GNU Linux-libre 4.4.284-gnu1
[releases.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/seq_file.h>
17 #include <linux/debugfs.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20
21 #define ODEBUG_HASH_BITS        14
22 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
23
24 #define ODEBUG_POOL_SIZE        512
25 #define ODEBUG_POOL_MIN_LEVEL   256
26
27 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
28 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
29 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
30
31 struct debug_bucket {
32         struct hlist_head       list;
33         raw_spinlock_t          lock;
34 };
35
36 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
37
38 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
39
40 static DEFINE_RAW_SPINLOCK(pool_lock);
41
42 static HLIST_HEAD(obj_pool);
43
44 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
45 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
46 static int                      obj_pool_used;
47 static int                      obj_pool_max_used;
48 static struct kmem_cache        *obj_cache;
49
50 static int                      debug_objects_maxchain __read_mostly;
51 static int                      debug_objects_fixups __read_mostly;
52 static int                      debug_objects_warnings __read_mostly;
53 static int                      debug_objects_enabled __read_mostly
54                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
55
56 static struct debug_obj_descr   *descr_test  __read_mostly;
57
58 static void free_obj_work(struct work_struct *work);
59 static DECLARE_WORK(debug_obj_work, free_obj_work);
60
61 static int __init enable_object_debug(char *str)
62 {
63         debug_objects_enabled = 1;
64         return 0;
65 }
66
67 static int __init disable_object_debug(char *str)
68 {
69         debug_objects_enabled = 0;
70         return 0;
71 }
72
73 early_param("debug_objects", enable_object_debug);
74 early_param("no_debug_objects", disable_object_debug);
75
76 static const char *obj_states[ODEBUG_STATE_MAX] = {
77         [ODEBUG_STATE_NONE]             = "none",
78         [ODEBUG_STATE_INIT]             = "initialized",
79         [ODEBUG_STATE_INACTIVE]         = "inactive",
80         [ODEBUG_STATE_ACTIVE]           = "active",
81         [ODEBUG_STATE_DESTROYED]        = "destroyed",
82         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
83 };
84
85 static void fill_pool(void)
86 {
87         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
88         struct debug_obj *new;
89         unsigned long flags;
90
91         if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
92                 return;
93
94         if (unlikely(!obj_cache))
95                 return;
96
97         while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
98
99                 new = kmem_cache_zalloc(obj_cache, gfp);
100                 if (!new)
101                         return;
102
103                 raw_spin_lock_irqsave(&pool_lock, flags);
104                 hlist_add_head(&new->node, &obj_pool);
105                 obj_pool_free++;
106                 raw_spin_unlock_irqrestore(&pool_lock, flags);
107         }
108 }
109
110 /*
111  * Lookup an object in the hash bucket.
112  */
113 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
114 {
115         struct debug_obj *obj;
116         int cnt = 0;
117
118         hlist_for_each_entry(obj, &b->list, node) {
119                 cnt++;
120                 if (obj->object == addr)
121                         return obj;
122         }
123         if (cnt > debug_objects_maxchain)
124                 debug_objects_maxchain = cnt;
125
126         return NULL;
127 }
128
129 /*
130  * Allocate a new object. If the pool is empty, switch off the debugger.
131  * Must be called with interrupts disabled.
132  */
133 static struct debug_obj *
134 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
135 {
136         struct debug_obj *obj = NULL;
137
138         raw_spin_lock(&pool_lock);
139         if (obj_pool.first) {
140                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
141
142                 obj->object = addr;
143                 obj->descr  = descr;
144                 obj->state  = ODEBUG_STATE_NONE;
145                 obj->astate = 0;
146                 hlist_del(&obj->node);
147
148                 hlist_add_head(&obj->node, &b->list);
149
150                 obj_pool_used++;
151                 if (obj_pool_used > obj_pool_max_used)
152                         obj_pool_max_used = obj_pool_used;
153
154                 obj_pool_free--;
155                 if (obj_pool_free < obj_pool_min_free)
156                         obj_pool_min_free = obj_pool_free;
157         }
158         raw_spin_unlock(&pool_lock);
159
160         return obj;
161 }
162
163 /*
164  * workqueue function to free objects.
165  */
166 static void free_obj_work(struct work_struct *work)
167 {
168         struct debug_obj *obj;
169         unsigned long flags;
170
171         raw_spin_lock_irqsave(&pool_lock, flags);
172         while (obj_pool_free > ODEBUG_POOL_SIZE) {
173                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
174                 hlist_del(&obj->node);
175                 obj_pool_free--;
176                 /*
177                  * We release pool_lock across kmem_cache_free() to
178                  * avoid contention on pool_lock.
179                  */
180                 raw_spin_unlock_irqrestore(&pool_lock, flags);
181                 kmem_cache_free(obj_cache, obj);
182                 raw_spin_lock_irqsave(&pool_lock, flags);
183         }
184         raw_spin_unlock_irqrestore(&pool_lock, flags);
185 }
186
187 /*
188  * Put the object back into the pool and schedule work to free objects
189  * if necessary.
190  */
191 static void free_object(struct debug_obj *obj)
192 {
193         unsigned long flags;
194         int sched = 0;
195
196         raw_spin_lock_irqsave(&pool_lock, flags);
197         /*
198          * schedule work when the pool is filled and the cache is
199          * initialized:
200          */
201         if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
202                 sched = keventd_up();
203         hlist_add_head(&obj->node, &obj_pool);
204         obj_pool_free++;
205         obj_pool_used--;
206         raw_spin_unlock_irqrestore(&pool_lock, flags);
207         if (sched)
208                 schedule_work(&debug_obj_work);
209 }
210
211 /*
212  * We run out of memory. That means we probably have tons of objects
213  * allocated.
214  */
215 static void debug_objects_oom(void)
216 {
217         struct debug_bucket *db = obj_hash;
218         struct hlist_node *tmp;
219         HLIST_HEAD(freelist);
220         struct debug_obj *obj;
221         unsigned long flags;
222         int i;
223
224         pr_warn("Out of memory. ODEBUG disabled\n");
225
226         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
227                 raw_spin_lock_irqsave(&db->lock, flags);
228                 hlist_move_list(&db->list, &freelist);
229                 raw_spin_unlock_irqrestore(&db->lock, flags);
230
231                 /* Now free them */
232                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
233                         hlist_del(&obj->node);
234                         free_object(obj);
235                 }
236         }
237 }
238
239 /*
240  * We use the pfn of the address for the hash. That way we can check
241  * for freed objects simply by checking the affected bucket.
242  */
243 static struct debug_bucket *get_bucket(unsigned long addr)
244 {
245         unsigned long hash;
246
247         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
248         return &obj_hash[hash];
249 }
250
251 static void debug_print_object(struct debug_obj *obj, char *msg)
252 {
253         struct debug_obj_descr *descr = obj->descr;
254         static int limit;
255
256         if (limit < 5 && descr != descr_test) {
257                 void *hint = descr->debug_hint ?
258                         descr->debug_hint(obj->object) : NULL;
259                 limit++;
260                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
261                                  "object type: %s hint: %pS\n",
262                         msg, obj_states[obj->state], obj->astate,
263                         descr->name, hint);
264         }
265         debug_objects_warnings++;
266 }
267
268 /*
269  * Try to repair the damage, so we have a better chance to get useful
270  * debug output.
271  */
272 static int
273 debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
274                    void * addr, enum debug_obj_state state)
275 {
276         int fixed = 0;
277
278         if (fixup)
279                 fixed = fixup(addr, state);
280         debug_objects_fixups += fixed;
281         return fixed;
282 }
283
284 static void debug_object_is_on_stack(void *addr, int onstack)
285 {
286         int is_on_stack;
287         static int limit;
288
289         if (limit > 4)
290                 return;
291
292         is_on_stack = object_is_on_stack(addr);
293         if (is_on_stack == onstack)
294                 return;
295
296         limit++;
297         if (is_on_stack)
298                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
299                          task_stack_page(current));
300         else
301                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
302                          task_stack_page(current));
303
304         WARN_ON(1);
305 }
306
307 static void
308 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
309 {
310         enum debug_obj_state state;
311         struct debug_bucket *db;
312         struct debug_obj *obj;
313         unsigned long flags;
314
315         fill_pool();
316
317         db = get_bucket((unsigned long) addr);
318
319         raw_spin_lock_irqsave(&db->lock, flags);
320
321         obj = lookup_object(addr, db);
322         if (!obj) {
323                 obj = alloc_object(addr, db, descr);
324                 if (!obj) {
325                         debug_objects_enabled = 0;
326                         raw_spin_unlock_irqrestore(&db->lock, flags);
327                         debug_objects_oom();
328                         return;
329                 }
330                 debug_object_is_on_stack(addr, onstack);
331         }
332
333         switch (obj->state) {
334         case ODEBUG_STATE_NONE:
335         case ODEBUG_STATE_INIT:
336         case ODEBUG_STATE_INACTIVE:
337                 obj->state = ODEBUG_STATE_INIT;
338                 break;
339
340         case ODEBUG_STATE_ACTIVE:
341                 debug_print_object(obj, "init");
342                 state = obj->state;
343                 raw_spin_unlock_irqrestore(&db->lock, flags);
344                 debug_object_fixup(descr->fixup_init, addr, state);
345                 return;
346
347         case ODEBUG_STATE_DESTROYED:
348                 debug_print_object(obj, "init");
349                 break;
350         default:
351                 break;
352         }
353
354         raw_spin_unlock_irqrestore(&db->lock, flags);
355 }
356
357 /**
358  * debug_object_init - debug checks when an object is initialized
359  * @addr:       address of the object
360  * @descr:      pointer to an object specific debug description structure
361  */
362 void debug_object_init(void *addr, struct debug_obj_descr *descr)
363 {
364         if (!debug_objects_enabled)
365                 return;
366
367         __debug_object_init(addr, descr, 0);
368 }
369
370 /**
371  * debug_object_init_on_stack - debug checks when an object on stack is
372  *                              initialized
373  * @addr:       address of the object
374  * @descr:      pointer to an object specific debug description structure
375  */
376 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
377 {
378         if (!debug_objects_enabled)
379                 return;
380
381         __debug_object_init(addr, descr, 1);
382 }
383
384 /**
385  * debug_object_activate - debug checks when an object is activated
386  * @addr:       address of the object
387  * @descr:      pointer to an object specific debug description structure
388  * Returns 0 for success, -EINVAL for check failed.
389  */
390 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
391 {
392         enum debug_obj_state state;
393         struct debug_bucket *db;
394         struct debug_obj *obj;
395         unsigned long flags;
396         int ret;
397         struct debug_obj o = { .object = addr,
398                                .state = ODEBUG_STATE_NOTAVAILABLE,
399                                .descr = descr };
400
401         if (!debug_objects_enabled)
402                 return 0;
403
404         db = get_bucket((unsigned long) addr);
405
406         raw_spin_lock_irqsave(&db->lock, flags);
407
408         obj = lookup_object(addr, db);
409         if (obj) {
410                 switch (obj->state) {
411                 case ODEBUG_STATE_INIT:
412                 case ODEBUG_STATE_INACTIVE:
413                         obj->state = ODEBUG_STATE_ACTIVE;
414                         ret = 0;
415                         break;
416
417                 case ODEBUG_STATE_ACTIVE:
418                         debug_print_object(obj, "activate");
419                         state = obj->state;
420                         raw_spin_unlock_irqrestore(&db->lock, flags);
421                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
422                         return ret ? -EINVAL : 0;
423
424                 case ODEBUG_STATE_DESTROYED:
425                         debug_print_object(obj, "activate");
426                         ret = -EINVAL;
427                         break;
428                 default:
429                         ret = 0;
430                         break;
431                 }
432                 raw_spin_unlock_irqrestore(&db->lock, flags);
433                 return ret;
434         }
435
436         raw_spin_unlock_irqrestore(&db->lock, flags);
437         /*
438          * This happens when a static object is activated. We
439          * let the type specific code decide whether this is
440          * true or not.
441          */
442         if (debug_object_fixup(descr->fixup_activate, addr,
443                            ODEBUG_STATE_NOTAVAILABLE)) {
444                 debug_print_object(&o, "activate");
445                 return -EINVAL;
446         }
447         return 0;
448 }
449
450 /**
451  * debug_object_deactivate - debug checks when an object is deactivated
452  * @addr:       address of the object
453  * @descr:      pointer to an object specific debug description structure
454  */
455 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
456 {
457         struct debug_bucket *db;
458         struct debug_obj *obj;
459         unsigned long flags;
460
461         if (!debug_objects_enabled)
462                 return;
463
464         db = get_bucket((unsigned long) addr);
465
466         raw_spin_lock_irqsave(&db->lock, flags);
467
468         obj = lookup_object(addr, db);
469         if (obj) {
470                 switch (obj->state) {
471                 case ODEBUG_STATE_INIT:
472                 case ODEBUG_STATE_INACTIVE:
473                 case ODEBUG_STATE_ACTIVE:
474                         if (!obj->astate)
475                                 obj->state = ODEBUG_STATE_INACTIVE;
476                         else
477                                 debug_print_object(obj, "deactivate");
478                         break;
479
480                 case ODEBUG_STATE_DESTROYED:
481                         debug_print_object(obj, "deactivate");
482                         break;
483                 default:
484                         break;
485                 }
486         } else {
487                 struct debug_obj o = { .object = addr,
488                                        .state = ODEBUG_STATE_NOTAVAILABLE,
489                                        .descr = descr };
490
491                 debug_print_object(&o, "deactivate");
492         }
493
494         raw_spin_unlock_irqrestore(&db->lock, flags);
495 }
496
497 /**
498  * debug_object_destroy - debug checks when an object is destroyed
499  * @addr:       address of the object
500  * @descr:      pointer to an object specific debug description structure
501  */
502 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
503 {
504         enum debug_obj_state state;
505         struct debug_bucket *db;
506         struct debug_obj *obj;
507         unsigned long flags;
508
509         if (!debug_objects_enabled)
510                 return;
511
512         db = get_bucket((unsigned long) addr);
513
514         raw_spin_lock_irqsave(&db->lock, flags);
515
516         obj = lookup_object(addr, db);
517         if (!obj)
518                 goto out_unlock;
519
520         switch (obj->state) {
521         case ODEBUG_STATE_NONE:
522         case ODEBUG_STATE_INIT:
523         case ODEBUG_STATE_INACTIVE:
524                 obj->state = ODEBUG_STATE_DESTROYED;
525                 break;
526         case ODEBUG_STATE_ACTIVE:
527                 debug_print_object(obj, "destroy");
528                 state = obj->state;
529                 raw_spin_unlock_irqrestore(&db->lock, flags);
530                 debug_object_fixup(descr->fixup_destroy, addr, state);
531                 return;
532
533         case ODEBUG_STATE_DESTROYED:
534                 debug_print_object(obj, "destroy");
535                 break;
536         default:
537                 break;
538         }
539 out_unlock:
540         raw_spin_unlock_irqrestore(&db->lock, flags);
541 }
542
543 /**
544  * debug_object_free - debug checks when an object is freed
545  * @addr:       address of the object
546  * @descr:      pointer to an object specific debug description structure
547  */
548 void debug_object_free(void *addr, struct debug_obj_descr *descr)
549 {
550         enum debug_obj_state state;
551         struct debug_bucket *db;
552         struct debug_obj *obj;
553         unsigned long flags;
554
555         if (!debug_objects_enabled)
556                 return;
557
558         db = get_bucket((unsigned long) addr);
559
560         raw_spin_lock_irqsave(&db->lock, flags);
561
562         obj = lookup_object(addr, db);
563         if (!obj)
564                 goto out_unlock;
565
566         switch (obj->state) {
567         case ODEBUG_STATE_ACTIVE:
568                 debug_print_object(obj, "free");
569                 state = obj->state;
570                 raw_spin_unlock_irqrestore(&db->lock, flags);
571                 debug_object_fixup(descr->fixup_free, addr, state);
572                 return;
573         default:
574                 hlist_del(&obj->node);
575                 raw_spin_unlock_irqrestore(&db->lock, flags);
576                 free_object(obj);
577                 return;
578         }
579 out_unlock:
580         raw_spin_unlock_irqrestore(&db->lock, flags);
581 }
582
583 /**
584  * debug_object_assert_init - debug checks when object should be init-ed
585  * @addr:       address of the object
586  * @descr:      pointer to an object specific debug description structure
587  */
588 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
589 {
590         struct debug_bucket *db;
591         struct debug_obj *obj;
592         unsigned long flags;
593
594         if (!debug_objects_enabled)
595                 return;
596
597         db = get_bucket((unsigned long) addr);
598
599         raw_spin_lock_irqsave(&db->lock, flags);
600
601         obj = lookup_object(addr, db);
602         if (!obj) {
603                 struct debug_obj o = { .object = addr,
604                                        .state = ODEBUG_STATE_NOTAVAILABLE,
605                                        .descr = descr };
606
607                 raw_spin_unlock_irqrestore(&db->lock, flags);
608                 /*
609                  * Maybe the object is static.  Let the type specific
610                  * code decide what to do.
611                  */
612                 if (debug_object_fixup(descr->fixup_assert_init, addr,
613                                        ODEBUG_STATE_NOTAVAILABLE))
614                         debug_print_object(&o, "assert_init");
615                 return;
616         }
617
618         raw_spin_unlock_irqrestore(&db->lock, flags);
619 }
620
621 /**
622  * debug_object_active_state - debug checks object usage state machine
623  * @addr:       address of the object
624  * @descr:      pointer to an object specific debug description structure
625  * @expect:     expected state
626  * @next:       state to move to if expected state is found
627  */
628 void
629 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
630                           unsigned int expect, unsigned int next)
631 {
632         struct debug_bucket *db;
633         struct debug_obj *obj;
634         unsigned long flags;
635
636         if (!debug_objects_enabled)
637                 return;
638
639         db = get_bucket((unsigned long) addr);
640
641         raw_spin_lock_irqsave(&db->lock, flags);
642
643         obj = lookup_object(addr, db);
644         if (obj) {
645                 switch (obj->state) {
646                 case ODEBUG_STATE_ACTIVE:
647                         if (obj->astate == expect)
648                                 obj->astate = next;
649                         else
650                                 debug_print_object(obj, "active_state");
651                         break;
652
653                 default:
654                         debug_print_object(obj, "active_state");
655                         break;
656                 }
657         } else {
658                 struct debug_obj o = { .object = addr,
659                                        .state = ODEBUG_STATE_NOTAVAILABLE,
660                                        .descr = descr };
661
662                 debug_print_object(&o, "active_state");
663         }
664
665         raw_spin_unlock_irqrestore(&db->lock, flags);
666 }
667
668 #ifdef CONFIG_DEBUG_OBJECTS_FREE
669 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
670 {
671         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
672         struct hlist_node *tmp;
673         HLIST_HEAD(freelist);
674         struct debug_obj_descr *descr;
675         enum debug_obj_state state;
676         struct debug_bucket *db;
677         struct debug_obj *obj;
678         int cnt;
679
680         saddr = (unsigned long) address;
681         eaddr = saddr + size;
682         paddr = saddr & ODEBUG_CHUNK_MASK;
683         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
684         chunks >>= ODEBUG_CHUNK_SHIFT;
685
686         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
687                 db = get_bucket(paddr);
688
689 repeat:
690                 cnt = 0;
691                 raw_spin_lock_irqsave(&db->lock, flags);
692                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
693                         cnt++;
694                         oaddr = (unsigned long) obj->object;
695                         if (oaddr < saddr || oaddr >= eaddr)
696                                 continue;
697
698                         switch (obj->state) {
699                         case ODEBUG_STATE_ACTIVE:
700                                 debug_print_object(obj, "free");
701                                 descr = obj->descr;
702                                 state = obj->state;
703                                 raw_spin_unlock_irqrestore(&db->lock, flags);
704                                 debug_object_fixup(descr->fixup_free,
705                                                    (void *) oaddr, state);
706                                 goto repeat;
707                         default:
708                                 hlist_del(&obj->node);
709                                 hlist_add_head(&obj->node, &freelist);
710                                 break;
711                         }
712                 }
713                 raw_spin_unlock_irqrestore(&db->lock, flags);
714
715                 /* Now free them */
716                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
717                         hlist_del(&obj->node);
718                         free_object(obj);
719                 }
720
721                 if (cnt > debug_objects_maxchain)
722                         debug_objects_maxchain = cnt;
723         }
724 }
725
726 void debug_check_no_obj_freed(const void *address, unsigned long size)
727 {
728         if (debug_objects_enabled)
729                 __debug_check_no_obj_freed(address, size);
730 }
731 #endif
732
733 #ifdef CONFIG_DEBUG_FS
734
735 static int debug_stats_show(struct seq_file *m, void *v)
736 {
737         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
738         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
739         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
740         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
741         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
742         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
743         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
744         return 0;
745 }
746
747 static int debug_stats_open(struct inode *inode, struct file *filp)
748 {
749         return single_open(filp, debug_stats_show, NULL);
750 }
751
752 static const struct file_operations debug_stats_fops = {
753         .open           = debug_stats_open,
754         .read           = seq_read,
755         .llseek         = seq_lseek,
756         .release        = single_release,
757 };
758
759 static int __init debug_objects_init_debugfs(void)
760 {
761         struct dentry *dbgdir, *dbgstats;
762
763         if (!debug_objects_enabled)
764                 return 0;
765
766         dbgdir = debugfs_create_dir("debug_objects", NULL);
767         if (!dbgdir)
768                 return -ENOMEM;
769
770         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
771                                        &debug_stats_fops);
772         if (!dbgstats)
773                 goto err;
774
775         return 0;
776
777 err:
778         debugfs_remove(dbgdir);
779
780         return -ENOMEM;
781 }
782 __initcall(debug_objects_init_debugfs);
783
784 #else
785 static inline void debug_objects_init_debugfs(void) { }
786 #endif
787
788 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
789
790 /* Random data structure for the self test */
791 struct self_test {
792         unsigned long   dummy1[6];
793         int             static_init;
794         unsigned long   dummy2[3];
795 };
796
797 static __initdata struct debug_obj_descr descr_type_test;
798
799 /*
800  * fixup_init is called when:
801  * - an active object is initialized
802  */
803 static int __init fixup_init(void *addr, enum debug_obj_state state)
804 {
805         struct self_test *obj = addr;
806
807         switch (state) {
808         case ODEBUG_STATE_ACTIVE:
809                 debug_object_deactivate(obj, &descr_type_test);
810                 debug_object_init(obj, &descr_type_test);
811                 return 1;
812         default:
813                 return 0;
814         }
815 }
816
817 /*
818  * fixup_activate is called when:
819  * - an active object is activated
820  * - an unknown object is activated (might be a statically initialized object)
821  */
822 static int __init fixup_activate(void *addr, enum debug_obj_state state)
823 {
824         struct self_test *obj = addr;
825
826         switch (state) {
827         case ODEBUG_STATE_NOTAVAILABLE:
828                 if (obj->static_init == 1) {
829                         debug_object_init(obj, &descr_type_test);
830                         debug_object_activate(obj, &descr_type_test);
831                         return 0;
832                 }
833                 return 1;
834
835         case ODEBUG_STATE_ACTIVE:
836                 debug_object_deactivate(obj, &descr_type_test);
837                 debug_object_activate(obj, &descr_type_test);
838                 return 1;
839
840         default:
841                 return 0;
842         }
843 }
844
845 /*
846  * fixup_destroy is called when:
847  * - an active object is destroyed
848  */
849 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
850 {
851         struct self_test *obj = addr;
852
853         switch (state) {
854         case ODEBUG_STATE_ACTIVE:
855                 debug_object_deactivate(obj, &descr_type_test);
856                 debug_object_destroy(obj, &descr_type_test);
857                 return 1;
858         default:
859                 return 0;
860         }
861 }
862
863 /*
864  * fixup_free is called when:
865  * - an active object is freed
866  */
867 static int __init fixup_free(void *addr, enum debug_obj_state state)
868 {
869         struct self_test *obj = addr;
870
871         switch (state) {
872         case ODEBUG_STATE_ACTIVE:
873                 debug_object_deactivate(obj, &descr_type_test);
874                 debug_object_free(obj, &descr_type_test);
875                 return 1;
876         default:
877                 return 0;
878         }
879 }
880
881 static int __init
882 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
883 {
884         struct debug_bucket *db;
885         struct debug_obj *obj;
886         unsigned long flags;
887         int res = -EINVAL;
888
889         db = get_bucket((unsigned long) addr);
890
891         raw_spin_lock_irqsave(&db->lock, flags);
892
893         obj = lookup_object(addr, db);
894         if (!obj && state != ODEBUG_STATE_NONE) {
895                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
896                 goto out;
897         }
898         if (obj && obj->state != state) {
899                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
900                        obj->state, state);
901                 goto out;
902         }
903         if (fixups != debug_objects_fixups) {
904                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
905                        fixups, debug_objects_fixups);
906                 goto out;
907         }
908         if (warnings != debug_objects_warnings) {
909                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
910                        warnings, debug_objects_warnings);
911                 goto out;
912         }
913         res = 0;
914 out:
915         raw_spin_unlock_irqrestore(&db->lock, flags);
916         if (res)
917                 debug_objects_enabled = 0;
918         return res;
919 }
920
921 static __initdata struct debug_obj_descr descr_type_test = {
922         .name                   = "selftest",
923         .fixup_init             = fixup_init,
924         .fixup_activate         = fixup_activate,
925         .fixup_destroy          = fixup_destroy,
926         .fixup_free             = fixup_free,
927 };
928
929 static __initdata struct self_test obj = { .static_init = 0 };
930
931 static void __init debug_objects_selftest(void)
932 {
933         int fixups, oldfixups, warnings, oldwarnings;
934         unsigned long flags;
935
936         local_irq_save(flags);
937
938         fixups = oldfixups = debug_objects_fixups;
939         warnings = oldwarnings = debug_objects_warnings;
940         descr_test = &descr_type_test;
941
942         debug_object_init(&obj, &descr_type_test);
943         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
944                 goto out;
945         debug_object_activate(&obj, &descr_type_test);
946         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
947                 goto out;
948         debug_object_activate(&obj, &descr_type_test);
949         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
950                 goto out;
951         debug_object_deactivate(&obj, &descr_type_test);
952         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
953                 goto out;
954         debug_object_destroy(&obj, &descr_type_test);
955         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
956                 goto out;
957         debug_object_init(&obj, &descr_type_test);
958         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
959                 goto out;
960         debug_object_activate(&obj, &descr_type_test);
961         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
962                 goto out;
963         debug_object_deactivate(&obj, &descr_type_test);
964         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
965                 goto out;
966         debug_object_free(&obj, &descr_type_test);
967         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
968                 goto out;
969
970         obj.static_init = 1;
971         debug_object_activate(&obj, &descr_type_test);
972         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
973                 goto out;
974         debug_object_init(&obj, &descr_type_test);
975         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
976                 goto out;
977         debug_object_free(&obj, &descr_type_test);
978         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
979                 goto out;
980
981 #ifdef CONFIG_DEBUG_OBJECTS_FREE
982         debug_object_init(&obj, &descr_type_test);
983         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
984                 goto out;
985         debug_object_activate(&obj, &descr_type_test);
986         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
987                 goto out;
988         __debug_check_no_obj_freed(&obj, sizeof(obj));
989         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
990                 goto out;
991 #endif
992         pr_info("selftest passed\n");
993
994 out:
995         debug_objects_fixups = oldfixups;
996         debug_objects_warnings = oldwarnings;
997         descr_test = NULL;
998
999         local_irq_restore(flags);
1000 }
1001 #else
1002 static inline void debug_objects_selftest(void) { }
1003 #endif
1004
1005 /*
1006  * Called during early boot to initialize the hash buckets and link
1007  * the static object pool objects into the poll list. After this call
1008  * the object tracker is fully operational.
1009  */
1010 void __init debug_objects_early_init(void)
1011 {
1012         int i;
1013
1014         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1015                 raw_spin_lock_init(&obj_hash[i].lock);
1016
1017         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1018                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1019 }
1020
1021 /*
1022  * Convert the statically allocated objects to dynamic ones:
1023  */
1024 static int __init debug_objects_replace_static_objects(void)
1025 {
1026         struct debug_bucket *db = obj_hash;
1027         struct hlist_node *tmp;
1028         struct debug_obj *obj, *new;
1029         HLIST_HEAD(objects);
1030         int i, cnt = 0;
1031
1032         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1033                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1034                 if (!obj)
1035                         goto free;
1036                 hlist_add_head(&obj->node, &objects);
1037         }
1038
1039         /*
1040          * When debug_objects_mem_init() is called we know that only
1041          * one CPU is up, so disabling interrupts is enough
1042          * protection. This avoids the lockdep hell of lock ordering.
1043          */
1044         local_irq_disable();
1045
1046         /* Remove the statically allocated objects from the pool */
1047         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1048                 hlist_del(&obj->node);
1049         /* Move the allocated objects to the pool */
1050         hlist_move_list(&objects, &obj_pool);
1051
1052         /* Replace the active object references */
1053         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1054                 hlist_move_list(&db->list, &objects);
1055
1056                 hlist_for_each_entry(obj, &objects, node) {
1057                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1058                         hlist_del(&new->node);
1059                         /* copy object data */
1060                         *new = *obj;
1061                         hlist_add_head(&new->node, &db->list);
1062                         cnt++;
1063                 }
1064         }
1065         local_irq_enable();
1066
1067         pr_debug("%d of %d active objects replaced\n",
1068                  cnt, obj_pool_used);
1069         return 0;
1070 free:
1071         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1072                 hlist_del(&obj->node);
1073                 kmem_cache_free(obj_cache, obj);
1074         }
1075         return -ENOMEM;
1076 }
1077
1078 /*
1079  * Called after the kmem_caches are functional to setup a dedicated
1080  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1081  * prevents that the debug code is called on kmem_cache_free() for the
1082  * debug tracker objects to avoid recursive calls.
1083  */
1084 void __init debug_objects_mem_init(void)
1085 {
1086         if (!debug_objects_enabled)
1087                 return;
1088
1089         obj_cache = kmem_cache_create("debug_objects_cache",
1090                                       sizeof (struct debug_obj), 0,
1091                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1092                                       NULL);
1093
1094         if (!obj_cache || debug_objects_replace_static_objects()) {
1095                 debug_objects_enabled = 0;
1096                 if (obj_cache)
1097                         kmem_cache_destroy(obj_cache);
1098                 pr_warn("out of memory.\n");
1099         } else
1100                 debug_objects_selftest();
1101 }