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63
64#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
65
66#include <linux/init.h>
67#include <linux/kernel.h>
68#include <linux/list.h>
69#include <linux/sched.h>
70#include <linux/jiffies.h>
71#include <linux/delay.h>
72#include <linux/module.h>
73#include <linux/kthread.h>
74#include <linux/prio_tree.h>
75#include <linux/fs.h>
76#include <linux/debugfs.h>
77#include <linux/seq_file.h>
78#include <linux/cpumask.h>
79#include <linux/spinlock.h>
80#include <linux/mutex.h>
81#include <linux/rcupdate.h>
82#include <linux/stacktrace.h>
83#include <linux/cache.h>
84#include <linux/percpu.h>
85#include <linux/hardirq.h>
86#include <linux/mmzone.h>
87#include <linux/slab.h>
88#include <linux/thread_info.h>
89#include <linux/err.h>
90#include <linux/uaccess.h>
91#include <linux/string.h>
92#include <linux/nodemask.h>
93#include <linux/mm.h>
94#include <linux/workqueue.h>
95#include <linux/crc32.h>
96
97#include <asm/sections.h>
98#include <asm/processor.h>
99#include <asm/atomic.h>
100
101#include <linux/kmemcheck.h>
102#include <linux/kmemleak.h>
103
104
105
106
107#define MAX_TRACE 16
108#define MSECS_MIN_AGE 5000
109#define SECS_FIRST_SCAN 60
110#define SECS_SCAN_WAIT 600
111#define MAX_SCAN_SIZE 4096
112
113#define BYTES_PER_POINTER sizeof(void *)
114
115
116#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
117 __GFP_NORETRY | __GFP_NOMEMALLOC | \
118 __GFP_NOWARN)
119
120
121struct kmemleak_scan_area {
122 struct hlist_node node;
123 unsigned long start;
124 size_t size;
125};
126
127#define KMEMLEAK_GREY 0
128#define KMEMLEAK_BLACK -1
129
130
131
132
133
134
135
136
137
138struct kmemleak_object {
139 spinlock_t lock;
140 unsigned long flags;
141 struct list_head object_list;
142 struct list_head gray_list;
143 struct prio_tree_node tree_node;
144 struct rcu_head rcu;
145
146 atomic_t use_count;
147 unsigned long pointer;
148 size_t size;
149
150 int min_count;
151
152 int count;
153
154 u32 checksum;
155
156 struct hlist_head area_list;
157 unsigned long trace[MAX_TRACE];
158 unsigned int trace_len;
159 unsigned long jiffies;
160 pid_t pid;
161 char comm[TASK_COMM_LEN];
162};
163
164
165#define OBJECT_ALLOCATED (1 << 0)
166
167#define OBJECT_REPORTED (1 << 1)
168
169#define OBJECT_NO_SCAN (1 << 2)
170
171
172#define HEX_ROW_SIZE 16
173
174#define HEX_GROUP_SIZE 1
175
176#define HEX_ASCII 1
177
178#define HEX_MAX_LINES 2
179
180
181static LIST_HEAD(object_list);
182
183static LIST_HEAD(gray_list);
184
185static struct prio_tree_root object_tree_root;
186
187static DEFINE_RWLOCK(kmemleak_lock);
188
189
190static struct kmem_cache *object_cache;
191static struct kmem_cache *scan_area_cache;
192
193
194static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
195
196static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
197
198static atomic_t kmemleak_early_log = ATOMIC_INIT(1);
199
200static atomic_t kmemleak_error = ATOMIC_INIT(0);
201
202
203static unsigned long min_addr = ULONG_MAX;
204static unsigned long max_addr;
205
206static struct task_struct *scan_thread;
207
208static unsigned long jiffies_min_age;
209static unsigned long jiffies_last_scan;
210
211static signed long jiffies_scan_wait;
212
213static int kmemleak_stack_scan = 1;
214
215static DEFINE_MUTEX(scan_mutex);
216
217static int kmemleak_skip_disable;
218
219
220
221
222
223
224
225
226
227
228
229enum {
230 KMEMLEAK_ALLOC,
231 KMEMLEAK_FREE,
232 KMEMLEAK_FREE_PART,
233 KMEMLEAK_NOT_LEAK,
234 KMEMLEAK_IGNORE,
235 KMEMLEAK_SCAN_AREA,
236 KMEMLEAK_NO_SCAN
237};
238
239
240
241
242
243struct early_log {
244 int op_type;
245 const void *ptr;
246 size_t size;
247 int min_count;
248 unsigned long trace[MAX_TRACE];
249 unsigned int trace_len;
250};
251
252
253static struct early_log
254 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
255static int crt_early_log __initdata;
256
257static void kmemleak_disable(void);
258
259
260
261
262#define kmemleak_warn(x...) do { \
263 pr_warning(x); \
264 dump_stack(); \
265} while (0)
266
267
268
269
270
271
272#define kmemleak_stop(x...) do { \
273 kmemleak_warn(x); \
274 kmemleak_disable(); \
275} while (0)
276
277
278
279
280
281
282
283static void hex_dump_object(struct seq_file *seq,
284 struct kmemleak_object *object)
285{
286 const u8 *ptr = (const u8 *)object->pointer;
287 int i, len, remaining;
288 unsigned char linebuf[HEX_ROW_SIZE * 5];
289
290
291 remaining = len =
292 min(object->size, (size_t)(HEX_MAX_LINES * HEX_ROW_SIZE));
293
294 seq_printf(seq, " hex dump (first %d bytes):\n", len);
295 for (i = 0; i < len; i += HEX_ROW_SIZE) {
296 int linelen = min(remaining, HEX_ROW_SIZE);
297
298 remaining -= HEX_ROW_SIZE;
299 hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE,
300 HEX_GROUP_SIZE, linebuf, sizeof(linebuf),
301 HEX_ASCII);
302 seq_printf(seq, " %s\n", linebuf);
303 }
304}
305
306
307
308
309
310
311
312
313
314
315
316static bool color_white(const struct kmemleak_object *object)
317{
318 return object->count != KMEMLEAK_BLACK &&
319 object->count < object->min_count;
320}
321
322static bool color_gray(const struct kmemleak_object *object)
323{
324 return object->min_count != KMEMLEAK_BLACK &&
325 object->count >= object->min_count;
326}
327
328
329
330
331
332
333static bool unreferenced_object(struct kmemleak_object *object)
334{
335 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
336 time_before_eq(object->jiffies + jiffies_min_age,
337 jiffies_last_scan);
338}
339
340
341
342
343
344static void print_unreferenced(struct seq_file *seq,
345 struct kmemleak_object *object)
346{
347 int i;
348 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
349
350 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
351 object->pointer, object->size);
352 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
353 object->comm, object->pid, object->jiffies,
354 msecs_age / 1000, msecs_age % 1000);
355 hex_dump_object(seq, object);
356 seq_printf(seq, " backtrace:\n");
357
358 for (i = 0; i < object->trace_len; i++) {
359 void *ptr = (void *)object->trace[i];
360 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
361 }
362}
363
364
365
366
367
368
369static void dump_object_info(struct kmemleak_object *object)
370{
371 struct stack_trace trace;
372
373 trace.nr_entries = object->trace_len;
374 trace.entries = object->trace;
375
376 pr_notice("Object 0x%08lx (size %zu):\n",
377 object->tree_node.start, object->size);
378 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
379 object->comm, object->pid, object->jiffies);
380 pr_notice(" min_count = %d\n", object->min_count);
381 pr_notice(" count = %d\n", object->count);
382 pr_notice(" flags = 0x%lx\n", object->flags);
383 pr_notice(" checksum = %d\n", object->checksum);
384 pr_notice(" backtrace:\n");
385 print_stack_trace(&trace, 4);
386}
387
388
389
390
391
392
393
394static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
395{
396 struct prio_tree_node *node;
397 struct prio_tree_iter iter;
398 struct kmemleak_object *object;
399
400 prio_tree_iter_init(&iter, &object_tree_root, ptr, ptr);
401 node = prio_tree_next(&iter);
402 if (node) {
403 object = prio_tree_entry(node, struct kmemleak_object,
404 tree_node);
405 if (!alias && object->pointer != ptr) {
406 pr_warning("Found object by alias at 0x%08lx\n", ptr);
407 dump_stack();
408 dump_object_info(object);
409 object = NULL;
410 }
411 } else
412 object = NULL;
413
414 return object;
415}
416
417
418
419
420
421
422
423static int get_object(struct kmemleak_object *object)
424{
425 return atomic_inc_not_zero(&object->use_count);
426}
427
428
429
430
431static void free_object_rcu(struct rcu_head *rcu)
432{
433 struct hlist_node *elem, *tmp;
434 struct kmemleak_scan_area *area;
435 struct kmemleak_object *object =
436 container_of(rcu, struct kmemleak_object, rcu);
437
438
439
440
441
442 hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) {
443 hlist_del(elem);
444 kmem_cache_free(scan_area_cache, area);
445 }
446 kmem_cache_free(object_cache, object);
447}
448
449
450
451
452
453
454
455
456static void put_object(struct kmemleak_object *object)
457{
458 if (!atomic_dec_and_test(&object->use_count))
459 return;
460
461
462 WARN_ON(object->flags & OBJECT_ALLOCATED);
463
464 call_rcu(&object->rcu, free_object_rcu);
465}
466
467
468
469
470static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
471{
472 unsigned long flags;
473 struct kmemleak_object *object = NULL;
474
475 rcu_read_lock();
476 read_lock_irqsave(&kmemleak_lock, flags);
477 if (ptr >= min_addr && ptr < max_addr)
478 object = lookup_object(ptr, alias);
479 read_unlock_irqrestore(&kmemleak_lock, flags);
480
481
482 if (object && !get_object(object))
483 object = NULL;
484 rcu_read_unlock();
485
486 return object;
487}
488
489
490
491
492static int __save_stack_trace(unsigned long *trace)
493{
494 struct stack_trace stack_trace;
495
496 stack_trace.max_entries = MAX_TRACE;
497 stack_trace.nr_entries = 0;
498 stack_trace.entries = trace;
499 stack_trace.skip = 2;
500 save_stack_trace(&stack_trace);
501
502 return stack_trace.nr_entries;
503}
504
505
506
507
508
509static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
510 int min_count, gfp_t gfp)
511{
512 unsigned long flags;
513 struct kmemleak_object *object;
514 struct prio_tree_node *node;
515
516 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
517 if (!object) {
518 pr_warning("Cannot allocate a kmemleak_object structure\n");
519 kmemleak_disable();
520 return NULL;
521 }
522
523 INIT_LIST_HEAD(&object->object_list);
524 INIT_LIST_HEAD(&object->gray_list);
525 INIT_HLIST_HEAD(&object->area_list);
526 spin_lock_init(&object->lock);
527 atomic_set(&object->use_count, 1);
528 object->flags = OBJECT_ALLOCATED;
529 object->pointer = ptr;
530 object->size = size;
531 object->min_count = min_count;
532 object->count = 0;
533 object->jiffies = jiffies;
534 object->checksum = 0;
535
536
537 if (in_irq()) {
538 object->pid = 0;
539 strncpy(object->comm, "hardirq", sizeof(object->comm));
540 } else if (in_softirq()) {
541 object->pid = 0;
542 strncpy(object->comm, "softirq", sizeof(object->comm));
543 } else {
544 object->pid = current->pid;
545
546
547
548
549
550
551 strncpy(object->comm, current->comm, sizeof(object->comm));
552 }
553
554
555 object->trace_len = __save_stack_trace(object->trace);
556
557 INIT_PRIO_TREE_NODE(&object->tree_node);
558 object->tree_node.start = ptr;
559 object->tree_node.last = ptr + size - 1;
560
561 write_lock_irqsave(&kmemleak_lock, flags);
562
563 min_addr = min(min_addr, ptr);
564 max_addr = max(max_addr, ptr + size);
565 node = prio_tree_insert(&object_tree_root, &object->tree_node);
566
567
568
569
570
571
572 if (node != &object->tree_node) {
573 kmemleak_stop("Cannot insert 0x%lx into the object search tree "
574 "(already existing)\n", ptr);
575 object = lookup_object(ptr, 1);
576 spin_lock(&object->lock);
577 dump_object_info(object);
578 spin_unlock(&object->lock);
579
580 goto out;
581 }
582 list_add_tail_rcu(&object->object_list, &object_list);
583out:
584 write_unlock_irqrestore(&kmemleak_lock, flags);
585 return object;
586}
587
588
589
590
591
592static void __delete_object(struct kmemleak_object *object)
593{
594 unsigned long flags;
595
596 write_lock_irqsave(&kmemleak_lock, flags);
597 prio_tree_remove(&object_tree_root, &object->tree_node);
598 list_del_rcu(&object->object_list);
599 write_unlock_irqrestore(&kmemleak_lock, flags);
600
601 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
602 WARN_ON(atomic_read(&object->use_count) < 2);
603
604
605
606
607
608 spin_lock_irqsave(&object->lock, flags);
609 object->flags &= ~OBJECT_ALLOCATED;
610 spin_unlock_irqrestore(&object->lock, flags);
611 put_object(object);
612}
613
614
615
616
617
618static void delete_object_full(unsigned long ptr)
619{
620 struct kmemleak_object *object;
621
622 object = find_and_get_object(ptr, 0);
623 if (!object) {
624#ifdef DEBUG
625 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
626 ptr);
627#endif
628 return;
629 }
630 __delete_object(object);
631 put_object(object);
632}
633
634
635
636
637
638
639static void delete_object_part(unsigned long ptr, size_t size)
640{
641 struct kmemleak_object *object;
642 unsigned long start, end;
643
644 object = find_and_get_object(ptr, 1);
645 if (!object) {
646#ifdef DEBUG
647 kmemleak_warn("Partially freeing unknown object at 0x%08lx "
648 "(size %zu)\n", ptr, size);
649#endif
650 return;
651 }
652 __delete_object(object);
653
654
655
656
657
658
659
660
661 start = object->pointer;
662 end = object->pointer + object->size;
663 if (ptr > start)
664 create_object(start, ptr - start, object->min_count,
665 GFP_KERNEL);
666 if (ptr + size < end)
667 create_object(ptr + size, end - ptr - size, object->min_count,
668 GFP_KERNEL);
669
670 put_object(object);
671}
672
673static void __paint_it(struct kmemleak_object *object, int color)
674{
675 object->min_count = color;
676 if (color == KMEMLEAK_BLACK)
677 object->flags |= OBJECT_NO_SCAN;
678}
679
680static void paint_it(struct kmemleak_object *object, int color)
681{
682 unsigned long flags;
683
684 spin_lock_irqsave(&object->lock, flags);
685 __paint_it(object, color);
686 spin_unlock_irqrestore(&object->lock, flags);
687}
688
689static void paint_ptr(unsigned long ptr, int color)
690{
691 struct kmemleak_object *object;
692
693 object = find_and_get_object(ptr, 0);
694 if (!object) {
695 kmemleak_warn("Trying to color unknown object "
696 "at 0x%08lx as %s\n", ptr,
697 (color == KMEMLEAK_GREY) ? "Grey" :
698 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
699 return;
700 }
701 paint_it(object, color);
702 put_object(object);
703}
704
705
706
707
708
709static void make_gray_object(unsigned long ptr)
710{
711 paint_ptr(ptr, KMEMLEAK_GREY);
712}
713
714
715
716
717
718static void make_black_object(unsigned long ptr)
719{
720 paint_ptr(ptr, KMEMLEAK_BLACK);
721}
722
723
724
725
726
727static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
728{
729 unsigned long flags;
730 struct kmemleak_object *object;
731 struct kmemleak_scan_area *area;
732
733 object = find_and_get_object(ptr, 1);
734 if (!object) {
735 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
736 ptr);
737 return;
738 }
739
740 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
741 if (!area) {
742 pr_warning("Cannot allocate a scan area\n");
743 goto out;
744 }
745
746 spin_lock_irqsave(&object->lock, flags);
747 if (ptr + size > object->pointer + object->size) {
748 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
749 dump_object_info(object);
750 kmem_cache_free(scan_area_cache, area);
751 goto out_unlock;
752 }
753
754 INIT_HLIST_NODE(&area->node);
755 area->start = ptr;
756 area->size = size;
757
758 hlist_add_head(&area->node, &object->area_list);
759out_unlock:
760 spin_unlock_irqrestore(&object->lock, flags);
761out:
762 put_object(object);
763}
764
765
766
767
768
769
770static void object_no_scan(unsigned long ptr)
771{
772 unsigned long flags;
773 struct kmemleak_object *object;
774
775 object = find_and_get_object(ptr, 0);
776 if (!object) {
777 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
778 return;
779 }
780
781 spin_lock_irqsave(&object->lock, flags);
782 object->flags |= OBJECT_NO_SCAN;
783 spin_unlock_irqrestore(&object->lock, flags);
784 put_object(object);
785}
786
787
788
789
790
791static void __init log_early(int op_type, const void *ptr, size_t size,
792 int min_count)
793{
794 unsigned long flags;
795 struct early_log *log;
796
797 if (crt_early_log >= ARRAY_SIZE(early_log)) {
798 pr_warning("Early log buffer exceeded, "
799 "please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n");
800 kmemleak_disable();
801 return;
802 }
803
804
805
806
807
808 local_irq_save(flags);
809 log = &early_log[crt_early_log];
810 log->op_type = op_type;
811 log->ptr = ptr;
812 log->size = size;
813 log->min_count = min_count;
814 if (op_type == KMEMLEAK_ALLOC)
815 log->trace_len = __save_stack_trace(log->trace);
816 crt_early_log++;
817 local_irq_restore(flags);
818}
819
820
821
822
823static void early_alloc(struct early_log *log)
824{
825 struct kmemleak_object *object;
826 unsigned long flags;
827 int i;
828
829 if (!atomic_read(&kmemleak_enabled) || !log->ptr || IS_ERR(log->ptr))
830 return;
831
832
833
834
835 rcu_read_lock();
836 object = create_object((unsigned long)log->ptr, log->size,
837 log->min_count, GFP_ATOMIC);
838 if (!object)
839 goto out;
840 spin_lock_irqsave(&object->lock, flags);
841 for (i = 0; i < log->trace_len; i++)
842 object->trace[i] = log->trace[i];
843 object->trace_len = log->trace_len;
844 spin_unlock_irqrestore(&object->lock, flags);
845out:
846 rcu_read_unlock();
847}
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
864 gfp_t gfp)
865{
866 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
867
868 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
869 create_object((unsigned long)ptr, size, min_count, gfp);
870 else if (atomic_read(&kmemleak_early_log))
871 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
872}
873EXPORT_SYMBOL_GPL(kmemleak_alloc);
874
875
876
877
878
879
880
881
882void __ref kmemleak_free(const void *ptr)
883{
884 pr_debug("%s(0x%p)\n", __func__, ptr);
885
886 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
887 delete_object_full((unsigned long)ptr);
888 else if (atomic_read(&kmemleak_early_log))
889 log_early(KMEMLEAK_FREE, ptr, 0, 0);
890}
891EXPORT_SYMBOL_GPL(kmemleak_free);
892
893
894
895
896
897
898
899
900
901
902void __ref kmemleak_free_part(const void *ptr, size_t size)
903{
904 pr_debug("%s(0x%p)\n", __func__, ptr);
905
906 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
907 delete_object_part((unsigned long)ptr, size);
908 else if (atomic_read(&kmemleak_early_log))
909 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
910}
911EXPORT_SYMBOL_GPL(kmemleak_free_part);
912
913
914
915
916
917
918
919
920void __ref kmemleak_not_leak(const void *ptr)
921{
922 pr_debug("%s(0x%p)\n", __func__, ptr);
923
924 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
925 make_gray_object((unsigned long)ptr);
926 else if (atomic_read(&kmemleak_early_log))
927 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
928}
929EXPORT_SYMBOL(kmemleak_not_leak);
930
931
932
933
934
935
936
937
938
939
940void __ref kmemleak_ignore(const void *ptr)
941{
942 pr_debug("%s(0x%p)\n", __func__, ptr);
943
944 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
945 make_black_object((unsigned long)ptr);
946 else if (atomic_read(&kmemleak_early_log))
947 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
948}
949EXPORT_SYMBOL(kmemleak_ignore);
950
951
952
953
954
955
956
957
958
959
960
961
962void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
963{
964 pr_debug("%s(0x%p)\n", __func__, ptr);
965
966 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
967 add_scan_area((unsigned long)ptr, size, gfp);
968 else if (atomic_read(&kmemleak_early_log))
969 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
970}
971EXPORT_SYMBOL(kmemleak_scan_area);
972
973
974
975
976
977
978
979
980
981
982void __ref kmemleak_no_scan(const void *ptr)
983{
984 pr_debug("%s(0x%p)\n", __func__, ptr);
985
986 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
987 object_no_scan((unsigned long)ptr);
988 else if (atomic_read(&kmemleak_early_log))
989 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
990}
991EXPORT_SYMBOL(kmemleak_no_scan);
992
993
994
995
996static bool update_checksum(struct kmemleak_object *object)
997{
998 u32 old_csum = object->checksum;
999
1000 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1001 return false;
1002
1003 object->checksum = crc32(0, (void *)object->pointer, object->size);
1004 return object->checksum != old_csum;
1005}
1006
1007
1008
1009
1010
1011static int scan_should_stop(void)
1012{
1013 if (!atomic_read(&kmemleak_enabled))
1014 return 1;
1015
1016
1017
1018
1019
1020 if (current->mm)
1021 return signal_pending(current);
1022 else
1023 return kthread_should_stop();
1024
1025 return 0;
1026}
1027
1028
1029
1030
1031
1032static void scan_block(void *_start, void *_end,
1033 struct kmemleak_object *scanned, int allow_resched)
1034{
1035 unsigned long *ptr;
1036 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1037 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
1038
1039 for (ptr = start; ptr < end; ptr++) {
1040 struct kmemleak_object *object;
1041 unsigned long flags;
1042 unsigned long pointer;
1043
1044 if (allow_resched)
1045 cond_resched();
1046 if (scan_should_stop())
1047 break;
1048
1049
1050 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1051 BYTES_PER_POINTER))
1052 continue;
1053
1054 pointer = *ptr;
1055
1056 object = find_and_get_object(pointer, 1);
1057 if (!object)
1058 continue;
1059 if (object == scanned) {
1060
1061 put_object(object);
1062 continue;
1063 }
1064
1065
1066
1067
1068
1069
1070 spin_lock_irqsave_nested(&object->lock, flags,
1071 SINGLE_DEPTH_NESTING);
1072 if (!color_white(object)) {
1073
1074 spin_unlock_irqrestore(&object->lock, flags);
1075 put_object(object);
1076 continue;
1077 }
1078
1079
1080
1081
1082
1083
1084
1085 object->count++;
1086 if (color_gray(object)) {
1087 list_add_tail(&object->gray_list, &gray_list);
1088 spin_unlock_irqrestore(&object->lock, flags);
1089 continue;
1090 }
1091
1092 spin_unlock_irqrestore(&object->lock, flags);
1093 put_object(object);
1094 }
1095}
1096
1097
1098
1099
1100
1101static void scan_object(struct kmemleak_object *object)
1102{
1103 struct kmemleak_scan_area *area;
1104 struct hlist_node *elem;
1105 unsigned long flags;
1106
1107
1108
1109
1110
1111 spin_lock_irqsave(&object->lock, flags);
1112 if (object->flags & OBJECT_NO_SCAN)
1113 goto out;
1114 if (!(object->flags & OBJECT_ALLOCATED))
1115
1116 goto out;
1117 if (hlist_empty(&object->area_list)) {
1118 void *start = (void *)object->pointer;
1119 void *end = (void *)(object->pointer + object->size);
1120
1121 while (start < end && (object->flags & OBJECT_ALLOCATED) &&
1122 !(object->flags & OBJECT_NO_SCAN)) {
1123 scan_block(start, min(start + MAX_SCAN_SIZE, end),
1124 object, 0);
1125 start += MAX_SCAN_SIZE;
1126
1127 spin_unlock_irqrestore(&object->lock, flags);
1128 cond_resched();
1129 spin_lock_irqsave(&object->lock, flags);
1130 }
1131 } else
1132 hlist_for_each_entry(area, elem, &object->area_list, node)
1133 scan_block((void *)area->start,
1134 (void *)(area->start + area->size),
1135 object, 0);
1136out:
1137 spin_unlock_irqrestore(&object->lock, flags);
1138}
1139
1140
1141
1142
1143
1144static void scan_gray_list(void)
1145{
1146 struct kmemleak_object *object, *tmp;
1147
1148
1149
1150
1151
1152
1153 object = list_entry(gray_list.next, typeof(*object), gray_list);
1154 while (&object->gray_list != &gray_list) {
1155 cond_resched();
1156
1157
1158 if (!scan_should_stop())
1159 scan_object(object);
1160
1161 tmp = list_entry(object->gray_list.next, typeof(*object),
1162 gray_list);
1163
1164
1165 list_del(&object->gray_list);
1166 put_object(object);
1167
1168 object = tmp;
1169 }
1170 WARN_ON(!list_empty(&gray_list));
1171}
1172
1173
1174
1175
1176
1177
1178static void kmemleak_scan(void)
1179{
1180 unsigned long flags;
1181 struct kmemleak_object *object;
1182 int i;
1183 int new_leaks = 0;
1184
1185 jiffies_last_scan = jiffies;
1186
1187
1188 rcu_read_lock();
1189 list_for_each_entry_rcu(object, &object_list, object_list) {
1190 spin_lock_irqsave(&object->lock, flags);
1191#ifdef DEBUG
1192
1193
1194
1195
1196 if (atomic_read(&object->use_count) > 1) {
1197 pr_debug("object->use_count = %d\n",
1198 atomic_read(&object->use_count));
1199 dump_object_info(object);
1200 }
1201#endif
1202
1203 object->count = 0;
1204 if (color_gray(object) && get_object(object))
1205 list_add_tail(&object->gray_list, &gray_list);
1206
1207 spin_unlock_irqrestore(&object->lock, flags);
1208 }
1209 rcu_read_unlock();
1210
1211
1212 scan_block(_sdata, _edata, NULL, 1);
1213 scan_block(__bss_start, __bss_stop, NULL, 1);
1214
1215#ifdef CONFIG_SMP
1216
1217 for_each_possible_cpu(i)
1218 scan_block(__per_cpu_start + per_cpu_offset(i),
1219 __per_cpu_end + per_cpu_offset(i), NULL, 1);
1220#endif
1221
1222
1223
1224
1225
1226 for_each_online_node(i) {
1227 pg_data_t *pgdat = NODE_DATA(i);
1228 unsigned long start_pfn = pgdat->node_start_pfn;
1229 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1230 unsigned long pfn;
1231
1232 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1233 struct page *page;
1234
1235 if (!pfn_valid(pfn))
1236 continue;
1237 page = pfn_to_page(pfn);
1238
1239 if (page_count(page) == 0)
1240 continue;
1241 scan_block(page, page + 1, NULL, 1);
1242 }
1243 }
1244
1245
1246
1247
1248 if (kmemleak_stack_scan) {
1249 struct task_struct *p, *g;
1250
1251 read_lock(&tasklist_lock);
1252 do_each_thread(g, p) {
1253 scan_block(task_stack_page(p), task_stack_page(p) +
1254 THREAD_SIZE, NULL, 0);
1255 } while_each_thread(g, p);
1256 read_unlock(&tasklist_lock);
1257 }
1258
1259
1260
1261
1262
1263 scan_gray_list();
1264
1265
1266
1267
1268
1269 rcu_read_lock();
1270 list_for_each_entry_rcu(object, &object_list, object_list) {
1271 spin_lock_irqsave(&object->lock, flags);
1272 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1273 && update_checksum(object) && get_object(object)) {
1274
1275 object->count = object->min_count;
1276 list_add_tail(&object->gray_list, &gray_list);
1277 }
1278 spin_unlock_irqrestore(&object->lock, flags);
1279 }
1280 rcu_read_unlock();
1281
1282
1283
1284
1285 scan_gray_list();
1286
1287
1288
1289
1290 if (scan_should_stop())
1291 return;
1292
1293
1294
1295
1296 rcu_read_lock();
1297 list_for_each_entry_rcu(object, &object_list, object_list) {
1298 spin_lock_irqsave(&object->lock, flags);
1299 if (unreferenced_object(object) &&
1300 !(object->flags & OBJECT_REPORTED)) {
1301 object->flags |= OBJECT_REPORTED;
1302 new_leaks++;
1303 }
1304 spin_unlock_irqrestore(&object->lock, flags);
1305 }
1306 rcu_read_unlock();
1307
1308 if (new_leaks)
1309 pr_info("%d new suspected memory leaks (see "
1310 "/sys/kernel/debug/kmemleak)\n", new_leaks);
1311
1312}
1313
1314
1315
1316
1317
1318static int kmemleak_scan_thread(void *arg)
1319{
1320 static int first_run = 1;
1321
1322 pr_info("Automatic memory scanning thread started\n");
1323 set_user_nice(current, 10);
1324
1325
1326
1327
1328 if (first_run) {
1329 first_run = 0;
1330 ssleep(SECS_FIRST_SCAN);
1331 }
1332
1333 while (!kthread_should_stop()) {
1334 signed long timeout = jiffies_scan_wait;
1335
1336 mutex_lock(&scan_mutex);
1337 kmemleak_scan();
1338 mutex_unlock(&scan_mutex);
1339
1340
1341 while (timeout && !kthread_should_stop())
1342 timeout = schedule_timeout_interruptible(timeout);
1343 }
1344
1345 pr_info("Automatic memory scanning thread ended\n");
1346
1347 return 0;
1348}
1349
1350
1351
1352
1353
1354static void start_scan_thread(void)
1355{
1356 if (scan_thread)
1357 return;
1358 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1359 if (IS_ERR(scan_thread)) {
1360 pr_warning("Failed to create the scan thread\n");
1361 scan_thread = NULL;
1362 }
1363}
1364
1365
1366
1367
1368
1369static void stop_scan_thread(void)
1370{
1371 if (scan_thread) {
1372 kthread_stop(scan_thread);
1373 scan_thread = NULL;
1374 }
1375}
1376
1377
1378
1379
1380
1381
1382static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1383{
1384 struct kmemleak_object *object;
1385 loff_t n = *pos;
1386 int err;
1387
1388 err = mutex_lock_interruptible(&scan_mutex);
1389 if (err < 0)
1390 return ERR_PTR(err);
1391
1392 rcu_read_lock();
1393 list_for_each_entry_rcu(object, &object_list, object_list) {
1394 if (n-- > 0)
1395 continue;
1396 if (get_object(object))
1397 goto out;
1398 }
1399 object = NULL;
1400out:
1401 return object;
1402}
1403
1404
1405
1406
1407
1408static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1409{
1410 struct kmemleak_object *prev_obj = v;
1411 struct kmemleak_object *next_obj = NULL;
1412 struct list_head *n = &prev_obj->object_list;
1413
1414 ++(*pos);
1415
1416 list_for_each_continue_rcu(n, &object_list) {
1417 next_obj = list_entry(n, struct kmemleak_object, object_list);
1418 if (get_object(next_obj))
1419 break;
1420 }
1421
1422 put_object(prev_obj);
1423 return next_obj;
1424}
1425
1426
1427
1428
1429static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1430{
1431 if (!IS_ERR(v)) {
1432
1433
1434
1435
1436 rcu_read_unlock();
1437 mutex_unlock(&scan_mutex);
1438 if (v)
1439 put_object(v);
1440 }
1441}
1442
1443
1444
1445
1446static int kmemleak_seq_show(struct seq_file *seq, void *v)
1447{
1448 struct kmemleak_object *object = v;
1449 unsigned long flags;
1450
1451 spin_lock_irqsave(&object->lock, flags);
1452 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
1453 print_unreferenced(seq, object);
1454 spin_unlock_irqrestore(&object->lock, flags);
1455 return 0;
1456}
1457
1458static const struct seq_operations kmemleak_seq_ops = {
1459 .start = kmemleak_seq_start,
1460 .next = kmemleak_seq_next,
1461 .stop = kmemleak_seq_stop,
1462 .show = kmemleak_seq_show,
1463};
1464
1465static int kmemleak_open(struct inode *inode, struct file *file)
1466{
1467 if (!atomic_read(&kmemleak_enabled))
1468 return -EBUSY;
1469
1470 return seq_open(file, &kmemleak_seq_ops);
1471}
1472
1473static int kmemleak_release(struct inode *inode, struct file *file)
1474{
1475 return seq_release(inode, file);
1476}
1477
1478static int dump_str_object_info(const char *str)
1479{
1480 unsigned long flags;
1481 struct kmemleak_object *object;
1482 unsigned long addr;
1483
1484 addr= simple_strtoul(str, NULL, 0);
1485 object = find_and_get_object(addr, 0);
1486 if (!object) {
1487 pr_info("Unknown object at 0x%08lx\n", addr);
1488 return -EINVAL;
1489 }
1490
1491 spin_lock_irqsave(&object->lock, flags);
1492 dump_object_info(object);
1493 spin_unlock_irqrestore(&object->lock, flags);
1494
1495 put_object(object);
1496 return 0;
1497}
1498
1499
1500
1501
1502
1503
1504
1505static void kmemleak_clear(void)
1506{
1507 struct kmemleak_object *object;
1508 unsigned long flags;
1509
1510 rcu_read_lock();
1511 list_for_each_entry_rcu(object, &object_list, object_list) {
1512 spin_lock_irqsave(&object->lock, flags);
1513 if ((object->flags & OBJECT_REPORTED) &&
1514 unreferenced_object(object))
1515 __paint_it(object, KMEMLEAK_GREY);
1516 spin_unlock_irqrestore(&object->lock, flags);
1517 }
1518 rcu_read_unlock();
1519}
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1537 size_t size, loff_t *ppos)
1538{
1539 char buf[64];
1540 int buf_size;
1541 int ret;
1542
1543 buf_size = min(size, (sizeof(buf) - 1));
1544 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1545 return -EFAULT;
1546 buf[buf_size] = 0;
1547
1548 ret = mutex_lock_interruptible(&scan_mutex);
1549 if (ret < 0)
1550 return ret;
1551
1552 if (strncmp(buf, "off", 3) == 0)
1553 kmemleak_disable();
1554 else if (strncmp(buf, "stack=on", 8) == 0)
1555 kmemleak_stack_scan = 1;
1556 else if (strncmp(buf, "stack=off", 9) == 0)
1557 kmemleak_stack_scan = 0;
1558 else if (strncmp(buf, "scan=on", 7) == 0)
1559 start_scan_thread();
1560 else if (strncmp(buf, "scan=off", 8) == 0)
1561 stop_scan_thread();
1562 else if (strncmp(buf, "scan=", 5) == 0) {
1563 unsigned long secs;
1564
1565 ret = strict_strtoul(buf + 5, 0, &secs);
1566 if (ret < 0)
1567 goto out;
1568 stop_scan_thread();
1569 if (secs) {
1570 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1571 start_scan_thread();
1572 }
1573 } else if (strncmp(buf, "scan", 4) == 0)
1574 kmemleak_scan();
1575 else if (strncmp(buf, "clear", 5) == 0)
1576 kmemleak_clear();
1577 else if (strncmp(buf, "dump=", 5) == 0)
1578 ret = dump_str_object_info(buf + 5);
1579 else
1580 ret = -EINVAL;
1581
1582out:
1583 mutex_unlock(&scan_mutex);
1584 if (ret < 0)
1585 return ret;
1586
1587
1588 *ppos += size;
1589 return size;
1590}
1591
1592static const struct file_operations kmemleak_fops = {
1593 .owner = THIS_MODULE,
1594 .open = kmemleak_open,
1595 .read = seq_read,
1596 .write = kmemleak_write,
1597 .llseek = seq_lseek,
1598 .release = kmemleak_release,
1599};
1600
1601
1602
1603
1604
1605static void kmemleak_do_cleanup(struct work_struct *work)
1606{
1607 struct kmemleak_object *object;
1608
1609 mutex_lock(&scan_mutex);
1610 stop_scan_thread();
1611
1612 rcu_read_lock();
1613 list_for_each_entry_rcu(object, &object_list, object_list)
1614 delete_object_full(object->pointer);
1615 rcu_read_unlock();
1616 mutex_unlock(&scan_mutex);
1617}
1618
1619static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
1620
1621
1622
1623
1624
1625static void kmemleak_disable(void)
1626{
1627
1628 if (atomic_cmpxchg(&kmemleak_error, 0, 1))
1629 return;
1630
1631
1632 atomic_set(&kmemleak_early_log, 0);
1633 atomic_set(&kmemleak_enabled, 0);
1634
1635
1636 if (atomic_read(&kmemleak_initialized))
1637 schedule_work(&cleanup_work);
1638
1639 pr_info("Kernel memory leak detector disabled\n");
1640}
1641
1642
1643
1644
1645static int kmemleak_boot_config(char *str)
1646{
1647 if (!str)
1648 return -EINVAL;
1649 if (strcmp(str, "off") == 0)
1650 kmemleak_disable();
1651 else if (strcmp(str, "on") == 0)
1652 kmemleak_skip_disable = 1;
1653 else
1654 return -EINVAL;
1655 return 0;
1656}
1657early_param("kmemleak", kmemleak_boot_config);
1658
1659
1660
1661
1662void __init kmemleak_init(void)
1663{
1664 int i;
1665 unsigned long flags;
1666
1667#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1668 if (!kmemleak_skip_disable) {
1669 kmemleak_disable();
1670 return;
1671 }
1672#endif
1673
1674 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1675 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1676
1677 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1678 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
1679 INIT_PRIO_TREE_ROOT(&object_tree_root);
1680
1681
1682 local_irq_save(flags);
1683 if (!atomic_read(&kmemleak_error)) {
1684 atomic_set(&kmemleak_enabled, 1);
1685 atomic_set(&kmemleak_early_log, 0);
1686 }
1687 local_irq_restore(flags);
1688
1689
1690
1691
1692
1693
1694 for (i = 0; i < crt_early_log; i++) {
1695 struct early_log *log = &early_log[i];
1696
1697 switch (log->op_type) {
1698 case KMEMLEAK_ALLOC:
1699 early_alloc(log);
1700 break;
1701 case KMEMLEAK_FREE:
1702 kmemleak_free(log->ptr);
1703 break;
1704 case KMEMLEAK_FREE_PART:
1705 kmemleak_free_part(log->ptr, log->size);
1706 break;
1707 case KMEMLEAK_NOT_LEAK:
1708 kmemleak_not_leak(log->ptr);
1709 break;
1710 case KMEMLEAK_IGNORE:
1711 kmemleak_ignore(log->ptr);
1712 break;
1713 case KMEMLEAK_SCAN_AREA:
1714 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
1715 break;
1716 case KMEMLEAK_NO_SCAN:
1717 kmemleak_no_scan(log->ptr);
1718 break;
1719 default:
1720 WARN_ON(1);
1721 }
1722 }
1723}
1724
1725
1726
1727
1728static int __init kmemleak_late_init(void)
1729{
1730 struct dentry *dentry;
1731
1732 atomic_set(&kmemleak_initialized, 1);
1733
1734 if (atomic_read(&kmemleak_error)) {
1735
1736
1737
1738
1739
1740
1741 schedule_work(&cleanup_work);
1742 return -ENOMEM;
1743 }
1744
1745 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
1746 &kmemleak_fops);
1747 if (!dentry)
1748 pr_warning("Failed to create the debugfs kmemleak file\n");
1749 mutex_lock(&scan_mutex);
1750 start_scan_thread();
1751 mutex_unlock(&scan_mutex);
1752
1753 pr_info("Kernel memory leak detector initialized\n");
1754
1755 return 0;
1756}
1757late_initcall(kmemleak_late_init);
1758