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[linux-2.6-microblaze.git] / lib / debugobjects.c
1 /*
2  * Generic infrastructure for lifetime debugging of objects.
3  *
4  * Started by Thomas Gleixner
5  *
6  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
7  *
8  * For licencing details see kernel-base/COPYING
9  */
10
11 #define pr_fmt(fmt) "ODEBUG: " fmt
12
13 #include <linux/debugobjects.h>
14 #include <linux/interrupt.h>
15 #include <linux/sched.h>
16 #include <linux/sched/task_stack.h>
17 #include <linux/seq_file.h>
18 #include <linux/debugfs.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/kmemleak.h>
22 #include <linux/cpu.h>
23
24 #define ODEBUG_HASH_BITS        14
25 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
26
27 #define ODEBUG_POOL_SIZE        1024
28 #define ODEBUG_POOL_MIN_LEVEL   256
29 #define ODEBUG_POOL_PERCPU_SIZE 64
30 #define ODEBUG_BATCH_SIZE       16
31
32 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
33 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
34 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
35
36 /*
37  * We limit the freeing of debug objects via workqueue at a maximum
38  * frequency of 10Hz and about 1024 objects for each freeing operation.
39  * So it is freeing at most 10k debug objects per second.
40  */
41 #define ODEBUG_FREE_WORK_MAX    1024
42 #define ODEBUG_FREE_WORK_DELAY  DIV_ROUND_UP(HZ, 10)
43
44 struct debug_bucket {
45         struct hlist_head       list;
46         raw_spinlock_t          lock;
47 };
48
49 /*
50  * Debug object percpu free list
51  * Access is protected by disabling irq
52  */
53 struct debug_percpu_free {
54         struct hlist_head       free_objs;
55         int                     obj_free;
56 };
57
58 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
59
60 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
61
62 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
63
64 static DEFINE_RAW_SPINLOCK(pool_lock);
65
66 static HLIST_HEAD(obj_pool);
67 static HLIST_HEAD(obj_to_free);
68
69 /*
70  * Because of the presence of percpu free pools, obj_pool_free will
71  * under-count those in the percpu free pools. Similarly, obj_pool_used
72  * will over-count those in the percpu free pools. Adjustments will be
73  * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
74  * can be off.
75  */
76 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
77 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
78 static int                      obj_pool_used;
79 static int                      obj_pool_max_used;
80 static bool                     obj_freeing;
81 /* The number of objs on the global free list */
82 static int                      obj_nr_tofree;
83
84 static int                      debug_objects_maxchain __read_mostly;
85 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
86 static int                      debug_objects_fixups __read_mostly;
87 static int                      debug_objects_warnings __read_mostly;
88 static int                      debug_objects_enabled __read_mostly
89                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
90 static int                      debug_objects_pool_size __read_mostly
91                                 = ODEBUG_POOL_SIZE;
92 static int                      debug_objects_pool_min_level __read_mostly
93                                 = ODEBUG_POOL_MIN_LEVEL;
94 static const struct debug_obj_descr *descr_test  __read_mostly;
95 static struct kmem_cache        *obj_cache __read_mostly;
96
97 /*
98  * Track numbers of kmem_cache_alloc()/free() calls done.
99  */
100 static int                      debug_objects_allocated;
101 static int                      debug_objects_freed;
102
103 static void free_obj_work(struct work_struct *work);
104 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
105
106 static int __init enable_object_debug(char *str)
107 {
108         debug_objects_enabled = 1;
109         return 0;
110 }
111
112 static int __init disable_object_debug(char *str)
113 {
114         debug_objects_enabled = 0;
115         return 0;
116 }
117
118 early_param("debug_objects", enable_object_debug);
119 early_param("no_debug_objects", disable_object_debug);
120
121 static const char *obj_states[ODEBUG_STATE_MAX] = {
122         [ODEBUG_STATE_NONE]             = "none",
123         [ODEBUG_STATE_INIT]             = "initialized",
124         [ODEBUG_STATE_INACTIVE]         = "inactive",
125         [ODEBUG_STATE_ACTIVE]           = "active",
126         [ODEBUG_STATE_DESTROYED]        = "destroyed",
127         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
128 };
129
130 static void fill_pool(void)
131 {
132         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
133         struct debug_obj *obj;
134         unsigned long flags;
135
136         if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
137                 return;
138
139         /*
140          * Reuse objs from the global free list; they will be reinitialized
141          * when allocating.
142          *
143          * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
144          * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
145          * sections.
146          */
147         while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
148                 raw_spin_lock_irqsave(&pool_lock, flags);
149                 /*
150                  * Recheck with the lock held as the worker thread might have
151                  * won the race and freed the global free list already.
152                  */
153                 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
154                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
155                         hlist_del(&obj->node);
156                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
157                         hlist_add_head(&obj->node, &obj_pool);
158                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
159                 }
160                 raw_spin_unlock_irqrestore(&pool_lock, flags);
161         }
162
163         if (unlikely(!obj_cache))
164                 return;
165
166         while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
167                 struct debug_obj *new[ODEBUG_BATCH_SIZE];
168                 int cnt;
169
170                 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
171                         new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
172                         if (!new[cnt])
173                                 break;
174                 }
175                 if (!cnt)
176                         return;
177
178                 raw_spin_lock_irqsave(&pool_lock, flags);
179                 while (cnt) {
180                         hlist_add_head(&new[--cnt]->node, &obj_pool);
181                         debug_objects_allocated++;
182                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
183                 }
184                 raw_spin_unlock_irqrestore(&pool_lock, flags);
185         }
186 }
187
188 /*
189  * Lookup an object in the hash bucket.
190  */
191 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
192 {
193         struct debug_obj *obj;
194         int cnt = 0;
195
196         hlist_for_each_entry(obj, &b->list, node) {
197                 cnt++;
198                 if (obj->object == addr)
199                         return obj;
200         }
201         if (cnt > debug_objects_maxchain)
202                 debug_objects_maxchain = cnt;
203
204         return NULL;
205 }
206
207 /*
208  * Allocate a new object from the hlist
209  */
210 static struct debug_obj *__alloc_object(struct hlist_head *list)
211 {
212         struct debug_obj *obj = NULL;
213
214         if (list->first) {
215                 obj = hlist_entry(list->first, typeof(*obj), node);
216                 hlist_del(&obj->node);
217         }
218
219         return obj;
220 }
221
222 /*
223  * Allocate a new object. If the pool is empty, switch off the debugger.
224  * Must be called with interrupts disabled.
225  */
226 static struct debug_obj *
227 alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
228 {
229         struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
230         struct debug_obj *obj;
231
232         if (likely(obj_cache)) {
233                 obj = __alloc_object(&percpu_pool->free_objs);
234                 if (obj) {
235                         percpu_pool->obj_free--;
236                         goto init_obj;
237                 }
238         }
239
240         raw_spin_lock(&pool_lock);
241         obj = __alloc_object(&obj_pool);
242         if (obj) {
243                 obj_pool_used++;
244                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
245
246                 /*
247                  * Looking ahead, allocate one batch of debug objects and
248                  * put them into the percpu free pool.
249                  */
250                 if (likely(obj_cache)) {
251                         int i;
252
253                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
254                                 struct debug_obj *obj2;
255
256                                 obj2 = __alloc_object(&obj_pool);
257                                 if (!obj2)
258                                         break;
259                                 hlist_add_head(&obj2->node,
260                                                &percpu_pool->free_objs);
261                                 percpu_pool->obj_free++;
262                                 obj_pool_used++;
263                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
264                         }
265                 }
266
267                 if (obj_pool_used > obj_pool_max_used)
268                         obj_pool_max_used = obj_pool_used;
269
270                 if (obj_pool_free < obj_pool_min_free)
271                         obj_pool_min_free = obj_pool_free;
272         }
273         raw_spin_unlock(&pool_lock);
274
275 init_obj:
276         if (obj) {
277                 obj->object = addr;
278                 obj->descr  = descr;
279                 obj->state  = ODEBUG_STATE_NONE;
280                 obj->astate = 0;
281                 hlist_add_head(&obj->node, &b->list);
282         }
283         return obj;
284 }
285
286 /*
287  * workqueue function to free objects.
288  *
289  * To reduce contention on the global pool_lock, the actual freeing of
290  * debug objects will be delayed if the pool_lock is busy.
291  */
292 static void free_obj_work(struct work_struct *work)
293 {
294         struct hlist_node *tmp;
295         struct debug_obj *obj;
296         unsigned long flags;
297         HLIST_HEAD(tofree);
298
299         WRITE_ONCE(obj_freeing, false);
300         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
301                 return;
302
303         if (obj_pool_free >= debug_objects_pool_size)
304                 goto free_objs;
305
306         /*
307          * The objs on the pool list might be allocated before the work is
308          * run, so recheck if pool list it full or not, if not fill pool
309          * list from the global free list. As it is likely that a workload
310          * may be gearing up to use more and more objects, don't free any
311          * of them until the next round.
312          */
313         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
314                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
315                 hlist_del(&obj->node);
316                 hlist_add_head(&obj->node, &obj_pool);
317                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
318                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
319         }
320         raw_spin_unlock_irqrestore(&pool_lock, flags);
321         return;
322
323 free_objs:
324         /*
325          * Pool list is already full and there are still objs on the free
326          * list. Move remaining free objs to a temporary list to free the
327          * memory outside the pool_lock held region.
328          */
329         if (obj_nr_tofree) {
330                 hlist_move_list(&obj_to_free, &tofree);
331                 debug_objects_freed += obj_nr_tofree;
332                 WRITE_ONCE(obj_nr_tofree, 0);
333         }
334         raw_spin_unlock_irqrestore(&pool_lock, flags);
335
336         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
337                 hlist_del(&obj->node);
338                 kmem_cache_free(obj_cache, obj);
339         }
340 }
341
342 static void __free_object(struct debug_obj *obj)
343 {
344         struct debug_obj *objs[ODEBUG_BATCH_SIZE];
345         struct debug_percpu_free *percpu_pool;
346         int lookahead_count = 0;
347         unsigned long flags;
348         bool work;
349
350         local_irq_save(flags);
351         if (!obj_cache)
352                 goto free_to_obj_pool;
353
354         /*
355          * Try to free it into the percpu pool first.
356          */
357         percpu_pool = this_cpu_ptr(&percpu_obj_pool);
358         if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
359                 hlist_add_head(&obj->node, &percpu_pool->free_objs);
360                 percpu_pool->obj_free++;
361                 local_irq_restore(flags);
362                 return;
363         }
364
365         /*
366          * As the percpu pool is full, look ahead and pull out a batch
367          * of objects from the percpu pool and free them as well.
368          */
369         for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
370                 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
371                 if (!objs[lookahead_count])
372                         break;
373                 percpu_pool->obj_free--;
374         }
375
376 free_to_obj_pool:
377         raw_spin_lock(&pool_lock);
378         work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
379                (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
380         obj_pool_used--;
381
382         if (work) {
383                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
384                 hlist_add_head(&obj->node, &obj_to_free);
385                 if (lookahead_count) {
386                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
387                         obj_pool_used -= lookahead_count;
388                         while (lookahead_count) {
389                                 hlist_add_head(&objs[--lookahead_count]->node,
390                                                &obj_to_free);
391                         }
392                 }
393
394                 if ((obj_pool_free > debug_objects_pool_size) &&
395                     (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
396                         int i;
397
398                         /*
399                          * Free one more batch of objects from obj_pool.
400                          */
401                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
402                                 obj = __alloc_object(&obj_pool);
403                                 hlist_add_head(&obj->node, &obj_to_free);
404                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
405                                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
406                         }
407                 }
408         } else {
409                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
410                 hlist_add_head(&obj->node, &obj_pool);
411                 if (lookahead_count) {
412                         WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
413                         obj_pool_used -= lookahead_count;
414                         while (lookahead_count) {
415                                 hlist_add_head(&objs[--lookahead_count]->node,
416                                                &obj_pool);
417                         }
418                 }
419         }
420         raw_spin_unlock(&pool_lock);
421         local_irq_restore(flags);
422 }
423
424 /*
425  * Put the object back into the pool and schedule work to free objects
426  * if necessary.
427  */
428 static void free_object(struct debug_obj *obj)
429 {
430         __free_object(obj);
431         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
432                 WRITE_ONCE(obj_freeing, true);
433                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
434         }
435 }
436
437 #ifdef CONFIG_HOTPLUG_CPU
438 static int object_cpu_offline(unsigned int cpu)
439 {
440         struct debug_percpu_free *percpu_pool;
441         struct hlist_node *tmp;
442         struct debug_obj *obj;
443
444         /* Remote access is safe as the CPU is dead already */
445         percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
446         hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
447                 hlist_del(&obj->node);
448                 kmem_cache_free(obj_cache, obj);
449         }
450         percpu_pool->obj_free = 0;
451
452         return 0;
453 }
454 #endif
455
456 /*
457  * We run out of memory. That means we probably have tons of objects
458  * allocated.
459  */
460 static void debug_objects_oom(void)
461 {
462         struct debug_bucket *db = obj_hash;
463         struct hlist_node *tmp;
464         HLIST_HEAD(freelist);
465         struct debug_obj *obj;
466         unsigned long flags;
467         int i;
468
469         pr_warn("Out of memory. ODEBUG disabled\n");
470
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);
475
476                 /* Now free them */
477                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
478                         hlist_del(&obj->node);
479                         free_object(obj);
480                 }
481         }
482 }
483
484 /*
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.
487  */
488 static struct debug_bucket *get_bucket(unsigned long addr)
489 {
490         unsigned long hash;
491
492         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
493         return &obj_hash[hash];
494 }
495
496 static void debug_print_object(struct debug_obj *obj, char *msg)
497 {
498         const struct debug_obj_descr *descr = obj->descr;
499         static int limit;
500
501         if (limit < 5 && descr != descr_test) {
502                 void *hint = descr->debug_hint ?
503                         descr->debug_hint(obj->object) : NULL;
504                 limit++;
505                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
506                                  "object type: %s hint: %pS\n",
507                         msg, obj_states[obj->state], obj->astate,
508                         descr->name, hint);
509         }
510         debug_objects_warnings++;
511 }
512
513 /*
514  * Try to repair the damage, so we have a better chance to get useful
515  * debug output.
516  */
517 static bool
518 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
519                    void * addr, enum debug_obj_state state)
520 {
521         if (fixup && fixup(addr, state)) {
522                 debug_objects_fixups++;
523                 return true;
524         }
525         return false;
526 }
527
528 static void debug_object_is_on_stack(void *addr, int onstack)
529 {
530         int is_on_stack;
531         static int limit;
532
533         if (limit > 4)
534                 return;
535
536         is_on_stack = object_is_on_stack(addr);
537         if (is_on_stack == onstack)
538                 return;
539
540         limit++;
541         if (is_on_stack)
542                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
543                          task_stack_page(current));
544         else
545                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
546                          task_stack_page(current));
547
548         WARN_ON(1);
549 }
550
551 static void
552 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
553 {
554         enum debug_obj_state state;
555         bool check_stack = false;
556         struct debug_bucket *db;
557         struct debug_obj *obj;
558         unsigned long flags;
559
560         fill_pool();
561
562         db = get_bucket((unsigned long) addr);
563
564         raw_spin_lock_irqsave(&db->lock, flags);
565
566         obj = lookup_object(addr, db);
567         if (!obj) {
568                 obj = alloc_object(addr, db, descr);
569                 if (!obj) {
570                         debug_objects_enabled = 0;
571                         raw_spin_unlock_irqrestore(&db->lock, flags);
572                         debug_objects_oom();
573                         return;
574                 }
575                 check_stack = true;
576         }
577
578         switch (obj->state) {
579         case ODEBUG_STATE_NONE:
580         case ODEBUG_STATE_INIT:
581         case ODEBUG_STATE_INACTIVE:
582                 obj->state = ODEBUG_STATE_INIT;
583                 break;
584
585         case ODEBUG_STATE_ACTIVE:
586                 state = obj->state;
587                 raw_spin_unlock_irqrestore(&db->lock, flags);
588                 debug_print_object(obj, "init");
589                 debug_object_fixup(descr->fixup_init, addr, state);
590                 return;
591
592         case ODEBUG_STATE_DESTROYED:
593                 raw_spin_unlock_irqrestore(&db->lock, flags);
594                 debug_print_object(obj, "init");
595                 return;
596         default:
597                 break;
598         }
599
600         raw_spin_unlock_irqrestore(&db->lock, flags);
601         if (check_stack)
602                 debug_object_is_on_stack(addr, onstack);
603 }
604
605 /**
606  * debug_object_init - debug checks when an object is initialized
607  * @addr:       address of the object
608  * @descr:      pointer to an object specific debug description structure
609  */
610 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
611 {
612         if (!debug_objects_enabled)
613                 return;
614
615         __debug_object_init(addr, descr, 0);
616 }
617 EXPORT_SYMBOL_GPL(debug_object_init);
618
619 /**
620  * debug_object_init_on_stack - debug checks when an object on stack is
621  *                              initialized
622  * @addr:       address of the object
623  * @descr:      pointer to an object specific debug description structure
624  */
625 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
626 {
627         if (!debug_objects_enabled)
628                 return;
629
630         __debug_object_init(addr, descr, 1);
631 }
632 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
633
634 /**
635  * debug_object_activate - debug checks when an object is activated
636  * @addr:       address of the object
637  * @descr:      pointer to an object specific debug description structure
638  * Returns 0 for success, -EINVAL for check failed.
639  */
640 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
641 {
642         enum debug_obj_state state;
643         struct debug_bucket *db;
644         struct debug_obj *obj;
645         unsigned long flags;
646         int ret;
647         struct debug_obj o = { .object = addr,
648                                .state = ODEBUG_STATE_NOTAVAILABLE,
649                                .descr = descr };
650
651         if (!debug_objects_enabled)
652                 return 0;
653
654         db = get_bucket((unsigned long) addr);
655
656         raw_spin_lock_irqsave(&db->lock, flags);
657
658         obj = lookup_object(addr, db);
659         if (obj) {
660                 bool print_object = false;
661
662                 switch (obj->state) {
663                 case ODEBUG_STATE_INIT:
664                 case ODEBUG_STATE_INACTIVE:
665                         obj->state = ODEBUG_STATE_ACTIVE;
666                         ret = 0;
667                         break;
668
669                 case ODEBUG_STATE_ACTIVE:
670                         state = obj->state;
671                         raw_spin_unlock_irqrestore(&db->lock, flags);
672                         debug_print_object(obj, "activate");
673                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
674                         return ret ? 0 : -EINVAL;
675
676                 case ODEBUG_STATE_DESTROYED:
677                         print_object = true;
678                         ret = -EINVAL;
679                         break;
680                 default:
681                         ret = 0;
682                         break;
683                 }
684                 raw_spin_unlock_irqrestore(&db->lock, flags);
685                 if (print_object)
686                         debug_print_object(obj, "activate");
687                 return ret;
688         }
689
690         raw_spin_unlock_irqrestore(&db->lock, flags);
691
692         /*
693          * We are here when a static object is activated. We
694          * let the type specific code confirm whether this is
695          * true or not. if true, we just make sure that the
696          * static object is tracked in the object tracker. If
697          * not, this must be a bug, so we try to fix it up.
698          */
699         if (descr->is_static_object && descr->is_static_object(addr)) {
700                 /* track this static object */
701                 debug_object_init(addr, descr);
702                 debug_object_activate(addr, descr);
703         } else {
704                 debug_print_object(&o, "activate");
705                 ret = debug_object_fixup(descr->fixup_activate, addr,
706                                         ODEBUG_STATE_NOTAVAILABLE);
707                 return ret ? 0 : -EINVAL;
708         }
709         return 0;
710 }
711 EXPORT_SYMBOL_GPL(debug_object_activate);
712
713 /**
714  * debug_object_deactivate - debug checks when an object is deactivated
715  * @addr:       address of the object
716  * @descr:      pointer to an object specific debug description structure
717  */
718 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
719 {
720         struct debug_bucket *db;
721         struct debug_obj *obj;
722         unsigned long flags;
723         bool print_object = false;
724
725         if (!debug_objects_enabled)
726                 return;
727
728         db = get_bucket((unsigned long) addr);
729
730         raw_spin_lock_irqsave(&db->lock, flags);
731
732         obj = lookup_object(addr, db);
733         if (obj) {
734                 switch (obj->state) {
735                 case ODEBUG_STATE_INIT:
736                 case ODEBUG_STATE_INACTIVE:
737                 case ODEBUG_STATE_ACTIVE:
738                         if (!obj->astate)
739                                 obj->state = ODEBUG_STATE_INACTIVE;
740                         else
741                                 print_object = true;
742                         break;
743
744                 case ODEBUG_STATE_DESTROYED:
745                         print_object = true;
746                         break;
747                 default:
748                         break;
749                 }
750         }
751
752         raw_spin_unlock_irqrestore(&db->lock, flags);
753         if (!obj) {
754                 struct debug_obj o = { .object = addr,
755                                        .state = ODEBUG_STATE_NOTAVAILABLE,
756                                        .descr = descr };
757
758                 debug_print_object(&o, "deactivate");
759         } else if (print_object) {
760                 debug_print_object(obj, "deactivate");
761         }
762 }
763 EXPORT_SYMBOL_GPL(debug_object_deactivate);
764
765 /**
766  * debug_object_destroy - debug checks when an object is destroyed
767  * @addr:       address of the object
768  * @descr:      pointer to an object specific debug description structure
769  */
770 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
771 {
772         enum debug_obj_state state;
773         struct debug_bucket *db;
774         struct debug_obj *obj;
775         unsigned long flags;
776         bool print_object = false;
777
778         if (!debug_objects_enabled)
779                 return;
780
781         db = get_bucket((unsigned long) addr);
782
783         raw_spin_lock_irqsave(&db->lock, flags);
784
785         obj = lookup_object(addr, db);
786         if (!obj)
787                 goto out_unlock;
788
789         switch (obj->state) {
790         case ODEBUG_STATE_NONE:
791         case ODEBUG_STATE_INIT:
792         case ODEBUG_STATE_INACTIVE:
793                 obj->state = ODEBUG_STATE_DESTROYED;
794                 break;
795         case ODEBUG_STATE_ACTIVE:
796                 state = obj->state;
797                 raw_spin_unlock_irqrestore(&db->lock, flags);
798                 debug_print_object(obj, "destroy");
799                 debug_object_fixup(descr->fixup_destroy, addr, state);
800                 return;
801
802         case ODEBUG_STATE_DESTROYED:
803                 print_object = true;
804                 break;
805         default:
806                 break;
807         }
808 out_unlock:
809         raw_spin_unlock_irqrestore(&db->lock, flags);
810         if (print_object)
811                 debug_print_object(obj, "destroy");
812 }
813 EXPORT_SYMBOL_GPL(debug_object_destroy);
814
815 /**
816  * debug_object_free - debug checks when an object is freed
817  * @addr:       address of the object
818  * @descr:      pointer to an object specific debug description structure
819  */
820 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
821 {
822         enum debug_obj_state state;
823         struct debug_bucket *db;
824         struct debug_obj *obj;
825         unsigned long flags;
826
827         if (!debug_objects_enabled)
828                 return;
829
830         db = get_bucket((unsigned long) addr);
831
832         raw_spin_lock_irqsave(&db->lock, flags);
833
834         obj = lookup_object(addr, db);
835         if (!obj)
836                 goto out_unlock;
837
838         switch (obj->state) {
839         case ODEBUG_STATE_ACTIVE:
840                 state = obj->state;
841                 raw_spin_unlock_irqrestore(&db->lock, flags);
842                 debug_print_object(obj, "free");
843                 debug_object_fixup(descr->fixup_free, addr, state);
844                 return;
845         default:
846                 hlist_del(&obj->node);
847                 raw_spin_unlock_irqrestore(&db->lock, flags);
848                 free_object(obj);
849                 return;
850         }
851 out_unlock:
852         raw_spin_unlock_irqrestore(&db->lock, flags);
853 }
854 EXPORT_SYMBOL_GPL(debug_object_free);
855
856 /**
857  * debug_object_assert_init - debug checks when object should be init-ed
858  * @addr:       address of the object
859  * @descr:      pointer to an object specific debug description structure
860  */
861 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
862 {
863         struct debug_bucket *db;
864         struct debug_obj *obj;
865         unsigned long flags;
866
867         if (!debug_objects_enabled)
868                 return;
869
870         db = get_bucket((unsigned long) addr);
871
872         raw_spin_lock_irqsave(&db->lock, flags);
873
874         obj = lookup_object(addr, db);
875         if (!obj) {
876                 struct debug_obj o = { .object = addr,
877                                        .state = ODEBUG_STATE_NOTAVAILABLE,
878                                        .descr = descr };
879
880                 raw_spin_unlock_irqrestore(&db->lock, flags);
881                 /*
882                  * Maybe the object is static, and we let the type specific
883                  * code confirm. Track this static object if true, else invoke
884                  * fixup.
885                  */
886                 if (descr->is_static_object && descr->is_static_object(addr)) {
887                         /* Track this static object */
888                         debug_object_init(addr, descr);
889                 } else {
890                         debug_print_object(&o, "assert_init");
891                         debug_object_fixup(descr->fixup_assert_init, addr,
892                                            ODEBUG_STATE_NOTAVAILABLE);
893                 }
894                 return;
895         }
896
897         raw_spin_unlock_irqrestore(&db->lock, flags);
898 }
899 EXPORT_SYMBOL_GPL(debug_object_assert_init);
900
901 /**
902  * debug_object_active_state - debug checks object usage state machine
903  * @addr:       address of the object
904  * @descr:      pointer to an object specific debug description structure
905  * @expect:     expected state
906  * @next:       state to move to if expected state is found
907  */
908 void
909 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
910                           unsigned int expect, unsigned int next)
911 {
912         struct debug_bucket *db;
913         struct debug_obj *obj;
914         unsigned long flags;
915         bool print_object = false;
916
917         if (!debug_objects_enabled)
918                 return;
919
920         db = get_bucket((unsigned long) addr);
921
922         raw_spin_lock_irqsave(&db->lock, flags);
923
924         obj = lookup_object(addr, db);
925         if (obj) {
926                 switch (obj->state) {
927                 case ODEBUG_STATE_ACTIVE:
928                         if (obj->astate == expect)
929                                 obj->astate = next;
930                         else
931                                 print_object = true;
932                         break;
933
934                 default:
935                         print_object = true;
936                         break;
937                 }
938         }
939
940         raw_spin_unlock_irqrestore(&db->lock, flags);
941         if (!obj) {
942                 struct debug_obj o = { .object = addr,
943                                        .state = ODEBUG_STATE_NOTAVAILABLE,
944                                        .descr = descr };
945
946                 debug_print_object(&o, "active_state");
947         } else if (print_object) {
948                 debug_print_object(obj, "active_state");
949         }
950 }
951 EXPORT_SYMBOL_GPL(debug_object_active_state);
952
953 #ifdef CONFIG_DEBUG_OBJECTS_FREE
954 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
955 {
956         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
957         const struct debug_obj_descr *descr;
958         enum debug_obj_state state;
959         struct debug_bucket *db;
960         struct hlist_node *tmp;
961         struct debug_obj *obj;
962         int cnt, objs_checked = 0;
963
964         saddr = (unsigned long) address;
965         eaddr = saddr + size;
966         paddr = saddr & ODEBUG_CHUNK_MASK;
967         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
968         chunks >>= ODEBUG_CHUNK_SHIFT;
969
970         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
971                 db = get_bucket(paddr);
972
973 repeat:
974                 cnt = 0;
975                 raw_spin_lock_irqsave(&db->lock, flags);
976                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
977                         cnt++;
978                         oaddr = (unsigned long) obj->object;
979                         if (oaddr < saddr || oaddr >= eaddr)
980                                 continue;
981
982                         switch (obj->state) {
983                         case ODEBUG_STATE_ACTIVE:
984                                 descr = obj->descr;
985                                 state = obj->state;
986                                 raw_spin_unlock_irqrestore(&db->lock, flags);
987                                 debug_print_object(obj, "free");
988                                 debug_object_fixup(descr->fixup_free,
989                                                    (void *) oaddr, state);
990                                 goto repeat;
991                         default:
992                                 hlist_del(&obj->node);
993                                 __free_object(obj);
994                                 break;
995                         }
996                 }
997                 raw_spin_unlock_irqrestore(&db->lock, flags);
998
999                 if (cnt > debug_objects_maxchain)
1000                         debug_objects_maxchain = cnt;
1001
1002                 objs_checked += cnt;
1003         }
1004
1005         if (objs_checked > debug_objects_maxchecked)
1006                 debug_objects_maxchecked = objs_checked;
1007
1008         /* Schedule work to actually kmem_cache_free() objects */
1009         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1010                 WRITE_ONCE(obj_freeing, true);
1011                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1012         }
1013 }
1014
1015 void debug_check_no_obj_freed(const void *address, unsigned long size)
1016 {
1017         if (debug_objects_enabled)
1018                 __debug_check_no_obj_freed(address, size);
1019 }
1020 #endif
1021
1022 #ifdef CONFIG_DEBUG_FS
1023
1024 static int debug_stats_show(struct seq_file *m, void *v)
1025 {
1026         int cpu, obj_percpu_free = 0;
1027
1028         for_each_possible_cpu(cpu)
1029                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1030
1031         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1032         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1033         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1034         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1035         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1036         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1037         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1038         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1039         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1040         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1041         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1042         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1043         return 0;
1044 }
1045 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1046
1047 static int __init debug_objects_init_debugfs(void)
1048 {
1049         struct dentry *dbgdir;
1050
1051         if (!debug_objects_enabled)
1052                 return 0;
1053
1054         dbgdir = debugfs_create_dir("debug_objects", NULL);
1055
1056         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1057
1058         return 0;
1059 }
1060 __initcall(debug_objects_init_debugfs);
1061
1062 #else
1063 static inline void debug_objects_init_debugfs(void) { }
1064 #endif
1065
1066 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1067
1068 /* Random data structure for the self test */
1069 struct self_test {
1070         unsigned long   dummy1[6];
1071         int             static_init;
1072         unsigned long   dummy2[3];
1073 };
1074
1075 static __initconst const struct debug_obj_descr descr_type_test;
1076
1077 static bool __init is_static_object(void *addr)
1078 {
1079         struct self_test *obj = addr;
1080
1081         return obj->static_init;
1082 }
1083
1084 /*
1085  * fixup_init is called when:
1086  * - an active object is initialized
1087  */
1088 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1089 {
1090         struct self_test *obj = addr;
1091
1092         switch (state) {
1093         case ODEBUG_STATE_ACTIVE:
1094                 debug_object_deactivate(obj, &descr_type_test);
1095                 debug_object_init(obj, &descr_type_test);
1096                 return true;
1097         default:
1098                 return false;
1099         }
1100 }
1101
1102 /*
1103  * fixup_activate is called when:
1104  * - an active object is activated
1105  * - an unknown non-static object is activated
1106  */
1107 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1108 {
1109         struct self_test *obj = addr;
1110
1111         switch (state) {
1112         case ODEBUG_STATE_NOTAVAILABLE:
1113                 return true;
1114         case ODEBUG_STATE_ACTIVE:
1115                 debug_object_deactivate(obj, &descr_type_test);
1116                 debug_object_activate(obj, &descr_type_test);
1117                 return true;
1118
1119         default:
1120                 return false;
1121         }
1122 }
1123
1124 /*
1125  * fixup_destroy is called when:
1126  * - an active object is destroyed
1127  */
1128 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1129 {
1130         struct self_test *obj = addr;
1131
1132         switch (state) {
1133         case ODEBUG_STATE_ACTIVE:
1134                 debug_object_deactivate(obj, &descr_type_test);
1135                 debug_object_destroy(obj, &descr_type_test);
1136                 return true;
1137         default:
1138                 return false;
1139         }
1140 }
1141
1142 /*
1143  * fixup_free is called when:
1144  * - an active object is freed
1145  */
1146 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1147 {
1148         struct self_test *obj = addr;
1149
1150         switch (state) {
1151         case ODEBUG_STATE_ACTIVE:
1152                 debug_object_deactivate(obj, &descr_type_test);
1153                 debug_object_free(obj, &descr_type_test);
1154                 return true;
1155         default:
1156                 return false;
1157         }
1158 }
1159
1160 static int __init
1161 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1162 {
1163         struct debug_bucket *db;
1164         struct debug_obj *obj;
1165         unsigned long flags;
1166         int res = -EINVAL;
1167
1168         db = get_bucket((unsigned long) addr);
1169
1170         raw_spin_lock_irqsave(&db->lock, flags);
1171
1172         obj = lookup_object(addr, db);
1173         if (!obj && state != ODEBUG_STATE_NONE) {
1174                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1175                 goto out;
1176         }
1177         if (obj && obj->state != state) {
1178                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1179                        obj->state, state);
1180                 goto out;
1181         }
1182         if (fixups != debug_objects_fixups) {
1183                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1184                        fixups, debug_objects_fixups);
1185                 goto out;
1186         }
1187         if (warnings != debug_objects_warnings) {
1188                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1189                        warnings, debug_objects_warnings);
1190                 goto out;
1191         }
1192         res = 0;
1193 out:
1194         raw_spin_unlock_irqrestore(&db->lock, flags);
1195         if (res)
1196                 debug_objects_enabled = 0;
1197         return res;
1198 }
1199
1200 static __initconst const struct debug_obj_descr descr_type_test = {
1201         .name                   = "selftest",
1202         .is_static_object       = is_static_object,
1203         .fixup_init             = fixup_init,
1204         .fixup_activate         = fixup_activate,
1205         .fixup_destroy          = fixup_destroy,
1206         .fixup_free             = fixup_free,
1207 };
1208
1209 static __initdata struct self_test obj = { .static_init = 0 };
1210
1211 static void __init debug_objects_selftest(void)
1212 {
1213         int fixups, oldfixups, warnings, oldwarnings;
1214         unsigned long flags;
1215
1216         local_irq_save(flags);
1217
1218         fixups = oldfixups = debug_objects_fixups;
1219         warnings = oldwarnings = debug_objects_warnings;
1220         descr_test = &descr_type_test;
1221
1222         debug_object_init(&obj, &descr_type_test);
1223         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1224                 goto out;
1225         debug_object_activate(&obj, &descr_type_test);
1226         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1227                 goto out;
1228         debug_object_activate(&obj, &descr_type_test);
1229         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1230                 goto out;
1231         debug_object_deactivate(&obj, &descr_type_test);
1232         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1233                 goto out;
1234         debug_object_destroy(&obj, &descr_type_test);
1235         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1236                 goto out;
1237         debug_object_init(&obj, &descr_type_test);
1238         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1239                 goto out;
1240         debug_object_activate(&obj, &descr_type_test);
1241         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1242                 goto out;
1243         debug_object_deactivate(&obj, &descr_type_test);
1244         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1245                 goto out;
1246         debug_object_free(&obj, &descr_type_test);
1247         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1248                 goto out;
1249
1250         obj.static_init = 1;
1251         debug_object_activate(&obj, &descr_type_test);
1252         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1253                 goto out;
1254         debug_object_init(&obj, &descr_type_test);
1255         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1256                 goto out;
1257         debug_object_free(&obj, &descr_type_test);
1258         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1259                 goto out;
1260
1261 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1262         debug_object_init(&obj, &descr_type_test);
1263         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1264                 goto out;
1265         debug_object_activate(&obj, &descr_type_test);
1266         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1267                 goto out;
1268         __debug_check_no_obj_freed(&obj, sizeof(obj));
1269         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1270                 goto out;
1271 #endif
1272         pr_info("selftest passed\n");
1273
1274 out:
1275         debug_objects_fixups = oldfixups;
1276         debug_objects_warnings = oldwarnings;
1277         descr_test = NULL;
1278
1279         local_irq_restore(flags);
1280 }
1281 #else
1282 static inline void debug_objects_selftest(void) { }
1283 #endif
1284
1285 /*
1286  * Called during early boot to initialize the hash buckets and link
1287  * the static object pool objects into the poll list. After this call
1288  * the object tracker is fully operational.
1289  */
1290 void __init debug_objects_early_init(void)
1291 {
1292         int i;
1293
1294         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1295                 raw_spin_lock_init(&obj_hash[i].lock);
1296
1297         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1298                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1299 }
1300
1301 /*
1302  * Convert the statically allocated objects to dynamic ones:
1303  */
1304 static int __init debug_objects_replace_static_objects(void)
1305 {
1306         struct debug_bucket *db = obj_hash;
1307         struct hlist_node *tmp;
1308         struct debug_obj *obj, *new;
1309         HLIST_HEAD(objects);
1310         int i, cnt = 0;
1311
1312         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1313                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1314                 if (!obj)
1315                         goto free;
1316                 hlist_add_head(&obj->node, &objects);
1317         }
1318
1319         /*
1320          * debug_objects_mem_init() is now called early that only one CPU is up
1321          * and interrupts have been disabled, so it is safe to replace the
1322          * active object references.
1323          */
1324
1325         /* Remove the statically allocated objects from the pool */
1326         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1327                 hlist_del(&obj->node);
1328         /* Move the allocated objects to the pool */
1329         hlist_move_list(&objects, &obj_pool);
1330
1331         /* Replace the active object references */
1332         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1333                 hlist_move_list(&db->list, &objects);
1334
1335                 hlist_for_each_entry(obj, &objects, node) {
1336                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1337                         hlist_del(&new->node);
1338                         /* copy object data */
1339                         *new = *obj;
1340                         hlist_add_head(&new->node, &db->list);
1341                         cnt++;
1342                 }
1343         }
1344
1345         pr_debug("%d of %d active objects replaced\n",
1346                  cnt, obj_pool_used);
1347         return 0;
1348 free:
1349         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1350                 hlist_del(&obj->node);
1351                 kmem_cache_free(obj_cache, obj);
1352         }
1353         return -ENOMEM;
1354 }
1355
1356 /*
1357  * Called after the kmem_caches are functional to setup a dedicated
1358  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1359  * prevents that the debug code is called on kmem_cache_free() for the
1360  * debug tracker objects to avoid recursive calls.
1361  */
1362 void __init debug_objects_mem_init(void)
1363 {
1364         int cpu, extras;
1365
1366         if (!debug_objects_enabled)
1367                 return;
1368
1369         /*
1370          * Initialize the percpu object pools
1371          *
1372          * Initialization is not strictly necessary, but was done for
1373          * completeness.
1374          */
1375         for_each_possible_cpu(cpu)
1376                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1377
1378         obj_cache = kmem_cache_create("debug_objects_cache",
1379                                       sizeof (struct debug_obj), 0,
1380                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1381                                       NULL);
1382
1383         if (!obj_cache || debug_objects_replace_static_objects()) {
1384                 debug_objects_enabled = 0;
1385                 kmem_cache_destroy(obj_cache);
1386                 pr_warn("out of memory.\n");
1387         } else
1388                 debug_objects_selftest();
1389
1390 #ifdef CONFIG_HOTPLUG_CPU
1391         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1392                                         object_cpu_offline);
1393 #endif
1394
1395         /*
1396          * Increase the thresholds for allocating and freeing objects
1397          * according to the number of possible CPUs available in the system.
1398          */
1399         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1400         debug_objects_pool_size += extras;
1401         debug_objects_pool_min_level += extras;
1402 }