projects/linux·blob v7.2-rc1 · refs

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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Generic infrastructure for lifetime debugging of objects.
4 *
5 * Copyright (C) 2008, Linutronix GmbH, Thomas Gleixner <[email protected]>
6 */
7
8#define pr_fmt(fmt) "ODEBUG: " fmt
9
10#include <linux/cpu.h>
11#include <linux/debugobjects.h>
12#include <linux/debugfs.h>
13#include <linux/hash.h>
14#include <linux/kmemleak.h>
15#include <linux/sched.h>
16#include <linux/sched/loadavg.h>
17#include <linux/sched/task_stack.h>
18#include <linux/seq_file.h>
19#include <linux/slab.h>
20#include <linux/static_key.h>
21
22#define ODEBUG_HASH_BITS 14
23#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
24
25/* Must be power of two */
26#define ODEBUG_BATCH_SIZE 16
27
28/* Initial values. Must all be a multiple of batch size */
29#define ODEBUG_POOL_SIZE (64 * ODEBUG_BATCH_SIZE)
30#define ODEBUG_POOL_MIN_LEVEL (ODEBUG_POOL_SIZE / 4)
31
32#define ODEBUG_POOL_PERCPU_SIZE (8 * ODEBUG_BATCH_SIZE)
33
34#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
35#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
36#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
37
38/*
39 * We limit the freeing of debug objects via workqueue at a maximum
40 * frequency of 10Hz and about 1024 objects for each freeing operation.
41 * So it is freeing at most 10k debug objects per second.
42 */
43#define ODEBUG_FREE_WORK_MAX (1024 / ODEBUG_BATCH_SIZE)
44#define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
45
46struct debug_bucket {
47 struct hlist_head list;
48 raw_spinlock_t lock;
49};
50
51struct pool_stats {
52 unsigned int cur_used;
53 unsigned int max_used;
54 unsigned int min_fill;
55};
56
57struct obj_pool {
58 struct hlist_head objects;
59 unsigned int cnt;
60 unsigned int min_cnt;
61 unsigned int max_cnt;
62 struct pool_stats stats;
63} ____cacheline_aligned;
64
65
66static DEFINE_PER_CPU_ALIGNED(struct obj_pool, pool_pcpu) = {
67 .max_cnt = ODEBUG_POOL_PERCPU_SIZE,
68};
69
70static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
71
72static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
73
74static DEFINE_RAW_SPINLOCK(pool_lock);
75
76static struct obj_pool pool_global = {
77 .min_cnt = ODEBUG_POOL_MIN_LEVEL,
78 .max_cnt = ODEBUG_POOL_SIZE,
79 .stats = {
80 .min_fill = ODEBUG_POOL_SIZE,
81 },
82};
83
84static struct obj_pool pool_to_free = {
85 .max_cnt = UINT_MAX,
86};
87
88static HLIST_HEAD(pool_boot);
89
90static unsigned long avg_usage;
91static bool obj_freeing;
92
93static int __data_racy debug_objects_maxchain __read_mostly;
94static int __data_racy __maybe_unused debug_objects_maxchecked __read_mostly;
95static int __data_racy debug_objects_fixups __read_mostly;
96static int __data_racy debug_objects_warnings __read_mostly;
97static bool __data_racy debug_objects_enabled __read_mostly
98 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
99
100static const struct debug_obj_descr *descr_test __read_mostly;
101static struct kmem_cache *obj_cache __ro_after_init;
102
103/*
104 * Track numbers of kmem_cache_alloc()/free() calls done.
105 */
106static int __data_racy debug_objects_allocated;
107static int __data_racy debug_objects_freed;
108
109static void free_obj_work(struct work_struct *work);
110static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
111
112static DEFINE_STATIC_KEY_FALSE(obj_cache_enabled);
113
114static int __init enable_object_debug(char *str)
115{
116 debug_objects_enabled = true;
117 return 0;
118}
119early_param("debug_objects", enable_object_debug);
120
121static int __init disable_object_debug(char *str)
122{
123 debug_objects_enabled = false;
124 return 0;
125}
126early_param("no_debug_objects", disable_object_debug);
127
128static const char *obj_states[ODEBUG_STATE_MAX] = {
129 [ODEBUG_STATE_NONE] = "none",
130 [ODEBUG_STATE_INIT] = "initialized",
131 [ODEBUG_STATE_INACTIVE] = "inactive",
132 [ODEBUG_STATE_ACTIVE] = "active",
133 [ODEBUG_STATE_DESTROYED] = "destroyed",
134 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
135};
136
137static __always_inline unsigned int pool_count(struct obj_pool *pool)
138{
139 return READ_ONCE(pool->cnt);
140}
141
142static __always_inline bool pool_should_refill(struct obj_pool *pool)
143{
144 return pool_count(pool) < pool->min_cnt;
145}
146
147static __always_inline bool pool_must_refill(struct obj_pool *pool)
148{
149 return pool_count(pool) < pool->min_cnt / 2;
150}
151
152static bool pool_move_batch(struct obj_pool *dst, struct obj_pool *src)
153{
154 struct hlist_node *last, *next_batch, *first_batch;
155 struct debug_obj *obj;
156
157 if (dst->cnt >= dst->max_cnt || !src->cnt)
158 return false;
159
160 first_batch = src->objects.first;
161 obj = hlist_entry(first_batch, typeof(*obj), node);
162 last = obj->batch_last;
163 next_batch = last->next;
164
165 /* Move the next batch to the front of the source pool */
166 src->objects.first = next_batch;
167 if (next_batch)
168 next_batch->pprev = &src->objects.first;
169
170 /* Add the extracted batch to the destination pool */
171 last->next = dst->objects.first;
172 if (last->next)
173 last->next->pprev = &last->next;
174 first_batch->pprev = &dst->objects.first;
175 dst->objects.first = first_batch;
176
177 WRITE_ONCE(src->cnt, src->cnt - ODEBUG_BATCH_SIZE);
178 WRITE_ONCE(dst->cnt, dst->cnt + ODEBUG_BATCH_SIZE);
179 return true;
180}
181
182static bool pool_push_batch(struct obj_pool *dst, struct hlist_head *head)
183{
184 struct hlist_node *last;
185 struct debug_obj *obj;
186
187 if (dst->cnt >= dst->max_cnt)
188 return false;
189
190 obj = hlist_entry(head->first, typeof(*obj), node);
191 last = obj->batch_last;
192
193 hlist_splice_init(head, last, &dst->objects);
194 WRITE_ONCE(dst->cnt, dst->cnt + ODEBUG_BATCH_SIZE);
195 return true;
196}
197
198static bool pool_pop_batch(struct hlist_head *head, struct obj_pool *src)
199{
200 struct hlist_node *last, *next;
201 struct debug_obj *obj;
202
203 if (!src->cnt)
204 return false;
205
206 /* Move the complete list to the head */
207 hlist_move_list(&src->objects, head);
208
209 obj = hlist_entry(head->first, typeof(*obj), node);
210 last = obj->batch_last;
211 next = last->next;
212 /* Disconnect the batch from the list */
213 last->next = NULL;
214
215 /* Move the node after last back to the source pool. */
216 src->objects.first = next;
217 if (next)
218 next->pprev = &src->objects.first;
219
220 WRITE_ONCE(src->cnt, src->cnt - ODEBUG_BATCH_SIZE);
221 return true;
222}
223
224static struct debug_obj *__alloc_object(struct hlist_head *list)
225{
226 struct debug_obj *obj;
227
228 if (unlikely(!list->first))
229 return NULL;
230
231 obj = hlist_entry(list->first, typeof(*obj), node);
232 hlist_del(&obj->node);
233 return obj;
234}
235
236static void pcpu_refill_stats(void)
237{
238 struct pool_stats *stats = &pool_global.stats;
239
240 WRITE_ONCE(stats->cur_used, stats->cur_used + ODEBUG_BATCH_SIZE);
241
242 if (stats->cur_used > stats->max_used)
243 stats->max_used = stats->cur_used;
244
245 if (pool_global.cnt < stats->min_fill)
246 stats->min_fill = pool_global.cnt;
247}
248
249static struct debug_obj *pcpu_alloc(void)
250{
251 struct obj_pool *pcp = this_cpu_ptr(&pool_pcpu);
252
253 lockdep_assert_irqs_disabled();
254
255 for (;;) {
256 struct debug_obj *obj = __alloc_object(&pcp->objects);
257
258 if (likely(obj)) {
259 pcp->cnt--;
260 /*
261 * If this emptied a batch try to refill from the
262 * free pool. Don't do that if this was the top-most
263 * batch as pcpu_free() expects the per CPU pool
264 * to be less than ODEBUG_POOL_PERCPU_SIZE.
265 */
266 if (unlikely(pcp->cnt < (ODEBUG_POOL_PERCPU_SIZE - ODEBUG_BATCH_SIZE) &&
267 !(pcp->cnt % ODEBUG_BATCH_SIZE))) {
268 /*
269 * Don't try to allocate from the regular pool here
270 * to not exhaust it prematurely.
271 */
272 if (pool_count(&pool_to_free)) {
273 guard(raw_spinlock)(&pool_lock);
274 pool_move_batch(pcp, &pool_to_free);
275 pcpu_refill_stats();
276 }
277 }
278 return obj;
279 }
280
281 guard(raw_spinlock)(&pool_lock);
282 if (!pool_move_batch(pcp, &pool_to_free)) {
283 if (!pool_move_batch(pcp, &pool_global))
284 return NULL;
285 }
286 pcpu_refill_stats();
287 }
288}
289
290static void pcpu_free(struct debug_obj *obj)
291{
292 struct obj_pool *pcp = this_cpu_ptr(&pool_pcpu);
293 struct debug_obj *first;
294
295 lockdep_assert_irqs_disabled();
296
297 if (!(pcp->cnt % ODEBUG_BATCH_SIZE)) {
298 obj->batch_last = &obj->node;
299 } else {
300 first = hlist_entry(pcp->objects.first, typeof(*first), node);
301 obj->batch_last = first->batch_last;
302 }
303 hlist_add_head(&obj->node, &pcp->objects);
304 pcp->cnt++;
305
306 /* Pool full ? */
307 if (pcp->cnt < ODEBUG_POOL_PERCPU_SIZE)
308 return;
309
310 /* Remove a batch from the per CPU pool */
311 guard(raw_spinlock)(&pool_lock);
312 /* Try to fit the batch into the pool_global first */
313 if (!pool_move_batch(&pool_global, pcp))
314 pool_move_batch(&pool_to_free, pcp);
315 WRITE_ONCE(pool_global.stats.cur_used, pool_global.stats.cur_used - ODEBUG_BATCH_SIZE);
316}
317
318static void free_object_list(struct hlist_head *head)
319{
320 struct hlist_node *tmp;
321 struct debug_obj *obj;
322 int cnt = 0;
323
324 hlist_for_each_entry_safe(obj, tmp, head, node) {
325 hlist_del(&obj->node);
326 kmem_cache_free(obj_cache, obj);
327 cnt++;
328 }
329 debug_objects_freed += cnt;
330}
331
332static void fill_pool_from_freelist(void)
333{
334 static unsigned long state;
335
336 /*
337 * Reuse objs from the global obj_to_free list; they will be
338 * reinitialized when allocating.
339 */
340 if (!pool_count(&pool_to_free))
341 return;
342
343 /*
344 * Prevent the context from being scheduled or interrupted after
345 * setting the state flag;
346 */
347 guard(irqsave)();
348
349 /*
350 * Avoid lock contention on &pool_lock and avoid making the cache
351 * line exclusive by testing the bit before attempting to set it.
352 */
353 if (test_bit(0, &state) || test_and_set_bit(0, &state))
354 return;
355
356 /* Avoid taking the lock when there is no work to do */
357 while (pool_should_refill(&pool_global) && pool_count(&pool_to_free)) {
358 guard(raw_spinlock)(&pool_lock);
359 /* Move a batch if possible */
360 pool_move_batch(&pool_global, &pool_to_free);
361 }
362 clear_bit(0, &state);
363}
364
365static bool kmem_alloc_batch(struct hlist_head *head, struct kmem_cache *cache, gfp_t gfp)
366{
367 struct hlist_node *last = NULL;
368 struct debug_obj *obj;
369
370 for (int cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
371 obj = kmem_cache_zalloc(cache, gfp);
372 if (!obj) {
373 free_object_list(head);
374 return false;
375 }
376 debug_objects_allocated++;
377
378 if (!last)
379 last = &obj->node;
380 obj->batch_last = last;
381
382 hlist_add_head(&obj->node, head);
383 }
384 return true;
385}
386
387static void fill_pool(void)
388{
389 static atomic_t cpus_allocating;
390
391 /*
392 * Avoid allocation and lock contention when:
393 * - One other CPU is already allocating
394 * - the global pool has not reached the critical level yet
395 */
396 if (!pool_must_refill(&pool_global) && atomic_read(&cpus_allocating))
397 return;
398
399 atomic_inc(&cpus_allocating);
400 while (pool_should_refill(&pool_global)) {
401 gfp_t gfp = __GFP_HIGH | __GFP_NOWARN;
402 HLIST_HEAD(head);
403
404 /*
405 * Allow reclaim only in preemptible context and during
406 * early boot. If not preemptible, the caller might hold
407 * locks causing a deadlock in the allocator.
408 *
409 * If the reclaim flag is not set during early boot then
410 * allocations, which happen before deferred page
411 * initialization has completed, will fail.
412 *
413 * In preemptible context the flag is harmless and not a
414 * performance issue as that's usually invoked from slow
415 * path initialization context.
416 */
417 if (preemptible() || system_state < SYSTEM_SCHEDULING)
418 gfp |= __GFP_KSWAPD_RECLAIM;
419
420 if (!kmem_alloc_batch(&head, obj_cache, gfp))
421 break;
422
423 guard(raw_spinlock_irqsave)(&pool_lock);
424 if (!pool_push_batch(&pool_global, &head))
425 pool_push_batch(&pool_to_free, &head);
426 }
427 atomic_dec(&cpus_allocating);
428}
429
430/*
431 * Lookup an object in the hash bucket.
432 */
433static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
434{
435 struct debug_obj *obj;
436 int cnt = 0;
437
438 hlist_for_each_entry(obj, &b->list, node) {
439 cnt++;
440 if (obj->object == addr)
441 return obj;
442 }
443 if (cnt > debug_objects_maxchain)
444 debug_objects_maxchain = cnt;
445
446 return NULL;
447}
448
449static void calc_usage(void)
450{
451 static DEFINE_RAW_SPINLOCK(avg_lock);
452 static unsigned long avg_period;
453 unsigned long cur, now = jiffies;
454
455 if (!time_after_eq(now, READ_ONCE(avg_period)))
456 return;
457
458 if (!raw_spin_trylock(&avg_lock))
459 return;
460
461 WRITE_ONCE(avg_period, now + msecs_to_jiffies(10));
462 cur = READ_ONCE(pool_global.stats.cur_used) * ODEBUG_FREE_WORK_MAX;
463 WRITE_ONCE(avg_usage, calc_load(avg_usage, EXP_5, cur));
464 raw_spin_unlock(&avg_lock);
465}
466
467static struct debug_obj *alloc_object(void *addr, struct debug_bucket *b,
468 const struct debug_obj_descr *descr)
469{
470 struct debug_obj *obj;
471
472 calc_usage();
473
474 if (static_branch_likely(&obj_cache_enabled))
475 obj = pcpu_alloc();
476 else
477 obj = __alloc_object(&pool_boot);
478
479 if (likely(obj)) {
480 obj->object = addr;
481 obj->descr = descr;
482 obj->state = ODEBUG_STATE_NONE;
483 obj->astate = 0;
484 hlist_add_head(&obj->node, &b->list);
485 }
486 return obj;
487}
488
489/* workqueue function to free objects. */
490static void free_obj_work(struct work_struct *work)
491{
492 static unsigned long last_use_avg;
493 unsigned long cur_used, last_used, delta;
494 unsigned int max_free = 0;
495
496 WRITE_ONCE(obj_freeing, false);
497
498 /* Rate limit freeing based on current use average */
499 cur_used = READ_ONCE(avg_usage);
500 last_used = last_use_avg;
501 last_use_avg = cur_used;
502
503 if (!pool_count(&pool_to_free))
504 return;
505
506 if (cur_used <= last_used) {
507 delta = (last_used - cur_used) / ODEBUG_FREE_WORK_MAX;
508 max_free = min(delta, ODEBUG_FREE_WORK_MAX);
509 }
510
511 for (int cnt = 0; cnt < ODEBUG_FREE_WORK_MAX; cnt++) {
512 HLIST_HEAD(tofree);
513
514 /* Acquire and drop the lock for each batch */
515 scoped_guard(raw_spinlock_irqsave, &pool_lock) {
516 if (!pool_to_free.cnt)
517 return;
518
519 /* Refill the global pool if possible */
520 if (pool_move_batch(&pool_global, &pool_to_free)) {
521 /* Don't free as there seems to be demand */
522 max_free = 0;
523 } else if (max_free) {
524 pool_pop_batch(&tofree, &pool_to_free);
525 max_free--;
526 } else {
527 return;
528 }
529 }
530 free_object_list(&tofree);
531 }
532}
533
534static void __free_object(struct debug_obj *obj)
535{
536 guard(irqsave)();
537 if (static_branch_likely(&obj_cache_enabled))
538 pcpu_free(obj);
539 else
540 hlist_add_head(&obj->node, &pool_boot);
541}
542
543/*
544 * Put the object back into the pool and schedule work to free objects
545 * if necessary.
546 */
547static void free_object(struct debug_obj *obj)
548{
549 __free_object(obj);
550 if (!READ_ONCE(obj_freeing) && pool_count(&pool_to_free)) {
551 WRITE_ONCE(obj_freeing, true);
552 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
553 }
554}
555
556static void put_objects(struct hlist_head *list)
557{
558 struct hlist_node *tmp;
559 struct debug_obj *obj;
560
561 /*
562 * Using free_object() puts the objects into reuse or schedules
563 * them for freeing and it get's all the accounting correct.
564 */
565 hlist_for_each_entry_safe(obj, tmp, list, node) {
566 hlist_del(&obj->node);
567 free_object(obj);
568 }
569}
570
571#ifdef CONFIG_HOTPLUG_CPU
572static int object_cpu_offline(unsigned int cpu)
573{
574 /* Remote access is safe as the CPU is dead already */
575 struct obj_pool *pcp = per_cpu_ptr(&pool_pcpu, cpu);
576
577 put_objects(&pcp->objects);
578 pcp->cnt = 0;
579 return 0;
580}
581#endif
582
583/* Out of memory. Free all objects from hash */
584static void debug_objects_oom(void)
585{
586 struct debug_bucket *db = obj_hash;
587 HLIST_HEAD(freelist);
588
589 pr_warn("Out of memory. ODEBUG disabled\n");
590
591 for (int i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
592 scoped_guard(raw_spinlock_irqsave, &db->lock)
593 hlist_move_list(&db->list, &freelist);
594
595 put_objects(&freelist);
596 }
597}
598
599/*
600 * We use the pfn of the address for the hash. That way we can check
601 * for freed objects simply by checking the affected bucket.
602 */
603static struct debug_bucket *get_bucket(unsigned long addr)
604{
605 unsigned long hash;
606
607 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
608 return &obj_hash[hash];
609}
610
611static void debug_print_object(struct debug_obj *obj, char *msg)
612{
613 const struct debug_obj_descr *descr = obj->descr;
614 static int limit;
615
616 /*
617 * Don't report if lookup_object_or_alloc() by the current thread
618 * failed because lookup_object_or_alloc()/debug_objects_oom() by a
619 * concurrent thread turned off debug_objects_enabled and cleared
620 * the hash buckets.
621 */
622 if (!debug_objects_enabled)
623 return;
624
625 if (limit < 5 && descr != descr_test) {
626 void *hint = descr->debug_hint ?
627 descr->debug_hint(obj->object) : NULL;
628 limit++;
629 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
630 "object: %p object type: %s hint: %pS\n",
631 msg, obj_states[obj->state], obj->astate,
632 obj->object, descr->name, hint);
633 }
634 debug_objects_warnings++;
635}
636
637/*
638 * Try to repair the damage, so we have a better chance to get useful
639 * debug output.
640 */
641static bool
642debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
643 void * addr, enum debug_obj_state state)
644{
645 if (fixup && fixup(addr, state)) {
646 debug_objects_fixups++;
647 return true;
648 }
649 return false;
650}
651
652static void debug_object_is_on_stack(void *addr, int onstack)
653{
654 int is_on_stack;
655 static int limit;
656
657 if (limit > 4)
658 return;
659
660 is_on_stack = object_is_on_stack(addr);
661 if (is_on_stack == onstack)
662 return;
663
664 limit++;
665 if (is_on_stack)
666 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
667 task_stack_page(current));
668 else
669 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
670 task_stack_page(current));
671
672 WARN_ON(1);
673}
674
675static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
676 const struct debug_obj_descr *descr,
677 bool onstack, bool alloc_ifstatic)
678{
679 struct debug_obj *obj = lookup_object(addr, b);
680 enum debug_obj_state state = ODEBUG_STATE_NONE;
681
682 if (likely(obj))
683 return obj;
684
685 /*
686 * debug_object_init() unconditionally allocates untracked
687 * objects. It does not matter whether it is a static object or
688 * not.
689 *
690 * debug_object_assert_init() and debug_object_activate() allow
691 * allocation only if the descriptor callback confirms that the
692 * object is static and considered initialized. For non-static
693 * objects the allocation needs to be done from the fixup callback.
694 */
695 if (unlikely(alloc_ifstatic)) {
696 if (!descr->is_static_object || !descr->is_static_object(addr))
697 return ERR_PTR(-ENOENT);
698 /* Statically allocated objects are considered initialized */
699 state = ODEBUG_STATE_INIT;
700 }
701
702 obj = alloc_object(addr, b, descr);
703 if (likely(obj)) {
704 obj->state = state;
705 debug_object_is_on_stack(addr, onstack);
706 return obj;
707 }
708
709 /* Out of memory. Do the cleanup outside of the locked region */
710 debug_objects_enabled = false;
711 return NULL;
712}
713
714static inline bool debug_objects_is_pi_blocked_on(void)
715{
716#ifdef CONFIG_RT_MUTEXES
717 return current->pi_blocked_on != NULL;
718#else
719 return false;
720#endif
721}
722
723static inline bool can_fill_pool(void)
724{
725 /*
726 * On !RT enabled kernels there are no restrictions and spinlock_t and
727 * raw_spinlock_t are the same types.
728 */
729 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
730 return true;
731
732 /*
733 * On RT enabled kernels, the task must not be blocked on a lock as
734 * that could corrupt the PI state when blocking on a lock in the
735 * allocation path.
736 */
737 if (debug_objects_is_pi_blocked_on())
738 return false;
739
740 /*
741 * On RT enabled kernels the pool refill should happen in preemptible
742 * context.
743 */
744 if (preemptible())
745 return true;
746
747 /*
748 * Though during system boot before scheduling is set up, preemption is
749 * disabled and the pool can get exhausted. Before scheduling is active
750 * a task cannot be blocked on a sleeping lock, but it might hold a lock
751 * and if interrupted then hard interrupt context might run into a lock
752 * inversion. So exclude hard interrupt context from allocations before
753 * scheduling is active.
754 */
755 return system_state < SYSTEM_SCHEDULING && !in_hardirq();
756}
757
758static void debug_objects_fill_pool(void)
759{
760 if (!static_branch_likely(&obj_cache_enabled))
761 return;
762
763 if (likely(!pool_should_refill(&pool_global)))
764 return;
765
766 /* Try reusing objects from obj_to_free_list */
767 fill_pool_from_freelist();
768
769 if (likely(!pool_should_refill(&pool_global)))
770 return;
771
772 if (can_fill_pool()) {
773 /*
774 * Annotate away the spinlock_t inside raw_spinlock_t warning
775 * by temporarily raising the wait-type to LD_WAIT_CONFIG, matching
776 * the preemptible() condition in can_fill_pool().
777 */
778 static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_CONFIG);
779 lock_map_acquire_try(&fill_pool_map);
780 fill_pool();
781 lock_map_release(&fill_pool_map);
782 }
783}
784
785static void
786__debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
787{
788 struct debug_obj *obj, o;
789 struct debug_bucket *db;
790 unsigned long flags;
791
792 debug_objects_fill_pool();
793
794 db = get_bucket((unsigned long) addr);
795
796 raw_spin_lock_irqsave(&db->lock, flags);
797
798 obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
799 if (unlikely(!obj)) {
800 raw_spin_unlock_irqrestore(&db->lock, flags);
801 debug_objects_oom();
802 return;
803 }
804
805 switch (obj->state) {
806 case ODEBUG_STATE_NONE:
807 case ODEBUG_STATE_INIT:
808 case ODEBUG_STATE_INACTIVE:
809 obj->state = ODEBUG_STATE_INIT;
810 raw_spin_unlock_irqrestore(&db->lock, flags);
811 return;
812 default:
813 break;
814 }
815
816 o = *obj;
817 raw_spin_unlock_irqrestore(&db->lock, flags);
818 debug_print_object(&o, "init");
819
820 if (o.state == ODEBUG_STATE_ACTIVE)
821 debug_object_fixup(descr->fixup_init, addr, o.state);
822}
823
824/**
825 * debug_object_init - debug checks when an object is initialized
826 * @addr: address of the object
827 * @descr: pointer to an object specific debug description structure
828 */
829void debug_object_init(void *addr, const struct debug_obj_descr *descr)
830{
831 if (!debug_objects_enabled)
832 return;
833
834 __debug_object_init(addr, descr, 0);
835}
836EXPORT_SYMBOL_GPL(debug_object_init);
837
838/**
839 * debug_object_init_on_stack - debug checks when an object on stack is
840 * initialized
841 * @addr: address of the object
842 * @descr: pointer to an object specific debug description structure
843 */
844void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
845{
846 if (!debug_objects_enabled)
847 return;
848
849 __debug_object_init(addr, descr, 1);
850}
851EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
852
853/**
854 * debug_object_activate - debug checks when an object is activated
855 * @addr: address of the object
856 * @descr: pointer to an object specific debug description structure
857 * Returns 0 for success, -EINVAL for check failed.
858 */
859int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
860{
861 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
862 struct debug_bucket *db;
863 struct debug_obj *obj;
864 unsigned long flags;
865
866 if (!debug_objects_enabled)
867 return 0;
868
869 debug_objects_fill_pool();
870
871 db = get_bucket((unsigned long) addr);
872
873 raw_spin_lock_irqsave(&db->lock, flags);
874
875 obj = lookup_object_or_alloc(addr, db, descr, false, true);
876 if (unlikely(!obj)) {
877 raw_spin_unlock_irqrestore(&db->lock, flags);
878 debug_objects_oom();
879 return 0;
880 } else if (likely(!IS_ERR(obj))) {
881 switch (obj->state) {
882 case ODEBUG_STATE_ACTIVE:
883 case ODEBUG_STATE_DESTROYED:
884 o = *obj;
885 break;
886 case ODEBUG_STATE_INIT:
887 case ODEBUG_STATE_INACTIVE:
888 obj->state = ODEBUG_STATE_ACTIVE;
889 fallthrough;
890 default:
891 raw_spin_unlock_irqrestore(&db->lock, flags);
892 return 0;
893 }
894 }
895
896 raw_spin_unlock_irqrestore(&db->lock, flags);
897
898 /*
899 * lookup_object_or_alloc() might have raced with a concurrent
900 * allocation failure which disabled debug objects.
901 */
902 if (!debug_objects_enabled)
903 return 0;
904
905 debug_print_object(&o, "activate");
906
907 switch (o.state) {
908 case ODEBUG_STATE_ACTIVE:
909 case ODEBUG_STATE_NOTAVAILABLE:
910 if (debug_object_fixup(descr->fixup_activate, addr, o.state))
911 return 0;
912 fallthrough;
913 default:
914 return -EINVAL;
915 }
916}
917EXPORT_SYMBOL_GPL(debug_object_activate);
918
919/**
920 * debug_object_deactivate - debug checks when an object is deactivated
921 * @addr: address of the object
922 * @descr: pointer to an object specific debug description structure
923 */
924void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
925{
926 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
927 struct debug_bucket *db;
928 struct debug_obj *obj;
929 unsigned long flags;
930
931 if (!debug_objects_enabled)
932 return;
933
934 db = get_bucket((unsigned long) addr);
935
936 raw_spin_lock_irqsave(&db->lock, flags);
937
938 obj = lookup_object(addr, db);
939 if (obj) {
940 switch (obj->state) {
941 case ODEBUG_STATE_DESTROYED:
942 break;
943 case ODEBUG_STATE_INIT:
944 case ODEBUG_STATE_INACTIVE:
945 case ODEBUG_STATE_ACTIVE:
946 if (obj->astate)
947 break;
948 obj->state = ODEBUG_STATE_INACTIVE;
949 fallthrough;
950 default:
951 raw_spin_unlock_irqrestore(&db->lock, flags);
952 return;
953 }
954 o = *obj;
955 }
956
957 raw_spin_unlock_irqrestore(&db->lock, flags);
958 debug_print_object(&o, "deactivate");
959}
960EXPORT_SYMBOL_GPL(debug_object_deactivate);
961
962/**
963 * debug_object_destroy - debug checks when an object is destroyed
964 * @addr: address of the object
965 * @descr: pointer to an object specific debug description structure
966 */
967void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
968{
969 struct debug_obj *obj, o;
970 struct debug_bucket *db;
971 unsigned long flags;
972
973 if (!debug_objects_enabled)
974 return;
975
976 db = get_bucket((unsigned long) addr);
977
978 raw_spin_lock_irqsave(&db->lock, flags);
979
980 obj = lookup_object(addr, db);
981 if (!obj) {
982 raw_spin_unlock_irqrestore(&db->lock, flags);
983 return;
984 }
985
986 switch (obj->state) {
987 case ODEBUG_STATE_ACTIVE:
988 case ODEBUG_STATE_DESTROYED:
989 break;
990 case ODEBUG_STATE_NONE:
991 case ODEBUG_STATE_INIT:
992 case ODEBUG_STATE_INACTIVE:
993 obj->state = ODEBUG_STATE_DESTROYED;
994 fallthrough;
995 default:
996 raw_spin_unlock_irqrestore(&db->lock, flags);
997 return;
998 }
999
1000 o = *obj;
1001 raw_spin_unlock_irqrestore(&db->lock, flags);
1002 debug_print_object(&o, "destroy");
1003
1004 if (o.state == ODEBUG_STATE_ACTIVE)
1005 debug_object_fixup(descr->fixup_destroy, addr, o.state);
1006}
1007EXPORT_SYMBOL_GPL(debug_object_destroy);
1008
1009/**
1010 * debug_object_free - debug checks when an object is freed
1011 * @addr: address of the object
1012 * @descr: pointer to an object specific debug description structure
1013 */
1014void debug_object_free(void *addr, const struct debug_obj_descr *descr)
1015{
1016 struct debug_obj *obj, o;
1017 struct debug_bucket *db;
1018 unsigned long flags;
1019
1020 if (!debug_objects_enabled)
1021 return;
1022
1023 db = get_bucket((unsigned long) addr);
1024
1025 raw_spin_lock_irqsave(&db->lock, flags);
1026
1027 obj = lookup_object(addr, db);
1028 if (!obj) {
1029 raw_spin_unlock_irqrestore(&db->lock, flags);
1030 return;
1031 }
1032
1033 switch (obj->state) {
1034 case ODEBUG_STATE_ACTIVE:
1035 break;
1036 default:
1037 hlist_del(&obj->node);
1038 raw_spin_unlock_irqrestore(&db->lock, flags);
1039 free_object(obj);
1040 return;
1041 }
1042
1043 o = *obj;
1044 raw_spin_unlock_irqrestore(&db->lock, flags);
1045 debug_print_object(&o, "free");
1046
1047 debug_object_fixup(descr->fixup_free, addr, o.state);
1048}
1049EXPORT_SYMBOL_GPL(debug_object_free);
1050
1051/**
1052 * debug_object_assert_init - debug checks when object should be init-ed
1053 * @addr: address of the object
1054 * @descr: pointer to an object specific debug description structure
1055 */
1056void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
1057{
1058 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
1059 struct debug_bucket *db;
1060 struct debug_obj *obj;
1061 unsigned long flags;
1062
1063 if (!debug_objects_enabled)
1064 return;
1065
1066 debug_objects_fill_pool();
1067
1068 db = get_bucket((unsigned long) addr);
1069
1070 raw_spin_lock_irqsave(&db->lock, flags);
1071 obj = lookup_object_or_alloc(addr, db, descr, false, true);
1072 raw_spin_unlock_irqrestore(&db->lock, flags);
1073 if (!IS_ERR_OR_NULL(obj))
1074 return;
1075
1076 /* If NULL the allocation has hit OOM */
1077 if (!obj) {
1078 debug_objects_oom();
1079 return;
1080 }
1081
1082 /*
1083 * lookup_object_or_alloc() might have raced with a concurrent
1084 * allocation failure which disabled debug objects. Don't run the fixup
1085 * as it might turn a valid object useless. See for example
1086 * hrtimer_fixup_assert_init().
1087 */
1088 if (!debug_objects_enabled)
1089 return;
1090
1091 /* Object is neither tracked nor static. It's not initialized. */
1092 debug_print_object(&o, "assert_init");
1093 debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
1094}
1095EXPORT_SYMBOL_GPL(debug_object_assert_init);
1096
1097/**
1098 * debug_object_active_state - debug checks object usage state machine
1099 * @addr: address of the object
1100 * @descr: pointer to an object specific debug description structure
1101 * @expect: expected state
1102 * @next: state to move to if expected state is found
1103 */
1104void
1105debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
1106 unsigned int expect, unsigned int next)
1107{
1108 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
1109 struct debug_bucket *db;
1110 struct debug_obj *obj;
1111 unsigned long flags;
1112
1113 if (!debug_objects_enabled)
1114 return;
1115
1116 db = get_bucket((unsigned long) addr);
1117
1118 raw_spin_lock_irqsave(&db->lock, flags);
1119
1120 obj = lookup_object(addr, db);
1121 if (obj) {
1122 switch (obj->state) {
1123 case ODEBUG_STATE_ACTIVE:
1124 if (obj->astate != expect)
1125 break;
1126 obj->astate = next;
1127 raw_spin_unlock_irqrestore(&db->lock, flags);
1128 return;
1129 default:
1130 break;
1131 }
1132 o = *obj;
1133 }
1134
1135 raw_spin_unlock_irqrestore(&db->lock, flags);
1136 debug_print_object(&o, "active_state");
1137}
1138EXPORT_SYMBOL_GPL(debug_object_active_state);
1139
1140#ifdef CONFIG_DEBUG_OBJECTS_FREE
1141static void __debug_check_no_obj_freed(const void *address, unsigned long size)
1142{
1143 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
1144 int cnt, objs_checked = 0;
1145 struct debug_obj *obj, o;
1146 struct debug_bucket *db;
1147 struct hlist_node *tmp;
1148
1149 saddr = (unsigned long) address;
1150 eaddr = saddr + size;
1151 paddr = saddr & ODEBUG_CHUNK_MASK;
1152 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
1153 chunks >>= ODEBUG_CHUNK_SHIFT;
1154
1155 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
1156 db = get_bucket(paddr);
1157
1158repeat:
1159 cnt = 0;
1160 raw_spin_lock_irqsave(&db->lock, flags);
1161 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
1162 cnt++;
1163 oaddr = (unsigned long) obj->object;
1164 if (oaddr < saddr || oaddr >= eaddr)
1165 continue;
1166
1167 switch (obj->state) {
1168 case ODEBUG_STATE_ACTIVE:
1169 o = *obj;
1170 raw_spin_unlock_irqrestore(&db->lock, flags);
1171 debug_print_object(&o, "free");
1172 debug_object_fixup(o.descr->fixup_free, (void *)oaddr, o.state);
1173 goto repeat;
1174 default:
1175 hlist_del(&obj->node);
1176 __free_object(obj);
1177 break;
1178 }
1179 }
1180 raw_spin_unlock_irqrestore(&db->lock, flags);
1181
1182 if (cnt > debug_objects_maxchain)
1183 debug_objects_maxchain = cnt;
1184
1185 objs_checked += cnt;
1186 }
1187
1188 if (objs_checked > debug_objects_maxchecked)
1189 debug_objects_maxchecked = objs_checked;
1190
1191 /* Schedule work to actually kmem_cache_free() objects */
1192 if (!READ_ONCE(obj_freeing) && pool_count(&pool_to_free)) {
1193 WRITE_ONCE(obj_freeing, true);
1194 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1195 }
1196}
1197
1198void debug_check_no_obj_freed(const void *address, unsigned long size)
1199{
1200 if (debug_objects_enabled)
1201 __debug_check_no_obj_freed(address, size);
1202}
1203#endif
1204
1205#ifdef CONFIG_DEBUG_FS
1206
1207static int debug_stats_show(struct seq_file *m, void *v)
1208{
1209 unsigned int cpu, pool_used, pcp_free = 0;
1210
1211 /*
1212 * pool_global.stats.cur_used is the number of batches currently
1213 * handed out to per CPU pools. Convert it to number of objects
1214 * and subtract the number of free objects in the per CPU pools.
1215 * As this is lockless the number is an estimate.
1216 */
1217 for_each_possible_cpu(cpu)
1218 pcp_free += per_cpu(pool_pcpu.cnt, cpu);
1219
1220 pool_used = READ_ONCE(pool_global.stats.cur_used);
1221 pcp_free = min(pool_used, pcp_free);
1222 pool_used -= pcp_free;
1223
1224 seq_printf(m, "max_chain : %d\n", debug_objects_maxchain);
1225 seq_printf(m, "max_checked : %d\n", debug_objects_maxchecked);
1226 seq_printf(m, "warnings : %d\n", debug_objects_warnings);
1227 seq_printf(m, "fixups : %d\n", debug_objects_fixups);
1228 seq_printf(m, "pool_free : %u\n", pool_count(&pool_global) + pcp_free);
1229 seq_printf(m, "pool_pcp_free : %u\n", pcp_free);
1230 seq_printf(m, "pool_min_free : %u\n", data_race(pool_global.stats.min_fill));
1231 seq_printf(m, "pool_used : %u\n", pool_used);
1232 seq_printf(m, "pool_max_used : %u\n", data_race(pool_global.stats.max_used));
1233 seq_printf(m, "on_free_list : %u\n", pool_count(&pool_to_free));
1234 seq_printf(m, "objs_allocated: %d\n", debug_objects_allocated);
1235 seq_printf(m, "objs_freed : %d\n", debug_objects_freed);
1236 return 0;
1237}
1238DEFINE_SHOW_ATTRIBUTE(debug_stats);
1239
1240static int __init debug_objects_init_debugfs(void)
1241{
1242 struct dentry *dbgdir;
1243
1244 if (!debug_objects_enabled)
1245 return 0;
1246
1247 dbgdir = debugfs_create_dir("debug_objects", NULL);
1248
1249 debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1250
1251 return 0;
1252}
1253__initcall(debug_objects_init_debugfs);
1254
1255#else
1256static inline void debug_objects_init_debugfs(void) { }
1257#endif
1258
1259#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1260
1261/* Random data structure for the self test */
1262struct self_test {
1263 unsigned long dummy1[6];
1264 int static_init;
1265 unsigned long dummy2[3];
1266};
1267
1268static __initconst const struct debug_obj_descr descr_type_test;
1269
1270static __noipa bool __init is_static_object(void *addr)
1271{
1272 struct self_test *obj = addr;
1273
1274 return obj->static_init;
1275}
1276
1277/*
1278 * fixup_init is called when:
1279 * - an active object is initialized
1280 */
1281static bool __init fixup_init(void *addr, enum debug_obj_state state)
1282{
1283 struct self_test *obj = addr;
1284
1285 switch (state) {
1286 case ODEBUG_STATE_ACTIVE:
1287 debug_object_deactivate(obj, &descr_type_test);
1288 debug_object_init(obj, &descr_type_test);
1289 return true;
1290 default:
1291 return false;
1292 }
1293}
1294
1295/*
1296 * fixup_activate is called when:
1297 * - an active object is activated
1298 * - an unknown non-static object is activated
1299 */
1300static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1301{
1302 struct self_test *obj = addr;
1303
1304 switch (state) {
1305 case ODEBUG_STATE_NOTAVAILABLE:
1306 return true;
1307 case ODEBUG_STATE_ACTIVE:
1308 debug_object_deactivate(obj, &descr_type_test);
1309 debug_object_activate(obj, &descr_type_test);
1310 return true;
1311
1312 default:
1313 return false;
1314 }
1315}
1316
1317/*
1318 * fixup_destroy is called when:
1319 * - an active object is destroyed
1320 */
1321static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1322{
1323 struct self_test *obj = addr;
1324
1325 switch (state) {
1326 case ODEBUG_STATE_ACTIVE:
1327 debug_object_deactivate(obj, &descr_type_test);
1328 debug_object_destroy(obj, &descr_type_test);
1329 return true;
1330 default:
1331 return false;
1332 }
1333}
1334
1335/*
1336 * fixup_free is called when:
1337 * - an active object is freed
1338 */
1339static bool __init fixup_free(void *addr, enum debug_obj_state state)
1340{
1341 struct self_test *obj = addr;
1342
1343 switch (state) {
1344 case ODEBUG_STATE_ACTIVE:
1345 debug_object_deactivate(obj, &descr_type_test);
1346 debug_object_free(obj, &descr_type_test);
1347 return true;
1348 default:
1349 return false;
1350 }
1351}
1352
1353static int __init
1354check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1355{
1356 struct debug_bucket *db;
1357 struct debug_obj *obj;
1358 unsigned long flags;
1359 int res = -EINVAL;
1360
1361 db = get_bucket((unsigned long) addr);
1362
1363 raw_spin_lock_irqsave(&db->lock, flags);
1364
1365 obj = lookup_object(addr, db);
1366 if (!obj && state != ODEBUG_STATE_NONE) {
1367 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1368 goto out;
1369 }
1370 if (obj && obj->state != state) {
1371 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1372 obj->state, state);
1373 goto out;
1374 }
1375 if (fixups != debug_objects_fixups) {
1376 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1377 fixups, debug_objects_fixups);
1378 goto out;
1379 }
1380 if (warnings != debug_objects_warnings) {
1381 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1382 warnings, debug_objects_warnings);
1383 goto out;
1384 }
1385 res = 0;
1386out:
1387 raw_spin_unlock_irqrestore(&db->lock, flags);
1388 if (res)
1389 debug_objects_enabled = false;
1390 return res;
1391}
1392
1393static __initconst const struct debug_obj_descr descr_type_test = {
1394 .name = "selftest",
1395 .is_static_object = is_static_object,
1396 .fixup_init = fixup_init,
1397 .fixup_activate = fixup_activate,
1398 .fixup_destroy = fixup_destroy,
1399 .fixup_free = fixup_free,
1400};
1401
1402static __initdata struct self_test obj = { .static_init = 0 };
1403
1404static bool __init debug_objects_selftest(void)
1405{
1406 int fixups, oldfixups, warnings, oldwarnings;
1407 unsigned long flags;
1408
1409 local_irq_save(flags);
1410
1411 fixups = oldfixups = debug_objects_fixups;
1412 warnings = oldwarnings = debug_objects_warnings;
1413 descr_test = &descr_type_test;
1414
1415 debug_object_init(&obj, &descr_type_test);
1416 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1417 goto out;
1418 debug_object_activate(&obj, &descr_type_test);
1419 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1420 goto out;
1421 debug_object_activate(&obj, &descr_type_test);
1422 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1423 goto out;
1424 debug_object_deactivate(&obj, &descr_type_test);
1425 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1426 goto out;
1427 debug_object_destroy(&obj, &descr_type_test);
1428 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1429 goto out;
1430 debug_object_init(&obj, &descr_type_test);
1431 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1432 goto out;
1433 debug_object_activate(&obj, &descr_type_test);
1434 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1435 goto out;
1436 debug_object_deactivate(&obj, &descr_type_test);
1437 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1438 goto out;
1439 debug_object_free(&obj, &descr_type_test);
1440 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1441 goto out;
1442
1443 obj.static_init = 1;
1444 debug_object_activate(&obj, &descr_type_test);
1445 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1446 goto out;
1447 debug_object_init(&obj, &descr_type_test);
1448 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1449 goto out;
1450 debug_object_free(&obj, &descr_type_test);
1451 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1452 goto out;
1453
1454#ifdef CONFIG_DEBUG_OBJECTS_FREE
1455 debug_object_init(&obj, &descr_type_test);
1456 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1457 goto out;
1458 debug_object_activate(&obj, &descr_type_test);
1459 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1460 goto out;
1461 __debug_check_no_obj_freed(&obj, sizeof(obj));
1462 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1463 goto out;
1464#endif
1465 pr_info("selftest passed\n");
1466
1467out:
1468 debug_objects_fixups = oldfixups;
1469 debug_objects_warnings = oldwarnings;
1470 descr_test = NULL;
1471
1472 local_irq_restore(flags);
1473 return debug_objects_enabled;
1474}
1475#else
1476static inline bool debug_objects_selftest(void) { return true; }
1477#endif
1478
1479/*
1480 * Called during early boot to initialize the hash buckets and link
1481 * the static object pool objects into the poll list. After this call
1482 * the object tracker is fully operational.
1483 */
1484void __init debug_objects_early_init(void)
1485{
1486 int i;
1487
1488 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1489 raw_spin_lock_init(&obj_hash[i].lock);
1490
1491 /* Keep early boot simple and add everything to the boot list */
1492 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1493 hlist_add_head(&obj_static_pool[i].node, &pool_boot);
1494}
1495
1496/*
1497 * Convert the statically allocated objects to dynamic ones.
1498 * debug_objects_mem_init() is called early so only one CPU is up and
1499 * interrupts are disabled, which means it is safe to replace the active
1500 * object references.
1501 */
1502static bool __init debug_objects_replace_static_objects(struct kmem_cache *cache)
1503{
1504 struct debug_bucket *db = obj_hash;
1505 struct hlist_node *tmp;
1506 struct debug_obj *obj;
1507 HLIST_HEAD(objects);
1508 int i;
1509
1510 for (i = 0; i < ODEBUG_POOL_SIZE; i += ODEBUG_BATCH_SIZE) {
1511 if (!kmem_alloc_batch(&objects, cache, GFP_KERNEL))
1512 goto free;
1513 pool_push_batch(&pool_global, &objects);
1514 }
1515
1516 /* Disconnect the boot pool. */
1517 pool_boot.first = NULL;
1518
1519 /* Replace the active object references */
1520 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1521 hlist_move_list(&db->list, &objects);
1522
1523 hlist_for_each_entry(obj, &objects, node) {
1524 struct debug_obj *new = pcpu_alloc();
1525
1526 /* copy object data */
1527 *new = *obj;
1528 hlist_add_head(&new->node, &db->list);
1529 }
1530 }
1531 return true;
1532free:
1533 /* Can't use free_object_list() as the cache is not populated yet */
1534 hlist_for_each_entry_safe(obj, tmp, &pool_global.objects, node) {
1535 hlist_del(&obj->node);
1536 kmem_cache_free(cache, obj);
1537 }
1538 return false;
1539}
1540
1541/*
1542 * Called after the kmem_caches are functional to setup a dedicated
1543 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1544 * prevents that the debug code is called on kmem_cache_free() for the
1545 * debug tracker objects to avoid recursive calls.
1546 */
1547void __init debug_objects_mem_init(void)
1548{
1549 struct kmem_cache *cache;
1550 int extras;
1551
1552 if (!debug_objects_enabled)
1553 return;
1554
1555 if (!debug_objects_selftest())
1556 return;
1557
1558 cache = kmem_cache_create("debug_objects_cache", sizeof (struct debug_obj), 0,
1559 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE, NULL);
1560
1561 if (!cache || !debug_objects_replace_static_objects(cache)) {
1562 debug_objects_enabled = false;
1563 pr_warn("Out of memory.\n");
1564 return;
1565 }
1566
1567 /*
1568 * Adjust the thresholds for allocating and freeing objects
1569 * according to the number of possible CPUs available in the
1570 * system.
1571 */
1572 extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1573 pool_global.max_cnt += extras;
1574 pool_global.min_cnt += extras;
1575
1576 /* Everything worked. Expose the cache */
1577 obj_cache = cache;
1578 static_branch_enable(&obj_cache_enabled);
1579
1580#ifdef CONFIG_HOTPLUG_CPU
1581 cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1582 object_cpu_offline);
1583#endif
1584 return;
1585}