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_ATOMIC | __GFP_NORETRY | __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;
501 if (limit < 5 && descr != descr_test) {
502 void *hint = descr->debug_hint ?
503 descr->debug_hint(obj->object) : NULL;
505 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
506 "object: %p object type: %s hint: %pS\n",
507 msg, obj_states[obj->state], obj->astate,
508 obj->object, descr->name, hint);
510 debug_objects_warnings++;
514 * Try to repair the damage, so we have a better chance to get useful
518 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
519 void * addr, enum debug_obj_state state)
521 if (fixup && fixup(addr, state)) {
522 debug_objects_fixups++;
528 static void debug_object_is_on_stack(void *addr, int onstack)
536 is_on_stack = object_is_on_stack(addr);
537 if (is_on_stack == onstack)
542 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
543 task_stack_page(current));
545 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
546 task_stack_page(current));
551 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
552 const struct debug_obj_descr *descr,
553 bool onstack, bool alloc_ifstatic)
555 struct debug_obj *obj = lookup_object(addr, b);
556 enum debug_obj_state state = ODEBUG_STATE_NONE;
562 * debug_object_init() unconditionally allocates untracked
563 * objects. It does not matter whether it is a static object or
566 * debug_object_assert_init() and debug_object_activate() allow
567 * allocation only if the descriptor callback confirms that the
568 * object is static and considered initialized. For non-static
569 * objects the allocation needs to be done from the fixup callback.
571 if (unlikely(alloc_ifstatic)) {
572 if (!descr->is_static_object || !descr->is_static_object(addr))
573 return ERR_PTR(-ENOENT);
574 /* Statically allocated objects are considered initialized */
575 state = ODEBUG_STATE_INIT;
578 obj = alloc_object(addr, b, descr);
581 debug_object_is_on_stack(addr, onstack);
585 /* Out of memory. Do the cleanup outside of the locked region */
586 debug_objects_enabled = 0;
591 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
593 enum debug_obj_state state;
594 struct debug_bucket *db;
595 struct debug_obj *obj;
599 * On RT enabled kernels the pool refill must happen in preemptible
602 if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
605 db = get_bucket((unsigned long) addr);
607 raw_spin_lock_irqsave(&db->lock, flags);
609 obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
610 if (unlikely(!obj)) {
611 raw_spin_unlock_irqrestore(&db->lock, flags);
616 switch (obj->state) {
617 case ODEBUG_STATE_NONE:
618 case ODEBUG_STATE_INIT:
619 case ODEBUG_STATE_INACTIVE:
620 obj->state = ODEBUG_STATE_INIT;
623 case ODEBUG_STATE_ACTIVE:
625 raw_spin_unlock_irqrestore(&db->lock, flags);
626 debug_print_object(obj, "init");
627 debug_object_fixup(descr->fixup_init, addr, state);
630 case ODEBUG_STATE_DESTROYED:
631 raw_spin_unlock_irqrestore(&db->lock, flags);
632 debug_print_object(obj, "init");
638 raw_spin_unlock_irqrestore(&db->lock, flags);
642 * debug_object_init - debug checks when an object is initialized
643 * @addr: address of the object
644 * @descr: pointer to an object specific debug description structure
646 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
648 if (!debug_objects_enabled)
651 __debug_object_init(addr, descr, 0);
653 EXPORT_SYMBOL_GPL(debug_object_init);
656 * debug_object_init_on_stack - debug checks when an object on stack is
658 * @addr: address of the object
659 * @descr: pointer to an object specific debug description structure
661 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
663 if (!debug_objects_enabled)
666 __debug_object_init(addr, descr, 1);
668 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
671 * debug_object_activate - debug checks when an object is activated
672 * @addr: address of the object
673 * @descr: pointer to an object specific debug description structure
674 * Returns 0 for success, -EINVAL for check failed.
676 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
678 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
679 enum debug_obj_state state;
680 struct debug_bucket *db;
681 struct debug_obj *obj;
685 if (!debug_objects_enabled)
688 db = get_bucket((unsigned long) addr);
690 raw_spin_lock_irqsave(&db->lock, flags);
692 obj = lookup_object_or_alloc(addr, db, descr, false, true);
693 if (likely(!IS_ERR_OR_NULL(obj))) {
694 bool print_object = false;
696 switch (obj->state) {
697 case ODEBUG_STATE_INIT:
698 case ODEBUG_STATE_INACTIVE:
699 obj->state = ODEBUG_STATE_ACTIVE;
703 case ODEBUG_STATE_ACTIVE:
705 raw_spin_unlock_irqrestore(&db->lock, flags);
706 debug_print_object(obj, "activate");
707 ret = debug_object_fixup(descr->fixup_activate, addr, state);
708 return ret ? 0 : -EINVAL;
710 case ODEBUG_STATE_DESTROYED:
718 raw_spin_unlock_irqrestore(&db->lock, flags);
720 debug_print_object(obj, "activate");
724 raw_spin_unlock_irqrestore(&db->lock, flags);
726 /* If NULL the allocation has hit OOM */
732 /* Object is neither static nor tracked. It's not initialized */
733 debug_print_object(&o, "activate");
734 ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
735 return ret ? 0 : -EINVAL;
737 EXPORT_SYMBOL_GPL(debug_object_activate);
740 * debug_object_deactivate - debug checks when an object is deactivated
741 * @addr: address of the object
742 * @descr: pointer to an object specific debug description structure
744 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
746 struct debug_bucket *db;
747 struct debug_obj *obj;
749 bool print_object = false;
751 if (!debug_objects_enabled)
754 db = get_bucket((unsigned long) addr);
756 raw_spin_lock_irqsave(&db->lock, flags);
758 obj = lookup_object(addr, db);
760 switch (obj->state) {
761 case ODEBUG_STATE_INIT:
762 case ODEBUG_STATE_INACTIVE:
763 case ODEBUG_STATE_ACTIVE:
765 obj->state = ODEBUG_STATE_INACTIVE;
770 case ODEBUG_STATE_DESTROYED:
778 raw_spin_unlock_irqrestore(&db->lock, flags);
780 struct debug_obj o = { .object = addr,
781 .state = ODEBUG_STATE_NOTAVAILABLE,
784 debug_print_object(&o, "deactivate");
785 } else if (print_object) {
786 debug_print_object(obj, "deactivate");
789 EXPORT_SYMBOL_GPL(debug_object_deactivate);
792 * debug_object_destroy - debug checks when an object is destroyed
793 * @addr: address of the object
794 * @descr: pointer to an object specific debug description structure
796 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
798 enum debug_obj_state state;
799 struct debug_bucket *db;
800 struct debug_obj *obj;
802 bool print_object = false;
804 if (!debug_objects_enabled)
807 db = get_bucket((unsigned long) addr);
809 raw_spin_lock_irqsave(&db->lock, flags);
811 obj = lookup_object(addr, db);
815 switch (obj->state) {
816 case ODEBUG_STATE_NONE:
817 case ODEBUG_STATE_INIT:
818 case ODEBUG_STATE_INACTIVE:
819 obj->state = ODEBUG_STATE_DESTROYED;
821 case ODEBUG_STATE_ACTIVE:
823 raw_spin_unlock_irqrestore(&db->lock, flags);
824 debug_print_object(obj, "destroy");
825 debug_object_fixup(descr->fixup_destroy, addr, state);
828 case ODEBUG_STATE_DESTROYED:
835 raw_spin_unlock_irqrestore(&db->lock, flags);
837 debug_print_object(obj, "destroy");
839 EXPORT_SYMBOL_GPL(debug_object_destroy);
842 * debug_object_free - debug checks when an object is freed
843 * @addr: address of the object
844 * @descr: pointer to an object specific debug description structure
846 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
848 enum debug_obj_state state;
849 struct debug_bucket *db;
850 struct debug_obj *obj;
853 if (!debug_objects_enabled)
856 db = get_bucket((unsigned long) addr);
858 raw_spin_lock_irqsave(&db->lock, flags);
860 obj = lookup_object(addr, db);
864 switch (obj->state) {
865 case ODEBUG_STATE_ACTIVE:
867 raw_spin_unlock_irqrestore(&db->lock, flags);
868 debug_print_object(obj, "free");
869 debug_object_fixup(descr->fixup_free, addr, state);
872 hlist_del(&obj->node);
873 raw_spin_unlock_irqrestore(&db->lock, flags);
878 raw_spin_unlock_irqrestore(&db->lock, flags);
880 EXPORT_SYMBOL_GPL(debug_object_free);
883 * debug_object_assert_init - debug checks when object should be init-ed
884 * @addr: address of the object
885 * @descr: pointer to an object specific debug description structure
887 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
889 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
890 struct debug_bucket *db;
891 struct debug_obj *obj;
894 if (!debug_objects_enabled)
897 db = get_bucket((unsigned long) addr);
899 raw_spin_lock_irqsave(&db->lock, flags);
900 obj = lookup_object_or_alloc(addr, db, descr, false, true);
901 raw_spin_unlock_irqrestore(&db->lock, flags);
902 if (likely(!IS_ERR_OR_NULL(obj)))
905 /* If NULL the allocation has hit OOM */
911 /* Object is neither tracked nor static. It's not initialized. */
912 debug_print_object(&o, "assert_init");
913 debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
915 EXPORT_SYMBOL_GPL(debug_object_assert_init);
918 * debug_object_active_state - debug checks object usage state machine
919 * @addr: address of the object
920 * @descr: pointer to an object specific debug description structure
921 * @expect: expected state
922 * @next: state to move to if expected state is found
925 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
926 unsigned int expect, unsigned int next)
928 struct debug_bucket *db;
929 struct debug_obj *obj;
931 bool print_object = false;
933 if (!debug_objects_enabled)
936 db = get_bucket((unsigned long) addr);
938 raw_spin_lock_irqsave(&db->lock, flags);
940 obj = lookup_object(addr, db);
942 switch (obj->state) {
943 case ODEBUG_STATE_ACTIVE:
944 if (obj->astate == expect)
956 raw_spin_unlock_irqrestore(&db->lock, flags);
958 struct debug_obj o = { .object = addr,
959 .state = ODEBUG_STATE_NOTAVAILABLE,
962 debug_print_object(&o, "active_state");
963 } else if (print_object) {
964 debug_print_object(obj, "active_state");
967 EXPORT_SYMBOL_GPL(debug_object_active_state);
969 #ifdef CONFIG_DEBUG_OBJECTS_FREE
970 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
972 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
973 const struct debug_obj_descr *descr;
974 enum debug_obj_state state;
975 struct debug_bucket *db;
976 struct hlist_node *tmp;
977 struct debug_obj *obj;
978 int cnt, objs_checked = 0;
980 saddr = (unsigned long) address;
981 eaddr = saddr + size;
982 paddr = saddr & ODEBUG_CHUNK_MASK;
983 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
984 chunks >>= ODEBUG_CHUNK_SHIFT;
986 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
987 db = get_bucket(paddr);
991 raw_spin_lock_irqsave(&db->lock, flags);
992 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
994 oaddr = (unsigned long) obj->object;
995 if (oaddr < saddr || oaddr >= eaddr)
998 switch (obj->state) {
999 case ODEBUG_STATE_ACTIVE:
1002 raw_spin_unlock_irqrestore(&db->lock, flags);
1003 debug_print_object(obj, "free");
1004 debug_object_fixup(descr->fixup_free,
1005 (void *) oaddr, state);
1008 hlist_del(&obj->node);
1013 raw_spin_unlock_irqrestore(&db->lock, flags);
1015 if (cnt > debug_objects_maxchain)
1016 debug_objects_maxchain = cnt;
1018 objs_checked += cnt;
1021 if (objs_checked > debug_objects_maxchecked)
1022 debug_objects_maxchecked = objs_checked;
1024 /* Schedule work to actually kmem_cache_free() objects */
1025 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1026 WRITE_ONCE(obj_freeing, true);
1027 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1031 void debug_check_no_obj_freed(const void *address, unsigned long size)
1033 if (debug_objects_enabled)
1034 __debug_check_no_obj_freed(address, size);
1038 #ifdef CONFIG_DEBUG_FS
1040 static int debug_stats_show(struct seq_file *m, void *v)
1042 int cpu, obj_percpu_free = 0;
1044 for_each_possible_cpu(cpu)
1045 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1047 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
1048 seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
1049 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
1050 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
1051 seq_printf(m, "pool_free :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1052 seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1053 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1054 seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
1055 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1056 seq_printf(m, "on_free_list :%d\n", READ_ONCE(obj_nr_tofree));
1057 seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1058 seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
1061 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1063 static int __init debug_objects_init_debugfs(void)
1065 struct dentry *dbgdir;
1067 if (!debug_objects_enabled)
1070 dbgdir = debugfs_create_dir("debug_objects", NULL);
1072 debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1076 __initcall(debug_objects_init_debugfs);
1079 static inline void debug_objects_init_debugfs(void) { }
1082 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1084 /* Random data structure for the self test */
1086 unsigned long dummy1[6];
1088 unsigned long dummy2[3];
1091 static __initconst const struct debug_obj_descr descr_type_test;
1093 static bool __init is_static_object(void *addr)
1095 struct self_test *obj = addr;
1097 return obj->static_init;
1101 * fixup_init is called when:
1102 * - an active object is initialized
1104 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1106 struct self_test *obj = addr;
1109 case ODEBUG_STATE_ACTIVE:
1110 debug_object_deactivate(obj, &descr_type_test);
1111 debug_object_init(obj, &descr_type_test);
1119 * fixup_activate is called when:
1120 * - an active object is activated
1121 * - an unknown non-static object is activated
1123 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1125 struct self_test *obj = addr;
1128 case ODEBUG_STATE_NOTAVAILABLE:
1130 case ODEBUG_STATE_ACTIVE:
1131 debug_object_deactivate(obj, &descr_type_test);
1132 debug_object_activate(obj, &descr_type_test);
1141 * fixup_destroy is called when:
1142 * - an active object is destroyed
1144 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1146 struct self_test *obj = addr;
1149 case ODEBUG_STATE_ACTIVE:
1150 debug_object_deactivate(obj, &descr_type_test);
1151 debug_object_destroy(obj, &descr_type_test);
1159 * fixup_free is called when:
1160 * - an active object is freed
1162 static bool __init fixup_free(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_free(obj, &descr_type_test);
1177 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1179 struct debug_bucket *db;
1180 struct debug_obj *obj;
1181 unsigned long flags;
1184 db = get_bucket((unsigned long) addr);
1186 raw_spin_lock_irqsave(&db->lock, flags);
1188 obj = lookup_object(addr, db);
1189 if (!obj && state != ODEBUG_STATE_NONE) {
1190 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1193 if (obj && obj->state != state) {
1194 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1198 if (fixups != debug_objects_fixups) {
1199 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1200 fixups, debug_objects_fixups);
1203 if (warnings != debug_objects_warnings) {
1204 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1205 warnings, debug_objects_warnings);
1210 raw_spin_unlock_irqrestore(&db->lock, flags);
1212 debug_objects_enabled = 0;
1216 static __initconst const struct debug_obj_descr descr_type_test = {
1218 .is_static_object = is_static_object,
1219 .fixup_init = fixup_init,
1220 .fixup_activate = fixup_activate,
1221 .fixup_destroy = fixup_destroy,
1222 .fixup_free = fixup_free,
1225 static __initdata struct self_test obj = { .static_init = 0 };
1227 static void __init debug_objects_selftest(void)
1229 int fixups, oldfixups, warnings, oldwarnings;
1230 unsigned long flags;
1232 local_irq_save(flags);
1234 fixups = oldfixups = debug_objects_fixups;
1235 warnings = oldwarnings = debug_objects_warnings;
1236 descr_test = &descr_type_test;
1238 debug_object_init(&obj, &descr_type_test);
1239 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1241 debug_object_activate(&obj, &descr_type_test);
1242 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1244 debug_object_activate(&obj, &descr_type_test);
1245 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1247 debug_object_deactivate(&obj, &descr_type_test);
1248 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1250 debug_object_destroy(&obj, &descr_type_test);
1251 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1253 debug_object_init(&obj, &descr_type_test);
1254 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1256 debug_object_activate(&obj, &descr_type_test);
1257 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1259 debug_object_deactivate(&obj, &descr_type_test);
1260 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1262 debug_object_free(&obj, &descr_type_test);
1263 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1266 obj.static_init = 1;
1267 debug_object_activate(&obj, &descr_type_test);
1268 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1270 debug_object_init(&obj, &descr_type_test);
1271 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1273 debug_object_free(&obj, &descr_type_test);
1274 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1277 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1278 debug_object_init(&obj, &descr_type_test);
1279 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1281 debug_object_activate(&obj, &descr_type_test);
1282 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1284 __debug_check_no_obj_freed(&obj, sizeof(obj));
1285 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1288 pr_info("selftest passed\n");
1291 debug_objects_fixups = oldfixups;
1292 debug_objects_warnings = oldwarnings;
1295 local_irq_restore(flags);
1298 static inline void debug_objects_selftest(void) { }
1302 * Called during early boot to initialize the hash buckets and link
1303 * the static object pool objects into the poll list. After this call
1304 * the object tracker is fully operational.
1306 void __init debug_objects_early_init(void)
1310 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1311 raw_spin_lock_init(&obj_hash[i].lock);
1313 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1314 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1318 * Convert the statically allocated objects to dynamic ones:
1320 static int __init debug_objects_replace_static_objects(void)
1322 struct debug_bucket *db = obj_hash;
1323 struct hlist_node *tmp;
1324 struct debug_obj *obj, *new;
1325 HLIST_HEAD(objects);
1328 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1329 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1332 hlist_add_head(&obj->node, &objects);
1335 debug_objects_allocated += i;
1338 * debug_objects_mem_init() is now called early that only one CPU is up
1339 * and interrupts have been disabled, so it is safe to replace the
1340 * active object references.
1343 /* Remove the statically allocated objects from the pool */
1344 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1345 hlist_del(&obj->node);
1346 /* Move the allocated objects to the pool */
1347 hlist_move_list(&objects, &obj_pool);
1349 /* Replace the active object references */
1350 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1351 hlist_move_list(&db->list, &objects);
1353 hlist_for_each_entry(obj, &objects, node) {
1354 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1355 hlist_del(&new->node);
1356 /* copy object data */
1358 hlist_add_head(&new->node, &db->list);
1363 pr_debug("%d of %d active objects replaced\n",
1364 cnt, obj_pool_used);
1367 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1368 hlist_del(&obj->node);
1369 kmem_cache_free(obj_cache, obj);
1375 * Called after the kmem_caches are functional to setup a dedicated
1376 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1377 * prevents that the debug code is called on kmem_cache_free() for the
1378 * debug tracker objects to avoid recursive calls.
1380 void __init debug_objects_mem_init(void)
1384 if (!debug_objects_enabled)
1388 * Initialize the percpu object pools
1390 * Initialization is not strictly necessary, but was done for
1393 for_each_possible_cpu(cpu)
1394 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1396 obj_cache = kmem_cache_create("debug_objects_cache",
1397 sizeof (struct debug_obj), 0,
1398 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1401 if (!obj_cache || debug_objects_replace_static_objects()) {
1402 debug_objects_enabled = 0;
1403 kmem_cache_destroy(obj_cache);
1404 pr_warn("out of memory.\n");
1407 debug_objects_selftest();
1409 #ifdef CONFIG_HOTPLUG_CPU
1410 cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1411 object_cpu_offline);
1415 * Increase the thresholds for allocating and freeing objects
1416 * according to the number of possible CPUs available in the system.
1418 extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1419 debug_objects_pool_size += extras;
1420 debug_objects_pool_min_level += extras;