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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 WL |
16 | * - kmemleak_lock (raw_spinlock_t): protects the object_list as well as |
17 | * del_state modifications and accesses to the object_tree_root (or | |
18 | * object_phys_tree_root). The object_list is the main list holding the | |
19 | * metadata (struct kmemleak_object) for the allocated memory blocks. | |
20 | * The object_tree_root and object_phys_tree_root are red | |
21 | * black trees used to look-up metadata based on a pointer to the | |
0c24e061 PW |
22 | * corresponding memory block. The object_phys_tree_root is for objects |
23 | * allocated with physical address. The kmemleak_object structures are | |
24 | * added to the object_list and object_tree_root (or object_phys_tree_root) | |
25 | * in the create_object() function called from the kmemleak_alloc() (or | |
26 | * kmemleak_alloc_phys()) callback and removed in delete_object() called from | |
27 | * the kmemleak_free() callback | |
8c96f1bc HZ |
28 | * - kmemleak_object.lock (raw_spinlock_t): protects a kmemleak_object. |
29 | * Accesses to the metadata (e.g. count) are protected by this lock. Note | |
30 | * that some members of this structure may be protected by other means | |
31 | * (atomic or kmemleak_lock). This lock is also held when scanning the | |
32 | * corresponding memory block to avoid the kernel freeing it via the | |
33 | * kmemleak_free() callback. This is less heavyweight than holding a global | |
34 | * lock like kmemleak_lock during scanning. | |
3c7b4e6b CM |
35 | * - scan_mutex (mutex): ensures that only one thread may scan the memory for |
36 | * unreferenced objects at a time. The gray_list contains the objects which | |
37 | * are already referenced or marked as false positives and need to be | |
38 | * scanned. This list is only modified during a scanning episode when the | |
39 | * scan_mutex is held. At the end of a scan, the gray_list is always empty. | |
40 | * Note that the kmemleak_object.use_count is incremented when an object is | |
4698c1f2 CM |
41 | * added to the gray_list and therefore cannot be freed. This mutex also |
42 | * prevents multiple users of the "kmemleak" debugfs file together with | |
43 | * modifications to the memory scanning parameters including the scan_thread | |
44 | * pointer | |
3c7b4e6b | 45 | * |
93ada579 | 46 | * Locks and mutexes are acquired/nested in the following order: |
9d5a4c73 | 47 | * |
93ada579 CM |
48 | * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING) |
49 | * | |
50 | * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex | |
51 | * regions. | |
9d5a4c73 | 52 | * |
3c7b4e6b CM |
53 | * The kmemleak_object structures have a use_count incremented or decremented |
54 | * using the get_object()/put_object() functions. When the use_count becomes | |
55 | * 0, this count can no longer be incremented and put_object() schedules the | |
56 | * kmemleak_object freeing via an RCU callback. All calls to the get_object() | |
57 | * function must be protected by rcu_read_lock() to avoid accessing a freed | |
58 | * structure. | |
59 | */ | |
60 | ||
ae281064 JP |
61 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
62 | ||
3c7b4e6b CM |
63 | #include <linux/init.h> |
64 | #include <linux/kernel.h> | |
65 | #include <linux/list.h> | |
3f07c014 | 66 | #include <linux/sched/signal.h> |
29930025 | 67 | #include <linux/sched/task.h> |
68db0cf1 | 68 | #include <linux/sched/task_stack.h> |
3c7b4e6b CM |
69 | #include <linux/jiffies.h> |
70 | #include <linux/delay.h> | |
b95f1b31 | 71 | #include <linux/export.h> |
3c7b4e6b | 72 | #include <linux/kthread.h> |
85d3a316 | 73 | #include <linux/rbtree.h> |
3c7b4e6b CM |
74 | #include <linux/fs.h> |
75 | #include <linux/debugfs.h> | |
76 | #include <linux/seq_file.h> | |
77 | #include <linux/cpumask.h> | |
78 | #include <linux/spinlock.h> | |
154221c3 | 79 | #include <linux/module.h> |
3c7b4e6b CM |
80 | #include <linux/mutex.h> |
81 | #include <linux/rcupdate.h> | |
82 | #include <linux/stacktrace.h> | |
56a61617 | 83 | #include <linux/stackdepot.h> |
3c7b4e6b CM |
84 | #include <linux/cache.h> |
85 | #include <linux/percpu.h> | |
57c8a661 | 86 | #include <linux/memblock.h> |
9099daed | 87 | #include <linux/pfn.h> |
3c7b4e6b CM |
88 | #include <linux/mmzone.h> |
89 | #include <linux/slab.h> | |
90 | #include <linux/thread_info.h> | |
91 | #include <linux/err.h> | |
92 | #include <linux/uaccess.h> | |
93 | #include <linux/string.h> | |
94 | #include <linux/nodemask.h> | |
95 | #include <linux/mm.h> | |
179a8100 | 96 | #include <linux/workqueue.h> |
04609ccc | 97 | #include <linux/crc32.h> |
3c7b4e6b CM |
98 | |
99 | #include <asm/sections.h> | |
100 | #include <asm/processor.h> | |
60063497 | 101 | #include <linux/atomic.h> |
3c7b4e6b | 102 | |
e79ed2f1 | 103 | #include <linux/kasan.h> |
95511580 | 104 | #include <linux/kfence.h> |
3c7b4e6b | 105 | #include <linux/kmemleak.h> |
029aeff5 | 106 | #include <linux/memory_hotplug.h> |
3c7b4e6b CM |
107 | |
108 | /* | |
109 | * Kmemleak configuration and common defines. | |
110 | */ | |
111 | #define MAX_TRACE 16 /* stack trace length */ | |
3c7b4e6b | 112 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
3c7b4e6b CM |
113 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
114 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ | |
af98603d | 115 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
3c7b4e6b CM |
116 | |
117 | #define BYTES_PER_POINTER sizeof(void *) | |
118 | ||
216c04b0 | 119 | /* GFP bitmask for kmemleak internal allocations */ |
79d37050 NA |
120 | #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \ |
121 | __GFP_NOLOCKDEP)) | \ | |
6ae4bd1f | 122 | __GFP_NORETRY | __GFP_NOMEMALLOC | \ |
df9576de | 123 | __GFP_NOWARN) |
216c04b0 | 124 | |
3c7b4e6b CM |
125 | /* scanning area inside a memory block */ |
126 | struct kmemleak_scan_area { | |
127 | struct hlist_node node; | |
c017b4be CM |
128 | unsigned long start; |
129 | size_t size; | |
3c7b4e6b CM |
130 | }; |
131 | ||
a1084c87 LR |
132 | #define KMEMLEAK_GREY 0 |
133 | #define KMEMLEAK_BLACK -1 | |
134 | ||
3c7b4e6b CM |
135 | /* |
136 | * Structure holding the metadata for each allocated memory block. | |
137 | * Modifications to such objects should be made while holding the | |
138 | * object->lock. Insertions or deletions from object_list, gray_list or | |
85d3a316 | 139 | * rb_node are already protected by the corresponding locks or mutex (see |
3c7b4e6b CM |
140 | * the notes on locking above). These objects are reference-counted |
141 | * (use_count) and freed using the RCU mechanism. | |
142 | */ | |
143 | struct kmemleak_object { | |
8c96f1bc | 144 | raw_spinlock_t lock; |
f66abf09 | 145 | unsigned int flags; /* object status flags */ |
3c7b4e6b CM |
146 | struct list_head object_list; |
147 | struct list_head gray_list; | |
85d3a316 | 148 | struct rb_node rb_node; |
3c7b4e6b CM |
149 | struct rcu_head rcu; /* object_list lockless traversal */ |
150 | /* object usage count; object freed when use_count == 0 */ | |
151 | atomic_t use_count; | |
782e4179 | 152 | unsigned int del_state; /* deletion state */ |
3c7b4e6b CM |
153 | unsigned long pointer; |
154 | size_t size; | |
94f4a161 CM |
155 | /* pass surplus references to this pointer */ |
156 | unsigned long excess_ref; | |
3c7b4e6b CM |
157 | /* minimum number of a pointers found before it is considered leak */ |
158 | int min_count; | |
159 | /* the total number of pointers found pointing to this object */ | |
160 | int count; | |
04609ccc CM |
161 | /* checksum for detecting modified objects */ |
162 | u32 checksum; | |
3c7b4e6b CM |
163 | /* memory ranges to be scanned inside an object (empty for all) */ |
164 | struct hlist_head area_list; | |
56a61617 | 165 | depot_stack_handle_t trace_handle; |
3c7b4e6b CM |
166 | unsigned long jiffies; /* creation timestamp */ |
167 | pid_t pid; /* pid of the current task */ | |
168 | char comm[TASK_COMM_LEN]; /* executable name */ | |
169 | }; | |
170 | ||
171 | /* flag representing the memory block allocation status */ | |
172 | #define OBJECT_ALLOCATED (1 << 0) | |
173 | /* flag set after the first reporting of an unreference object */ | |
174 | #define OBJECT_REPORTED (1 << 1) | |
175 | /* flag set to not scan the object */ | |
176 | #define OBJECT_NO_SCAN (1 << 2) | |
dba82d94 CM |
177 | /* flag set to fully scan the object when scan_area allocation failed */ |
178 | #define OBJECT_FULL_SCAN (1 << 3) | |
8e0c4ab3 PW |
179 | /* flag set for object allocated with physical address */ |
180 | #define OBJECT_PHYS (1 << 4) | |
3c7b4e6b | 181 | |
782e4179 WL |
182 | /* set when __remove_object() called */ |
183 | #define DELSTATE_REMOVED (1 << 0) | |
184 | /* set to temporarily prevent deletion from object_list */ | |
185 | #define DELSTATE_NO_DELETE (1 << 1) | |
186 | ||
154221c3 | 187 | #define HEX_PREFIX " " |
0494e082 SS |
188 | /* number of bytes to print per line; must be 16 or 32 */ |
189 | #define HEX_ROW_SIZE 16 | |
190 | /* number of bytes to print at a time (1, 2, 4, 8) */ | |
191 | #define HEX_GROUP_SIZE 1 | |
192 | /* include ASCII after the hex output */ | |
193 | #define HEX_ASCII 1 | |
194 | /* max number of lines to be printed */ | |
195 | #define HEX_MAX_LINES 2 | |
196 | ||
3c7b4e6b CM |
197 | /* the list of all allocated objects */ |
198 | static LIST_HEAD(object_list); | |
199 | /* the list of gray-colored objects (see color_gray comment below) */ | |
200 | static LIST_HEAD(gray_list); | |
0647398a | 201 | /* memory pool allocation */ |
c5665868 | 202 | static struct kmemleak_object mem_pool[CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE]; |
0647398a CM |
203 | static int mem_pool_free_count = ARRAY_SIZE(mem_pool); |
204 | static LIST_HEAD(mem_pool_free_list); | |
85d3a316 ML |
205 | /* search tree for object boundaries */ |
206 | static struct rb_root object_tree_root = RB_ROOT; | |
0c24e061 PW |
207 | /* search tree for object (with OBJECT_PHYS flag) boundaries */ |
208 | static struct rb_root object_phys_tree_root = RB_ROOT; | |
209 | /* protecting the access to object_list, object_tree_root (or object_phys_tree_root) */ | |
8c96f1bc | 210 | static DEFINE_RAW_SPINLOCK(kmemleak_lock); |
3c7b4e6b CM |
211 | |
212 | /* allocation caches for kmemleak internal data */ | |
213 | static struct kmem_cache *object_cache; | |
214 | static struct kmem_cache *scan_area_cache; | |
215 | ||
216 | /* set if tracing memory operations is enabled */ | |
c5665868 | 217 | static int kmemleak_enabled = 1; |
c5f3b1a5 | 218 | /* same as above but only for the kmemleak_free() callback */ |
c5665868 | 219 | static int kmemleak_free_enabled = 1; |
3c7b4e6b | 220 | /* set in the late_initcall if there were no errors */ |
d160ef71 | 221 | static int kmemleak_late_initialized; |
5f79020c | 222 | /* set if a kmemleak warning was issued */ |
8910ae89 | 223 | static int kmemleak_warning; |
5f79020c | 224 | /* set if a fatal kmemleak error has occurred */ |
8910ae89 | 225 | static int kmemleak_error; |
3c7b4e6b CM |
226 | |
227 | /* minimum and maximum address that may be valid pointers */ | |
228 | static unsigned long min_addr = ULONG_MAX; | |
229 | static unsigned long max_addr; | |
230 | ||
3c7b4e6b | 231 | static struct task_struct *scan_thread; |
acf4968e | 232 | /* used to avoid reporting of recently allocated objects */ |
3c7b4e6b | 233 | static unsigned long jiffies_min_age; |
acf4968e | 234 | static unsigned long jiffies_last_scan; |
3c7b4e6b | 235 | /* delay between automatic memory scannings */ |
54dd200c | 236 | static unsigned long jiffies_scan_wait; |
3c7b4e6b | 237 | /* enables or disables the task stacks scanning */ |
e0a2a160 | 238 | static int kmemleak_stack_scan = 1; |
4698c1f2 | 239 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
3c7b4e6b | 240 | static DEFINE_MUTEX(scan_mutex); |
ab0155a2 JB |
241 | /* setting kmemleak=on, will set this var, skipping the disable */ |
242 | static int kmemleak_skip_disable; | |
dc9b3f42 LZ |
243 | /* If there are leaks that can be reported */ |
244 | static bool kmemleak_found_leaks; | |
3c7b4e6b | 245 | |
154221c3 VW |
246 | static bool kmemleak_verbose; |
247 | module_param_named(verbose, kmemleak_verbose, bool, 0600); | |
248 | ||
3c7b4e6b CM |
249 | static void kmemleak_disable(void); |
250 | ||
251 | /* | |
252 | * Print a warning and dump the stack trace. | |
253 | */ | |
5f79020c | 254 | #define kmemleak_warn(x...) do { \ |
598d8091 | 255 | pr_warn(x); \ |
5f79020c | 256 | dump_stack(); \ |
8910ae89 | 257 | kmemleak_warning = 1; \ |
3c7b4e6b CM |
258 | } while (0) |
259 | ||
260 | /* | |
25985edc | 261 | * Macro invoked when a serious kmemleak condition occurred and cannot be |
2030117d | 262 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
3c7b4e6b CM |
263 | * tracing no longer available. |
264 | */ | |
000814f4 | 265 | #define kmemleak_stop(x...) do { \ |
3c7b4e6b CM |
266 | kmemleak_warn(x); \ |
267 | kmemleak_disable(); \ | |
268 | } while (0) | |
269 | ||
154221c3 VW |
270 | #define warn_or_seq_printf(seq, fmt, ...) do { \ |
271 | if (seq) \ | |
272 | seq_printf(seq, fmt, ##__VA_ARGS__); \ | |
273 | else \ | |
274 | pr_warn(fmt, ##__VA_ARGS__); \ | |
275 | } while (0) | |
276 | ||
277 | static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type, | |
278 | int rowsize, int groupsize, const void *buf, | |
279 | size_t len, bool ascii) | |
280 | { | |
281 | if (seq) | |
282 | seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize, | |
283 | buf, len, ascii); | |
284 | else | |
285 | print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type, | |
286 | rowsize, groupsize, buf, len, ascii); | |
287 | } | |
288 | ||
0494e082 SS |
289 | /* |
290 | * Printing of the objects hex dump to the seq file. The number of lines to be | |
291 | * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The | |
292 | * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called | |
293 | * with the object->lock held. | |
294 | */ | |
295 | static void hex_dump_object(struct seq_file *seq, | |
296 | struct kmemleak_object *object) | |
297 | { | |
298 | const u8 *ptr = (const u8 *)object->pointer; | |
6fc37c49 | 299 | size_t len; |
0494e082 | 300 | |
0c24e061 PW |
301 | if (WARN_ON_ONCE(object->flags & OBJECT_PHYS)) |
302 | return; | |
303 | ||
0494e082 | 304 | /* limit the number of lines to HEX_MAX_LINES */ |
6fc37c49 | 305 | len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); |
0494e082 | 306 | |
154221c3 | 307 | warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len); |
5c335fe0 | 308 | kasan_disable_current(); |
154221c3 | 309 | warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE, |
6c7a00b8 | 310 | HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII); |
5c335fe0 | 311 | kasan_enable_current(); |
0494e082 SS |
312 | } |
313 | ||
3c7b4e6b CM |
314 | /* |
315 | * Object colors, encoded with count and min_count: | |
316 | * - white - orphan object, not enough references to it (count < min_count) | |
317 | * - gray - not orphan, not marked as false positive (min_count == 0) or | |
318 | * sufficient references to it (count >= min_count) | |
319 | * - black - ignore, it doesn't contain references (e.g. text section) | |
320 | * (min_count == -1). No function defined for this color. | |
321 | * Newly created objects don't have any color assigned (object->count == -1) | |
322 | * before the next memory scan when they become white. | |
323 | */ | |
4a558dd6 | 324 | static bool color_white(const struct kmemleak_object *object) |
3c7b4e6b | 325 | { |
a1084c87 LR |
326 | return object->count != KMEMLEAK_BLACK && |
327 | object->count < object->min_count; | |
3c7b4e6b CM |
328 | } |
329 | ||
4a558dd6 | 330 | static bool color_gray(const struct kmemleak_object *object) |
3c7b4e6b | 331 | { |
a1084c87 LR |
332 | return object->min_count != KMEMLEAK_BLACK && |
333 | object->count >= object->min_count; | |
3c7b4e6b CM |
334 | } |
335 | ||
3c7b4e6b CM |
336 | /* |
337 | * Objects are considered unreferenced only if their color is white, they have | |
338 | * not be deleted and have a minimum age to avoid false positives caused by | |
339 | * pointers temporarily stored in CPU registers. | |
340 | */ | |
4a558dd6 | 341 | static bool unreferenced_object(struct kmemleak_object *object) |
3c7b4e6b | 342 | { |
04609ccc | 343 | return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
acf4968e CM |
344 | time_before_eq(object->jiffies + jiffies_min_age, |
345 | jiffies_last_scan); | |
3c7b4e6b CM |
346 | } |
347 | ||
348 | /* | |
bab4a34a CM |
349 | * Printing of the unreferenced objects information to the seq file. The |
350 | * print_unreferenced function must be called with the object->lock held. | |
3c7b4e6b | 351 | */ |
3c7b4e6b CM |
352 | static void print_unreferenced(struct seq_file *seq, |
353 | struct kmemleak_object *object) | |
354 | { | |
355 | int i; | |
56a61617 ZH |
356 | unsigned long *entries; |
357 | unsigned int nr_entries; | |
fefdd336 | 358 | unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); |
3c7b4e6b | 359 | |
56a61617 | 360 | nr_entries = stack_depot_fetch(object->trace_handle, &entries); |
154221c3 | 361 | warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
56a61617 | 362 | object->pointer, object->size); |
154221c3 | 363 | warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", |
56a61617 ZH |
364 | object->comm, object->pid, object->jiffies, |
365 | msecs_age / 1000, msecs_age % 1000); | |
0494e082 | 366 | hex_dump_object(seq, object); |
154221c3 | 367 | warn_or_seq_printf(seq, " backtrace:\n"); |
3c7b4e6b | 368 | |
56a61617 ZH |
369 | for (i = 0; i < nr_entries; i++) { |
370 | void *ptr = (void *)entries[i]; | |
3a6f33d8 | 371 | warn_or_seq_printf(seq, " [<%pK>] %pS\n", ptr, ptr); |
3c7b4e6b CM |
372 | } |
373 | } | |
374 | ||
375 | /* | |
376 | * Print the kmemleak_object information. This function is used mainly for | |
377 | * debugging special cases when kmemleak operations. It must be called with | |
378 | * the object->lock held. | |
379 | */ | |
380 | static void dump_object_info(struct kmemleak_object *object) | |
381 | { | |
ae281064 | 382 | pr_notice("Object 0x%08lx (size %zu):\n", |
56a61617 | 383 | object->pointer, object->size); |
3c7b4e6b | 384 | pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", |
56a61617 | 385 | object->comm, object->pid, object->jiffies); |
3c7b4e6b CM |
386 | pr_notice(" min_count = %d\n", object->min_count); |
387 | pr_notice(" count = %d\n", object->count); | |
f66abf09 | 388 | pr_notice(" flags = 0x%x\n", object->flags); |
aae0ad7a | 389 | pr_notice(" checksum = %u\n", object->checksum); |
3c7b4e6b | 390 | pr_notice(" backtrace:\n"); |
56a61617 ZH |
391 | if (object->trace_handle) |
392 | stack_depot_print(object->trace_handle); | |
3c7b4e6b CM |
393 | } |
394 | ||
395 | /* | |
85d3a316 | 396 | * Look-up a memory block metadata (kmemleak_object) in the object search |
3c7b4e6b CM |
397 | * tree based on a pointer value. If alias is 0, only values pointing to the |
398 | * beginning of the memory block are allowed. The kmemleak_lock must be held | |
399 | * when calling this function. | |
400 | */ | |
0c24e061 PW |
401 | static struct kmemleak_object *__lookup_object(unsigned long ptr, int alias, |
402 | bool is_phys) | |
3c7b4e6b | 403 | { |
0c24e061 PW |
404 | struct rb_node *rb = is_phys ? object_phys_tree_root.rb_node : |
405 | object_tree_root.rb_node; | |
ad1a3e15 | 406 | unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); |
85d3a316 ML |
407 | |
408 | while (rb) { | |
ad1a3e15 KYL |
409 | struct kmemleak_object *object; |
410 | unsigned long untagged_objp; | |
411 | ||
412 | object = rb_entry(rb, struct kmemleak_object, rb_node); | |
413 | untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); | |
414 | ||
415 | if (untagged_ptr < untagged_objp) | |
85d3a316 | 416 | rb = object->rb_node.rb_left; |
ad1a3e15 | 417 | else if (untagged_objp + object->size <= untagged_ptr) |
85d3a316 | 418 | rb = object->rb_node.rb_right; |
ad1a3e15 | 419 | else if (untagged_objp == untagged_ptr || alias) |
85d3a316 ML |
420 | return object; |
421 | else { | |
5f79020c CM |
422 | kmemleak_warn("Found object by alias at 0x%08lx\n", |
423 | ptr); | |
a7686a45 | 424 | dump_object_info(object); |
85d3a316 | 425 | break; |
3c7b4e6b | 426 | } |
85d3a316 ML |
427 | } |
428 | return NULL; | |
3c7b4e6b CM |
429 | } |
430 | ||
0c24e061 PW |
431 | /* Look-up a kmemleak object which allocated with virtual address. */ |
432 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) | |
433 | { | |
434 | return __lookup_object(ptr, alias, false); | |
435 | } | |
436 | ||
3c7b4e6b CM |
437 | /* |
438 | * Increment the object use_count. Return 1 if successful or 0 otherwise. Note | |
439 | * that once an object's use_count reached 0, the RCU freeing was already | |
440 | * registered and the object should no longer be used. This function must be | |
441 | * called under the protection of rcu_read_lock(). | |
442 | */ | |
443 | static int get_object(struct kmemleak_object *object) | |
444 | { | |
445 | return atomic_inc_not_zero(&object->use_count); | |
446 | } | |
447 | ||
0647398a CM |
448 | /* |
449 | * Memory pool allocation and freeing. kmemleak_lock must not be held. | |
450 | */ | |
451 | static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) | |
452 | { | |
453 | unsigned long flags; | |
454 | struct kmemleak_object *object; | |
455 | ||
456 | /* try the slab allocator first */ | |
c5665868 CM |
457 | if (object_cache) { |
458 | object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); | |
459 | if (object) | |
460 | return object; | |
461 | } | |
0647398a CM |
462 | |
463 | /* slab allocation failed, try the memory pool */ | |
8c96f1bc | 464 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
0647398a CM |
465 | object = list_first_entry_or_null(&mem_pool_free_list, |
466 | typeof(*object), object_list); | |
467 | if (object) | |
468 | list_del(&object->object_list); | |
469 | else if (mem_pool_free_count) | |
470 | object = &mem_pool[--mem_pool_free_count]; | |
c5665868 CM |
471 | else |
472 | pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n"); | |
8c96f1bc | 473 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
0647398a CM |
474 | |
475 | return object; | |
476 | } | |
477 | ||
478 | /* | |
479 | * Return the object to either the slab allocator or the memory pool. | |
480 | */ | |
481 | static void mem_pool_free(struct kmemleak_object *object) | |
482 | { | |
483 | unsigned long flags; | |
484 | ||
485 | if (object < mem_pool || object >= mem_pool + ARRAY_SIZE(mem_pool)) { | |
486 | kmem_cache_free(object_cache, object); | |
487 | return; | |
488 | } | |
489 | ||
490 | /* add the object to the memory pool free list */ | |
8c96f1bc | 491 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
0647398a | 492 | list_add(&object->object_list, &mem_pool_free_list); |
8c96f1bc | 493 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
0647398a CM |
494 | } |
495 | ||
3c7b4e6b CM |
496 | /* |
497 | * RCU callback to free a kmemleak_object. | |
498 | */ | |
499 | static void free_object_rcu(struct rcu_head *rcu) | |
500 | { | |
b67bfe0d | 501 | struct hlist_node *tmp; |
3c7b4e6b CM |
502 | struct kmemleak_scan_area *area; |
503 | struct kmemleak_object *object = | |
504 | container_of(rcu, struct kmemleak_object, rcu); | |
505 | ||
506 | /* | |
507 | * Once use_count is 0 (guaranteed by put_object), there is no other | |
508 | * code accessing this object, hence no need for locking. | |
509 | */ | |
b67bfe0d SL |
510 | hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { |
511 | hlist_del(&area->node); | |
3c7b4e6b CM |
512 | kmem_cache_free(scan_area_cache, area); |
513 | } | |
0647398a | 514 | mem_pool_free(object); |
3c7b4e6b CM |
515 | } |
516 | ||
517 | /* | |
518 | * Decrement the object use_count. Once the count is 0, free the object using | |
519 | * an RCU callback. Since put_object() may be called via the kmemleak_free() -> | |
520 | * delete_object() path, the delayed RCU freeing ensures that there is no | |
521 | * recursive call to the kernel allocator. Lock-less RCU object_list traversal | |
522 | * is also possible. | |
523 | */ | |
524 | static void put_object(struct kmemleak_object *object) | |
525 | { | |
526 | if (!atomic_dec_and_test(&object->use_count)) | |
527 | return; | |
528 | ||
529 | /* should only get here after delete_object was called */ | |
530 | WARN_ON(object->flags & OBJECT_ALLOCATED); | |
531 | ||
c5665868 CM |
532 | /* |
533 | * It may be too early for the RCU callbacks, however, there is no | |
534 | * concurrent object_list traversal when !object_cache and all objects | |
535 | * came from the memory pool. Free the object directly. | |
536 | */ | |
537 | if (object_cache) | |
538 | call_rcu(&object->rcu, free_object_rcu); | |
539 | else | |
540 | free_object_rcu(&object->rcu); | |
3c7b4e6b CM |
541 | } |
542 | ||
543 | /* | |
85d3a316 | 544 | * Look up an object in the object search tree and increase its use_count. |
3c7b4e6b | 545 | */ |
0c24e061 PW |
546 | static struct kmemleak_object *__find_and_get_object(unsigned long ptr, int alias, |
547 | bool is_phys) | |
3c7b4e6b CM |
548 | { |
549 | unsigned long flags; | |
9fbed254 | 550 | struct kmemleak_object *object; |
3c7b4e6b CM |
551 | |
552 | rcu_read_lock(); | |
8c96f1bc | 553 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
0c24e061 | 554 | object = __lookup_object(ptr, alias, is_phys); |
8c96f1bc | 555 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
3c7b4e6b CM |
556 | |
557 | /* check whether the object is still available */ | |
558 | if (object && !get_object(object)) | |
559 | object = NULL; | |
560 | rcu_read_unlock(); | |
561 | ||
562 | return object; | |
563 | } | |
564 | ||
0c24e061 PW |
565 | /* Look up and get an object which allocated with virtual address. */ |
566 | static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) | |
567 | { | |
568 | return __find_and_get_object(ptr, alias, false); | |
569 | } | |
570 | ||
2abd839a | 571 | /* |
0c24e061 PW |
572 | * Remove an object from the object_tree_root (or object_phys_tree_root) |
573 | * and object_list. Must be called with the kmemleak_lock held _if_ kmemleak | |
574 | * is still enabled. | |
2abd839a CM |
575 | */ |
576 | static void __remove_object(struct kmemleak_object *object) | |
577 | { | |
0c24e061 PW |
578 | rb_erase(&object->rb_node, object->flags & OBJECT_PHYS ? |
579 | &object_phys_tree_root : | |
580 | &object_tree_root); | |
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, | |
588 | bool is_phys) | |
589 | { | |
590 | struct kmemleak_object *object; | |
591 | ||
592 | object = __lookup_object(ptr, alias, is_phys); | |
593 | if (object) | |
594 | __remove_object(object); | |
595 | ||
596 | return object; | |
597 | } | |
598 | ||
e781a9ab CM |
599 | /* |
600 | * Look up an object in the object search tree and remove it from both | |
0c24e061 PW |
601 | * object_tree_root (or object_phys_tree_root) and object_list. The |
602 | * returned object's use_count should be at least 1, as initially set | |
603 | * by create_object(). | |
e781a9ab | 604 | */ |
0c24e061 PW |
605 | static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias, |
606 | bool is_phys) | |
e781a9ab CM |
607 | { |
608 | unsigned long flags; | |
609 | struct kmemleak_object *object; | |
610 | ||
8c96f1bc | 611 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
858a195b | 612 | object = __find_and_remove_object(ptr, alias, is_phys); |
8c96f1bc | 613 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
e781a9ab CM |
614 | |
615 | return object; | |
616 | } | |
617 | ||
56a61617 | 618 | static noinline depot_stack_handle_t set_track_prepare(void) |
fd678967 | 619 | { |
56a61617 ZH |
620 | depot_stack_handle_t trace_handle; |
621 | unsigned long entries[MAX_TRACE]; | |
622 | unsigned int nr_entries; | |
623 | ||
835bc157 XW |
624 | /* |
625 | * Use object_cache to determine whether kmemleak_init() has | |
626 | * been invoked. stack_depot_early_init() is called before | |
627 | * kmemleak_init() in mm_core_init(). | |
628 | */ | |
629 | if (!object_cache) | |
56a61617 ZH |
630 | return 0; |
631 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); | |
632 | trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); | |
633 | ||
634 | return trace_handle; | |
fd678967 CM |
635 | } |
636 | ||
0edd7b58 | 637 | static struct kmemleak_object *__alloc_object(gfp_t gfp) |
3c7b4e6b | 638 | { |
0edd7b58 | 639 | struct kmemleak_object *object; |
3c7b4e6b | 640 | |
0647398a | 641 | object = mem_pool_alloc(gfp); |
3c7b4e6b | 642 | if (!object) { |
598d8091 | 643 | pr_warn("Cannot allocate a kmemleak_object structure\n"); |
6ae4bd1f | 644 | kmemleak_disable(); |
4eff7d62 | 645 | return NULL; |
3c7b4e6b CM |
646 | } |
647 | ||
648 | INIT_LIST_HEAD(&object->object_list); | |
649 | INIT_LIST_HEAD(&object->gray_list); | |
650 | INIT_HLIST_HEAD(&object->area_list); | |
8c96f1bc | 651 | raw_spin_lock_init(&object->lock); |
3c7b4e6b | 652 | atomic_set(&object->use_count, 1); |
94f4a161 | 653 | object->excess_ref = 0; |
04609ccc | 654 | object->count = 0; /* white color initially */ |
04609ccc | 655 | object->checksum = 0; |
782e4179 | 656 | object->del_state = 0; |
3c7b4e6b CM |
657 | |
658 | /* task information */ | |
ea0eafea | 659 | if (in_hardirq()) { |
3c7b4e6b CM |
660 | object->pid = 0; |
661 | strncpy(object->comm, "hardirq", sizeof(object->comm)); | |
6ef90569 | 662 | } else if (in_serving_softirq()) { |
3c7b4e6b CM |
663 | object->pid = 0; |
664 | strncpy(object->comm, "softirq", sizeof(object->comm)); | |
665 | } else { | |
666 | object->pid = current->pid; | |
667 | /* | |
668 | * There is a small chance of a race with set_task_comm(), | |
669 | * however using get_task_comm() here may cause locking | |
670 | * dependency issues with current->alloc_lock. In the worst | |
671 | * case, the command line is not correct. | |
672 | */ | |
673 | strncpy(object->comm, current->comm, sizeof(object->comm)); | |
674 | } | |
675 | ||
676 | /* kernel backtrace */ | |
56a61617 | 677 | object->trace_handle = set_track_prepare(); |
3c7b4e6b | 678 | |
4eff7d62 LS |
679 | return object; |
680 | } | |
681 | ||
682 | static int __link_object(struct kmemleak_object *object, unsigned long ptr, | |
683 | size_t size, int min_count, bool is_phys) | |
684 | { | |
685 | ||
686 | struct kmemleak_object *parent; | |
687 | struct rb_node **link, *rb_parent; | |
688 | unsigned long untagged_ptr; | |
689 | unsigned long untagged_objp; | |
690 | ||
691 | object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0); | |
692 | object->pointer = ptr; | |
693 | object->size = kfence_ksize((void *)ptr) ?: size; | |
694 | object->min_count = min_count; | |
695 | object->jiffies = jiffies; | |
696 | ||
a2f77575 | 697 | untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); |
0c24e061 PW |
698 | /* |
699 | * Only update min_addr and max_addr with object | |
700 | * storing virtual address. | |
701 | */ | |
702 | if (!is_phys) { | |
703 | min_addr = min(min_addr, untagged_ptr); | |
704 | max_addr = max(max_addr, untagged_ptr + size); | |
705 | } | |
706 | link = is_phys ? &object_phys_tree_root.rb_node : | |
707 | &object_tree_root.rb_node; | |
85d3a316 ML |
708 | rb_parent = NULL; |
709 | while (*link) { | |
710 | rb_parent = *link; | |
711 | parent = rb_entry(rb_parent, struct kmemleak_object, rb_node); | |
ad1a3e15 KYL |
712 | untagged_objp = (unsigned long)kasan_reset_tag((void *)parent->pointer); |
713 | if (untagged_ptr + size <= untagged_objp) | |
85d3a316 | 714 | link = &parent->rb_node.rb_left; |
ad1a3e15 | 715 | else if (untagged_objp + parent->size <= untagged_ptr) |
85d3a316 ML |
716 | link = &parent->rb_node.rb_right; |
717 | else { | |
756a025f | 718 | kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n", |
85d3a316 | 719 | ptr); |
9d5a4c73 CM |
720 | /* |
721 | * No need for parent->lock here since "parent" cannot | |
722 | * be freed while the kmemleak_lock is held. | |
723 | */ | |
724 | dump_object_info(parent); | |
2e1d4738 | 725 | return -EEXIST; |
85d3a316 | 726 | } |
3c7b4e6b | 727 | } |
85d3a316 | 728 | rb_link_node(&object->rb_node, rb_parent, link); |
0c24e061 PW |
729 | rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root : |
730 | &object_tree_root); | |
3c7b4e6b | 731 | list_add_tail_rcu(&object->object_list, &object_list); |
2e1d4738 LS |
732 | |
733 | return 0; | |
0edd7b58 LS |
734 | } |
735 | ||
736 | /* | |
737 | * Create the metadata (struct kmemleak_object) corresponding to an allocated | |
738 | * memory block and add it to the object_list and object_tree_root (or | |
739 | * object_phys_tree_root). | |
740 | */ | |
741 | static void __create_object(unsigned long ptr, size_t size, | |
742 | int min_count, gfp_t gfp, bool is_phys) | |
743 | { | |
744 | struct kmemleak_object *object; | |
745 | unsigned long flags; | |
2e1d4738 | 746 | int ret; |
0edd7b58 LS |
747 | |
748 | object = __alloc_object(gfp); | |
749 | if (!object) | |
750 | return; | |
751 | ||
752 | raw_spin_lock_irqsave(&kmemleak_lock, flags); | |
2e1d4738 | 753 | ret = __link_object(object, ptr, size, min_count, is_phys); |
8c96f1bc | 754 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
2e1d4738 LS |
755 | if (ret) |
756 | mem_pool_free(object); | |
3c7b4e6b CM |
757 | } |
758 | ||
8e0c4ab3 | 759 | /* Create kmemleak object which allocated with virtual address. */ |
b955aa70 LS |
760 | static void create_object(unsigned long ptr, size_t size, |
761 | int min_count, gfp_t gfp) | |
8e0c4ab3 | 762 | { |
b955aa70 | 763 | __create_object(ptr, size, min_count, gfp, false); |
8e0c4ab3 PW |
764 | } |
765 | ||
766 | /* Create kmemleak object which allocated with physical address. */ | |
b955aa70 LS |
767 | static void create_object_phys(unsigned long ptr, size_t size, |
768 | int min_count, gfp_t gfp) | |
8e0c4ab3 | 769 | { |
b955aa70 | 770 | __create_object(ptr, size, min_count, gfp, true); |
8e0c4ab3 PW |
771 | } |
772 | ||
3c7b4e6b | 773 | /* |
e781a9ab | 774 | * Mark the object as not allocated and schedule RCU freeing via put_object(). |
3c7b4e6b | 775 | */ |
53238a60 | 776 | static void __delete_object(struct kmemleak_object *object) |
3c7b4e6b CM |
777 | { |
778 | unsigned long flags; | |
3c7b4e6b | 779 | |
3c7b4e6b | 780 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
e781a9ab | 781 | WARN_ON(atomic_read(&object->use_count) < 1); |
3c7b4e6b CM |
782 | |
783 | /* | |
784 | * Locking here also ensures that the corresponding memory block | |
785 | * cannot be freed when it is being scanned. | |
786 | */ | |
8c96f1bc | 787 | raw_spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b | 788 | object->flags &= ~OBJECT_ALLOCATED; |
8c96f1bc | 789 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
790 | put_object(object); |
791 | } | |
792 | ||
53238a60 CM |
793 | /* |
794 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
795 | * delete it. | |
796 | */ | |
797 | static void delete_object_full(unsigned long ptr) | |
798 | { | |
799 | struct kmemleak_object *object; | |
800 | ||
0c24e061 | 801 | object = find_and_remove_object(ptr, 0, false); |
53238a60 CM |
802 | if (!object) { |
803 | #ifdef DEBUG | |
804 | kmemleak_warn("Freeing unknown object at 0x%08lx\n", | |
805 | ptr); | |
806 | #endif | |
807 | return; | |
808 | } | |
809 | __delete_object(object); | |
53238a60 CM |
810 | } |
811 | ||
812 | /* | |
813 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and | |
814 | * delete it. If the memory block is partially freed, the function may create | |
815 | * additional metadata for the remaining parts of the block. | |
816 | */ | |
0c24e061 | 817 | static void delete_object_part(unsigned long ptr, size_t size, bool is_phys) |
53238a60 | 818 | { |
5e4fc577 LS |
819 | struct kmemleak_object *object, *object_l, *object_r; |
820 | unsigned long start, end, flags; | |
821 | ||
822 | object_l = __alloc_object(GFP_KERNEL); | |
823 | if (!object_l) | |
824 | return; | |
53238a60 | 825 | |
5e4fc577 LS |
826 | object_r = __alloc_object(GFP_KERNEL); |
827 | if (!object_r) | |
828 | goto out; | |
829 | ||
830 | raw_spin_lock_irqsave(&kmemleak_lock, flags); | |
831 | object = __find_and_remove_object(ptr, 1, is_phys); | |
53238a60 CM |
832 | if (!object) { |
833 | #ifdef DEBUG | |
756a025f JP |
834 | kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", |
835 | ptr, size); | |
53238a60 | 836 | #endif |
5e4fc577 | 837 | goto unlock; |
53238a60 | 838 | } |
53238a60 CM |
839 | |
840 | /* | |
841 | * Create one or two objects that may result from the memory block | |
842 | * split. Note that partial freeing is only done by free_bootmem() and | |
c5665868 | 843 | * this happens before kmemleak_init() is called. |
53238a60 CM |
844 | */ |
845 | start = object->pointer; | |
846 | end = object->pointer + object->size; | |
5e4fc577 LS |
847 | if ((ptr > start) && |
848 | !__link_object(object_l, start, ptr - start, | |
849 | object->min_count, is_phys)) | |
850 | object_l = NULL; | |
851 | if ((ptr + size < end) && | |
852 | !__link_object(object_r, ptr + size, end - ptr - size, | |
853 | object->min_count, is_phys)) | |
854 | object_r = NULL; | |
855 | ||
856 | unlock: | |
857 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); | |
858 | if (object) | |
859 | __delete_object(object); | |
53238a60 | 860 | |
5e4fc577 LS |
861 | out: |
862 | if (object_l) | |
863 | mem_pool_free(object_l); | |
864 | if (object_r) | |
865 | mem_pool_free(object_r); | |
53238a60 | 866 | } |
a1084c87 LR |
867 | |
868 | static void __paint_it(struct kmemleak_object *object, int color) | |
869 | { | |
870 | object->min_count = color; | |
871 | if (color == KMEMLEAK_BLACK) | |
872 | object->flags |= OBJECT_NO_SCAN; | |
873 | } | |
874 | ||
875 | static void paint_it(struct kmemleak_object *object, int color) | |
3c7b4e6b CM |
876 | { |
877 | unsigned long flags; | |
a1084c87 | 878 | |
8c96f1bc | 879 | raw_spin_lock_irqsave(&object->lock, flags); |
a1084c87 | 880 | __paint_it(object, color); |
8c96f1bc | 881 | raw_spin_unlock_irqrestore(&object->lock, flags); |
a1084c87 LR |
882 | } |
883 | ||
0c24e061 | 884 | static void paint_ptr(unsigned long ptr, int color, bool is_phys) |
a1084c87 | 885 | { |
3c7b4e6b CM |
886 | struct kmemleak_object *object; |
887 | ||
0c24e061 | 888 | object = __find_and_get_object(ptr, 0, is_phys); |
3c7b4e6b | 889 | if (!object) { |
756a025f JP |
890 | kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n", |
891 | ptr, | |
a1084c87 LR |
892 | (color == KMEMLEAK_GREY) ? "Grey" : |
893 | (color == KMEMLEAK_BLACK) ? "Black" : "Unknown"); | |
3c7b4e6b CM |
894 | return; |
895 | } | |
a1084c87 | 896 | paint_it(object, color); |
3c7b4e6b CM |
897 | put_object(object); |
898 | } | |
899 | ||
a1084c87 | 900 | /* |
145b64b9 | 901 | * Mark an object permanently as gray-colored so that it can no longer be |
a1084c87 LR |
902 | * reported as a leak. This is used in general to mark a false positive. |
903 | */ | |
904 | static void make_gray_object(unsigned long ptr) | |
905 | { | |
0c24e061 | 906 | paint_ptr(ptr, KMEMLEAK_GREY, false); |
a1084c87 LR |
907 | } |
908 | ||
3c7b4e6b CM |
909 | /* |
910 | * Mark the object as black-colored so that it is ignored from scans and | |
911 | * reporting. | |
912 | */ | |
0c24e061 | 913 | static void make_black_object(unsigned long ptr, bool is_phys) |
3c7b4e6b | 914 | { |
0c24e061 | 915 | paint_ptr(ptr, KMEMLEAK_BLACK, is_phys); |
3c7b4e6b CM |
916 | } |
917 | ||
918 | /* | |
919 | * Add a scanning area to the object. If at least one such area is added, | |
920 | * kmemleak will only scan these ranges rather than the whole memory block. | |
921 | */ | |
c017b4be | 922 | static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
3c7b4e6b CM |
923 | { |
924 | unsigned long flags; | |
925 | struct kmemleak_object *object; | |
c5665868 | 926 | struct kmemleak_scan_area *area = NULL; |
bfc8089f KYL |
927 | unsigned long untagged_ptr; |
928 | unsigned long untagged_objp; | |
3c7b4e6b | 929 | |
c017b4be | 930 | object = find_and_get_object(ptr, 1); |
3c7b4e6b | 931 | if (!object) { |
ae281064 JP |
932 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
933 | ptr); | |
3c7b4e6b CM |
934 | return; |
935 | } | |
936 | ||
bfc8089f KYL |
937 | untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); |
938 | untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); | |
939 | ||
c5665868 CM |
940 | if (scan_area_cache) |
941 | area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); | |
3c7b4e6b | 942 | |
8c96f1bc | 943 | raw_spin_lock_irqsave(&object->lock, flags); |
dba82d94 CM |
944 | if (!area) { |
945 | pr_warn_once("Cannot allocate a scan area, scanning the full object\n"); | |
946 | /* mark the object for full scan to avoid false positives */ | |
947 | object->flags |= OBJECT_FULL_SCAN; | |
948 | goto out_unlock; | |
949 | } | |
7f88f88f | 950 | if (size == SIZE_MAX) { |
bfc8089f KYL |
951 | size = untagged_objp + object->size - untagged_ptr; |
952 | } else if (untagged_ptr + size > untagged_objp + object->size) { | |
ae281064 | 953 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
3c7b4e6b CM |
954 | dump_object_info(object); |
955 | kmem_cache_free(scan_area_cache, area); | |
956 | goto out_unlock; | |
957 | } | |
958 | ||
959 | INIT_HLIST_NODE(&area->node); | |
c017b4be CM |
960 | area->start = ptr; |
961 | area->size = size; | |
3c7b4e6b CM |
962 | |
963 | hlist_add_head(&area->node, &object->area_list); | |
964 | out_unlock: | |
8c96f1bc | 965 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
966 | put_object(object); |
967 | } | |
968 | ||
94f4a161 CM |
969 | /* |
970 | * Any surplus references (object already gray) to 'ptr' are passed to | |
971 | * 'excess_ref'. This is used in the vmalloc() case where a pointer to | |
972 | * vm_struct may be used as an alternative reference to the vmalloc'ed object | |
973 | * (see free_thread_stack()). | |
974 | */ | |
975 | static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref) | |
976 | { | |
977 | unsigned long flags; | |
978 | struct kmemleak_object *object; | |
979 | ||
980 | object = find_and_get_object(ptr, 0); | |
981 | if (!object) { | |
982 | kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n", | |
983 | ptr); | |
984 | return; | |
985 | } | |
986 | ||
8c96f1bc | 987 | raw_spin_lock_irqsave(&object->lock, flags); |
94f4a161 | 988 | object->excess_ref = excess_ref; |
8c96f1bc | 989 | raw_spin_unlock_irqrestore(&object->lock, flags); |
94f4a161 CM |
990 | put_object(object); |
991 | } | |
992 | ||
3c7b4e6b CM |
993 | /* |
994 | * Set the OBJECT_NO_SCAN flag for the object corresponding to the give | |
995 | * pointer. Such object will not be scanned by kmemleak but references to it | |
996 | * are searched. | |
997 | */ | |
998 | static void object_no_scan(unsigned long ptr) | |
999 | { | |
1000 | unsigned long flags; | |
1001 | struct kmemleak_object *object; | |
1002 | ||
1003 | object = find_and_get_object(ptr, 0); | |
1004 | if (!object) { | |
ae281064 | 1005 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
3c7b4e6b CM |
1006 | return; |
1007 | } | |
1008 | ||
8c96f1bc | 1009 | raw_spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b | 1010 | object->flags |= OBJECT_NO_SCAN; |
8c96f1bc | 1011 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
1012 | put_object(object); |
1013 | } | |
1014 | ||
a2b6bf63 CM |
1015 | /** |
1016 | * kmemleak_alloc - register a newly allocated object | |
1017 | * @ptr: pointer to beginning of the object | |
1018 | * @size: size of the object | |
1019 | * @min_count: minimum number of references to this object. If during memory | |
1020 | * scanning a number of references less than @min_count is found, | |
1021 | * the object is reported as a memory leak. If @min_count is 0, | |
1022 | * the object is never reported as a leak. If @min_count is -1, | |
1023 | * the object is ignored (not scanned and not reported as a leak) | |
1024 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1025 | * | |
1026 | * This function is called from the kernel allocators when a new object | |
94f4a161 | 1027 | * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.). |
3c7b4e6b | 1028 | */ |
a6186d89 CM |
1029 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
1030 | gfp_t gfp) | |
3c7b4e6b | 1031 | { |
62047e0f | 1032 | pr_debug("%s(0x%px, %zu, %d)\n", __func__, ptr, size, min_count); |
3c7b4e6b | 1033 | |
8910ae89 | 1034 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1035 | create_object((unsigned long)ptr, size, min_count, gfp); |
3c7b4e6b CM |
1036 | } |
1037 | EXPORT_SYMBOL_GPL(kmemleak_alloc); | |
1038 | ||
f528f0b8 CM |
1039 | /** |
1040 | * kmemleak_alloc_percpu - register a newly allocated __percpu object | |
1041 | * @ptr: __percpu pointer to beginning of the object | |
1042 | * @size: size of the object | |
8a8c35fa | 1043 | * @gfp: flags used for kmemleak internal memory allocations |
f528f0b8 CM |
1044 | * |
1045 | * This function is called from the kernel percpu allocator when a new object | |
8a8c35fa | 1046 | * (memory block) is allocated (alloc_percpu). |
f528f0b8 | 1047 | */ |
8a8c35fa LF |
1048 | void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, |
1049 | gfp_t gfp) | |
f528f0b8 CM |
1050 | { |
1051 | unsigned int cpu; | |
1052 | ||
62047e0f | 1053 | pr_debug("%s(0x%px, %zu)\n", __func__, ptr, size); |
f528f0b8 CM |
1054 | |
1055 | /* | |
1056 | * Percpu allocations are only scanned and not reported as leaks | |
1057 | * (min_count is set to 0). | |
1058 | */ | |
8910ae89 | 1059 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
1060 | for_each_possible_cpu(cpu) |
1061 | create_object((unsigned long)per_cpu_ptr(ptr, cpu), | |
8a8c35fa | 1062 | size, 0, gfp); |
f528f0b8 CM |
1063 | } |
1064 | EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); | |
1065 | ||
94f4a161 CM |
1066 | /** |
1067 | * kmemleak_vmalloc - register a newly vmalloc'ed object | |
1068 | * @area: pointer to vm_struct | |
1069 | * @size: size of the object | |
1070 | * @gfp: __vmalloc() flags used for kmemleak internal memory allocations | |
1071 | * | |
1072 | * This function is called from the vmalloc() kernel allocator when a new | |
1073 | * object (memory block) is allocated. | |
1074 | */ | |
1075 | void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp) | |
1076 | { | |
62047e0f | 1077 | pr_debug("%s(0x%px, %zu)\n", __func__, area, size); |
94f4a161 CM |
1078 | |
1079 | /* | |
1080 | * A min_count = 2 is needed because vm_struct contains a reference to | |
1081 | * the virtual address of the vmalloc'ed block. | |
1082 | */ | |
1083 | if (kmemleak_enabled) { | |
1084 | create_object((unsigned long)area->addr, size, 2, gfp); | |
1085 | object_set_excess_ref((unsigned long)area, | |
1086 | (unsigned long)area->addr); | |
94f4a161 CM |
1087 | } |
1088 | } | |
1089 | EXPORT_SYMBOL_GPL(kmemleak_vmalloc); | |
1090 | ||
a2b6bf63 CM |
1091 | /** |
1092 | * kmemleak_free - unregister a previously registered object | |
1093 | * @ptr: pointer to beginning of the object | |
1094 | * | |
1095 | * This function is called from the kernel allocators when an object (memory | |
1096 | * block) is freed (kmem_cache_free, kfree, vfree etc.). | |
3c7b4e6b | 1097 | */ |
a6186d89 | 1098 | void __ref kmemleak_free(const void *ptr) |
3c7b4e6b | 1099 | { |
62047e0f | 1100 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1101 | |
c5f3b1a5 | 1102 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
53238a60 | 1103 | delete_object_full((unsigned long)ptr); |
3c7b4e6b CM |
1104 | } |
1105 | EXPORT_SYMBOL_GPL(kmemleak_free); | |
1106 | ||
a2b6bf63 CM |
1107 | /** |
1108 | * kmemleak_free_part - partially unregister a previously registered object | |
1109 | * @ptr: pointer to the beginning or inside the object. This also | |
1110 | * represents the start of the range to be freed | |
1111 | * @size: size to be unregistered | |
1112 | * | |
1113 | * This function is called when only a part of a memory block is freed | |
1114 | * (usually from the bootmem allocator). | |
53238a60 | 1115 | */ |
a6186d89 | 1116 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
53238a60 | 1117 | { |
62047e0f | 1118 | pr_debug("%s(0x%px)\n", __func__, ptr); |
53238a60 | 1119 | |
8910ae89 | 1120 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
0c24e061 | 1121 | delete_object_part((unsigned long)ptr, size, false); |
53238a60 CM |
1122 | } |
1123 | EXPORT_SYMBOL_GPL(kmemleak_free_part); | |
1124 | ||
f528f0b8 CM |
1125 | /** |
1126 | * kmemleak_free_percpu - unregister a previously registered __percpu object | |
1127 | * @ptr: __percpu pointer to beginning of the object | |
1128 | * | |
1129 | * This function is called from the kernel percpu allocator when an object | |
1130 | * (memory block) is freed (free_percpu). | |
1131 | */ | |
1132 | void __ref kmemleak_free_percpu(const void __percpu *ptr) | |
1133 | { | |
1134 | unsigned int cpu; | |
1135 | ||
62047e0f | 1136 | pr_debug("%s(0x%px)\n", __func__, ptr); |
f528f0b8 | 1137 | |
c5f3b1a5 | 1138 | if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8 CM |
1139 | for_each_possible_cpu(cpu) |
1140 | delete_object_full((unsigned long)per_cpu_ptr(ptr, | |
1141 | cpu)); | |
f528f0b8 CM |
1142 | } |
1143 | EXPORT_SYMBOL_GPL(kmemleak_free_percpu); | |
1144 | ||
ffe2c748 CM |
1145 | /** |
1146 | * kmemleak_update_trace - update object allocation stack trace | |
1147 | * @ptr: pointer to beginning of the object | |
1148 | * | |
1149 | * Override the object allocation stack trace for cases where the actual | |
1150 | * allocation place is not always useful. | |
1151 | */ | |
1152 | void __ref kmemleak_update_trace(const void *ptr) | |
1153 | { | |
1154 | struct kmemleak_object *object; | |
d63385a7 | 1155 | depot_stack_handle_t trace_handle; |
ffe2c748 CM |
1156 | unsigned long flags; |
1157 | ||
62047e0f | 1158 | pr_debug("%s(0x%px)\n", __func__, ptr); |
ffe2c748 CM |
1159 | |
1160 | if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr)) | |
1161 | return; | |
1162 | ||
1163 | object = find_and_get_object((unsigned long)ptr, 1); | |
1164 | if (!object) { | |
1165 | #ifdef DEBUG | |
1166 | kmemleak_warn("Updating stack trace for unknown object at %p\n", | |
1167 | ptr); | |
1168 | #endif | |
1169 | return; | |
1170 | } | |
1171 | ||
d63385a7 | 1172 | trace_handle = set_track_prepare(); |
8c96f1bc | 1173 | raw_spin_lock_irqsave(&object->lock, flags); |
d63385a7 | 1174 | object->trace_handle = trace_handle; |
8c96f1bc | 1175 | raw_spin_unlock_irqrestore(&object->lock, flags); |
ffe2c748 CM |
1176 | |
1177 | put_object(object); | |
1178 | } | |
1179 | EXPORT_SYMBOL(kmemleak_update_trace); | |
1180 | ||
a2b6bf63 CM |
1181 | /** |
1182 | * kmemleak_not_leak - mark an allocated object as false positive | |
1183 | * @ptr: pointer to beginning of the object | |
1184 | * | |
1185 | * Calling this function on an object will cause the memory block to no longer | |
1186 | * be reported as leak and always be scanned. | |
3c7b4e6b | 1187 | */ |
a6186d89 | 1188 | void __ref kmemleak_not_leak(const void *ptr) |
3c7b4e6b | 1189 | { |
62047e0f | 1190 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1191 | |
8910ae89 | 1192 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1193 | make_gray_object((unsigned long)ptr); |
3c7b4e6b CM |
1194 | } |
1195 | EXPORT_SYMBOL(kmemleak_not_leak); | |
1196 | ||
a2b6bf63 CM |
1197 | /** |
1198 | * kmemleak_ignore - ignore an allocated object | |
1199 | * @ptr: pointer to beginning of the object | |
1200 | * | |
1201 | * Calling this function on an object will cause the memory block to be | |
1202 | * ignored (not scanned and not reported as a leak). This is usually done when | |
1203 | * it is known that the corresponding block is not a leak and does not contain | |
1204 | * any references to other allocated memory blocks. | |
3c7b4e6b | 1205 | */ |
a6186d89 | 1206 | void __ref kmemleak_ignore(const void *ptr) |
3c7b4e6b | 1207 | { |
62047e0f | 1208 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1209 | |
8910ae89 | 1210 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
0c24e061 | 1211 | make_black_object((unsigned long)ptr, false); |
3c7b4e6b CM |
1212 | } |
1213 | EXPORT_SYMBOL(kmemleak_ignore); | |
1214 | ||
a2b6bf63 CM |
1215 | /** |
1216 | * kmemleak_scan_area - limit the range to be scanned in an allocated object | |
1217 | * @ptr: pointer to beginning or inside the object. This also | |
1218 | * represents the start of the scan area | |
1219 | * @size: size of the scan area | |
1220 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations | |
1221 | * | |
1222 | * This function is used when it is known that only certain parts of an object | |
1223 | * contain references to other objects. Kmemleak will only scan these areas | |
1224 | * reducing the number false negatives. | |
3c7b4e6b | 1225 | */ |
c017b4be | 1226 | void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
3c7b4e6b | 1227 | { |
62047e0f | 1228 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1229 | |
8910ae89 | 1230 | if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
c017b4be | 1231 | add_scan_area((unsigned long)ptr, size, gfp); |
3c7b4e6b CM |
1232 | } |
1233 | EXPORT_SYMBOL(kmemleak_scan_area); | |
1234 | ||
a2b6bf63 CM |
1235 | /** |
1236 | * kmemleak_no_scan - do not scan an allocated object | |
1237 | * @ptr: pointer to beginning of the object | |
1238 | * | |
1239 | * This function notifies kmemleak not to scan the given memory block. Useful | |
1240 | * in situations where it is known that the given object does not contain any | |
1241 | * references to other objects. Kmemleak will not scan such objects reducing | |
1242 | * the number of false negatives. | |
3c7b4e6b | 1243 | */ |
a6186d89 | 1244 | void __ref kmemleak_no_scan(const void *ptr) |
3c7b4e6b | 1245 | { |
62047e0f | 1246 | pr_debug("%s(0x%px)\n", __func__, ptr); |
3c7b4e6b | 1247 | |
8910ae89 | 1248 | if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b | 1249 | object_no_scan((unsigned long)ptr); |
3c7b4e6b CM |
1250 | } |
1251 | EXPORT_SYMBOL(kmemleak_no_scan); | |
1252 | ||
9099daed CM |
1253 | /** |
1254 | * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical | |
1255 | * address argument | |
e8b098fc MR |
1256 | * @phys: physical address of the object |
1257 | * @size: size of the object | |
e8b098fc | 1258 | * @gfp: kmalloc() flags used for kmemleak internal memory allocations |
9099daed | 1259 | */ |
c200d900 | 1260 | void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp) |
9099daed | 1261 | { |
62047e0f | 1262 | pr_debug("%s(0x%px, %zu)\n", __func__, &phys, size); |
8e0c4ab3 | 1263 | |
84c32629 | 1264 | if (kmemleak_enabled) |
8e0c4ab3 PW |
1265 | /* |
1266 | * Create object with OBJECT_PHYS flag and | |
1267 | * assume min_count 0. | |
1268 | */ | |
0c24e061 | 1269 | create_object_phys((unsigned long)phys, size, 0, gfp); |
9099daed CM |
1270 | } |
1271 | EXPORT_SYMBOL(kmemleak_alloc_phys); | |
1272 | ||
1273 | /** | |
1274 | * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a | |
1275 | * physical address argument | |
e8b098fc MR |
1276 | * @phys: physical address if the beginning or inside an object. This |
1277 | * also represents the start of the range to be freed | |
1278 | * @size: size to be unregistered | |
9099daed CM |
1279 | */ |
1280 | void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size) | |
1281 | { | |
62047e0f | 1282 | pr_debug("%s(0x%px)\n", __func__, &phys); |
0c24e061 | 1283 | |
84c32629 | 1284 | if (kmemleak_enabled) |
0c24e061 | 1285 | delete_object_part((unsigned long)phys, size, true); |
9099daed CM |
1286 | } |
1287 | EXPORT_SYMBOL(kmemleak_free_part_phys); | |
1288 | ||
9099daed CM |
1289 | /** |
1290 | * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical | |
1291 | * address argument | |
e8b098fc | 1292 | * @phys: physical address of the object |
9099daed CM |
1293 | */ |
1294 | void __ref kmemleak_ignore_phys(phys_addr_t phys) | |
1295 | { | |
62047e0f | 1296 | pr_debug("%s(0x%px)\n", __func__, &phys); |
0c24e061 | 1297 | |
84c32629 | 1298 | if (kmemleak_enabled) |
0c24e061 | 1299 | make_black_object((unsigned long)phys, true); |
9099daed CM |
1300 | } |
1301 | EXPORT_SYMBOL(kmemleak_ignore_phys); | |
1302 | ||
04609ccc CM |
1303 | /* |
1304 | * Update an object's checksum and return true if it was modified. | |
1305 | */ | |
1306 | static bool update_checksum(struct kmemleak_object *object) | |
1307 | { | |
1308 | u32 old_csum = object->checksum; | |
1309 | ||
0c24e061 PW |
1310 | if (WARN_ON_ONCE(object->flags & OBJECT_PHYS)) |
1311 | return false; | |
1312 | ||
e79ed2f1 | 1313 | kasan_disable_current(); |
69d0b54d | 1314 | kcsan_disable_current(); |
6c7a00b8 | 1315 | object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size); |
e79ed2f1 | 1316 | kasan_enable_current(); |
69d0b54d | 1317 | kcsan_enable_current(); |
e79ed2f1 | 1318 | |
04609ccc CM |
1319 | return object->checksum != old_csum; |
1320 | } | |
1321 | ||
04f70d13 CM |
1322 | /* |
1323 | * Update an object's references. object->lock must be held by the caller. | |
1324 | */ | |
1325 | static void update_refs(struct kmemleak_object *object) | |
1326 | { | |
1327 | if (!color_white(object)) { | |
1328 | /* non-orphan, ignored or new */ | |
1329 | return; | |
1330 | } | |
1331 | ||
1332 | /* | |
1333 | * Increase the object's reference count (number of pointers to the | |
1334 | * memory block). If this count reaches the required minimum, the | |
1335 | * object's color will become gray and it will be added to the | |
1336 | * gray_list. | |
1337 | */ | |
1338 | object->count++; | |
1339 | if (color_gray(object)) { | |
1340 | /* put_object() called when removing from gray_list */ | |
1341 | WARN_ON(!get_object(object)); | |
1342 | list_add_tail(&object->gray_list, &gray_list); | |
1343 | } | |
1344 | } | |
1345 | ||
3c7b4e6b | 1346 | /* |
0b5121ef | 1347 | * Memory scanning is a long process and it needs to be interruptible. This |
25985edc | 1348 | * function checks whether such interrupt condition occurred. |
3c7b4e6b CM |
1349 | */ |
1350 | static int scan_should_stop(void) | |
1351 | { | |
8910ae89 | 1352 | if (!kmemleak_enabled) |
3c7b4e6b CM |
1353 | return 1; |
1354 | ||
1355 | /* | |
1356 | * This function may be called from either process or kthread context, | |
1357 | * hence the need to check for both stop conditions. | |
1358 | */ | |
1359 | if (current->mm) | |
1360 | return signal_pending(current); | |
1361 | else | |
1362 | return kthread_should_stop(); | |
1363 | ||
1364 | return 0; | |
1365 | } | |
1366 | ||
1367 | /* | |
1368 | * Scan a memory block (exclusive range) for valid pointers and add those | |
1369 | * found to the gray list. | |
1370 | */ | |
1371 | static void scan_block(void *_start, void *_end, | |
93ada579 | 1372 | struct kmemleak_object *scanned) |
3c7b4e6b CM |
1373 | { |
1374 | unsigned long *ptr; | |
1375 | unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); | |
1376 | unsigned long *end = _end - (BYTES_PER_POINTER - 1); | |
93ada579 | 1377 | unsigned long flags; |
a2f77575 | 1378 | unsigned long untagged_ptr; |
3c7b4e6b | 1379 | |
8c96f1bc | 1380 | raw_spin_lock_irqsave(&kmemleak_lock, flags); |
3c7b4e6b | 1381 | for (ptr = start; ptr < end; ptr++) { |
3c7b4e6b | 1382 | struct kmemleak_object *object; |
8e019366 | 1383 | unsigned long pointer; |
94f4a161 | 1384 | unsigned long excess_ref; |
3c7b4e6b CM |
1385 | |
1386 | if (scan_should_stop()) | |
1387 | break; | |
1388 | ||
e79ed2f1 | 1389 | kasan_disable_current(); |
6c7a00b8 | 1390 | pointer = *(unsigned long *)kasan_reset_tag((void *)ptr); |
e79ed2f1 | 1391 | kasan_enable_current(); |
8e019366 | 1392 | |
a2f77575 AK |
1393 | untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer); |
1394 | if (untagged_ptr < min_addr || untagged_ptr >= max_addr) | |
93ada579 CM |
1395 | continue; |
1396 | ||
1397 | /* | |
1398 | * No need for get_object() here since we hold kmemleak_lock. | |
1399 | * object->use_count cannot be dropped to 0 while the object | |
1400 | * is still present in object_tree_root and object_list | |
1401 | * (with updates protected by kmemleak_lock). | |
1402 | */ | |
1403 | object = lookup_object(pointer, 1); | |
3c7b4e6b CM |
1404 | if (!object) |
1405 | continue; | |
93ada579 | 1406 | if (object == scanned) |
3c7b4e6b | 1407 | /* self referenced, ignore */ |
3c7b4e6b | 1408 | continue; |
3c7b4e6b CM |
1409 | |
1410 | /* | |
1411 | * Avoid the lockdep recursive warning on object->lock being | |
1412 | * previously acquired in scan_object(). These locks are | |
1413 | * enclosed by scan_mutex. | |
1414 | */ | |
8c96f1bc | 1415 | raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
94f4a161 CM |
1416 | /* only pass surplus references (object already gray) */ |
1417 | if (color_gray(object)) { | |
1418 | excess_ref = object->excess_ref; | |
1419 | /* no need for update_refs() if object already gray */ | |
1420 | } else { | |
1421 | excess_ref = 0; | |
1422 | update_refs(object); | |
1423 | } | |
8c96f1bc | 1424 | raw_spin_unlock(&object->lock); |
94f4a161 CM |
1425 | |
1426 | if (excess_ref) { | |
1427 | object = lookup_object(excess_ref, 0); | |
1428 | if (!object) | |
1429 | continue; | |
1430 | if (object == scanned) | |
1431 | /* circular reference, ignore */ | |
1432 | continue; | |
8c96f1bc | 1433 | raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
94f4a161 | 1434 | update_refs(object); |
8c96f1bc | 1435 | raw_spin_unlock(&object->lock); |
94f4a161 | 1436 | } |
93ada579 | 1437 | } |
8c96f1bc | 1438 | raw_spin_unlock_irqrestore(&kmemleak_lock, flags); |
93ada579 | 1439 | } |
0587da40 | 1440 | |
93ada579 CM |
1441 | /* |
1442 | * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency. | |
1443 | */ | |
dce5b0bd | 1444 | #ifdef CONFIG_SMP |
93ada579 CM |
1445 | static void scan_large_block(void *start, void *end) |
1446 | { | |
1447 | void *next; | |
1448 | ||
1449 | while (start < end) { | |
1450 | next = min(start + MAX_SCAN_SIZE, end); | |
1451 | scan_block(start, next, NULL); | |
1452 | start = next; | |
1453 | cond_resched(); | |
3c7b4e6b CM |
1454 | } |
1455 | } | |
dce5b0bd | 1456 | #endif |
3c7b4e6b CM |
1457 | |
1458 | /* | |
1459 | * Scan a memory block corresponding to a kmemleak_object. A condition is | |
1460 | * that object->use_count >= 1. | |
1461 | */ | |
1462 | static void scan_object(struct kmemleak_object *object) | |
1463 | { | |
1464 | struct kmemleak_scan_area *area; | |
3c7b4e6b | 1465 | unsigned long flags; |
0c24e061 | 1466 | void *obj_ptr; |
3c7b4e6b CM |
1467 | |
1468 | /* | |
21ae2956 UKK |
1469 | * Once the object->lock is acquired, the corresponding memory block |
1470 | * cannot be freed (the same lock is acquired in delete_object). | |
3c7b4e6b | 1471 | */ |
8c96f1bc | 1472 | raw_spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b CM |
1473 | if (object->flags & OBJECT_NO_SCAN) |
1474 | goto out; | |
1475 | if (!(object->flags & OBJECT_ALLOCATED)) | |
1476 | /* already freed object */ | |
1477 | goto out; | |
0c24e061 PW |
1478 | |
1479 | obj_ptr = object->flags & OBJECT_PHYS ? | |
1480 | __va((phys_addr_t)object->pointer) : | |
1481 | (void *)object->pointer; | |
1482 | ||
dba82d94 CM |
1483 | if (hlist_empty(&object->area_list) || |
1484 | object->flags & OBJECT_FULL_SCAN) { | |
0c24e061 PW |
1485 | void *start = obj_ptr; |
1486 | void *end = obj_ptr + object->size; | |
93ada579 CM |
1487 | void *next; |
1488 | ||
1489 | do { | |
1490 | next = min(start + MAX_SCAN_SIZE, end); | |
1491 | scan_block(start, next, object); | |
af98603d | 1492 | |
93ada579 CM |
1493 | start = next; |
1494 | if (start >= end) | |
1495 | break; | |
af98603d | 1496 | |
8c96f1bc | 1497 | raw_spin_unlock_irqrestore(&object->lock, flags); |
af98603d | 1498 | cond_resched(); |
8c96f1bc | 1499 | raw_spin_lock_irqsave(&object->lock, flags); |
93ada579 | 1500 | } while (object->flags & OBJECT_ALLOCATED); |
af98603d | 1501 | } else |
b67bfe0d | 1502 | hlist_for_each_entry(area, &object->area_list, node) |
c017b4be CM |
1503 | scan_block((void *)area->start, |
1504 | (void *)(area->start + area->size), | |
93ada579 | 1505 | object); |
3c7b4e6b | 1506 | out: |
8c96f1bc | 1507 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
1508 | } |
1509 | ||
04609ccc CM |
1510 | /* |
1511 | * Scan the objects already referenced (gray objects). More objects will be | |
1512 | * referenced and, if there are no memory leaks, all the objects are scanned. | |
1513 | */ | |
1514 | static void scan_gray_list(void) | |
1515 | { | |
1516 | struct kmemleak_object *object, *tmp; | |
1517 | ||
1518 | /* | |
1519 | * The list traversal is safe for both tail additions and removals | |
1520 | * from inside the loop. The kmemleak objects cannot be freed from | |
1521 | * outside the loop because their use_count was incremented. | |
1522 | */ | |
1523 | object = list_entry(gray_list.next, typeof(*object), gray_list); | |
1524 | while (&object->gray_list != &gray_list) { | |
1525 | cond_resched(); | |
1526 | ||
1527 | /* may add new objects to the list */ | |
1528 | if (!scan_should_stop()) | |
1529 | scan_object(object); | |
1530 | ||
1531 | tmp = list_entry(object->gray_list.next, typeof(*object), | |
1532 | gray_list); | |
1533 | ||
1534 | /* remove the object from the list and release it */ | |
1535 | list_del(&object->gray_list); | |
1536 | put_object(object); | |
1537 | ||
1538 | object = tmp; | |
1539 | } | |
1540 | WARN_ON(!list_empty(&gray_list)); | |
1541 | } | |
1542 | ||
984a6083 | 1543 | /* |
25e9fa22 | 1544 | * Conditionally call resched() in an object iteration loop while making sure |
984a6083 | 1545 | * that the given object won't go away without RCU read lock by performing a |
6061e740 | 1546 | * get_object() if necessaary. |
984a6083 | 1547 | */ |
6061e740 | 1548 | static void kmemleak_cond_resched(struct kmemleak_object *object) |
984a6083 | 1549 | { |
6061e740 WL |
1550 | if (!get_object(object)) |
1551 | return; /* Try next object */ | |
984a6083 | 1552 | |
782e4179 WL |
1553 | raw_spin_lock_irq(&kmemleak_lock); |
1554 | if (object->del_state & DELSTATE_REMOVED) | |
1555 | goto unlock_put; /* Object removed */ | |
1556 | object->del_state |= DELSTATE_NO_DELETE; | |
1557 | raw_spin_unlock_irq(&kmemleak_lock); | |
1558 | ||
984a6083 WL |
1559 | rcu_read_unlock(); |
1560 | cond_resched(); | |
1561 | rcu_read_lock(); | |
782e4179 WL |
1562 | |
1563 | raw_spin_lock_irq(&kmemleak_lock); | |
1564 | if (object->del_state & DELSTATE_REMOVED) | |
1565 | list_del_rcu(&object->object_list); | |
1566 | object->del_state &= ~DELSTATE_NO_DELETE; | |
1567 | unlock_put: | |
1568 | raw_spin_unlock_irq(&kmemleak_lock); | |
6061e740 | 1569 | put_object(object); |
984a6083 WL |
1570 | } |
1571 | ||
3c7b4e6b CM |
1572 | /* |
1573 | * Scan data sections and all the referenced memory blocks allocated via the | |
1574 | * kernel's standard allocators. This function must be called with the | |
1575 | * scan_mutex held. | |
1576 | */ | |
1577 | static void kmemleak_scan(void) | |
1578 | { | |
04609ccc | 1579 | struct kmemleak_object *object; |
c10a0f87 LY |
1580 | struct zone *zone; |
1581 | int __maybe_unused i; | |
4698c1f2 | 1582 | int new_leaks = 0; |
3c7b4e6b | 1583 | |
acf4968e CM |
1584 | jiffies_last_scan = jiffies; |
1585 | ||
3c7b4e6b CM |
1586 | /* prepare the kmemleak_object's */ |
1587 | rcu_read_lock(); | |
1588 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
00c15506 | 1589 | raw_spin_lock_irq(&object->lock); |
3c7b4e6b CM |
1590 | #ifdef DEBUG |
1591 | /* | |
1592 | * With a few exceptions there should be a maximum of | |
1593 | * 1 reference to any object at this point. | |
1594 | */ | |
1595 | if (atomic_read(&object->use_count) > 1) { | |
ae281064 | 1596 | pr_debug("object->use_count = %d\n", |
3c7b4e6b CM |
1597 | atomic_read(&object->use_count)); |
1598 | dump_object_info(object); | |
1599 | } | |
1600 | #endif | |
84c32629 PW |
1601 | |
1602 | /* ignore objects outside lowmem (paint them black) */ | |
1603 | if ((object->flags & OBJECT_PHYS) && | |
1604 | !(object->flags & OBJECT_NO_SCAN)) { | |
1605 | unsigned long phys = object->pointer; | |
1606 | ||
1607 | if (PHYS_PFN(phys) < min_low_pfn || | |
1608 | PHYS_PFN(phys + object->size) >= max_low_pfn) | |
1609 | __paint_it(object, KMEMLEAK_BLACK); | |
1610 | } | |
1611 | ||
3c7b4e6b CM |
1612 | /* reset the reference count (whiten the object) */ |
1613 | object->count = 0; | |
6061e740 | 1614 | if (color_gray(object) && get_object(object)) |
3c7b4e6b CM |
1615 | list_add_tail(&object->gray_list, &gray_list); |
1616 | ||
00c15506 | 1617 | raw_spin_unlock_irq(&object->lock); |
6edda04c | 1618 | |
6061e740 WL |
1619 | if (need_resched()) |
1620 | kmemleak_cond_resched(object); | |
3c7b4e6b CM |
1621 | } |
1622 | rcu_read_unlock(); | |
1623 | ||
3c7b4e6b CM |
1624 | #ifdef CONFIG_SMP |
1625 | /* per-cpu sections scanning */ | |
1626 | for_each_possible_cpu(i) | |
93ada579 CM |
1627 | scan_large_block(__per_cpu_start + per_cpu_offset(i), |
1628 | __per_cpu_end + per_cpu_offset(i)); | |
3c7b4e6b CM |
1629 | #endif |
1630 | ||
1631 | /* | |
029aeff5 | 1632 | * Struct page scanning for each node. |
3c7b4e6b | 1633 | */ |
bfc8c901 | 1634 | get_online_mems(); |
c10a0f87 LY |
1635 | for_each_populated_zone(zone) { |
1636 | unsigned long start_pfn = zone->zone_start_pfn; | |
1637 | unsigned long end_pfn = zone_end_pfn(zone); | |
3c7b4e6b CM |
1638 | unsigned long pfn; |
1639 | ||
1640 | for (pfn = start_pfn; pfn < end_pfn; pfn++) { | |
9f1eb38e | 1641 | struct page *page = pfn_to_online_page(pfn); |
3c7b4e6b | 1642 | |
e68d343d WL |
1643 | if (!(pfn & 63)) |
1644 | cond_resched(); | |
1645 | ||
9f1eb38e OS |
1646 | if (!page) |
1647 | continue; | |
1648 | ||
c10a0f87 LY |
1649 | /* only scan pages belonging to this zone */ |
1650 | if (page_zone(page) != zone) | |
3c7b4e6b | 1651 | continue; |
3c7b4e6b CM |
1652 | /* only scan if page is in use */ |
1653 | if (page_count(page) == 0) | |
1654 | continue; | |
93ada579 | 1655 | scan_block(page, page + 1, NULL); |
3c7b4e6b CM |
1656 | } |
1657 | } | |
bfc8c901 | 1658 | put_online_mems(); |
3c7b4e6b CM |
1659 | |
1660 | /* | |
43ed5d6e | 1661 | * Scanning the task stacks (may introduce false negatives). |
3c7b4e6b CM |
1662 | */ |
1663 | if (kmemleak_stack_scan) { | |
43ed5d6e CM |
1664 | struct task_struct *p, *g; |
1665 | ||
c4b28963 DB |
1666 | rcu_read_lock(); |
1667 | for_each_process_thread(g, p) { | |
37df49f4 CM |
1668 | void *stack = try_get_task_stack(p); |
1669 | if (stack) { | |
1670 | scan_block(stack, stack + THREAD_SIZE, NULL); | |
1671 | put_task_stack(p); | |
1672 | } | |
c4b28963 DB |
1673 | } |
1674 | rcu_read_unlock(); | |
3c7b4e6b CM |
1675 | } |
1676 | ||
1677 | /* | |
1678 | * Scan the objects already referenced from the sections scanned | |
04609ccc | 1679 | * above. |
3c7b4e6b | 1680 | */ |
04609ccc | 1681 | scan_gray_list(); |
2587362e CM |
1682 | |
1683 | /* | |
04609ccc CM |
1684 | * Check for new or unreferenced objects modified since the previous |
1685 | * scan and color them gray until the next scan. | |
2587362e CM |
1686 | */ |
1687 | rcu_read_lock(); | |
1688 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
6061e740 WL |
1689 | if (need_resched()) |
1690 | kmemleak_cond_resched(object); | |
984a6083 | 1691 | |
64977918 WL |
1692 | /* |
1693 | * This is racy but we can save the overhead of lock/unlock | |
1694 | * calls. The missed objects, if any, should be caught in | |
1695 | * the next scan. | |
1696 | */ | |
1697 | if (!color_white(object)) | |
1698 | continue; | |
00c15506 | 1699 | raw_spin_lock_irq(&object->lock); |
04609ccc CM |
1700 | if (color_white(object) && (object->flags & OBJECT_ALLOCATED) |
1701 | && update_checksum(object) && get_object(object)) { | |
1702 | /* color it gray temporarily */ | |
1703 | object->count = object->min_count; | |
2587362e CM |
1704 | list_add_tail(&object->gray_list, &gray_list); |
1705 | } | |
00c15506 | 1706 | raw_spin_unlock_irq(&object->lock); |
2587362e CM |
1707 | } |
1708 | rcu_read_unlock(); | |
1709 | ||
04609ccc CM |
1710 | /* |
1711 | * Re-scan the gray list for modified unreferenced objects. | |
1712 | */ | |
1713 | scan_gray_list(); | |
4698c1f2 | 1714 | |
17bb9e0d | 1715 | /* |
04609ccc | 1716 | * If scanning was stopped do not report any new unreferenced objects. |
17bb9e0d | 1717 | */ |
04609ccc | 1718 | if (scan_should_stop()) |
17bb9e0d CM |
1719 | return; |
1720 | ||
4698c1f2 CM |
1721 | /* |
1722 | * Scanning result reporting. | |
1723 | */ | |
1724 | rcu_read_lock(); | |
1725 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
6061e740 WL |
1726 | if (need_resched()) |
1727 | kmemleak_cond_resched(object); | |
984a6083 | 1728 | |
64977918 WL |
1729 | /* |
1730 | * This is racy but we can save the overhead of lock/unlock | |
1731 | * calls. The missed objects, if any, should be caught in | |
1732 | * the next scan. | |
1733 | */ | |
1734 | if (!color_white(object)) | |
1735 | continue; | |
00c15506 | 1736 | raw_spin_lock_irq(&object->lock); |
4698c1f2 CM |
1737 | if (unreferenced_object(object) && |
1738 | !(object->flags & OBJECT_REPORTED)) { | |
1739 | object->flags |= OBJECT_REPORTED; | |
154221c3 VW |
1740 | |
1741 | if (kmemleak_verbose) | |
1742 | print_unreferenced(NULL, object); | |
1743 | ||
4698c1f2 CM |
1744 | new_leaks++; |
1745 | } | |
00c15506 | 1746 | raw_spin_unlock_irq(&object->lock); |
4698c1f2 CM |
1747 | } |
1748 | rcu_read_unlock(); | |
1749 | ||
dc9b3f42 LZ |
1750 | if (new_leaks) { |
1751 | kmemleak_found_leaks = true; | |
1752 | ||
756a025f JP |
1753 | pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n", |
1754 | new_leaks); | |
dc9b3f42 | 1755 | } |
4698c1f2 | 1756 | |
3c7b4e6b CM |
1757 | } |
1758 | ||
1759 | /* | |
1760 | * Thread function performing automatic memory scanning. Unreferenced objects | |
1761 | * at the end of a memory scan are reported but only the first time. | |
1762 | */ | |
1763 | static int kmemleak_scan_thread(void *arg) | |
1764 | { | |
d53ce042 | 1765 | static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN); |
3c7b4e6b | 1766 | |
ae281064 | 1767 | pr_info("Automatic memory scanning thread started\n"); |
bf2a76b3 | 1768 | set_user_nice(current, 10); |
3c7b4e6b CM |
1769 | |
1770 | /* | |
1771 | * Wait before the first scan to allow the system to fully initialize. | |
1772 | */ | |
1773 | if (first_run) { | |
98c42d94 | 1774 | signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000); |
3c7b4e6b | 1775 | first_run = 0; |
98c42d94 VN |
1776 | while (timeout && !kthread_should_stop()) |
1777 | timeout = schedule_timeout_interruptible(timeout); | |
3c7b4e6b CM |
1778 | } |
1779 | ||
1780 | while (!kthread_should_stop()) { | |
54dd200c | 1781 | signed long timeout = READ_ONCE(jiffies_scan_wait); |
3c7b4e6b CM |
1782 | |
1783 | mutex_lock(&scan_mutex); | |
3c7b4e6b | 1784 | kmemleak_scan(); |
3c7b4e6b | 1785 | mutex_unlock(&scan_mutex); |
4698c1f2 | 1786 | |
3c7b4e6b CM |
1787 | /* wait before the next scan */ |
1788 | while (timeout && !kthread_should_stop()) | |
1789 | timeout = schedule_timeout_interruptible(timeout); | |
1790 | } | |
1791 | ||
ae281064 | 1792 | pr_info("Automatic memory scanning thread ended\n"); |
3c7b4e6b CM |
1793 | |
1794 | return 0; | |
1795 | } | |
1796 | ||
1797 | /* | |
1798 | * Start the automatic memory scanning thread. This function must be called | |
4698c1f2 | 1799 | * with the scan_mutex held. |
3c7b4e6b | 1800 | */ |
7eb0d5e5 | 1801 | static void start_scan_thread(void) |
3c7b4e6b CM |
1802 | { |
1803 | if (scan_thread) | |
1804 | return; | |
1805 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); | |
1806 | if (IS_ERR(scan_thread)) { | |
598d8091 | 1807 | pr_warn("Failed to create the scan thread\n"); |
3c7b4e6b CM |
1808 | scan_thread = NULL; |
1809 | } | |
1810 | } | |
1811 | ||
1812 | /* | |
914b6dff | 1813 | * Stop the automatic memory scanning thread. |
3c7b4e6b | 1814 | */ |
7eb0d5e5 | 1815 | static void stop_scan_thread(void) |
3c7b4e6b CM |
1816 | { |
1817 | if (scan_thread) { | |
1818 | kthread_stop(scan_thread); | |
1819 | scan_thread = NULL; | |
1820 | } | |
1821 | } | |
1822 | ||
1823 | /* | |
1824 | * Iterate over the object_list and return the first valid object at or after | |
1825 | * the required position with its use_count incremented. The function triggers | |
1826 | * a memory scanning when the pos argument points to the first position. | |
1827 | */ | |
1828 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) | |
1829 | { | |
1830 | struct kmemleak_object *object; | |
1831 | loff_t n = *pos; | |
b87324d0 CM |
1832 | int err; |
1833 | ||
1834 | err = mutex_lock_interruptible(&scan_mutex); | |
1835 | if (err < 0) | |
1836 | return ERR_PTR(err); | |
3c7b4e6b | 1837 | |
3c7b4e6b CM |
1838 | rcu_read_lock(); |
1839 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
1840 | if (n-- > 0) | |
1841 | continue; | |
1842 | if (get_object(object)) | |
1843 | goto out; | |
1844 | } | |
1845 | object = NULL; | |
1846 | out: | |
3c7b4e6b CM |
1847 | return object; |
1848 | } | |
1849 | ||
1850 | /* | |
1851 | * Return the next object in the object_list. The function decrements the | |
1852 | * use_count of the previous object and increases that of the next one. | |
1853 | */ | |
1854 | static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
1855 | { | |
1856 | struct kmemleak_object *prev_obj = v; | |
1857 | struct kmemleak_object *next_obj = NULL; | |
58fac095 | 1858 | struct kmemleak_object *obj = prev_obj; |
3c7b4e6b CM |
1859 | |
1860 | ++(*pos); | |
3c7b4e6b | 1861 | |
58fac095 | 1862 | list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
52c3ce4e CM |
1863 | if (get_object(obj)) { |
1864 | next_obj = obj; | |
3c7b4e6b | 1865 | break; |
52c3ce4e | 1866 | } |
3c7b4e6b | 1867 | } |
288c857d | 1868 | |
3c7b4e6b CM |
1869 | put_object(prev_obj); |
1870 | return next_obj; | |
1871 | } | |
1872 | ||
1873 | /* | |
1874 | * Decrement the use_count of the last object required, if any. | |
1875 | */ | |
1876 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) | |
1877 | { | |
b87324d0 CM |
1878 | if (!IS_ERR(v)) { |
1879 | /* | |
1880 | * kmemleak_seq_start may return ERR_PTR if the scan_mutex | |
1881 | * waiting was interrupted, so only release it if !IS_ERR. | |
1882 | */ | |
f5886c7f | 1883 | rcu_read_unlock(); |
b87324d0 CM |
1884 | mutex_unlock(&scan_mutex); |
1885 | if (v) | |
1886 | put_object(v); | |
1887 | } | |
3c7b4e6b CM |
1888 | } |
1889 | ||
1890 | /* | |
1891 | * Print the information for an unreferenced object to the seq file. | |
1892 | */ | |
1893 | static int kmemleak_seq_show(struct seq_file *seq, void *v) | |
1894 | { | |
1895 | struct kmemleak_object *object = v; | |
1896 | unsigned long flags; | |
1897 | ||
8c96f1bc | 1898 | raw_spin_lock_irqsave(&object->lock, flags); |
288c857d | 1899 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
17bb9e0d | 1900 | print_unreferenced(seq, object); |
8c96f1bc | 1901 | raw_spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b CM |
1902 | return 0; |
1903 | } | |
1904 | ||
1905 | static const struct seq_operations kmemleak_seq_ops = { | |
1906 | .start = kmemleak_seq_start, | |
1907 | .next = kmemleak_seq_next, | |
1908 | .stop = kmemleak_seq_stop, | |
1909 | .show = kmemleak_seq_show, | |
1910 | }; | |
1911 | ||
1912 | static int kmemleak_open(struct inode *inode, struct file *file) | |
1913 | { | |
b87324d0 | 1914 | return seq_open(file, &kmemleak_seq_ops); |
3c7b4e6b CM |
1915 | } |
1916 | ||
189d84ed CM |
1917 | static int dump_str_object_info(const char *str) |
1918 | { | |
1919 | unsigned long flags; | |
1920 | struct kmemleak_object *object; | |
1921 | unsigned long addr; | |
1922 | ||
dc053733 AP |
1923 | if (kstrtoul(str, 0, &addr)) |
1924 | return -EINVAL; | |
189d84ed CM |
1925 | object = find_and_get_object(addr, 0); |
1926 | if (!object) { | |
1927 | pr_info("Unknown object at 0x%08lx\n", addr); | |
1928 | return -EINVAL; | |
1929 | } | |
1930 | ||
8c96f1bc | 1931 | raw_spin_lock_irqsave(&object->lock, flags); |
189d84ed | 1932 | dump_object_info(object); |
8c96f1bc | 1933 | raw_spin_unlock_irqrestore(&object->lock, flags); |
189d84ed CM |
1934 | |
1935 | put_object(object); | |
1936 | return 0; | |
1937 | } | |
1938 | ||
30b37101 LR |
1939 | /* |
1940 | * We use grey instead of black to ensure we can do future scans on the same | |
1941 | * objects. If we did not do future scans these black objects could | |
1942 | * potentially contain references to newly allocated objects in the future and | |
1943 | * we'd end up with false positives. | |
1944 | */ | |
1945 | static void kmemleak_clear(void) | |
1946 | { | |
1947 | struct kmemleak_object *object; | |
30b37101 LR |
1948 | |
1949 | rcu_read_lock(); | |
1950 | list_for_each_entry_rcu(object, &object_list, object_list) { | |
00c15506 | 1951 | raw_spin_lock_irq(&object->lock); |
30b37101 LR |
1952 | if ((object->flags & OBJECT_REPORTED) && |
1953 | unreferenced_object(object)) | |
a1084c87 | 1954 | __paint_it(object, KMEMLEAK_GREY); |
00c15506 | 1955 | raw_spin_unlock_irq(&object->lock); |
30b37101 LR |
1956 | } |
1957 | rcu_read_unlock(); | |
dc9b3f42 LZ |
1958 | |
1959 | kmemleak_found_leaks = false; | |
30b37101 LR |
1960 | } |
1961 | ||
c89da70c LZ |
1962 | static void __kmemleak_do_cleanup(void); |
1963 | ||
3c7b4e6b CM |
1964 | /* |
1965 | * File write operation to configure kmemleak at run-time. The following | |
1966 | * commands can be written to the /sys/kernel/debug/kmemleak file: | |
1967 | * off - disable kmemleak (irreversible) | |
1968 | * stack=on - enable the task stacks scanning | |
1969 | * stack=off - disable the tasks stacks scanning | |
1970 | * scan=on - start the automatic memory scanning thread | |
1971 | * scan=off - stop the automatic memory scanning thread | |
1972 | * scan=... - set the automatic memory scanning period in seconds (0 to | |
1973 | * disable it) | |
4698c1f2 | 1974 | * scan - trigger a memory scan |
30b37101 | 1975 | * clear - mark all current reported unreferenced kmemleak objects as |
c89da70c LZ |
1976 | * grey to ignore printing them, or free all kmemleak objects |
1977 | * if kmemleak has been disabled. | |
189d84ed | 1978 | * dump=... - dump information about the object found at the given address |
3c7b4e6b CM |
1979 | */ |
1980 | static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, | |
1981 | size_t size, loff_t *ppos) | |
1982 | { | |
1983 | char buf[64]; | |
1984 | int buf_size; | |
b87324d0 | 1985 | int ret; |
3c7b4e6b CM |
1986 | |
1987 | buf_size = min(size, (sizeof(buf) - 1)); | |
1988 | if (strncpy_from_user(buf, user_buf, buf_size) < 0) | |
1989 | return -EFAULT; | |
1990 | buf[buf_size] = 0; | |
1991 | ||
b87324d0 CM |
1992 | ret = mutex_lock_interruptible(&scan_mutex); |
1993 | if (ret < 0) | |
1994 | return ret; | |
1995 | ||
c89da70c | 1996 | if (strncmp(buf, "clear", 5) == 0) { |
8910ae89 | 1997 | if (kmemleak_enabled) |
c89da70c LZ |
1998 | kmemleak_clear(); |
1999 | else | |
2000 | __kmemleak_do_cleanup(); | |
2001 | goto out; | |
2002 | } | |
2003 | ||
8910ae89 | 2004 | if (!kmemleak_enabled) { |
4e4dfce2 | 2005 | ret = -EPERM; |
c89da70c LZ |
2006 | goto out; |
2007 | } | |
2008 | ||
3c7b4e6b CM |
2009 | if (strncmp(buf, "off", 3) == 0) |
2010 | kmemleak_disable(); | |
2011 | else if (strncmp(buf, "stack=on", 8) == 0) | |
2012 | kmemleak_stack_scan = 1; | |
2013 | else if (strncmp(buf, "stack=off", 9) == 0) | |
2014 | kmemleak_stack_scan = 0; | |
2015 | else if (strncmp(buf, "scan=on", 7) == 0) | |
2016 | start_scan_thread(); | |
2017 | else if (strncmp(buf, "scan=off", 8) == 0) | |
2018 | stop_scan_thread(); | |
2019 | else if (strncmp(buf, "scan=", 5) == 0) { | |
54dd200c YX |
2020 | unsigned secs; |
2021 | unsigned long msecs; | |
3c7b4e6b | 2022 | |
54dd200c | 2023 | ret = kstrtouint(buf + 5, 0, &secs); |
b87324d0 CM |
2024 | if (ret < 0) |
2025 | goto out; | |
54dd200c YX |
2026 | |
2027 | msecs = secs * MSEC_PER_SEC; | |
2028 | if (msecs > UINT_MAX) | |
2029 | msecs = UINT_MAX; | |
2030 | ||
3c7b4e6b | 2031 | stop_scan_thread(); |
54dd200c YX |
2032 | if (msecs) { |
2033 | WRITE_ONCE(jiffies_scan_wait, msecs_to_jiffies(msecs)); | |
3c7b4e6b CM |
2034 | start_scan_thread(); |
2035 | } | |
4698c1f2 CM |
2036 | } else if (strncmp(buf, "scan", 4) == 0) |
2037 | kmemleak_scan(); | |
189d84ed CM |
2038 | else if (strncmp(buf, "dump=", 5) == 0) |
2039 | ret = dump_str_object_info(buf + 5); | |
4698c1f2 | 2040 | else |
b87324d0 CM |
2041 | ret = -EINVAL; |
2042 | ||
2043 | out: | |
2044 | mutex_unlock(&scan_mutex); | |
2045 | if (ret < 0) | |
2046 | return ret; | |
3c7b4e6b CM |
2047 | |
2048 | /* ignore the rest of the buffer, only one command at a time */ | |
2049 | *ppos += size; | |
2050 | return size; | |
2051 | } | |
2052 | ||
2053 | static const struct file_operations kmemleak_fops = { | |
2054 | .owner = THIS_MODULE, | |
2055 | .open = kmemleak_open, | |
2056 | .read = seq_read, | |
2057 | .write = kmemleak_write, | |
2058 | .llseek = seq_lseek, | |
5f3bf19a | 2059 | .release = seq_release, |
3c7b4e6b CM |
2060 | }; |
2061 | ||
c89da70c LZ |
2062 | static void __kmemleak_do_cleanup(void) |
2063 | { | |
2abd839a | 2064 | struct kmemleak_object *object, *tmp; |
c89da70c | 2065 | |
2abd839a CM |
2066 | /* |
2067 | * Kmemleak has already been disabled, no need for RCU list traversal | |
2068 | * or kmemleak_lock held. | |
2069 | */ | |
2070 | list_for_each_entry_safe(object, tmp, &object_list, object_list) { | |
2071 | __remove_object(object); | |
2072 | __delete_object(object); | |
2073 | } | |
c89da70c LZ |
2074 | } |
2075 | ||
3c7b4e6b | 2076 | /* |
74341703 CM |
2077 | * Stop the memory scanning thread and free the kmemleak internal objects if |
2078 | * no previous scan thread (otherwise, kmemleak may still have some useful | |
2079 | * information on memory leaks). | |
3c7b4e6b | 2080 | */ |
179a8100 | 2081 | static void kmemleak_do_cleanup(struct work_struct *work) |
3c7b4e6b | 2082 | { |
3c7b4e6b | 2083 | stop_scan_thread(); |
3c7b4e6b | 2084 | |
914b6dff | 2085 | mutex_lock(&scan_mutex); |
c5f3b1a5 | 2086 | /* |
914b6dff VM |
2087 | * Once it is made sure that kmemleak_scan has stopped, it is safe to no |
2088 | * longer track object freeing. Ordering of the scan thread stopping and | |
2089 | * the memory accesses below is guaranteed by the kthread_stop() | |
2090 | * function. | |
c5f3b1a5 CM |
2091 | */ |
2092 | kmemleak_free_enabled = 0; | |
914b6dff | 2093 | mutex_unlock(&scan_mutex); |
c5f3b1a5 | 2094 | |
c89da70c LZ |
2095 | if (!kmemleak_found_leaks) |
2096 | __kmemleak_do_cleanup(); | |
2097 | else | |
756a025f | 2098 | pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n"); |
3c7b4e6b CM |
2099 | } |
2100 | ||
179a8100 | 2101 | static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
3c7b4e6b CM |
2102 | |
2103 | /* | |
2104 | * Disable kmemleak. No memory allocation/freeing will be traced once this | |
2105 | * function is called. Disabling kmemleak is an irreversible operation. | |
2106 | */ | |
2107 | static void kmemleak_disable(void) | |
2108 | { | |
2109 | /* atomically check whether it was already invoked */ | |
8910ae89 | 2110 | if (cmpxchg(&kmemleak_error, 0, 1)) |
3c7b4e6b CM |
2111 | return; |
2112 | ||
2113 | /* stop any memory operation tracing */ | |
8910ae89 | 2114 | kmemleak_enabled = 0; |
3c7b4e6b CM |
2115 | |
2116 | /* check whether it is too early for a kernel thread */ | |
d160ef71 | 2117 | if (kmemleak_late_initialized) |
179a8100 | 2118 | schedule_work(&cleanup_work); |
c5f3b1a5 CM |
2119 | else |
2120 | kmemleak_free_enabled = 0; | |
3c7b4e6b CM |
2121 | |
2122 | pr_info("Kernel memory leak detector disabled\n"); | |
2123 | } | |
2124 | ||
2125 | /* | |
2126 | * Allow boot-time kmemleak disabling (enabled by default). | |
2127 | */ | |
8bd30c10 | 2128 | static int __init kmemleak_boot_config(char *str) |
3c7b4e6b CM |
2129 | { |
2130 | if (!str) | |
2131 | return -EINVAL; | |
2132 | if (strcmp(str, "off") == 0) | |
2133 | kmemleak_disable(); | |
993f57e0 | 2134 | else if (strcmp(str, "on") == 0) { |
ab0155a2 | 2135 | kmemleak_skip_disable = 1; |
1c0310ad | 2136 | stack_depot_request_early_init(); |
993f57e0 | 2137 | } |
ab0155a2 | 2138 | else |
3c7b4e6b CM |
2139 | return -EINVAL; |
2140 | return 0; | |
2141 | } | |
2142 | early_param("kmemleak", kmemleak_boot_config); | |
2143 | ||
2144 | /* | |
2030117d | 2145 | * Kmemleak initialization. |
3c7b4e6b CM |
2146 | */ |
2147 | void __init kmemleak_init(void) | |
2148 | { | |
ab0155a2 JB |
2149 | #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF |
2150 | if (!kmemleak_skip_disable) { | |
2151 | kmemleak_disable(); | |
2152 | return; | |
2153 | } | |
2154 | #endif | |
2155 | ||
c5665868 CM |
2156 | if (kmemleak_error) |
2157 | return; | |
2158 | ||
3c7b4e6b CM |
2159 | jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); |
2160 | jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); | |
2161 | ||
2162 | object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); | |
2163 | scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); | |
3c7b4e6b | 2164 | |
298a32b1 CM |
2165 | /* register the data/bss sections */ |
2166 | create_object((unsigned long)_sdata, _edata - _sdata, | |
2167 | KMEMLEAK_GREY, GFP_ATOMIC); | |
2168 | create_object((unsigned long)__bss_start, __bss_stop - __bss_start, | |
2169 | KMEMLEAK_GREY, GFP_ATOMIC); | |
2170 | /* only register .data..ro_after_init if not within .data */ | |
b0d14fc4 | 2171 | if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata) |
298a32b1 CM |
2172 | create_object((unsigned long)__start_ro_after_init, |
2173 | __end_ro_after_init - __start_ro_after_init, | |
2174 | KMEMLEAK_GREY, GFP_ATOMIC); | |
3c7b4e6b CM |
2175 | } |
2176 | ||
2177 | /* | |
2178 | * Late initialization function. | |
2179 | */ | |
2180 | static int __init kmemleak_late_init(void) | |
2181 | { | |
d160ef71 | 2182 | kmemleak_late_initialized = 1; |
3c7b4e6b | 2183 | |
282401df | 2184 | debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops); |
b353756b | 2185 | |
8910ae89 | 2186 | if (kmemleak_error) { |
3c7b4e6b | 2187 | /* |
25985edc | 2188 | * Some error occurred and kmemleak was disabled. There is a |
3c7b4e6b | 2189 | * small chance that kmemleak_disable() was called immediately |
d160ef71 | 2190 | * after setting kmemleak_late_initialized and we may end up with |
3c7b4e6b CM |
2191 | * two clean-up threads but serialized by scan_mutex. |
2192 | */ | |
179a8100 | 2193 | schedule_work(&cleanup_work); |
3c7b4e6b CM |
2194 | return -ENOMEM; |
2195 | } | |
2196 | ||
d53ce042 SK |
2197 | if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) { |
2198 | mutex_lock(&scan_mutex); | |
2199 | start_scan_thread(); | |
2200 | mutex_unlock(&scan_mutex); | |
2201 | } | |
3c7b4e6b | 2202 | |
0e965a6b QC |
2203 | pr_info("Kernel memory leak detector initialized (mem pool available: %d)\n", |
2204 | mem_pool_free_count); | |
3c7b4e6b CM |
2205 | |
2206 | return 0; | |
2207 | } | |
2208 | late_initcall(kmemleak_late_init); |