1 // SPDX-License-Identifier: GPL-2.0
3 * Generic infrastructure for lifetime debugging of objects.
5 * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
8 #define pr_fmt(fmt) "ODEBUG: " fmt
10 #include <linux/debugobjects.h>
11 #include <linux/interrupt.h>
12 #include <linux/sched.h>
13 #include <linux/sched/task_stack.h>
14 #include <linux/seq_file.h>
15 #include <linux/debugfs.h>
16 #include <linux/slab.h>
17 #include <linux/hash.h>
18 #include <linux/kmemleak.h>
19 #include <linux/cpu.h>
21 #define ODEBUG_HASH_BITS 14
22 #define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
24 #define ODEBUG_POOL_SIZE 1024
25 #define ODEBUG_POOL_MIN_LEVEL 256
26 #define ODEBUG_POOL_PERCPU_SIZE 64
27 #define ODEBUG_BATCH_SIZE 16
29 #define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
30 #define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
31 #define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
34 * We limit the freeing of debug objects via workqueue at a maximum
35 * frequency of 10Hz and about 1024 objects for each freeing operation.
36 * So it is freeing at most 10k debug objects per second.
38 #define ODEBUG_FREE_WORK_MAX 1024
39 #define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
42 struct hlist_head list;
47 * Debug object percpu free list
48 * Access is protected by disabling irq
50 struct debug_percpu_free {
51 struct hlist_head free_objs;
55 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
57 static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
59 static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
61 static DEFINE_RAW_SPINLOCK(pool_lock);
63 static HLIST_HEAD(obj_pool);
64 static HLIST_HEAD(obj_to_free);
67 * Because of the presence of percpu free pools, obj_pool_free will
68 * under-count those in the percpu free pools. Similarly, obj_pool_used
69 * will over-count those in the percpu free pools. Adjustments will be
70 * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
73 static int obj_pool_min_free = ODEBUG_POOL_SIZE;
74 static int obj_pool_free = ODEBUG_POOL_SIZE;
75 static int obj_pool_used;
76 static int obj_pool_max_used;
77 static bool obj_freeing;
78 /* The number of objs on the global free list */
79 static int obj_nr_tofree;
81 static int debug_objects_maxchain __read_mostly;
82 static int __maybe_unused debug_objects_maxchecked __read_mostly;
83 static int debug_objects_fixups __read_mostly;
84 static int debug_objects_warnings __read_mostly;
85 static int debug_objects_enabled __read_mostly
86 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
87 static int debug_objects_pool_size __read_mostly
89 static int debug_objects_pool_min_level __read_mostly
90 = ODEBUG_POOL_MIN_LEVEL;
91 static const struct debug_obj_descr *descr_test __read_mostly;
92 static struct kmem_cache *obj_cache __read_mostly;
95 * Track numbers of kmem_cache_alloc()/free() calls done.
97 static int debug_objects_allocated;
98 static int debug_objects_freed;
100 static void free_obj_work(struct work_struct *work);
101 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
103 static int __init enable_object_debug(char *str)
105 debug_objects_enabled = 1;
109 static int __init disable_object_debug(char *str)
111 debug_objects_enabled = 0;
115 early_param("debug_objects", enable_object_debug);
116 early_param("no_debug_objects", disable_object_debug);
118 static const char *obj_states[ODEBUG_STATE_MAX] = {
119 [ODEBUG_STATE_NONE] = "none",
120 [ODEBUG_STATE_INIT] = "initialized",
121 [ODEBUG_STATE_INACTIVE] = "inactive",
122 [ODEBUG_STATE_ACTIVE] = "active",
123 [ODEBUG_STATE_DESTROYED] = "destroyed",
124 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
127 static void fill_pool(void)
129 gfp_t gfp = __GFP_HIGH | __GFP_NOWARN;
130 struct debug_obj *obj;
133 if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
137 * Reuse objs from the global free list; they will be reinitialized
140 * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
141 * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
144 while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
145 raw_spin_lock_irqsave(&pool_lock, flags);
147 * Recheck with the lock held as the worker thread might have
148 * won the race and freed the global free list already.
150 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
151 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
152 hlist_del(&obj->node);
153 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
154 hlist_add_head(&obj->node, &obj_pool);
155 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
157 raw_spin_unlock_irqrestore(&pool_lock, flags);
160 if (unlikely(!obj_cache))
163 while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
164 struct debug_obj *new[ODEBUG_BATCH_SIZE];
167 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
168 new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
175 raw_spin_lock_irqsave(&pool_lock, flags);
177 hlist_add_head(&new[--cnt]->node, &obj_pool);
178 debug_objects_allocated++;
179 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
181 raw_spin_unlock_irqrestore(&pool_lock, flags);
186 * Lookup an object in the hash bucket.
188 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
190 struct debug_obj *obj;
193 hlist_for_each_entry(obj, &b->list, node) {
195 if (obj->object == addr)
198 if (cnt > debug_objects_maxchain)
199 debug_objects_maxchain = cnt;
205 * Allocate a new object from the hlist
207 static struct debug_obj *__alloc_object(struct hlist_head *list)
209 struct debug_obj *obj = NULL;
212 obj = hlist_entry(list->first, typeof(*obj), node);
213 hlist_del(&obj->node);
219 static struct debug_obj *
220 alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
222 struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
223 struct debug_obj *obj;
225 if (likely(obj_cache)) {
226 obj = __alloc_object(&percpu_pool->free_objs);
228 percpu_pool->obj_free--;
233 raw_spin_lock(&pool_lock);
234 obj = __alloc_object(&obj_pool);
237 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
240 * Looking ahead, allocate one batch of debug objects and
241 * put them into the percpu free pool.
243 if (likely(obj_cache)) {
246 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
247 struct debug_obj *obj2;
249 obj2 = __alloc_object(&obj_pool);
252 hlist_add_head(&obj2->node,
253 &percpu_pool->free_objs);
254 percpu_pool->obj_free++;
256 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
260 if (obj_pool_used > obj_pool_max_used)
261 obj_pool_max_used = obj_pool_used;
263 if (obj_pool_free < obj_pool_min_free)
264 obj_pool_min_free = obj_pool_free;
266 raw_spin_unlock(&pool_lock);
272 obj->state = ODEBUG_STATE_NONE;
274 hlist_add_head(&obj->node, &b->list);
280 * workqueue function to free objects.
282 * To reduce contention on the global pool_lock, the actual freeing of
283 * debug objects will be delayed if the pool_lock is busy.
285 static void free_obj_work(struct work_struct *work)
287 struct hlist_node *tmp;
288 struct debug_obj *obj;
292 WRITE_ONCE(obj_freeing, false);
293 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
296 if (obj_pool_free >= debug_objects_pool_size)
300 * The objs on the pool list might be allocated before the work is
301 * run, so recheck if pool list it full or not, if not fill pool
302 * list from the global free list. As it is likely that a workload
303 * may be gearing up to use more and more objects, don't free any
304 * of them until the next round.
306 while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
307 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
308 hlist_del(&obj->node);
309 hlist_add_head(&obj->node, &obj_pool);
310 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
311 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
313 raw_spin_unlock_irqrestore(&pool_lock, flags);
318 * Pool list is already full and there are still objs on the free
319 * list. Move remaining free objs to a temporary list to free the
320 * memory outside the pool_lock held region.
323 hlist_move_list(&obj_to_free, &tofree);
324 debug_objects_freed += obj_nr_tofree;
325 WRITE_ONCE(obj_nr_tofree, 0);
327 raw_spin_unlock_irqrestore(&pool_lock, flags);
329 hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
330 hlist_del(&obj->node);
331 kmem_cache_free(obj_cache, obj);
335 static void __free_object(struct debug_obj *obj)
337 struct debug_obj *objs[ODEBUG_BATCH_SIZE];
338 struct debug_percpu_free *percpu_pool;
339 int lookahead_count = 0;
343 local_irq_save(flags);
345 goto free_to_obj_pool;
348 * Try to free it into the percpu pool first.
350 percpu_pool = this_cpu_ptr(&percpu_obj_pool);
351 if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
352 hlist_add_head(&obj->node, &percpu_pool->free_objs);
353 percpu_pool->obj_free++;
354 local_irq_restore(flags);
359 * As the percpu pool is full, look ahead and pull out a batch
360 * of objects from the percpu pool and free them as well.
362 for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
363 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
364 if (!objs[lookahead_count])
366 percpu_pool->obj_free--;
370 raw_spin_lock(&pool_lock);
371 work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
372 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
376 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
377 hlist_add_head(&obj->node, &obj_to_free);
378 if (lookahead_count) {
379 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
380 obj_pool_used -= lookahead_count;
381 while (lookahead_count) {
382 hlist_add_head(&objs[--lookahead_count]->node,
387 if ((obj_pool_free > debug_objects_pool_size) &&
388 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
392 * Free one more batch of objects from obj_pool.
394 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
395 obj = __alloc_object(&obj_pool);
396 hlist_add_head(&obj->node, &obj_to_free);
397 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
398 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
402 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
403 hlist_add_head(&obj->node, &obj_pool);
404 if (lookahead_count) {
405 WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
406 obj_pool_used -= lookahead_count;
407 while (lookahead_count) {
408 hlist_add_head(&objs[--lookahead_count]->node,
413 raw_spin_unlock(&pool_lock);
414 local_irq_restore(flags);
418 * Put the object back into the pool and schedule work to free objects
421 static void free_object(struct debug_obj *obj)
424 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
425 WRITE_ONCE(obj_freeing, true);
426 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
430 #ifdef CONFIG_HOTPLUG_CPU
431 static int object_cpu_offline(unsigned int cpu)
433 struct debug_percpu_free *percpu_pool;
434 struct hlist_node *tmp;
435 struct debug_obj *obj;
438 /* Remote access is safe as the CPU is dead already */
439 percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
440 hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
441 hlist_del(&obj->node);
442 kmem_cache_free(obj_cache, obj);
445 raw_spin_lock_irqsave(&pool_lock, flags);
446 obj_pool_used -= percpu_pool->obj_free;
447 debug_objects_freed += percpu_pool->obj_free;
448 raw_spin_unlock_irqrestore(&pool_lock, flags);
450 percpu_pool->obj_free = 0;
457 * We run out of memory. That means we probably have tons of objects
460 static void debug_objects_oom(void)
462 struct debug_bucket *db = obj_hash;
463 struct hlist_node *tmp;
464 HLIST_HEAD(freelist);
465 struct debug_obj *obj;
469 pr_warn("Out of memory. ODEBUG disabled\n");
471 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
472 raw_spin_lock_irqsave(&db->lock, flags);
473 hlist_move_list(&db->list, &freelist);
474 raw_spin_unlock_irqrestore(&db->lock, flags);
477 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
478 hlist_del(&obj->node);
485 * We use the pfn of the address for the hash. That way we can check
486 * for freed objects simply by checking the affected bucket.
488 static struct debug_bucket *get_bucket(unsigned long addr)
492 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
493 return &obj_hash[hash];
496 static void debug_print_object(struct debug_obj *obj, char *msg)
498 const struct debug_obj_descr *descr = obj->descr;
502 * Don't report if lookup_object_or_alloc() by the current thread
503 * failed because lookup_object_or_alloc()/debug_objects_oom() by a
504 * concurrent thread turned off debug_objects_enabled and cleared
507 if (!debug_objects_enabled)
510 if (limit < 5 && descr != descr_test) {
511 void *hint = descr->debug_hint ?
512 descr->debug_hint(obj->object) : NULL;
514 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
515 "object type: %s hint: %pS\n",
516 msg, obj_states[obj->state], obj->astate,
519 debug_objects_warnings++;
523 * Try to repair the damage, so we have a better chance to get useful
527 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
528 void * addr, enum debug_obj_state state)
530 if (fixup && fixup(addr, state)) {
531 debug_objects_fixups++;
537 static void debug_object_is_on_stack(void *addr, int onstack)
545 is_on_stack = object_is_on_stack(addr);
546 if (is_on_stack == onstack)
551 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
552 task_stack_page(current));
554 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
555 task_stack_page(current));
560 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
561 const struct debug_obj_descr *descr,
562 bool onstack, bool alloc_ifstatic)
564 struct debug_obj *obj = lookup_object(addr, b);
565 enum debug_obj_state state = ODEBUG_STATE_NONE;
571 * debug_object_init() unconditionally allocates untracked
572 * objects. It does not matter whether it is a static object or
575 * debug_object_assert_init() and debug_object_activate() allow
576 * allocation only if the descriptor callback confirms that the
577 * object is static and considered initialized. For non-static
578 * objects the allocation needs to be done from the fixup callback.
580 if (unlikely(alloc_ifstatic)) {
581 if (!descr->is_static_object || !descr->is_static_object(addr))
582 return ERR_PTR(-ENOENT);
583 /* Statically allocated objects are considered initialized */
584 state = ODEBUG_STATE_INIT;
587 obj = alloc_object(addr, b, descr);
590 debug_object_is_on_stack(addr, onstack);
594 /* Out of memory. Do the cleanup outside of the locked region */
595 debug_objects_enabled = 0;
599 static void debug_objects_fill_pool(void)
602 * On RT enabled kernels the pool refill must happen in preemptible
605 if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
610 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
612 enum debug_obj_state state;
613 struct debug_bucket *db;
614 struct debug_obj *obj;
617 debug_objects_fill_pool();
619 db = get_bucket((unsigned long) addr);
621 raw_spin_lock_irqsave(&db->lock, flags);
623 obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
624 if (unlikely(!obj)) {
625 raw_spin_unlock_irqrestore(&db->lock, flags);
630 switch (obj->state) {
631 case ODEBUG_STATE_NONE:
632 case ODEBUG_STATE_INIT:
633 case ODEBUG_STATE_INACTIVE:
634 obj->state = ODEBUG_STATE_INIT;
637 case ODEBUG_STATE_ACTIVE:
639 raw_spin_unlock_irqrestore(&db->lock, flags);
640 debug_print_object(obj, "init");
641 debug_object_fixup(descr->fixup_init, addr, state);
644 case ODEBUG_STATE_DESTROYED:
645 raw_spin_unlock_irqrestore(&db->lock, flags);
646 debug_print_object(obj, "init");
652 raw_spin_unlock_irqrestore(&db->lock, flags);
656 * debug_object_init - debug checks when an object is initialized
657 * @addr: address of the object
658 * @descr: pointer to an object specific debug description structure
660 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
662 if (!debug_objects_enabled)
665 __debug_object_init(addr, descr, 0);
667 EXPORT_SYMBOL_GPL(debug_object_init);
670 * debug_object_init_on_stack - debug checks when an object on stack is
672 * @addr: address of the object
673 * @descr: pointer to an object specific debug description structure
675 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
677 if (!debug_objects_enabled)
680 __debug_object_init(addr, descr, 1);
682 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
685 * debug_object_activate - debug checks when an object is activated
686 * @addr: address of the object
687 * @descr: pointer to an object specific debug description structure
688 * Returns 0 for success, -EINVAL for check failed.
690 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
692 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
693 enum debug_obj_state state;
694 struct debug_bucket *db;
695 struct debug_obj *obj;
699 if (!debug_objects_enabled)
702 debug_objects_fill_pool();
704 db = get_bucket((unsigned long) addr);
706 raw_spin_lock_irqsave(&db->lock, flags);
708 obj = lookup_object_or_alloc(addr, db, descr, false, true);
709 if (likely(!IS_ERR_OR_NULL(obj))) {
710 bool print_object = false;
712 switch (obj->state) {
713 case ODEBUG_STATE_INIT:
714 case ODEBUG_STATE_INACTIVE:
715 obj->state = ODEBUG_STATE_ACTIVE;
719 case ODEBUG_STATE_ACTIVE:
721 raw_spin_unlock_irqrestore(&db->lock, flags);
722 debug_print_object(obj, "activate");
723 ret = debug_object_fixup(descr->fixup_activate, addr, state);
724 return ret ? 0 : -EINVAL;
726 case ODEBUG_STATE_DESTROYED:
734 raw_spin_unlock_irqrestore(&db->lock, flags);
736 debug_print_object(obj, "activate");
740 raw_spin_unlock_irqrestore(&db->lock, flags);
742 /* If NULL the allocation has hit OOM */
748 /* Object is neither static nor tracked. It's not initialized */
749 debug_print_object(&o, "activate");
750 ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
751 return ret ? 0 : -EINVAL;
753 EXPORT_SYMBOL_GPL(debug_object_activate);
756 * debug_object_deactivate - debug checks when an object is deactivated
757 * @addr: address of the object
758 * @descr: pointer to an object specific debug description structure
760 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
762 struct debug_bucket *db;
763 struct debug_obj *obj;
765 bool print_object = false;
767 if (!debug_objects_enabled)
770 db = get_bucket((unsigned long) addr);
772 raw_spin_lock_irqsave(&db->lock, flags);
774 obj = lookup_object(addr, db);
776 switch (obj->state) {
777 case ODEBUG_STATE_INIT:
778 case ODEBUG_STATE_INACTIVE:
779 case ODEBUG_STATE_ACTIVE:
781 obj->state = ODEBUG_STATE_INACTIVE;
786 case ODEBUG_STATE_DESTROYED:
794 raw_spin_unlock_irqrestore(&db->lock, flags);
796 struct debug_obj o = { .object = addr,
797 .state = ODEBUG_STATE_NOTAVAILABLE,
800 debug_print_object(&o, "deactivate");
801 } else if (print_object) {
802 debug_print_object(obj, "deactivate");
805 EXPORT_SYMBOL_GPL(debug_object_deactivate);
808 * debug_object_destroy - debug checks when an object is destroyed
809 * @addr: address of the object
810 * @descr: pointer to an object specific debug description structure
812 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
814 enum debug_obj_state state;
815 struct debug_bucket *db;
816 struct debug_obj *obj;
818 bool print_object = false;
820 if (!debug_objects_enabled)
823 db = get_bucket((unsigned long) addr);
825 raw_spin_lock_irqsave(&db->lock, flags);
827 obj = lookup_object(addr, db);
831 switch (obj->state) {
832 case ODEBUG_STATE_NONE:
833 case ODEBUG_STATE_INIT:
834 case ODEBUG_STATE_INACTIVE:
835 obj->state = ODEBUG_STATE_DESTROYED;
837 case ODEBUG_STATE_ACTIVE:
839 raw_spin_unlock_irqrestore(&db->lock, flags);
840 debug_print_object(obj, "destroy");
841 debug_object_fixup(descr->fixup_destroy, addr, state);
844 case ODEBUG_STATE_DESTROYED:
851 raw_spin_unlock_irqrestore(&db->lock, flags);
853 debug_print_object(obj, "destroy");
855 EXPORT_SYMBOL_GPL(debug_object_destroy);
858 * debug_object_free - debug checks when an object is freed
859 * @addr: address of the object
860 * @descr: pointer to an object specific debug description structure
862 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
864 enum debug_obj_state state;
865 struct debug_bucket *db;
866 struct debug_obj *obj;
869 if (!debug_objects_enabled)
872 db = get_bucket((unsigned long) addr);
874 raw_spin_lock_irqsave(&db->lock, flags);
876 obj = lookup_object(addr, db);
880 switch (obj->state) {
881 case ODEBUG_STATE_ACTIVE:
883 raw_spin_unlock_irqrestore(&db->lock, flags);
884 debug_print_object(obj, "free");
885 debug_object_fixup(descr->fixup_free, addr, state);
888 hlist_del(&obj->node);
889 raw_spin_unlock_irqrestore(&db->lock, flags);
894 raw_spin_unlock_irqrestore(&db->lock, flags);
896 EXPORT_SYMBOL_GPL(debug_object_free);
899 * debug_object_assert_init - debug checks when object should be init-ed
900 * @addr: address of the object
901 * @descr: pointer to an object specific debug description structure
903 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
905 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
906 struct debug_bucket *db;
907 struct debug_obj *obj;
910 if (!debug_objects_enabled)
913 debug_objects_fill_pool();
915 db = get_bucket((unsigned long) addr);
917 raw_spin_lock_irqsave(&db->lock, flags);
918 obj = lookup_object_or_alloc(addr, db, descr, false, true);
919 raw_spin_unlock_irqrestore(&db->lock, flags);
920 if (likely(!IS_ERR_OR_NULL(obj)))
923 /* If NULL the allocation has hit OOM */
929 /* Object is neither tracked nor static. It's not initialized. */
930 debug_print_object(&o, "assert_init");
931 debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
933 EXPORT_SYMBOL_GPL(debug_object_assert_init);
936 * debug_object_active_state - debug checks object usage state machine
937 * @addr: address of the object
938 * @descr: pointer to an object specific debug description structure
939 * @expect: expected state
940 * @next: state to move to if expected state is found
943 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
944 unsigned int expect, unsigned int next)
946 struct debug_bucket *db;
947 struct debug_obj *obj;
949 bool print_object = false;
951 if (!debug_objects_enabled)
954 db = get_bucket((unsigned long) addr);
956 raw_spin_lock_irqsave(&db->lock, flags);
958 obj = lookup_object(addr, db);
960 switch (obj->state) {
961 case ODEBUG_STATE_ACTIVE:
962 if (obj->astate == expect)
974 raw_spin_unlock_irqrestore(&db->lock, flags);
976 struct debug_obj o = { .object = addr,
977 .state = ODEBUG_STATE_NOTAVAILABLE,
980 debug_print_object(&o, "active_state");
981 } else if (print_object) {
982 debug_print_object(obj, "active_state");
985 EXPORT_SYMBOL_GPL(debug_object_active_state);
987 #ifdef CONFIG_DEBUG_OBJECTS_FREE
988 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
990 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
991 const struct debug_obj_descr *descr;
992 enum debug_obj_state state;
993 struct debug_bucket *db;
994 struct hlist_node *tmp;
995 struct debug_obj *obj;
996 int cnt, objs_checked = 0;
998 saddr = (unsigned long) address;
999 eaddr = saddr + size;
1000 paddr = saddr & ODEBUG_CHUNK_MASK;
1001 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
1002 chunks >>= ODEBUG_CHUNK_SHIFT;
1004 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
1005 db = get_bucket(paddr);
1009 raw_spin_lock_irqsave(&db->lock, flags);
1010 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
1012 oaddr = (unsigned long) obj->object;
1013 if (oaddr < saddr || oaddr >= eaddr)
1016 switch (obj->state) {
1017 case ODEBUG_STATE_ACTIVE:
1020 raw_spin_unlock_irqrestore(&db->lock, flags);
1021 debug_print_object(obj, "free");
1022 debug_object_fixup(descr->fixup_free,
1023 (void *) oaddr, state);
1026 hlist_del(&obj->node);
1031 raw_spin_unlock_irqrestore(&db->lock, flags);
1033 if (cnt > debug_objects_maxchain)
1034 debug_objects_maxchain = cnt;
1036 objs_checked += cnt;
1039 if (objs_checked > debug_objects_maxchecked)
1040 debug_objects_maxchecked = objs_checked;
1042 /* Schedule work to actually kmem_cache_free() objects */
1043 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1044 WRITE_ONCE(obj_freeing, true);
1045 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1049 void debug_check_no_obj_freed(const void *address, unsigned long size)
1051 if (debug_objects_enabled)
1052 __debug_check_no_obj_freed(address, size);
1056 #ifdef CONFIG_DEBUG_FS
1058 static int debug_stats_show(struct seq_file *m, void *v)
1060 int cpu, obj_percpu_free = 0;
1062 for_each_possible_cpu(cpu)
1063 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1065 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
1066 seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
1067 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
1068 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
1069 seq_printf(m, "pool_free :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1070 seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1071 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1072 seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
1073 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1074 seq_printf(m, "on_free_list :%d\n", READ_ONCE(obj_nr_tofree));
1075 seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1076 seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
1079 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1081 static int __init debug_objects_init_debugfs(void)
1083 struct dentry *dbgdir;
1085 if (!debug_objects_enabled)
1088 dbgdir = debugfs_create_dir("debug_objects", NULL);
1090 debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1094 __initcall(debug_objects_init_debugfs);
1097 static inline void debug_objects_init_debugfs(void) { }
1100 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1102 /* Random data structure for the self test */
1104 unsigned long dummy1[6];
1106 unsigned long dummy2[3];
1109 static __initconst const struct debug_obj_descr descr_type_test;
1111 static bool __init is_static_object(void *addr)
1113 struct self_test *obj = addr;
1115 return obj->static_init;
1119 * fixup_init is called when:
1120 * - an active object is initialized
1122 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1124 struct self_test *obj = addr;
1127 case ODEBUG_STATE_ACTIVE:
1128 debug_object_deactivate(obj, &descr_type_test);
1129 debug_object_init(obj, &descr_type_test);
1137 * fixup_activate is called when:
1138 * - an active object is activated
1139 * - an unknown non-static object is activated
1141 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1143 struct self_test *obj = addr;
1146 case ODEBUG_STATE_NOTAVAILABLE:
1148 case ODEBUG_STATE_ACTIVE:
1149 debug_object_deactivate(obj, &descr_type_test);
1150 debug_object_activate(obj, &descr_type_test);
1159 * fixup_destroy is called when:
1160 * - an active object is destroyed
1162 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1164 struct self_test *obj = addr;
1167 case ODEBUG_STATE_ACTIVE:
1168 debug_object_deactivate(obj, &descr_type_test);
1169 debug_object_destroy(obj, &descr_type_test);
1177 * fixup_free is called when:
1178 * - an active object is freed
1180 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1182 struct self_test *obj = addr;
1185 case ODEBUG_STATE_ACTIVE:
1186 debug_object_deactivate(obj, &descr_type_test);
1187 debug_object_free(obj, &descr_type_test);
1195 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1197 struct debug_bucket *db;
1198 struct debug_obj *obj;
1199 unsigned long flags;
1202 db = get_bucket((unsigned long) addr);
1204 raw_spin_lock_irqsave(&db->lock, flags);
1206 obj = lookup_object(addr, db);
1207 if (!obj && state != ODEBUG_STATE_NONE) {
1208 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1211 if (obj && obj->state != state) {
1212 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1216 if (fixups != debug_objects_fixups) {
1217 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1218 fixups, debug_objects_fixups);
1221 if (warnings != debug_objects_warnings) {
1222 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1223 warnings, debug_objects_warnings);
1228 raw_spin_unlock_irqrestore(&db->lock, flags);
1230 debug_objects_enabled = 0;
1234 static __initconst const struct debug_obj_descr descr_type_test = {
1236 .is_static_object = is_static_object,
1237 .fixup_init = fixup_init,
1238 .fixup_activate = fixup_activate,
1239 .fixup_destroy = fixup_destroy,
1240 .fixup_free = fixup_free,
1243 static __initdata struct self_test obj = { .static_init = 0 };
1245 static void __init debug_objects_selftest(void)
1247 int fixups, oldfixups, warnings, oldwarnings;
1248 unsigned long flags;
1250 local_irq_save(flags);
1252 fixups = oldfixups = debug_objects_fixups;
1253 warnings = oldwarnings = debug_objects_warnings;
1254 descr_test = &descr_type_test;
1256 debug_object_init(&obj, &descr_type_test);
1257 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1259 debug_object_activate(&obj, &descr_type_test);
1260 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1262 debug_object_activate(&obj, &descr_type_test);
1263 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1265 debug_object_deactivate(&obj, &descr_type_test);
1266 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1268 debug_object_destroy(&obj, &descr_type_test);
1269 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1271 debug_object_init(&obj, &descr_type_test);
1272 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1274 debug_object_activate(&obj, &descr_type_test);
1275 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1277 debug_object_deactivate(&obj, &descr_type_test);
1278 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1280 debug_object_free(&obj, &descr_type_test);
1281 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1284 obj.static_init = 1;
1285 debug_object_activate(&obj, &descr_type_test);
1286 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1288 debug_object_init(&obj, &descr_type_test);
1289 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1291 debug_object_free(&obj, &descr_type_test);
1292 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1295 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1296 debug_object_init(&obj, &descr_type_test);
1297 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1299 debug_object_activate(&obj, &descr_type_test);
1300 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1302 __debug_check_no_obj_freed(&obj, sizeof(obj));
1303 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1306 pr_info("selftest passed\n");
1309 debug_objects_fixups = oldfixups;
1310 debug_objects_warnings = oldwarnings;
1313 local_irq_restore(flags);
1316 static inline void debug_objects_selftest(void) { }
1320 * Called during early boot to initialize the hash buckets and link
1321 * the static object pool objects into the poll list. After this call
1322 * the object tracker is fully operational.
1324 void __init debug_objects_early_init(void)
1328 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1329 raw_spin_lock_init(&obj_hash[i].lock);
1331 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1332 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1336 * Convert the statically allocated objects to dynamic ones:
1338 static int __init debug_objects_replace_static_objects(void)
1340 struct debug_bucket *db = obj_hash;
1341 struct hlist_node *tmp;
1342 struct debug_obj *obj, *new;
1343 HLIST_HEAD(objects);
1346 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1347 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1350 hlist_add_head(&obj->node, &objects);
1353 debug_objects_allocated += i;
1356 * debug_objects_mem_init() is now called early that only one CPU is up
1357 * and interrupts have been disabled, so it is safe to replace the
1358 * active object references.
1361 /* Remove the statically allocated objects from the pool */
1362 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1363 hlist_del(&obj->node);
1364 /* Move the allocated objects to the pool */
1365 hlist_move_list(&objects, &obj_pool);
1367 /* Replace the active object references */
1368 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1369 hlist_move_list(&db->list, &objects);
1371 hlist_for_each_entry(obj, &objects, node) {
1372 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1373 hlist_del(&new->node);
1374 /* copy object data */
1376 hlist_add_head(&new->node, &db->list);
1381 pr_debug("%d of %d active objects replaced\n",
1382 cnt, obj_pool_used);
1385 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1386 hlist_del(&obj->node);
1387 kmem_cache_free(obj_cache, obj);
1393 * Called after the kmem_caches are functional to setup a dedicated
1394 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1395 * prevents that the debug code is called on kmem_cache_free() for the
1396 * debug tracker objects to avoid recursive calls.
1398 void __init debug_objects_mem_init(void)
1402 if (!debug_objects_enabled)
1406 * Initialize the percpu object pools
1408 * Initialization is not strictly necessary, but was done for
1411 for_each_possible_cpu(cpu)
1412 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1414 obj_cache = kmem_cache_create("debug_objects_cache",
1415 sizeof (struct debug_obj), 0,
1416 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1419 if (!obj_cache || debug_objects_replace_static_objects()) {
1420 debug_objects_enabled = 0;
1421 kmem_cache_destroy(obj_cache);
1422 pr_warn("out of memory.\n");
1425 debug_objects_selftest();
1427 #ifdef CONFIG_HOTPLUG_CPU
1428 cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1429 object_cpu_offline);
1433 * Increase the thresholds for allocating and freeing objects
1434 * according to the number of possible CPUs available in the system.
1436 extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1437 debug_objects_pool_size += extras;
1438 debug_objects_pool_min_level += extras;