2043 | WRITE_ONCE(jiffies_scan_wait, msecs_to_jiffies(msecs)); | |
3c7b4e6b CM |
2044 | start_scan_thread(); |
2045 | } | |
4698c1f2 CM |
2046 | } else if (strncmp(buf, "scan", 4) == 0) |
2047 | kmemleak_scan(); | |
189d84ed CM |
2048 | else if (strncmp(buf, "dump=", 5) == 0) |
2049 | ret = dump_str_object_info(buf + 5); | |
4698c1f2 | 2050 | else |
b87324d0 CM |
2051 | ret = -EINVAL; |
2052 | ||
2053 | out: | |
2054 | mutex_unlock(&scan_mutex); | |
2055 | if (ret < 0) | |
2056 | return ret; | |
3c7b4e6b CM |
2057 | |
2058 | /* ignore the rest of the buffer, only one command at a time */ | |
2059 | *ppos += size; | |
2060 | return size; | |
2061 | } | |
2062 | ||
2063 | static const struct file_operations kmemleak_fops = { | |
2064 | .owner = THIS_MODULE, | |
2065 | .open = kmemleak_open, | |
2066 | .read = seq_read, | |
2067 | .write = kmemleak_write, | |
2068 | .llseek = seq_lseek, | |
5f3bf19a | 2069 | .release = seq_release, |
3c7b4e6b CM |
2070 | }; |
2071 | ||
c89da70c LZ |
2072 | static void __kmemleak_do_cleanup(void) |
2073 | { | |
2abd839a | 2074 | struct kmemleak_object *object, *tmp; |
c89da70c | 2075 | |
2abd839a CM |
2076 | /* |
2077 | * Kmemleak has already been disabled, no need for RCU list traversal | |
2078 | * or kmemleak_lock held. | |
2079 | */ | |
2080 | list_for_each_entry_safe(object, tmp, &object_list, object_list) { | |
2081 | __remove_object(object); | |
2082 | __delete_object(object); | |
2083 | } | |
c89da70c LZ |
2084 | } |
2085 | ||
3c7b4e6b | 2086 | /* |
74341703 CM |
2087 | * Stop the memory scanning thread and free the kmemleak internal objects if |
2088 | * no previous scan thread (otherwise, kmemleak may still have some useful | |
2089 | * information on memory leaks). | |
3c7b4e6b | 2090 | */ |
179a8100 | 2091 | static void kmemleak_do_cleanup(struct work_struct *work) |
3c7b4e6b | 2092 | { |
3c7b4e6b | 2093 | stop_scan_thread(); |
3c7b4e6b | 2094 | |
914b6dff | 2095 | mutex_lock(&scan_mutex); |
c5f3b1a5 | 2096 | /* |
914b6dff VM |
2097 | * Once it is made sure that kmemleak_scan has stopped, it is safe to no |
2098 | * longer track object freeing. Ordering of the scan thread stopping and | |
2099 | * the memory accesses below is guaranteed by the kthread_stop() | |
2100 | * function. | |
c5f3b1a5 CM |
2101 | */ |
2102 | kmemleak_free_enabled = 0; | |
914b6dff | 2103 | mutex_unlock(&scan_mutex); |
c5f3b1a5 | 2104 | |
c89da70c LZ |
2105 | if (!kmemleak_found_leaks) |
2106 | __kmemleak_do_cleanup(); | |
2107 | else | |
756a025f | 2108 | pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n"); |
3c7b4e6b CM |
2109 | } |
2110 | ||
179a8100 | 2111 | static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
3c7b4e6b CM |
2112 | |
2113 | /* | |
2114 | * Disable kmemleak. No memory allocation/freeing will be traced once this | |
2115 | * function is called. Disabling kmemleak is an irreversible operation. | |
2116 | */ | |
2117 | static void kmemleak_disable(void) | |
2118 | { | |
2119 | /* atomically check whether it was already invoked */ | |
8910ae89 | 2120 | if (cmpxchg(&kmemleak_error, 0, 1)) |
3c7b4e6b CM |
2121 | return; |
2122 | ||
2123 | /* stop any memory operation tracing */ | |
8910ae89 | 2124 | kmemleak_enabled = 0; |
3c7b4e6b CM |
2125 | |
2126 | /* check whether it is too early for a kernel thread */ | |
d160ef71 | 2127 | if (kmemleak_late_initialized) |
179a8100 | 2128 | schedule_work(&cleanup_work); |
c5f3b1a5 CM |
2129 | else |
2130 | kmemleak_free_enabled = 0; | |
3c7b4e6b CM |
2131 | |
2132 | pr_info("Kernel memory leak detector disabled\n"); | |
2133 | } | |
2134 | ||
2135 | /* | |
2136 | * Allow boot-time kmemleak disabling (enabled by default). | |
2137 | */ | |
8bd30c10 | 2138 | static int __init kmemleak_boot_config(char *str) |
3c7b4e6b CM |
2139 | { |
2140 | if (!str) | |
2141 | return -EINVAL; | |
2142 | if (strcmp(str, "off") == 0) | |
2143 | kmemleak_disable(); | |
993f57e0 | 2144 | else if (strcmp(str, "on") == 0) { |
ab0155a2 | 2145 | kmemleak_skip_disable = 1; |
1c0310ad | 2146 | stack_depot_request_early_init(); |
993f57e0 | 2147 | } |
ab0155a2 | 2148 | else |
3c7b4e6b CM |
2149 | return -EINVAL; |
2150 | return 0; | |
2151 | } | |
2152 | early_param("kmemleak", kmemleak_boot_config); | |
2153 | ||
2154 | /* | |
2030117d | 2155 | * Kmemleak initialization. |
3c7b4e6b CM |
2156 | */ |
2157 | void __init kmemleak_init(void) | |
2158 | { | |
ab0155a2 JB |
2159 | #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF |
2160 | if (!kmemleak_skip_disable) { | |
2161 | kmemleak_disable(); | |
2162 | return; | |
2163 | } | |
2164 | #endif | |
2165 | ||
c5665868 CM |
2166 | if (kmemleak_error) |
2167 | return; | |
2168 | ||
3c7b4e6b CM |
2169 | jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); |
2170 | jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); | |
2171 | ||
2172 | object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); | |
2173 | scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); | |
3c7b4e6b | 2174 | |
298a32b1 CM |
2175 | /* register the data/bss sections */ |
2176 | create_object((unsigned long)_sdata, _edata - _sdata, | |
2177 | KMEMLEAK_GREY, GFP_ATOMIC); | |
2178 | create_object((unsigned long)__bss_start, __bss_stop - __bss_start, | |
2179 | KMEMLEAK_GREY, GFP_ATOMIC); | |
2180 | /* only register .data..ro_after_init if not within .data */ | |
b0d14fc4 | 2181 | if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata) |
298a32b1 CM |
2182 | create_object((unsigned long)__start_ro_after_init, |
2183 | __end_ro_after_init - __start_ro_after_init, | |
2184 | KMEMLEAK_GREY, GFP_ATOMIC); | |
3c7b4e6b CM |
2185 | } |
2186 | ||
2187 | /* | |
2188 | * Late initialization function. | |
2189 | */ | |
2190 | static int __init kmemleak_late_init(void) | |
2191 | { | |
d160ef71 | 2192 | kmemleak_late_initialized = 1; |
3c7b4e6b | 2193 | |
282401df | 2194 | debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops); |
b353756b | 2195 | |
8910ae89 | 2196 | if (kmemleak_error) { |
3c7b4e6b | 2197 | /* |
25985edc | 2198 | * Some error occurred and kmemleak was disabled. There is a |
3c7b4e6b | 2199 | * small chance that kmemleak_disable() was called immediately |
d160ef71 | 2200 | * after setting kmemleak_late_initialized and we may end up with |
3c7b4e6b CM |
2201 | * two clean-up threads but serialized by scan_mutex. |
2202 | */ | |
179a8100 | 2203 | schedule_work(&cleanup_work); |
3c7b4e6b CM |
2204 | return -ENOMEM; |
2205 | } | |
2206 | ||
d53ce042 SK |
2207 | if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) { |
2208 | mutex_lock(&scan_mutex); | |
2209 | start_scan_thread(); | |
2210 | mutex_unlock(&scan_mutex); | |
2211 | } | |
3c7b4e6b | 2212 | |
0e965a6b QC |
2213 | pr_info("Kernel memory leak detector initialized (mem pool available: %d)\n", |
2214 | mem_pool_free_count); | |
3c7b4e6b CM |
2215 | |
2216 | return 0; | |
2217 | } | |
2218 | late_initcall(kmemleak_late_init); |