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TOMOYO Linux Cross Reference
Linux/lib/debugobjects.c

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

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