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

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