2 * Generic infrastructure for lifetime debugging of objects.
4 * Started by Thomas Gleixner
6 * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
8 * For licencing details see kernel-base/COPYING
11 #define pr_fmt(fmt) "ODEBUG: " fmt
13 #include <linux/debugobjects.h>
14 #include <linux/interrupt.h>
15 #include <linux/sched.h>
16 #include <linux/sched/task_stack.h>
17 #include <linux/seq_file.h>
18 #include <linux/debugfs.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/kmemleak.h>
23 #define ODEBUG_HASH_BITS 14
24 #define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
26 #define ODEBUG_POOL_SIZE 1024
27 #define ODEBUG_POOL_MIN_LEVEL 256
28 #define ODEBUG_POOL_PERCPU_SIZE 64
29 #define ODEBUG_BATCH_SIZE 16
31 #define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
32 #define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
33 #define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
36 * We limit the freeing of debug objects via workqueue at a maximum
37 * frequency of 10Hz and about 1024 objects for each freeing operation.
38 * So it is freeing at most 10k debug objects per second.
40 #define ODEBUG_FREE_WORK_MAX 1024
41 #define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
44 struct hlist_head list;
49 * Debug object percpu free list
50 * Access is protected by disabling irq
52 struct debug_percpu_free {
53 struct hlist_head free_objs;
57 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
59 static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
61 static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
63 static DEFINE_RAW_SPINLOCK(pool_lock);
65 static HLIST_HEAD(obj_pool);
66 static HLIST_HEAD(obj_to_free);
69 * Because of the presence of percpu free pools, obj_pool_free will
70 * under-count those in the percpu free pools. Similarly, obj_pool_used
71 * will over-count those in the percpu free pools. Adjustments will be
72 * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
75 static int obj_pool_min_free = ODEBUG_POOL_SIZE;
76 static int obj_pool_free = ODEBUG_POOL_SIZE;
77 static int obj_pool_used;
78 static int obj_pool_max_used;
79 static bool obj_freeing;
80 /* The number of objs on the global free list */
81 static int obj_nr_tofree;
83 static int debug_objects_maxchain __read_mostly;
84 static int __maybe_unused debug_objects_maxchecked __read_mostly;
85 static int debug_objects_fixups __read_mostly;
86 static int debug_objects_warnings __read_mostly;
87 static int debug_objects_enabled __read_mostly
88 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
89 static int debug_objects_pool_size __read_mostly
91 static int debug_objects_pool_min_level __read_mostly
92 = ODEBUG_POOL_MIN_LEVEL;
93 static struct debug_obj_descr *descr_test __read_mostly;
94 static struct kmem_cache *obj_cache __read_mostly;
97 * Track numbers of kmem_cache_alloc()/free() calls done.
99 static int debug_objects_allocated;
100 static int debug_objects_freed;
102 static void free_obj_work(struct work_struct *work);
103 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
105 static int __init enable_object_debug(char *str)
107 debug_objects_enabled = 1;
111 static int __init disable_object_debug(char *str)
113 debug_objects_enabled = 0;
117 early_param("debug_objects", enable_object_debug);
118 early_param("no_debug_objects", disable_object_debug);
120 static const char *obj_states[ODEBUG_STATE_MAX] = {
121 [ODEBUG_STATE_NONE] = "none",
122 [ODEBUG_STATE_INIT] = "initialized",
123 [ODEBUG_STATE_INACTIVE] = "inactive",
124 [ODEBUG_STATE_ACTIVE] = "active",
125 [ODEBUG_STATE_DESTROYED] = "destroyed",
126 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
129 static void fill_pool(void)
131 gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
132 struct debug_obj *obj;
135 if (likely(obj_pool_free >= debug_objects_pool_min_level))
139 * Reuse objs from the global free list; they will be reinitialized
142 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
143 raw_spin_lock_irqsave(&pool_lock, flags);
145 * Recheck with the lock held as the worker thread might have
146 * won the race and freed the global free list already.
148 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
149 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
150 hlist_del(&obj->node);
152 hlist_add_head(&obj->node, &obj_pool);
155 raw_spin_unlock_irqrestore(&pool_lock, flags);
158 if (unlikely(!obj_cache))
161 while (obj_pool_free < debug_objects_pool_min_level) {
162 struct debug_obj *new[ODEBUG_BATCH_SIZE];
165 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
166 new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
173 raw_spin_lock_irqsave(&pool_lock, flags);
175 hlist_add_head(&new[--cnt]->node, &obj_pool);
176 debug_objects_allocated++;
179 raw_spin_unlock_irqrestore(&pool_lock, flags);
184 * Lookup an object in the hash bucket.
186 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
188 struct debug_obj *obj;
191 hlist_for_each_entry(obj, &b->list, node) {
193 if (obj->object == addr)
196 if (cnt > debug_objects_maxchain)
197 debug_objects_maxchain = cnt;
203 * Allocate a new object from the hlist
205 static struct debug_obj *__alloc_object(struct hlist_head *list)
207 struct debug_obj *obj = NULL;
210 obj = hlist_entry(list->first, typeof(*obj), node);
211 hlist_del(&obj->node);
218 * Allocate a new object. If the pool is empty, switch off the debugger.
219 * Must be called with interrupts disabled.
221 static struct debug_obj *
222 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
224 struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
225 struct debug_obj *obj;
227 if (likely(obj_cache)) {
228 obj = __alloc_object(&percpu_pool->free_objs);
230 percpu_pool->obj_free--;
235 raw_spin_lock(&pool_lock);
236 obj = __alloc_object(&obj_pool);
242 * Looking ahead, allocate one batch of debug objects and
243 * put them into the percpu free pool.
245 if (likely(obj_cache)) {
248 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
249 struct debug_obj *obj2;
251 obj2 = __alloc_object(&obj_pool);
254 hlist_add_head(&obj2->node,
255 &percpu_pool->free_objs);
256 percpu_pool->obj_free++;
262 if (obj_pool_used > obj_pool_max_used)
263 obj_pool_max_used = obj_pool_used;
265 if (obj_pool_free < obj_pool_min_free)
266 obj_pool_min_free = obj_pool_free;
268 raw_spin_unlock(&pool_lock);
274 obj->state = ODEBUG_STATE_NONE;
276 hlist_add_head(&obj->node, &b->list);
282 * workqueue function to free objects.
284 * To reduce contention on the global pool_lock, the actual freeing of
285 * debug objects will be delayed if the pool_lock is busy.
287 static void free_obj_work(struct work_struct *work)
289 struct hlist_node *tmp;
290 struct debug_obj *obj;
294 WRITE_ONCE(obj_freeing, false);
295 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
298 if (obj_pool_free >= debug_objects_pool_size)
302 * The objs on the pool list might be allocated before the work is
303 * run, so recheck if pool list it full or not, if not fill pool
304 * list from the global free list. As it is likely that a workload
305 * may be gearing up to use more and more objects, don't free any
306 * of them until the next round.
308 while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
309 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
310 hlist_del(&obj->node);
311 hlist_add_head(&obj->node, &obj_pool);
315 raw_spin_unlock_irqrestore(&pool_lock, flags);
320 * Pool list is already full and there are still objs on the free
321 * list. Move remaining free objs to a temporary list to free the
322 * memory outside the pool_lock held region.
325 hlist_move_list(&obj_to_free, &tofree);
326 debug_objects_freed += obj_nr_tofree;
329 raw_spin_unlock_irqrestore(&pool_lock, flags);
331 hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
332 hlist_del(&obj->node);
333 kmem_cache_free(obj_cache, obj);
337 static void __free_object(struct debug_obj *obj)
339 struct debug_obj *objs[ODEBUG_BATCH_SIZE];
340 struct debug_percpu_free *percpu_pool;
341 int lookahead_count = 0;
345 local_irq_save(flags);
347 goto free_to_obj_pool;
350 * Try to free it into the percpu pool first.
352 percpu_pool = this_cpu_ptr(&percpu_obj_pool);
353 if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
354 hlist_add_head(&obj->node, &percpu_pool->free_objs);
355 percpu_pool->obj_free++;
356 local_irq_restore(flags);
361 * As the percpu pool is full, look ahead and pull out a batch
362 * of objects from the percpu pool and free them as well.
364 for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
365 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
366 if (!objs[lookahead_count])
368 percpu_pool->obj_free--;
372 raw_spin_lock(&pool_lock);
373 work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
374 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
379 hlist_add_head(&obj->node, &obj_to_free);
380 if (lookahead_count) {
381 obj_nr_tofree += lookahead_count;
382 obj_pool_used -= lookahead_count;
383 while (lookahead_count) {
384 hlist_add_head(&objs[--lookahead_count]->node,
389 if ((obj_pool_free > debug_objects_pool_size) &&
390 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
394 * Free one more batch of objects from obj_pool.
396 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
397 obj = __alloc_object(&obj_pool);
398 hlist_add_head(&obj->node, &obj_to_free);
405 hlist_add_head(&obj->node, &obj_pool);
406 if (lookahead_count) {
407 obj_pool_free += lookahead_count;
408 obj_pool_used -= lookahead_count;
409 while (lookahead_count) {
410 hlist_add_head(&objs[--lookahead_count]->node,
415 raw_spin_unlock(&pool_lock);
416 local_irq_restore(flags);
420 * Put the object back into the pool and schedule work to free objects
423 static void free_object(struct debug_obj *obj)
426 if (!obj_freeing && obj_nr_tofree) {
427 WRITE_ONCE(obj_freeing, true);
428 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
433 * We run out of memory. That means we probably have tons of objects
436 static void debug_objects_oom(void)
438 struct debug_bucket *db = obj_hash;
439 struct hlist_node *tmp;
440 HLIST_HEAD(freelist);
441 struct debug_obj *obj;
445 pr_warn("Out of memory. ODEBUG disabled\n");
447 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
448 raw_spin_lock_irqsave(&db->lock, flags);
449 hlist_move_list(&db->list, &freelist);
450 raw_spin_unlock_irqrestore(&db->lock, flags);
453 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
454 hlist_del(&obj->node);
461 * We use the pfn of the address for the hash. That way we can check
462 * for freed objects simply by checking the affected bucket.
464 static struct debug_bucket *get_bucket(unsigned long addr)
468 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
469 return &obj_hash[hash];
472 static void debug_print_object(struct debug_obj *obj, char *msg)
474 struct debug_obj_descr *descr = obj->descr;
477 if (limit < 5 && descr != descr_test) {
478 void *hint = descr->debug_hint ?
479 descr->debug_hint(obj->object) : NULL;
481 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
482 "object type: %s hint: %pS\n",
483 msg, obj_states[obj->state], obj->astate,
486 debug_objects_warnings++;
490 * Try to repair the damage, so we have a better chance to get useful
494 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
495 void * addr, enum debug_obj_state state)
497 if (fixup && fixup(addr, state)) {
498 debug_objects_fixups++;
504 static void debug_object_is_on_stack(void *addr, int onstack)
512 is_on_stack = object_is_on_stack(addr);
513 if (is_on_stack == onstack)
518 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
519 task_stack_page(current));
521 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
522 task_stack_page(current));
528 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
530 enum debug_obj_state state;
531 struct debug_bucket *db;
532 struct debug_obj *obj;
537 db = get_bucket((unsigned long) addr);
539 raw_spin_lock_irqsave(&db->lock, flags);
541 obj = lookup_object(addr, db);
543 obj = alloc_object(addr, db, descr);
545 debug_objects_enabled = 0;
546 raw_spin_unlock_irqrestore(&db->lock, flags);
550 debug_object_is_on_stack(addr, onstack);
553 switch (obj->state) {
554 case ODEBUG_STATE_NONE:
555 case ODEBUG_STATE_INIT:
556 case ODEBUG_STATE_INACTIVE:
557 obj->state = ODEBUG_STATE_INIT;
560 case ODEBUG_STATE_ACTIVE:
561 debug_print_object(obj, "init");
563 raw_spin_unlock_irqrestore(&db->lock, flags);
564 debug_object_fixup(descr->fixup_init, addr, state);
567 case ODEBUG_STATE_DESTROYED:
568 debug_print_object(obj, "init");
574 raw_spin_unlock_irqrestore(&db->lock, flags);
578 * debug_object_init - debug checks when an object is initialized
579 * @addr: address of the object
580 * @descr: pointer to an object specific debug description structure
582 void debug_object_init(void *addr, struct debug_obj_descr *descr)
584 if (!debug_objects_enabled)
587 __debug_object_init(addr, descr, 0);
589 EXPORT_SYMBOL_GPL(debug_object_init);
592 * debug_object_init_on_stack - debug checks when an object on stack is
594 * @addr: address of the object
595 * @descr: pointer to an object specific debug description structure
597 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
599 if (!debug_objects_enabled)
602 __debug_object_init(addr, descr, 1);
604 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
607 * debug_object_activate - debug checks when an object is activated
608 * @addr: address of the object
609 * @descr: pointer to an object specific debug description structure
610 * Returns 0 for success, -EINVAL for check failed.
612 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
614 enum debug_obj_state state;
615 struct debug_bucket *db;
616 struct debug_obj *obj;
619 struct debug_obj o = { .object = addr,
620 .state = ODEBUG_STATE_NOTAVAILABLE,
623 if (!debug_objects_enabled)
626 db = get_bucket((unsigned long) addr);
628 raw_spin_lock_irqsave(&db->lock, flags);
630 obj = lookup_object(addr, db);
632 switch (obj->state) {
633 case ODEBUG_STATE_INIT:
634 case ODEBUG_STATE_INACTIVE:
635 obj->state = ODEBUG_STATE_ACTIVE;
639 case ODEBUG_STATE_ACTIVE:
640 debug_print_object(obj, "activate");
642 raw_spin_unlock_irqrestore(&db->lock, flags);
643 ret = debug_object_fixup(descr->fixup_activate, addr, state);
644 return ret ? 0 : -EINVAL;
646 case ODEBUG_STATE_DESTROYED:
647 debug_print_object(obj, "activate");
654 raw_spin_unlock_irqrestore(&db->lock, flags);
658 raw_spin_unlock_irqrestore(&db->lock, flags);
660 * We are here when a static object is activated. We
661 * let the type specific code confirm whether this is
662 * true or not. if true, we just make sure that the
663 * static object is tracked in the object tracker. If
664 * not, this must be a bug, so we try to fix it up.
666 if (descr->is_static_object && descr->is_static_object(addr)) {
667 /* track this static object */
668 debug_object_init(addr, descr);
669 debug_object_activate(addr, descr);
671 debug_print_object(&o, "activate");
672 ret = debug_object_fixup(descr->fixup_activate, addr,
673 ODEBUG_STATE_NOTAVAILABLE);
674 return ret ? 0 : -EINVAL;
678 EXPORT_SYMBOL_GPL(debug_object_activate);
681 * debug_object_deactivate - debug checks when an object is deactivated
682 * @addr: address of the object
683 * @descr: pointer to an object specific debug description structure
685 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
687 struct debug_bucket *db;
688 struct debug_obj *obj;
691 if (!debug_objects_enabled)
694 db = get_bucket((unsigned long) addr);
696 raw_spin_lock_irqsave(&db->lock, flags);
698 obj = lookup_object(addr, db);
700 switch (obj->state) {
701 case ODEBUG_STATE_INIT:
702 case ODEBUG_STATE_INACTIVE:
703 case ODEBUG_STATE_ACTIVE:
705 obj->state = ODEBUG_STATE_INACTIVE;
707 debug_print_object(obj, "deactivate");
710 case ODEBUG_STATE_DESTROYED:
711 debug_print_object(obj, "deactivate");
717 struct debug_obj o = { .object = addr,
718 .state = ODEBUG_STATE_NOTAVAILABLE,
721 debug_print_object(&o, "deactivate");
724 raw_spin_unlock_irqrestore(&db->lock, flags);
726 EXPORT_SYMBOL_GPL(debug_object_deactivate);
729 * debug_object_destroy - debug checks when an object is destroyed
730 * @addr: address of the object
731 * @descr: pointer to an object specific debug description structure
733 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
735 enum debug_obj_state state;
736 struct debug_bucket *db;
737 struct debug_obj *obj;
740 if (!debug_objects_enabled)
743 db = get_bucket((unsigned long) addr);
745 raw_spin_lock_irqsave(&db->lock, flags);
747 obj = lookup_object(addr, db);
751 switch (obj->state) {
752 case ODEBUG_STATE_NONE:
753 case ODEBUG_STATE_INIT:
754 case ODEBUG_STATE_INACTIVE:
755 obj->state = ODEBUG_STATE_DESTROYED;
757 case ODEBUG_STATE_ACTIVE:
758 debug_print_object(obj, "destroy");
760 raw_spin_unlock_irqrestore(&db->lock, flags);
761 debug_object_fixup(descr->fixup_destroy, addr, state);
764 case ODEBUG_STATE_DESTROYED:
765 debug_print_object(obj, "destroy");
771 raw_spin_unlock_irqrestore(&db->lock, flags);
773 EXPORT_SYMBOL_GPL(debug_object_destroy);
776 * debug_object_free - debug checks when an object is freed
777 * @addr: address of the object
778 * @descr: pointer to an object specific debug description structure
780 void debug_object_free(void *addr, struct debug_obj_descr *descr)
782 enum debug_obj_state state;
783 struct debug_bucket *db;
784 struct debug_obj *obj;
787 if (!debug_objects_enabled)
790 db = get_bucket((unsigned long) addr);
792 raw_spin_lock_irqsave(&db->lock, flags);
794 obj = lookup_object(addr, db);
798 switch (obj->state) {
799 case ODEBUG_STATE_ACTIVE:
800 debug_print_object(obj, "free");
802 raw_spin_unlock_irqrestore(&db->lock, flags);
803 debug_object_fixup(descr->fixup_free, addr, state);
806 hlist_del(&obj->node);
807 raw_spin_unlock_irqrestore(&db->lock, flags);
812 raw_spin_unlock_irqrestore(&db->lock, flags);
814 EXPORT_SYMBOL_GPL(debug_object_free);
817 * debug_object_assert_init - debug checks when object should be init-ed
818 * @addr: address of the object
819 * @descr: pointer to an object specific debug description structure
821 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
823 struct debug_bucket *db;
824 struct debug_obj *obj;
827 if (!debug_objects_enabled)
830 db = get_bucket((unsigned long) addr);
832 raw_spin_lock_irqsave(&db->lock, flags);
834 obj = lookup_object(addr, db);
836 struct debug_obj o = { .object = addr,
837 .state = ODEBUG_STATE_NOTAVAILABLE,
840 raw_spin_unlock_irqrestore(&db->lock, flags);
842 * Maybe the object is static, and we let the type specific
843 * code confirm. Track this static object if true, else invoke
846 if (descr->is_static_object && descr->is_static_object(addr)) {
847 /* Track this static object */
848 debug_object_init(addr, descr);
850 debug_print_object(&o, "assert_init");
851 debug_object_fixup(descr->fixup_assert_init, addr,
852 ODEBUG_STATE_NOTAVAILABLE);
857 raw_spin_unlock_irqrestore(&db->lock, flags);
859 EXPORT_SYMBOL_GPL(debug_object_assert_init);
862 * debug_object_active_state - debug checks object usage state machine
863 * @addr: address of the object
864 * @descr: pointer to an object specific debug description structure
865 * @expect: expected state
866 * @next: state to move to if expected state is found
869 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
870 unsigned int expect, unsigned int next)
872 struct debug_bucket *db;
873 struct debug_obj *obj;
876 if (!debug_objects_enabled)
879 db = get_bucket((unsigned long) addr);
881 raw_spin_lock_irqsave(&db->lock, flags);
883 obj = lookup_object(addr, db);
885 switch (obj->state) {
886 case ODEBUG_STATE_ACTIVE:
887 if (obj->astate == expect)
890 debug_print_object(obj, "active_state");
894 debug_print_object(obj, "active_state");
898 struct debug_obj o = { .object = addr,
899 .state = ODEBUG_STATE_NOTAVAILABLE,
902 debug_print_object(&o, "active_state");
905 raw_spin_unlock_irqrestore(&db->lock, flags);
907 EXPORT_SYMBOL_GPL(debug_object_active_state);
909 #ifdef CONFIG_DEBUG_OBJECTS_FREE
910 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
912 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
913 struct debug_obj_descr *descr;
914 enum debug_obj_state state;
915 struct debug_bucket *db;
916 struct hlist_node *tmp;
917 struct debug_obj *obj;
918 int cnt, objs_checked = 0;
920 saddr = (unsigned long) address;
921 eaddr = saddr + size;
922 paddr = saddr & ODEBUG_CHUNK_MASK;
923 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
924 chunks >>= ODEBUG_CHUNK_SHIFT;
926 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
927 db = get_bucket(paddr);
931 raw_spin_lock_irqsave(&db->lock, flags);
932 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
934 oaddr = (unsigned long) obj->object;
935 if (oaddr < saddr || oaddr >= eaddr)
938 switch (obj->state) {
939 case ODEBUG_STATE_ACTIVE:
940 debug_print_object(obj, "free");
943 raw_spin_unlock_irqrestore(&db->lock, flags);
944 debug_object_fixup(descr->fixup_free,
945 (void *) oaddr, state);
948 hlist_del(&obj->node);
953 raw_spin_unlock_irqrestore(&db->lock, flags);
955 if (cnt > debug_objects_maxchain)
956 debug_objects_maxchain = cnt;
961 if (objs_checked > debug_objects_maxchecked)
962 debug_objects_maxchecked = objs_checked;
964 /* Schedule work to actually kmem_cache_free() objects */
965 if (!obj_freeing && obj_nr_tofree) {
966 WRITE_ONCE(obj_freeing, true);
967 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
971 void debug_check_no_obj_freed(const void *address, unsigned long size)
973 if (debug_objects_enabled)
974 __debug_check_no_obj_freed(address, size);
978 #ifdef CONFIG_DEBUG_FS
980 static int debug_stats_show(struct seq_file *m, void *v)
982 int cpu, obj_percpu_free = 0;
984 for_each_possible_cpu(cpu)
985 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
987 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
988 seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
989 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
990 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
991 seq_printf(m, "pool_free :%d\n", obj_pool_free + obj_percpu_free);
992 seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
993 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
994 seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
995 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
996 seq_printf(m, "on_free_list :%d\n", obj_nr_tofree);
997 seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
998 seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
1002 static int debug_stats_open(struct inode *inode, struct file *filp)
1004 return single_open(filp, debug_stats_show, NULL);
1007 static const struct file_operations debug_stats_fops = {
1008 .open = debug_stats_open,
1010 .llseek = seq_lseek,
1011 .release = single_release,
1014 static int __init debug_objects_init_debugfs(void)
1016 struct dentry *dbgdir;
1018 if (!debug_objects_enabled)
1021 dbgdir = debugfs_create_dir("debug_objects", NULL);
1023 debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1027 __initcall(debug_objects_init_debugfs);
1030 static inline void debug_objects_init_debugfs(void) { }
1033 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1035 /* Random data structure for the self test */
1037 unsigned long dummy1[6];
1039 unsigned long dummy2[3];
1042 static __initdata struct debug_obj_descr descr_type_test;
1044 static bool __init is_static_object(void *addr)
1046 struct self_test *obj = addr;
1048 return obj->static_init;
1052 * fixup_init is called when:
1053 * - an active object is initialized
1055 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1057 struct self_test *obj = addr;
1060 case ODEBUG_STATE_ACTIVE:
1061 debug_object_deactivate(obj, &descr_type_test);
1062 debug_object_init(obj, &descr_type_test);
1070 * fixup_activate is called when:
1071 * - an active object is activated
1072 * - an unknown non-static object is activated
1074 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1076 struct self_test *obj = addr;
1079 case ODEBUG_STATE_NOTAVAILABLE:
1081 case ODEBUG_STATE_ACTIVE:
1082 debug_object_deactivate(obj, &descr_type_test);
1083 debug_object_activate(obj, &descr_type_test);
1092 * fixup_destroy is called when:
1093 * - an active object is destroyed
1095 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1097 struct self_test *obj = addr;
1100 case ODEBUG_STATE_ACTIVE:
1101 debug_object_deactivate(obj, &descr_type_test);
1102 debug_object_destroy(obj, &descr_type_test);
1110 * fixup_free is called when:
1111 * - an active object is freed
1113 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1115 struct self_test *obj = addr;
1118 case ODEBUG_STATE_ACTIVE:
1119 debug_object_deactivate(obj, &descr_type_test);
1120 debug_object_free(obj, &descr_type_test);
1128 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1130 struct debug_bucket *db;
1131 struct debug_obj *obj;
1132 unsigned long flags;
1135 db = get_bucket((unsigned long) addr);
1137 raw_spin_lock_irqsave(&db->lock, flags);
1139 obj = lookup_object(addr, db);
1140 if (!obj && state != ODEBUG_STATE_NONE) {
1141 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1144 if (obj && obj->state != state) {
1145 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1149 if (fixups != debug_objects_fixups) {
1150 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1151 fixups, debug_objects_fixups);
1154 if (warnings != debug_objects_warnings) {
1155 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1156 warnings, debug_objects_warnings);
1161 raw_spin_unlock_irqrestore(&db->lock, flags);
1163 debug_objects_enabled = 0;
1167 static __initdata struct debug_obj_descr descr_type_test = {
1169 .is_static_object = is_static_object,
1170 .fixup_init = fixup_init,
1171 .fixup_activate = fixup_activate,
1172 .fixup_destroy = fixup_destroy,
1173 .fixup_free = fixup_free,
1176 static __initdata struct self_test obj = { .static_init = 0 };
1178 static void __init debug_objects_selftest(void)
1180 int fixups, oldfixups, warnings, oldwarnings;
1181 unsigned long flags;
1183 local_irq_save(flags);
1185 fixups = oldfixups = debug_objects_fixups;
1186 warnings = oldwarnings = debug_objects_warnings;
1187 descr_test = &descr_type_test;
1189 debug_object_init(&obj, &descr_type_test);
1190 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1192 debug_object_activate(&obj, &descr_type_test);
1193 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1195 debug_object_activate(&obj, &descr_type_test);
1196 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1198 debug_object_deactivate(&obj, &descr_type_test);
1199 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1201 debug_object_destroy(&obj, &descr_type_test);
1202 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1204 debug_object_init(&obj, &descr_type_test);
1205 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1207 debug_object_activate(&obj, &descr_type_test);
1208 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1210 debug_object_deactivate(&obj, &descr_type_test);
1211 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1213 debug_object_free(&obj, &descr_type_test);
1214 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1217 obj.static_init = 1;
1218 debug_object_activate(&obj, &descr_type_test);
1219 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1221 debug_object_init(&obj, &descr_type_test);
1222 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1224 debug_object_free(&obj, &descr_type_test);
1225 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1228 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1229 debug_object_init(&obj, &descr_type_test);
1230 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1232 debug_object_activate(&obj, &descr_type_test);
1233 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1235 __debug_check_no_obj_freed(&obj, sizeof(obj));
1236 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1239 pr_info("selftest passed\n");
1242 debug_objects_fixups = oldfixups;
1243 debug_objects_warnings = oldwarnings;
1246 local_irq_restore(flags);
1249 static inline void debug_objects_selftest(void) { }
1253 * Called during early boot to initialize the hash buckets and link
1254 * the static object pool objects into the poll list. After this call
1255 * the object tracker is fully operational.
1257 void __init debug_objects_early_init(void)
1261 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1262 raw_spin_lock_init(&obj_hash[i].lock);
1264 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1265 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1269 * Convert the statically allocated objects to dynamic ones:
1271 static int __init debug_objects_replace_static_objects(void)
1273 struct debug_bucket *db = obj_hash;
1274 struct hlist_node *tmp;
1275 struct debug_obj *obj, *new;
1276 HLIST_HEAD(objects);
1279 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1280 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1283 hlist_add_head(&obj->node, &objects);
1287 * debug_objects_mem_init() is now called early that only one CPU is up
1288 * and interrupts have been disabled, so it is safe to replace the
1289 * active object references.
1292 /* Remove the statically allocated objects from the pool */
1293 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1294 hlist_del(&obj->node);
1295 /* Move the allocated objects to the pool */
1296 hlist_move_list(&objects, &obj_pool);
1298 /* Replace the active object references */
1299 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1300 hlist_move_list(&db->list, &objects);
1302 hlist_for_each_entry(obj, &objects, node) {
1303 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1304 hlist_del(&new->node);
1305 /* copy object data */
1307 hlist_add_head(&new->node, &db->list);
1312 pr_debug("%d of %d active objects replaced\n",
1313 cnt, obj_pool_used);
1316 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1317 hlist_del(&obj->node);
1318 kmem_cache_free(obj_cache, obj);
1324 * Called after the kmem_caches are functional to setup a dedicated
1325 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1326 * prevents that the debug code is called on kmem_cache_free() for the
1327 * debug tracker objects to avoid recursive calls.
1329 void __init debug_objects_mem_init(void)
1333 if (!debug_objects_enabled)
1337 * Initialize the percpu object pools
1339 * Initialization is not strictly necessary, but was done for
1342 for_each_possible_cpu(cpu)
1343 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1345 obj_cache = kmem_cache_create("debug_objects_cache",
1346 sizeof (struct debug_obj), 0,
1347 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1350 if (!obj_cache || debug_objects_replace_static_objects()) {
1351 debug_objects_enabled = 0;
1352 kmem_cache_destroy(obj_cache);
1353 pr_warn("out of memory.\n");
1355 debug_objects_selftest();
1358 * Increase the thresholds for allocating and freeing objects
1359 * according to the number of possible CPUs available in the system.
1361 extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1362 debug_objects_pool_size += extras;
1363 debug_objects_pool_min_level += extras;