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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
22 #define ODEBUG_HASH_BITS        14
23 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
24
25 #define ODEBUG_POOL_SIZE        1024
26 #define ODEBUG_POOL_MIN_LEVEL   256
27
28 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
29 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
30 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
31
32 struct debug_bucket {
33         struct hlist_head       list;
34         raw_spinlock_t          lock;
35 };
36
37 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
38
39 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
40
41 static DEFINE_RAW_SPINLOCK(pool_lock);
42
43 static HLIST_HEAD(obj_pool);
44
45 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
46 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
47 static int                      obj_pool_used;
48 static int                      obj_pool_max_used;
49 static struct kmem_cache        *obj_cache;
50
51 static int                      debug_objects_maxchain __read_mostly;
52 static int                      debug_objects_fixups __read_mostly;
53 static int                      debug_objects_warnings __read_mostly;
54 static int                      debug_objects_enabled __read_mostly
55                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
56 static int                      debug_objects_pool_size __read_mostly
57                                 = ODEBUG_POOL_SIZE;
58 static int                      debug_objects_pool_min_level __read_mostly
59                                 = ODEBUG_POOL_MIN_LEVEL;
60 static struct debug_obj_descr   *descr_test  __read_mostly;
61
62 /*
63  * Track numbers of kmem_cache_alloc()/free() calls done.
64  */
65 static int                      debug_objects_allocated;
66 static int                      debug_objects_freed;
67
68 static void free_obj_work(struct work_struct *work);
69 static DECLARE_WORK(debug_obj_work, free_obj_work);
70
71 static int __init enable_object_debug(char *str)
72 {
73         debug_objects_enabled = 1;
74         return 0;
75 }
76
77 static int __init disable_object_debug(char *str)
78 {
79         debug_objects_enabled = 0;
80         return 0;
81 }
82
83 early_param("debug_objects", enable_object_debug);
84 early_param("no_debug_objects", disable_object_debug);
85
86 static const char *obj_states[ODEBUG_STATE_MAX] = {
87         [ODEBUG_STATE_NONE]             = "none",
88         [ODEBUG_STATE_INIT]             = "initialized",
89         [ODEBUG_STATE_INACTIVE]         = "inactive",
90         [ODEBUG_STATE_ACTIVE]           = "active",
91         [ODEBUG_STATE_DESTROYED]        = "destroyed",
92         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
93 };
94
95 static void fill_pool(void)
96 {
97         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
98         struct debug_obj *new;
99         unsigned long flags;
100
101         if (likely(obj_pool_free >= debug_objects_pool_min_level))
102                 return;
103
104         if (unlikely(!obj_cache))
105                 return;
106
107         while (obj_pool_free < debug_objects_pool_min_level) {
108
109                 new = kmem_cache_zalloc(obj_cache, gfp);
110                 if (!new)
111                         return;
112
113                 raw_spin_lock_irqsave(&pool_lock, flags);
114                 hlist_add_head(&new->node, &obj_pool);
115                 debug_objects_allocated++;
116                 obj_pool_free++;
117                 raw_spin_unlock_irqrestore(&pool_lock, flags);
118         }
119 }
120
121 /*
122  * Lookup an object in the hash bucket.
123  */
124 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
125 {
126         struct debug_obj *obj;
127         int cnt = 0;
128
129         hlist_for_each_entry(obj, &b->list, node) {
130                 cnt++;
131                 if (obj->object == addr)
132                         return obj;
133         }
134         if (cnt > debug_objects_maxchain)
135                 debug_objects_maxchain = cnt;
136
137         return NULL;
138 }
139
140 /*
141  * Allocate a new object. If the pool is empty, switch off the debugger.
142  * Must be called with interrupts disabled.
143  */
144 static struct debug_obj *
145 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
146 {
147         struct debug_obj *obj = NULL;
148
149         raw_spin_lock(&pool_lock);
150         if (obj_pool.first) {
151                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
152
153                 obj->object = addr;
154                 obj->descr  = descr;
155                 obj->state  = ODEBUG_STATE_NONE;
156                 obj->astate = 0;
157                 hlist_del(&obj->node);
158
159                 hlist_add_head(&obj->node, &b->list);
160
161                 obj_pool_used++;
162                 if (obj_pool_used > obj_pool_max_used)
163                         obj_pool_max_used = obj_pool_used;
164
165                 obj_pool_free--;
166                 if (obj_pool_free < obj_pool_min_free)
167                         obj_pool_min_free = obj_pool_free;
168         }
169         raw_spin_unlock(&pool_lock);
170
171         return obj;
172 }
173
174 /*
175  * workqueue function to free objects.
176  *
177  * To reduce contention on the global pool_lock, the actual freeing of
178  * debug objects will be delayed if the pool_lock is busy. We also free
179  * the objects in a batch of 4 for each lock/unlock cycle.
180  */
181 #define ODEBUG_FREE_BATCH       4
182
183 static void free_obj_work(struct work_struct *work)
184 {
185         struct debug_obj *objs[ODEBUG_FREE_BATCH];
186         unsigned long flags;
187         int i;
188
189         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
190                 return;
191         while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
192                 for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
193                         objs[i] = hlist_entry(obj_pool.first,
194                                               typeof(*objs[0]), node);
195                         hlist_del(&objs[i]->node);
196                 }
197
198                 obj_pool_free -= ODEBUG_FREE_BATCH;
199                 debug_objects_freed += ODEBUG_FREE_BATCH;
200                 /*
201                  * We release pool_lock across kmem_cache_free() to
202                  * avoid contention on pool_lock.
203                  */
204                 raw_spin_unlock_irqrestore(&pool_lock, flags);
205                 for (i = 0; i < ODEBUG_FREE_BATCH; i++)
206                         kmem_cache_free(obj_cache, objs[i]);
207                 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
208                         return;
209         }
210         raw_spin_unlock_irqrestore(&pool_lock, flags);
211 }
212
213 /*
214  * Put the object back into the pool and schedule work to free objects
215  * if necessary.
216  */
217 static void free_object(struct debug_obj *obj)
218 {
219         unsigned long flags;
220         int sched = 0;
221
222         raw_spin_lock_irqsave(&pool_lock, flags);
223         /*
224          * schedule work when the pool is filled and the cache is
225          * initialized:
226          */
227         if (obj_pool_free > debug_objects_pool_size && obj_cache)
228                 sched = 1;
229         hlist_add_head(&obj->node, &obj_pool);
230         obj_pool_free++;
231         obj_pool_used--;
232         raw_spin_unlock_irqrestore(&pool_lock, flags);
233         if (sched)
234                 schedule_work(&debug_obj_work);
235 }
236
237 /*
238  * We run out of memory. That means we probably have tons of objects
239  * allocated.
240  */
241 static void debug_objects_oom(void)
242 {
243         struct debug_bucket *db = obj_hash;
244         struct hlist_node *tmp;
245         HLIST_HEAD(freelist);
246         struct debug_obj *obj;
247         unsigned long flags;
248         int i;
249
250         pr_warn("Out of memory. ODEBUG disabled\n");
251
252         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
253                 raw_spin_lock_irqsave(&db->lock, flags);
254                 hlist_move_list(&db->list, &freelist);
255                 raw_spin_unlock_irqrestore(&db->lock, flags);
256
257                 /* Now free them */
258                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
259                         hlist_del(&obj->node);
260                         free_object(obj);
261                 }
262         }
263 }
264
265 /*
266  * We use the pfn of the address for the hash. That way we can check
267  * for freed objects simply by checking the affected bucket.
268  */
269 static struct debug_bucket *get_bucket(unsigned long addr)
270 {
271         unsigned long hash;
272
273         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
274         return &obj_hash[hash];
275 }
276
277 static void debug_print_object(struct debug_obj *obj, char *msg)
278 {
279         struct debug_obj_descr *descr = obj->descr;
280         static int limit;
281
282         if (limit < 5 && descr != descr_test) {
283                 void *hint = descr->debug_hint ?
284                         descr->debug_hint(obj->object) : NULL;
285                 limit++;
286                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
287                                  "object type: %s hint: %pS\n",
288                         msg, obj_states[obj->state], obj->astate,
289                         descr->name, hint);
290         }
291         debug_objects_warnings++;
292 }
293
294 /*
295  * Try to repair the damage, so we have a better chance to get useful
296  * debug output.
297  */
298 static bool
299 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
300                    void * addr, enum debug_obj_state state)
301 {
302         if (fixup && fixup(addr, state)) {
303                 debug_objects_fixups++;
304                 return true;
305         }
306         return false;
307 }
308
309 static void debug_object_is_on_stack(void *addr, int onstack)
310 {
311         int is_on_stack;
312         static int limit;
313
314         if (limit > 4)
315                 return;
316
317         is_on_stack = object_is_on_stack(addr);
318         if (is_on_stack == onstack)
319                 return;
320
321         limit++;
322         if (is_on_stack)
323                 pr_warn("object is on stack, but not annotated\n");
324         else
325                 pr_warn("object is not on stack, but annotated\n");
326         WARN_ON(1);
327 }
328
329 static void
330 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
331 {
332         enum debug_obj_state state;
333         struct debug_bucket *db;
334         struct debug_obj *obj;
335         unsigned long flags;
336
337         fill_pool();
338
339         db = get_bucket((unsigned long) addr);
340
341         raw_spin_lock_irqsave(&db->lock, flags);
342
343         obj = lookup_object(addr, db);
344         if (!obj) {
345                 obj = alloc_object(addr, db, descr);
346                 if (!obj) {
347                         debug_objects_enabled = 0;
348                         raw_spin_unlock_irqrestore(&db->lock, flags);
349                         debug_objects_oom();
350                         return;
351                 }
352                 debug_object_is_on_stack(addr, onstack);
353         }
354
355         switch (obj->state) {
356         case ODEBUG_STATE_NONE:
357         case ODEBUG_STATE_INIT:
358         case ODEBUG_STATE_INACTIVE:
359                 obj->state = ODEBUG_STATE_INIT;
360                 break;
361
362         case ODEBUG_STATE_ACTIVE:
363                 debug_print_object(obj, "init");
364                 state = obj->state;
365                 raw_spin_unlock_irqrestore(&db->lock, flags);
366                 debug_object_fixup(descr->fixup_init, addr, state);
367                 return;
368
369         case ODEBUG_STATE_DESTROYED:
370                 debug_print_object(obj, "init");
371                 break;
372         default:
373                 break;
374         }
375
376         raw_spin_unlock_irqrestore(&db->lock, flags);
377 }
378
379 /**
380  * debug_object_init - debug checks when an object is initialized
381  * @addr:       address of the object
382  * @descr:      pointer to an object specific debug description structure
383  */
384 void debug_object_init(void *addr, struct debug_obj_descr *descr)
385 {
386         if (!debug_objects_enabled)
387                 return;
388
389         __debug_object_init(addr, descr, 0);
390 }
391 EXPORT_SYMBOL_GPL(debug_object_init);
392
393 /**
394  * debug_object_init_on_stack - debug checks when an object on stack is
395  *                              initialized
396  * @addr:       address of the object
397  * @descr:      pointer to an object specific debug description structure
398  */
399 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
400 {
401         if (!debug_objects_enabled)
402                 return;
403
404         __debug_object_init(addr, descr, 1);
405 }
406 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
407
408 /**
409  * debug_object_activate - debug checks when an object is activated
410  * @addr:       address of the object
411  * @descr:      pointer to an object specific debug description structure
412  * Returns 0 for success, -EINVAL for check failed.
413  */
414 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
415 {
416         enum debug_obj_state state;
417         struct debug_bucket *db;
418         struct debug_obj *obj;
419         unsigned long flags;
420         int ret;
421         struct debug_obj o = { .object = addr,
422                                .state = ODEBUG_STATE_NOTAVAILABLE,
423                                .descr = descr };
424
425         if (!debug_objects_enabled)
426                 return 0;
427
428         db = get_bucket((unsigned long) addr);
429
430         raw_spin_lock_irqsave(&db->lock, flags);
431
432         obj = lookup_object(addr, db);
433         if (obj) {
434                 switch (obj->state) {
435                 case ODEBUG_STATE_INIT:
436                 case ODEBUG_STATE_INACTIVE:
437                         obj->state = ODEBUG_STATE_ACTIVE;
438                         ret = 0;
439                         break;
440
441                 case ODEBUG_STATE_ACTIVE:
442                         debug_print_object(obj, "activate");
443                         state = obj->state;
444                         raw_spin_unlock_irqrestore(&db->lock, flags);
445                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
446                         return ret ? 0 : -EINVAL;
447
448                 case ODEBUG_STATE_DESTROYED:
449                         debug_print_object(obj, "activate");
450                         ret = -EINVAL;
451                         break;
452                 default:
453                         ret = 0;
454                         break;
455                 }
456                 raw_spin_unlock_irqrestore(&db->lock, flags);
457                 return ret;
458         }
459
460         raw_spin_unlock_irqrestore(&db->lock, flags);
461         /*
462          * We are here when a static object is activated. We
463          * let the type specific code confirm whether this is
464          * true or not. if true, we just make sure that the
465          * static object is tracked in the object tracker. If
466          * not, this must be a bug, so we try to fix it up.
467          */
468         if (descr->is_static_object && descr->is_static_object(addr)) {
469                 /* track this static object */
470                 debug_object_init(addr, descr);
471                 debug_object_activate(addr, descr);
472         } else {
473                 debug_print_object(&o, "activate");
474                 ret = debug_object_fixup(descr->fixup_activate, addr,
475                                         ODEBUG_STATE_NOTAVAILABLE);
476                 return ret ? 0 : -EINVAL;
477         }
478         return 0;
479 }
480 EXPORT_SYMBOL_GPL(debug_object_activate);
481
482 /**
483  * debug_object_deactivate - debug checks when an object is deactivated
484  * @addr:       address of the object
485  * @descr:      pointer to an object specific debug description structure
486  */
487 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
488 {
489         struct debug_bucket *db;
490         struct debug_obj *obj;
491         unsigned long flags;
492
493         if (!debug_objects_enabled)
494                 return;
495
496         db = get_bucket((unsigned long) addr);
497
498         raw_spin_lock_irqsave(&db->lock, flags);
499
500         obj = lookup_object(addr, db);
501         if (obj) {
502                 switch (obj->state) {
503                 case ODEBUG_STATE_INIT:
504                 case ODEBUG_STATE_INACTIVE:
505                 case ODEBUG_STATE_ACTIVE:
506                         if (!obj->astate)
507                                 obj->state = ODEBUG_STATE_INACTIVE;
508                         else
509                                 debug_print_object(obj, "deactivate");
510                         break;
511
512                 case ODEBUG_STATE_DESTROYED:
513                         debug_print_object(obj, "deactivate");
514                         break;
515                 default:
516                         break;
517                 }
518         } else {
519                 struct debug_obj o = { .object = addr,
520                                        .state = ODEBUG_STATE_NOTAVAILABLE,
521                                        .descr = descr };
522
523                 debug_print_object(&o, "deactivate");
524         }
525
526         raw_spin_unlock_irqrestore(&db->lock, flags);
527 }
528 EXPORT_SYMBOL_GPL(debug_object_deactivate);
529
530 /**
531  * debug_object_destroy - debug checks when an object is destroyed
532  * @addr:       address of the object
533  * @descr:      pointer to an object specific debug description structure
534  */
535 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
536 {
537         enum debug_obj_state state;
538         struct debug_bucket *db;
539         struct debug_obj *obj;
540         unsigned long flags;
541
542         if (!debug_objects_enabled)
543                 return;
544
545         db = get_bucket((unsigned long) addr);
546
547         raw_spin_lock_irqsave(&db->lock, flags);
548
549         obj = lookup_object(addr, db);
550         if (!obj)
551                 goto out_unlock;
552
553         switch (obj->state) {
554         case ODEBUG_STATE_NONE:
555         case ODEBUG_STATE_INIT:
556         case ODEBUG_STATE_INACTIVE:
557                 obj->state = ODEBUG_STATE_DESTROYED;
558                 break;
559         case ODEBUG_STATE_ACTIVE:
560                 debug_print_object(obj, "destroy");
561                 state = obj->state;
562                 raw_spin_unlock_irqrestore(&db->lock, flags);
563                 debug_object_fixup(descr->fixup_destroy, addr, state);
564                 return;
565
566         case ODEBUG_STATE_DESTROYED:
567                 debug_print_object(obj, "destroy");
568                 break;
569         default:
570                 break;
571         }
572 out_unlock:
573         raw_spin_unlock_irqrestore(&db->lock, flags);
574 }
575 EXPORT_SYMBOL_GPL(debug_object_destroy);
576
577 /**
578  * debug_object_free - debug checks when an object is freed
579  * @addr:       address of the object
580  * @descr:      pointer to an object specific debug description structure
581  */
582 void debug_object_free(void *addr, struct debug_obj_descr *descr)
583 {
584         enum debug_obj_state state;
585         struct debug_bucket *db;
586         struct debug_obj *obj;
587         unsigned long flags;
588
589         if (!debug_objects_enabled)
590                 return;
591
592         db = get_bucket((unsigned long) addr);
593
594         raw_spin_lock_irqsave(&db->lock, flags);
595
596         obj = lookup_object(addr, db);
597         if (!obj)
598                 goto out_unlock;
599
600         switch (obj->state) {
601         case ODEBUG_STATE_ACTIVE:
602                 debug_print_object(obj, "free");
603                 state = obj->state;
604                 raw_spin_unlock_irqrestore(&db->lock, flags);
605                 debug_object_fixup(descr->fixup_free, addr, state);
606                 return;
607         default:
608                 hlist_del(&obj->node);
609                 raw_spin_unlock_irqrestore(&db->lock, flags);
610                 free_object(obj);
611                 return;
612         }
613 out_unlock:
614         raw_spin_unlock_irqrestore(&db->lock, flags);
615 }
616 EXPORT_SYMBOL_GPL(debug_object_free);
617
618 /**
619  * debug_object_assert_init - debug checks when object should be init-ed
620  * @addr:       address of the object
621  * @descr:      pointer to an object specific debug description structure
622  */
623 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
624 {
625         struct debug_bucket *db;
626         struct debug_obj *obj;
627         unsigned long flags;
628
629         if (!debug_objects_enabled)
630                 return;
631
632         db = get_bucket((unsigned long) addr);
633
634         raw_spin_lock_irqsave(&db->lock, flags);
635
636         obj = lookup_object(addr, db);
637         if (!obj) {
638                 struct debug_obj o = { .object = addr,
639                                        .state = ODEBUG_STATE_NOTAVAILABLE,
640                                        .descr = descr };
641
642                 raw_spin_unlock_irqrestore(&db->lock, flags);
643                 /*
644                  * Maybe the object is static, and we let the type specific
645                  * code confirm. Track this static object if true, else invoke
646                  * fixup.
647                  */
648                 if (descr->is_static_object && descr->is_static_object(addr)) {
649                         /* Track this static object */
650                         debug_object_init(addr, descr);
651                 } else {
652                         debug_print_object(&o, "assert_init");
653                         debug_object_fixup(descr->fixup_assert_init, addr,
654                                            ODEBUG_STATE_NOTAVAILABLE);
655                 }
656                 return;
657         }
658
659         raw_spin_unlock_irqrestore(&db->lock, flags);
660 }
661 EXPORT_SYMBOL_GPL(debug_object_assert_init);
662
663 /**
664  * debug_object_active_state - debug checks object usage state machine
665  * @addr:       address of the object
666  * @descr:      pointer to an object specific debug description structure
667  * @expect:     expected state
668  * @next:       state to move to if expected state is found
669  */
670 void
671 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
672                           unsigned int expect, unsigned int next)
673 {
674         struct debug_bucket *db;
675         struct debug_obj *obj;
676         unsigned long flags;
677
678         if (!debug_objects_enabled)
679                 return;
680
681         db = get_bucket((unsigned long) addr);
682
683         raw_spin_lock_irqsave(&db->lock, flags);
684
685         obj = lookup_object(addr, db);
686         if (obj) {
687                 switch (obj->state) {
688                 case ODEBUG_STATE_ACTIVE:
689                         if (obj->astate == expect)
690                                 obj->astate = next;
691                         else
692                                 debug_print_object(obj, "active_state");
693                         break;
694
695                 default:
696                         debug_print_object(obj, "active_state");
697                         break;
698                 }
699         } else {
700                 struct debug_obj o = { .object = addr,
701                                        .state = ODEBUG_STATE_NOTAVAILABLE,
702                                        .descr = descr };
703
704                 debug_print_object(&o, "active_state");
705         }
706
707         raw_spin_unlock_irqrestore(&db->lock, flags);
708 }
709 EXPORT_SYMBOL_GPL(debug_object_active_state);
710
711 #ifdef CONFIG_DEBUG_OBJECTS_FREE
712 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
713 {
714         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
715         struct hlist_node *tmp;
716         HLIST_HEAD(freelist);
717         struct debug_obj_descr *descr;
718         enum debug_obj_state state;
719         struct debug_bucket *db;
720         struct debug_obj *obj;
721         int cnt;
722
723         saddr = (unsigned long) address;
724         eaddr = saddr + size;
725         paddr = saddr & ODEBUG_CHUNK_MASK;
726         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
727         chunks >>= ODEBUG_CHUNK_SHIFT;
728
729         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
730                 db = get_bucket(paddr);
731
732 repeat:
733                 cnt = 0;
734                 raw_spin_lock_irqsave(&db->lock, flags);
735                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
736                         cnt++;
737                         oaddr = (unsigned long) obj->object;
738                         if (oaddr < saddr || oaddr >= eaddr)
739                                 continue;
740
741                         switch (obj->state) {
742                         case ODEBUG_STATE_ACTIVE:
743                                 debug_print_object(obj, "free");
744                                 descr = obj->descr;
745                                 state = obj->state;
746                                 raw_spin_unlock_irqrestore(&db->lock, flags);
747                                 debug_object_fixup(descr->fixup_free,
748                                                    (void *) oaddr, state);
749                                 goto repeat;
750                         default:
751                                 hlist_del(&obj->node);
752                                 hlist_add_head(&obj->node, &freelist);
753                                 break;
754                         }
755                 }
756                 raw_spin_unlock_irqrestore(&db->lock, flags);
757
758                 /* Now free them */
759                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
760                         hlist_del(&obj->node);
761                         free_object(obj);
762                 }
763
764                 if (cnt > debug_objects_maxchain)
765                         debug_objects_maxchain = cnt;
766         }
767 }
768
769 void debug_check_no_obj_freed(const void *address, unsigned long size)
770 {
771         if (debug_objects_enabled)
772                 __debug_check_no_obj_freed(address, size);
773 }
774 #endif
775
776 #ifdef CONFIG_DEBUG_FS
777
778 static int debug_stats_show(struct seq_file *m, void *v)
779 {
780         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
781         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
782         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
783         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
784         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
785         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
786         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
787         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
788         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
789         return 0;
790 }
791
792 static int debug_stats_open(struct inode *inode, struct file *filp)
793 {
794         return single_open(filp, debug_stats_show, NULL);
795 }
796
797 static const struct file_operations debug_stats_fops = {
798         .open           = debug_stats_open,
799         .read           = seq_read,
800         .llseek         = seq_lseek,
801         .release        = single_release,
802 };
803
804 static int __init debug_objects_init_debugfs(void)
805 {
806         struct dentry *dbgdir, *dbgstats;
807
808         if (!debug_objects_enabled)
809                 return 0;
810
811         dbgdir = debugfs_create_dir("debug_objects", NULL);
812         if (!dbgdir)
813                 return -ENOMEM;
814
815         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
816                                        &debug_stats_fops);
817         if (!dbgstats)
818                 goto err;
819
820         return 0;
821
822 err:
823         debugfs_remove(dbgdir);
824
825         return -ENOMEM;
826 }
827 __initcall(debug_objects_init_debugfs);
828
829 #else
830 static inline void debug_objects_init_debugfs(void) { }
831 #endif
832
833 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
834
835 /* Random data structure for the self test */
836 struct self_test {
837         unsigned long   dummy1[6];
838         int             static_init;
839         unsigned long   dummy2[3];
840 };
841
842 static __initdata struct debug_obj_descr descr_type_test;
843
844 static bool __init is_static_object(void *addr)
845 {
846         struct self_test *obj = addr;
847
848         return obj->static_init;
849 }
850
851 /*
852  * fixup_init is called when:
853  * - an active object is initialized
854  */
855 static bool __init fixup_init(void *addr, enum debug_obj_state state)
856 {
857         struct self_test *obj = addr;
858
859         switch (state) {
860         case ODEBUG_STATE_ACTIVE:
861                 debug_object_deactivate(obj, &descr_type_test);
862                 debug_object_init(obj, &descr_type_test);
863                 return true;
864         default:
865                 return false;
866         }
867 }
868
869 /*
870  * fixup_activate is called when:
871  * - an active object is activated
872  * - an unknown non-static object is activated
873  */
874 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
875 {
876         struct self_test *obj = addr;
877
878         switch (state) {
879         case ODEBUG_STATE_NOTAVAILABLE:
880                 return true;
881         case ODEBUG_STATE_ACTIVE:
882                 debug_object_deactivate(obj, &descr_type_test);
883                 debug_object_activate(obj, &descr_type_test);
884                 return true;
885
886         default:
887                 return false;
888         }
889 }
890
891 /*
892  * fixup_destroy is called when:
893  * - an active object is destroyed
894  */
895 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
896 {
897         struct self_test *obj = addr;
898
899         switch (state) {
900         case ODEBUG_STATE_ACTIVE:
901                 debug_object_deactivate(obj, &descr_type_test);
902                 debug_object_destroy(obj, &descr_type_test);
903                 return true;
904         default:
905                 return false;
906         }
907 }
908
909 /*
910  * fixup_free is called when:
911  * - an active object is freed
912  */
913 static bool __init fixup_free(void *addr, enum debug_obj_state state)
914 {
915         struct self_test *obj = addr;
916
917         switch (state) {
918         case ODEBUG_STATE_ACTIVE:
919                 debug_object_deactivate(obj, &descr_type_test);
920                 debug_object_free(obj, &descr_type_test);
921                 return true;
922         default:
923                 return false;
924         }
925 }
926
927 static int __init
928 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
929 {
930         struct debug_bucket *db;
931         struct debug_obj *obj;
932         unsigned long flags;
933         int res = -EINVAL;
934
935         db = get_bucket((unsigned long) addr);
936
937         raw_spin_lock_irqsave(&db->lock, flags);
938
939         obj = lookup_object(addr, db);
940         if (!obj && state != ODEBUG_STATE_NONE) {
941                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
942                 goto out;
943         }
944         if (obj && obj->state != state) {
945                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
946                        obj->state, state);
947                 goto out;
948         }
949         if (fixups != debug_objects_fixups) {
950                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
951                        fixups, debug_objects_fixups);
952                 goto out;
953         }
954         if (warnings != debug_objects_warnings) {
955                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
956                        warnings, debug_objects_warnings);
957                 goto out;
958         }
959         res = 0;
960 out:
961         raw_spin_unlock_irqrestore(&db->lock, flags);
962         if (res)
963                 debug_objects_enabled = 0;
964         return res;
965 }
966
967 static __initdata struct debug_obj_descr descr_type_test = {
968         .name                   = "selftest",
969         .is_static_object       = is_static_object,
970         .fixup_init             = fixup_init,
971         .fixup_activate         = fixup_activate,
972         .fixup_destroy          = fixup_destroy,
973         .fixup_free             = fixup_free,
974 };
975
976 static __initdata struct self_test obj = { .static_init = 0 };
977
978 static void __init debug_objects_selftest(void)
979 {
980         int fixups, oldfixups, warnings, oldwarnings;
981         unsigned long flags;
982
983         local_irq_save(flags);
984
985         fixups = oldfixups = debug_objects_fixups;
986         warnings = oldwarnings = debug_objects_warnings;
987         descr_test = &descr_type_test;
988
989         debug_object_init(&obj, &descr_type_test);
990         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
991                 goto out;
992         debug_object_activate(&obj, &descr_type_test);
993         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
994                 goto out;
995         debug_object_activate(&obj, &descr_type_test);
996         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
997                 goto out;
998         debug_object_deactivate(&obj, &descr_type_test);
999         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1000                 goto out;
1001         debug_object_destroy(&obj, &descr_type_test);
1002         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1003                 goto out;
1004         debug_object_init(&obj, &descr_type_test);
1005         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1006                 goto out;
1007         debug_object_activate(&obj, &descr_type_test);
1008         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1009                 goto out;
1010         debug_object_deactivate(&obj, &descr_type_test);
1011         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1012                 goto out;
1013         debug_object_free(&obj, &descr_type_test);
1014         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1015                 goto out;
1016
1017         obj.static_init = 1;
1018         debug_object_activate(&obj, &descr_type_test);
1019         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1020                 goto out;
1021         debug_object_init(&obj, &descr_type_test);
1022         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1023                 goto out;
1024         debug_object_free(&obj, &descr_type_test);
1025         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1026                 goto out;
1027
1028 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1029         debug_object_init(&obj, &descr_type_test);
1030         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1031                 goto out;
1032         debug_object_activate(&obj, &descr_type_test);
1033         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1034                 goto out;
1035         __debug_check_no_obj_freed(&obj, sizeof(obj));
1036         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1037                 goto out;
1038 #endif
1039         pr_info("selftest passed\n");
1040
1041 out:
1042         debug_objects_fixups = oldfixups;
1043         debug_objects_warnings = oldwarnings;
1044         descr_test = NULL;
1045
1046         local_irq_restore(flags);
1047 }
1048 #else
1049 static inline void debug_objects_selftest(void) { }
1050 #endif
1051
1052 /*
1053  * Called during early boot to initialize the hash buckets and link
1054  * the static object pool objects into the poll list. After this call
1055  * the object tracker is fully operational.
1056  */
1057 void __init debug_objects_early_init(void)
1058 {
1059         int i;
1060
1061         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1062                 raw_spin_lock_init(&obj_hash[i].lock);
1063
1064         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1065                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1066 }
1067
1068 /*
1069  * Convert the statically allocated objects to dynamic ones:
1070  */
1071 static int __init debug_objects_replace_static_objects(void)
1072 {
1073         struct debug_bucket *db = obj_hash;
1074         struct hlist_node *tmp;
1075         struct debug_obj *obj, *new;
1076         HLIST_HEAD(objects);
1077         int i, cnt = 0;
1078
1079         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1080                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1081                 if (!obj)
1082                         goto free;
1083                 hlist_add_head(&obj->node, &objects);
1084         }
1085
1086         /*
1087          * When debug_objects_mem_init() is called we know that only
1088          * one CPU is up, so disabling interrupts is enough
1089          * protection. This avoids the lockdep hell of lock ordering.
1090          */
1091         local_irq_disable();
1092
1093         /* Remove the statically allocated objects from the pool */
1094         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1095                 hlist_del(&obj->node);
1096         /* Move the allocated objects to the pool */
1097         hlist_move_list(&objects, &obj_pool);
1098
1099         /* Replace the active object references */
1100         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1101                 hlist_move_list(&db->list, &objects);
1102
1103                 hlist_for_each_entry(obj, &objects, node) {
1104                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1105                         hlist_del(&new->node);
1106                         /* copy object data */
1107                         *new = *obj;
1108                         hlist_add_head(&new->node, &db->list);
1109                         cnt++;
1110                 }
1111         }
1112         local_irq_enable();
1113
1114         pr_debug("%d of %d active objects replaced\n",
1115                  cnt, obj_pool_used);
1116         return 0;
1117 free:
1118         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1119                 hlist_del(&obj->node);
1120                 kmem_cache_free(obj_cache, obj);
1121         }
1122         return -ENOMEM;
1123 }
1124
1125 /*
1126  * Called after the kmem_caches are functional to setup a dedicated
1127  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1128  * prevents that the debug code is called on kmem_cache_free() for the
1129  * debug tracker objects to avoid recursive calls.
1130  */
1131 void __init debug_objects_mem_init(void)
1132 {
1133         if (!debug_objects_enabled)
1134                 return;
1135
1136         obj_cache = kmem_cache_create("debug_objects_cache",
1137                                       sizeof (struct debug_obj), 0,
1138                                       SLAB_DEBUG_OBJECTS, NULL);
1139
1140         if (!obj_cache || debug_objects_replace_static_objects()) {
1141                 debug_objects_enabled = 0;
1142                 if (obj_cache)
1143                         kmem_cache_destroy(obj_cache);
1144                 pr_warn("out of memory.\n");
1145         } else
1146                 debug_objects_selftest();
1147
1148         /*
1149          * Increase the thresholds for allocating and freeing objects
1150          * according to the number of possible CPUs available in the system.
1151          */
1152         debug_objects_pool_size += num_possible_cpus() * 32;
1153         debug_objects_pool_min_level += num_possible_cpus() * 4;
1154 }