Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[pandora-kernel.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 is on stack, but not annotated\n");
299         else
300                 pr_warn("object is not on stack, but annotated\n");
301         WARN_ON(1);
302 }
303
304 static void
305 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
306 {
307         enum debug_obj_state state;
308         struct debug_bucket *db;
309         struct debug_obj *obj;
310         unsigned long flags;
311
312         fill_pool();
313
314         db = get_bucket((unsigned long) addr);
315
316         raw_spin_lock_irqsave(&db->lock, flags);
317
318         obj = lookup_object(addr, db);
319         if (!obj) {
320                 obj = alloc_object(addr, db, descr);
321                 if (!obj) {
322                         debug_objects_enabled = 0;
323                         raw_spin_unlock_irqrestore(&db->lock, flags);
324                         debug_objects_oom();
325                         return;
326                 }
327                 debug_object_is_on_stack(addr, onstack);
328         }
329
330         switch (obj->state) {
331         case ODEBUG_STATE_NONE:
332         case ODEBUG_STATE_INIT:
333         case ODEBUG_STATE_INACTIVE:
334                 obj->state = ODEBUG_STATE_INIT;
335                 break;
336
337         case ODEBUG_STATE_ACTIVE:
338                 debug_print_object(obj, "init");
339                 state = obj->state;
340                 raw_spin_unlock_irqrestore(&db->lock, flags);
341                 debug_object_fixup(descr->fixup_init, addr, state);
342                 return;
343
344         case ODEBUG_STATE_DESTROYED:
345                 debug_print_object(obj, "init");
346                 break;
347         default:
348                 break;
349         }
350
351         raw_spin_unlock_irqrestore(&db->lock, flags);
352 }
353
354 /**
355  * debug_object_init - debug checks when an object is initialized
356  * @addr:       address of the object
357  * @descr:      pointer to an object specific debug description structure
358  */
359 void debug_object_init(void *addr, struct debug_obj_descr *descr)
360 {
361         if (!debug_objects_enabled)
362                 return;
363
364         __debug_object_init(addr, descr, 0);
365 }
366
367 /**
368  * debug_object_init_on_stack - debug checks when an object on stack is
369  *                              initialized
370  * @addr:       address of the object
371  * @descr:      pointer to an object specific debug description structure
372  */
373 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
374 {
375         if (!debug_objects_enabled)
376                 return;
377
378         __debug_object_init(addr, descr, 1);
379 }
380
381 /**
382  * debug_object_activate - debug checks when an object is activated
383  * @addr:       address of the object
384  * @descr:      pointer to an object specific debug description structure
385  * Returns 0 for success, -EINVAL for check failed.
386  */
387 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
388 {
389         enum debug_obj_state state;
390         struct debug_bucket *db;
391         struct debug_obj *obj;
392         unsigned long flags;
393         int ret;
394         struct debug_obj o = { .object = addr,
395                                .state = ODEBUG_STATE_NOTAVAILABLE,
396                                .descr = descr };
397
398         if (!debug_objects_enabled)
399                 return 0;
400
401         db = get_bucket((unsigned long) addr);
402
403         raw_spin_lock_irqsave(&db->lock, flags);
404
405         obj = lookup_object(addr, db);
406         if (obj) {
407                 switch (obj->state) {
408                 case ODEBUG_STATE_INIT:
409                 case ODEBUG_STATE_INACTIVE:
410                         obj->state = ODEBUG_STATE_ACTIVE;
411                         ret = 0;
412                         break;
413
414                 case ODEBUG_STATE_ACTIVE:
415                         debug_print_object(obj, "activate");
416                         state = obj->state;
417                         raw_spin_unlock_irqrestore(&db->lock, flags);
418                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
419                         return ret ? -EINVAL : 0;
420
421                 case ODEBUG_STATE_DESTROYED:
422                         debug_print_object(obj, "activate");
423                         ret = -EINVAL;
424                         break;
425                 default:
426                         ret = 0;
427                         break;
428                 }
429                 raw_spin_unlock_irqrestore(&db->lock, flags);
430                 return ret;
431         }
432
433         raw_spin_unlock_irqrestore(&db->lock, flags);
434         /*
435          * This happens when a static object is activated. We
436          * let the type specific code decide whether this is
437          * true or not.
438          */
439         if (debug_object_fixup(descr->fixup_activate, addr,
440                            ODEBUG_STATE_NOTAVAILABLE)) {
441                 debug_print_object(&o, "activate");
442                 return -EINVAL;
443         }
444         return 0;
445 }
446
447 /**
448  * debug_object_deactivate - debug checks when an object is deactivated
449  * @addr:       address of the object
450  * @descr:      pointer to an object specific debug description structure
451  */
452 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
453 {
454         struct debug_bucket *db;
455         struct debug_obj *obj;
456         unsigned long flags;
457
458         if (!debug_objects_enabled)
459                 return;
460
461         db = get_bucket((unsigned long) addr);
462
463         raw_spin_lock_irqsave(&db->lock, flags);
464
465         obj = lookup_object(addr, db);
466         if (obj) {
467                 switch (obj->state) {
468                 case ODEBUG_STATE_INIT:
469                 case ODEBUG_STATE_INACTIVE:
470                 case ODEBUG_STATE_ACTIVE:
471                         if (!obj->astate)
472                                 obj->state = ODEBUG_STATE_INACTIVE;
473                         else
474                                 debug_print_object(obj, "deactivate");
475                         break;
476
477                 case ODEBUG_STATE_DESTROYED:
478                         debug_print_object(obj, "deactivate");
479                         break;
480                 default:
481                         break;
482                 }
483         } else {
484                 struct debug_obj o = { .object = addr,
485                                        .state = ODEBUG_STATE_NOTAVAILABLE,
486                                        .descr = descr };
487
488                 debug_print_object(&o, "deactivate");
489         }
490
491         raw_spin_unlock_irqrestore(&db->lock, flags);
492 }
493
494 /**
495  * debug_object_destroy - debug checks when an object is destroyed
496  * @addr:       address of the object
497  * @descr:      pointer to an object specific debug description structure
498  */
499 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
500 {
501         enum debug_obj_state state;
502         struct debug_bucket *db;
503         struct debug_obj *obj;
504         unsigned long flags;
505
506         if (!debug_objects_enabled)
507                 return;
508
509         db = get_bucket((unsigned long) addr);
510
511         raw_spin_lock_irqsave(&db->lock, flags);
512
513         obj = lookup_object(addr, db);
514         if (!obj)
515                 goto out_unlock;
516
517         switch (obj->state) {
518         case ODEBUG_STATE_NONE:
519         case ODEBUG_STATE_INIT:
520         case ODEBUG_STATE_INACTIVE:
521                 obj->state = ODEBUG_STATE_DESTROYED;
522                 break;
523         case ODEBUG_STATE_ACTIVE:
524                 debug_print_object(obj, "destroy");
525                 state = obj->state;
526                 raw_spin_unlock_irqrestore(&db->lock, flags);
527                 debug_object_fixup(descr->fixup_destroy, addr, state);
528                 return;
529
530         case ODEBUG_STATE_DESTROYED:
531                 debug_print_object(obj, "destroy");
532                 break;
533         default:
534                 break;
535         }
536 out_unlock:
537         raw_spin_unlock_irqrestore(&db->lock, flags);
538 }
539
540 /**
541  * debug_object_free - debug checks when an object is freed
542  * @addr:       address of the object
543  * @descr:      pointer to an object specific debug description structure
544  */
545 void debug_object_free(void *addr, struct debug_obj_descr *descr)
546 {
547         enum debug_obj_state state;
548         struct debug_bucket *db;
549         struct debug_obj *obj;
550         unsigned long flags;
551
552         if (!debug_objects_enabled)
553                 return;
554
555         db = get_bucket((unsigned long) addr);
556
557         raw_spin_lock_irqsave(&db->lock, flags);
558
559         obj = lookup_object(addr, db);
560         if (!obj)
561                 goto out_unlock;
562
563         switch (obj->state) {
564         case ODEBUG_STATE_ACTIVE:
565                 debug_print_object(obj, "free");
566                 state = obj->state;
567                 raw_spin_unlock_irqrestore(&db->lock, flags);
568                 debug_object_fixup(descr->fixup_free, addr, state);
569                 return;
570         default:
571                 hlist_del(&obj->node);
572                 raw_spin_unlock_irqrestore(&db->lock, flags);
573                 free_object(obj);
574                 return;
575         }
576 out_unlock:
577         raw_spin_unlock_irqrestore(&db->lock, flags);
578 }
579
580 /**
581  * debug_object_assert_init - debug checks when object should be init-ed
582  * @addr:       address of the object
583  * @descr:      pointer to an object specific debug description structure
584  */
585 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
586 {
587         struct debug_bucket *db;
588         struct debug_obj *obj;
589         unsigned long flags;
590
591         if (!debug_objects_enabled)
592                 return;
593
594         db = get_bucket((unsigned long) addr);
595
596         raw_spin_lock_irqsave(&db->lock, flags);
597
598         obj = lookup_object(addr, db);
599         if (!obj) {
600                 struct debug_obj o = { .object = addr,
601                                        .state = ODEBUG_STATE_NOTAVAILABLE,
602                                        .descr = descr };
603
604                 raw_spin_unlock_irqrestore(&db->lock, flags);
605                 /*
606                  * Maybe the object is static.  Let the type specific
607                  * code decide what to do.
608                  */
609                 if (debug_object_fixup(descr->fixup_assert_init, addr,
610                                        ODEBUG_STATE_NOTAVAILABLE))
611                         debug_print_object(&o, "assert_init");
612                 return;
613         }
614
615         raw_spin_unlock_irqrestore(&db->lock, flags);
616 }
617
618 /**
619  * debug_object_active_state - debug checks object usage state machine
620  * @addr:       address of the object
621  * @descr:      pointer to an object specific debug description structure
622  * @expect:     expected state
623  * @next:       state to move to if expected state is found
624  */
625 void
626 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
627                           unsigned int expect, unsigned int next)
628 {
629         struct debug_bucket *db;
630         struct debug_obj *obj;
631         unsigned long flags;
632
633         if (!debug_objects_enabled)
634                 return;
635
636         db = get_bucket((unsigned long) addr);
637
638         raw_spin_lock_irqsave(&db->lock, flags);
639
640         obj = lookup_object(addr, db);
641         if (obj) {
642                 switch (obj->state) {
643                 case ODEBUG_STATE_ACTIVE:
644                         if (obj->astate == expect)
645                                 obj->astate = next;
646                         else
647                                 debug_print_object(obj, "active_state");
648                         break;
649
650                 default:
651                         debug_print_object(obj, "active_state");
652                         break;
653                 }
654         } else {
655                 struct debug_obj o = { .object = addr,
656                                        .state = ODEBUG_STATE_NOTAVAILABLE,
657                                        .descr = descr };
658
659                 debug_print_object(&o, "active_state");
660         }
661
662         raw_spin_unlock_irqrestore(&db->lock, flags);
663 }
664
665 #ifdef CONFIG_DEBUG_OBJECTS_FREE
666 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
667 {
668         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
669         struct hlist_node *tmp;
670         HLIST_HEAD(freelist);
671         struct debug_obj_descr *descr;
672         enum debug_obj_state state;
673         struct debug_bucket *db;
674         struct debug_obj *obj;
675         int cnt;
676
677         saddr = (unsigned long) address;
678         eaddr = saddr + size;
679         paddr = saddr & ODEBUG_CHUNK_MASK;
680         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
681         chunks >>= ODEBUG_CHUNK_SHIFT;
682
683         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
684                 db = get_bucket(paddr);
685
686 repeat:
687                 cnt = 0;
688                 raw_spin_lock_irqsave(&db->lock, flags);
689                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
690                         cnt++;
691                         oaddr = (unsigned long) obj->object;
692                         if (oaddr < saddr || oaddr >= eaddr)
693                                 continue;
694
695                         switch (obj->state) {
696                         case ODEBUG_STATE_ACTIVE:
697                                 debug_print_object(obj, "free");
698                                 descr = obj->descr;
699                                 state = obj->state;
700                                 raw_spin_unlock_irqrestore(&db->lock, flags);
701                                 debug_object_fixup(descr->fixup_free,
702                                                    (void *) oaddr, state);
703                                 goto repeat;
704                         default:
705                                 hlist_del(&obj->node);
706                                 hlist_add_head(&obj->node, &freelist);
707                                 break;
708                         }
709                 }
710                 raw_spin_unlock_irqrestore(&db->lock, flags);
711
712                 /* Now free them */
713                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
714                         hlist_del(&obj->node);
715                         free_object(obj);
716                 }
717
718                 if (cnt > debug_objects_maxchain)
719                         debug_objects_maxchain = cnt;
720         }
721 }
722
723 void debug_check_no_obj_freed(const void *address, unsigned long size)
724 {
725         if (debug_objects_enabled)
726                 __debug_check_no_obj_freed(address, size);
727 }
728 #endif
729
730 #ifdef CONFIG_DEBUG_FS
731
732 static int debug_stats_show(struct seq_file *m, void *v)
733 {
734         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
735         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
736         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
737         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
738         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
739         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
740         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
741         return 0;
742 }
743
744 static int debug_stats_open(struct inode *inode, struct file *filp)
745 {
746         return single_open(filp, debug_stats_show, NULL);
747 }
748
749 static const struct file_operations debug_stats_fops = {
750         .open           = debug_stats_open,
751         .read           = seq_read,
752         .llseek         = seq_lseek,
753         .release        = single_release,
754 };
755
756 static int __init debug_objects_init_debugfs(void)
757 {
758         struct dentry *dbgdir, *dbgstats;
759
760         if (!debug_objects_enabled)
761                 return 0;
762
763         dbgdir = debugfs_create_dir("debug_objects", NULL);
764         if (!dbgdir)
765                 return -ENOMEM;
766
767         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
768                                        &debug_stats_fops);
769         if (!dbgstats)
770                 goto err;
771
772         return 0;
773
774 err:
775         debugfs_remove(dbgdir);
776
777         return -ENOMEM;
778 }
779 __initcall(debug_objects_init_debugfs);
780
781 #else
782 static inline void debug_objects_init_debugfs(void) { }
783 #endif
784
785 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
786
787 /* Random data structure for the self test */
788 struct self_test {
789         unsigned long   dummy1[6];
790         int             static_init;
791         unsigned long   dummy2[3];
792 };
793
794 static __initdata struct debug_obj_descr descr_type_test;
795
796 /*
797  * fixup_init is called when:
798  * - an active object is initialized
799  */
800 static int __init fixup_init(void *addr, enum debug_obj_state state)
801 {
802         struct self_test *obj = addr;
803
804         switch (state) {
805         case ODEBUG_STATE_ACTIVE:
806                 debug_object_deactivate(obj, &descr_type_test);
807                 debug_object_init(obj, &descr_type_test);
808                 return 1;
809         default:
810                 return 0;
811         }
812 }
813
814 /*
815  * fixup_activate is called when:
816  * - an active object is activated
817  * - an unknown object is activated (might be a statically initialized object)
818  */
819 static int __init fixup_activate(void *addr, enum debug_obj_state state)
820 {
821         struct self_test *obj = addr;
822
823         switch (state) {
824         case ODEBUG_STATE_NOTAVAILABLE:
825                 if (obj->static_init == 1) {
826                         debug_object_init(obj, &descr_type_test);
827                         debug_object_activate(obj, &descr_type_test);
828                         return 0;
829                 }
830                 return 1;
831
832         case ODEBUG_STATE_ACTIVE:
833                 debug_object_deactivate(obj, &descr_type_test);
834                 debug_object_activate(obj, &descr_type_test);
835                 return 1;
836
837         default:
838                 return 0;
839         }
840 }
841
842 /*
843  * fixup_destroy is called when:
844  * - an active object is destroyed
845  */
846 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
847 {
848         struct self_test *obj = addr;
849
850         switch (state) {
851         case ODEBUG_STATE_ACTIVE:
852                 debug_object_deactivate(obj, &descr_type_test);
853                 debug_object_destroy(obj, &descr_type_test);
854                 return 1;
855         default:
856                 return 0;
857         }
858 }
859
860 /*
861  * fixup_free is called when:
862  * - an active object is freed
863  */
864 static int __init fixup_free(void *addr, enum debug_obj_state state)
865 {
866         struct self_test *obj = addr;
867
868         switch (state) {
869         case ODEBUG_STATE_ACTIVE:
870                 debug_object_deactivate(obj, &descr_type_test);
871                 debug_object_free(obj, &descr_type_test);
872                 return 1;
873         default:
874                 return 0;
875         }
876 }
877
878 static int __init
879 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
880 {
881         struct debug_bucket *db;
882         struct debug_obj *obj;
883         unsigned long flags;
884         int res = -EINVAL;
885
886         db = get_bucket((unsigned long) addr);
887
888         raw_spin_lock_irqsave(&db->lock, flags);
889
890         obj = lookup_object(addr, db);
891         if (!obj && state != ODEBUG_STATE_NONE) {
892                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
893                 goto out;
894         }
895         if (obj && obj->state != state) {
896                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
897                        obj->state, state);
898                 goto out;
899         }
900         if (fixups != debug_objects_fixups) {
901                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
902                        fixups, debug_objects_fixups);
903                 goto out;
904         }
905         if (warnings != debug_objects_warnings) {
906                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
907                        warnings, debug_objects_warnings);
908                 goto out;
909         }
910         res = 0;
911 out:
912         raw_spin_unlock_irqrestore(&db->lock, flags);
913         if (res)
914                 debug_objects_enabled = 0;
915         return res;
916 }
917
918 static __initdata struct debug_obj_descr descr_type_test = {
919         .name                   = "selftest",
920         .fixup_init             = fixup_init,
921         .fixup_activate         = fixup_activate,
922         .fixup_destroy          = fixup_destroy,
923         .fixup_free             = fixup_free,
924 };
925
926 static __initdata struct self_test obj = { .static_init = 0 };
927
928 static void __init debug_objects_selftest(void)
929 {
930         int fixups, oldfixups, warnings, oldwarnings;
931         unsigned long flags;
932
933         local_irq_save(flags);
934
935         fixups = oldfixups = debug_objects_fixups;
936         warnings = oldwarnings = debug_objects_warnings;
937         descr_test = &descr_type_test;
938
939         debug_object_init(&obj, &descr_type_test);
940         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
941                 goto out;
942         debug_object_activate(&obj, &descr_type_test);
943         if (check_results(&obj, ODEBUG_STATE_ACTIVE, 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_deactivate(&obj, &descr_type_test);
949         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
950                 goto out;
951         debug_object_destroy(&obj, &descr_type_test);
952         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
953                 goto out;
954         debug_object_init(&obj, &descr_type_test);
955         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
956                 goto out;
957         debug_object_activate(&obj, &descr_type_test);
958         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
959                 goto out;
960         debug_object_deactivate(&obj, &descr_type_test);
961         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
962                 goto out;
963         debug_object_free(&obj, &descr_type_test);
964         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
965                 goto out;
966
967         obj.static_init = 1;
968         debug_object_activate(&obj, &descr_type_test);
969         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
970                 goto out;
971         debug_object_init(&obj, &descr_type_test);
972         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
973                 goto out;
974         debug_object_free(&obj, &descr_type_test);
975         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
976                 goto out;
977
978 #ifdef CONFIG_DEBUG_OBJECTS_FREE
979         debug_object_init(&obj, &descr_type_test);
980         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
981                 goto out;
982         debug_object_activate(&obj, &descr_type_test);
983         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
984                 goto out;
985         __debug_check_no_obj_freed(&obj, sizeof(obj));
986         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
987                 goto out;
988 #endif
989         pr_info("selftest passed\n");
990
991 out:
992         debug_objects_fixups = oldfixups;
993         debug_objects_warnings = oldwarnings;
994         descr_test = NULL;
995
996         local_irq_restore(flags);
997 }
998 #else
999 static inline void debug_objects_selftest(void) { }
1000 #endif
1001
1002 /*
1003  * Called during early boot to initialize the hash buckets and link
1004  * the static object pool objects into the poll list. After this call
1005  * the object tracker is fully operational.
1006  */
1007 void __init debug_objects_early_init(void)
1008 {
1009         int i;
1010
1011         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1012                 raw_spin_lock_init(&obj_hash[i].lock);
1013
1014         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1015                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1016 }
1017
1018 /*
1019  * Convert the statically allocated objects to dynamic ones:
1020  */
1021 static int __init debug_objects_replace_static_objects(void)
1022 {
1023         struct debug_bucket *db = obj_hash;
1024         struct hlist_node *tmp;
1025         struct debug_obj *obj, *new;
1026         HLIST_HEAD(objects);
1027         int i, cnt = 0;
1028
1029         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1030                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1031                 if (!obj)
1032                         goto free;
1033                 hlist_add_head(&obj->node, &objects);
1034         }
1035
1036         /*
1037          * When debug_objects_mem_init() is called we know that only
1038          * one CPU is up, so disabling interrupts is enough
1039          * protection. This avoids the lockdep hell of lock ordering.
1040          */
1041         local_irq_disable();
1042
1043         /* Remove the statically allocated objects from the pool */
1044         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1045                 hlist_del(&obj->node);
1046         /* Move the allocated objects to the pool */
1047         hlist_move_list(&objects, &obj_pool);
1048
1049         /* Replace the active object references */
1050         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1051                 hlist_move_list(&db->list, &objects);
1052
1053                 hlist_for_each_entry(obj, &objects, node) {
1054                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1055                         hlist_del(&new->node);
1056                         /* copy object data */
1057                         *new = *obj;
1058                         hlist_add_head(&new->node, &db->list);
1059                         cnt++;
1060                 }
1061         }
1062         local_irq_enable();
1063
1064         pr_debug("%d of %d active objects replaced\n",
1065                  cnt, obj_pool_used);
1066         return 0;
1067 free:
1068         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1069                 hlist_del(&obj->node);
1070                 kmem_cache_free(obj_cache, obj);
1071         }
1072         return -ENOMEM;
1073 }
1074
1075 /*
1076  * Called after the kmem_caches are functional to setup a dedicated
1077  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1078  * prevents that the debug code is called on kmem_cache_free() for the
1079  * debug tracker objects to avoid recursive calls.
1080  */
1081 void __init debug_objects_mem_init(void)
1082 {
1083         if (!debug_objects_enabled)
1084                 return;
1085
1086         obj_cache = kmem_cache_create("debug_objects_cache",
1087                                       sizeof (struct debug_obj), 0,
1088                                       SLAB_DEBUG_OBJECTS, NULL);
1089
1090         if (!obj_cache || debug_objects_replace_static_objects()) {
1091                 debug_objects_enabled = 0;
1092                 if (obj_cache)
1093                         kmem_cache_destroy(obj_cache);
1094                 pr_warn("out of memory.\n");
1095         } else
1096                 debug_objects_selftest();
1097 }