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
enable_object_debug(char * str)61 static int __init enable_object_debug(char *str)
62 {
63 debug_objects_enabled = 1;
64 return 0;
65 }
66
disable_object_debug(char * str)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
fill_pool(void)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 */
lookup_object(void * addr,struct debug_bucket * b)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 *
alloc_object(void * addr,struct debug_bucket * b,struct debug_obj_descr * descr)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 */
free_obj_work(struct work_struct * work)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 */
free_object(struct debug_obj * obj)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 */
debug_objects_oom(void)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 */
get_bucket(unsigned long addr)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
debug_print_object(struct debug_obj * obj,char * msg)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
debug_object_fixup(int (* fixup)(void * addr,enum debug_obj_state state),void * addr,enum debug_obj_state state)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
debug_object_is_on_stack(void * addr,int onstack)284 static void debug_object_is_on_stack(void *addr, int onstack)
285 {
286 int is_on_stack;
287 static int limit;
288
289 if (limit > 4)
290 return;
291
292 is_on_stack = object_is_on_stack(addr);
293 if (is_on_stack == onstack)
294 return;
295
296 limit++;
297 if (is_on_stack)
298 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
299 task_stack_page(current));
300 else
301 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
302 task_stack_page(current));
303
304 WARN_ON(1);
305 }
306
307 static void
__debug_object_init(void * addr,struct debug_obj_descr * descr,int onstack)308 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
309 {
310 enum debug_obj_state state;
311 struct debug_bucket *db;
312 struct debug_obj *obj;
313 unsigned long flags;
314
315 fill_pool();
316
317 db = get_bucket((unsigned long) addr);
318
319 raw_spin_lock_irqsave(&db->lock, flags);
320
321 obj = lookup_object(addr, db);
322 if (!obj) {
323 obj = alloc_object(addr, db, descr);
324 if (!obj) {
325 debug_objects_enabled = 0;
326 raw_spin_unlock_irqrestore(&db->lock, flags);
327 debug_objects_oom();
328 return;
329 }
330 debug_object_is_on_stack(addr, onstack);
331 }
332
333 switch (obj->state) {
334 case ODEBUG_STATE_NONE:
335 case ODEBUG_STATE_INIT:
336 case ODEBUG_STATE_INACTIVE:
337 obj->state = ODEBUG_STATE_INIT;
338 break;
339
340 case ODEBUG_STATE_ACTIVE:
341 debug_print_object(obj, "init");
342 state = obj->state;
343 raw_spin_unlock_irqrestore(&db->lock, flags);
344 debug_object_fixup(descr->fixup_init, addr, state);
345 return;
346
347 case ODEBUG_STATE_DESTROYED:
348 debug_print_object(obj, "init");
349 break;
350 default:
351 break;
352 }
353
354 raw_spin_unlock_irqrestore(&db->lock, flags);
355 }
356
357 /**
358 * debug_object_init - debug checks when an object is initialized
359 * @addr: address of the object
360 * @descr: pointer to an object specific debug description structure
361 */
debug_object_init(void * addr,struct debug_obj_descr * descr)362 void debug_object_init(void *addr, struct debug_obj_descr *descr)
363 {
364 if (!debug_objects_enabled)
365 return;
366
367 __debug_object_init(addr, descr, 0);
368 }
369
370 /**
371 * debug_object_init_on_stack - debug checks when an object on stack is
372 * initialized
373 * @addr: address of the object
374 * @descr: pointer to an object specific debug description structure
375 */
debug_object_init_on_stack(void * addr,struct debug_obj_descr * descr)376 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
377 {
378 if (!debug_objects_enabled)
379 return;
380
381 __debug_object_init(addr, descr, 1);
382 }
383
384 /**
385 * debug_object_activate - debug checks when an object is activated
386 * @addr: address of the object
387 * @descr: pointer to an object specific debug description structure
388 * Returns 0 for success, -EINVAL for check failed.
389 */
debug_object_activate(void * addr,struct debug_obj_descr * descr)390 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
391 {
392 enum debug_obj_state state;
393 struct debug_bucket *db;
394 struct debug_obj *obj;
395 unsigned long flags;
396 int ret;
397 struct debug_obj o = { .object = addr,
398 .state = ODEBUG_STATE_NOTAVAILABLE,
399 .descr = descr };
400
401 if (!debug_objects_enabled)
402 return 0;
403
404 db = get_bucket((unsigned long) addr);
405
406 raw_spin_lock_irqsave(&db->lock, flags);
407
408 obj = lookup_object(addr, db);
409 if (obj) {
410 switch (obj->state) {
411 case ODEBUG_STATE_INIT:
412 case ODEBUG_STATE_INACTIVE:
413 obj->state = ODEBUG_STATE_ACTIVE;
414 ret = 0;
415 break;
416
417 case ODEBUG_STATE_ACTIVE:
418 debug_print_object(obj, "activate");
419 state = obj->state;
420 raw_spin_unlock_irqrestore(&db->lock, flags);
421 ret = debug_object_fixup(descr->fixup_activate, addr, state);
422 return ret ? -EINVAL : 0;
423
424 case ODEBUG_STATE_DESTROYED:
425 debug_print_object(obj, "activate");
426 ret = -EINVAL;
427 break;
428 default:
429 ret = 0;
430 break;
431 }
432 raw_spin_unlock_irqrestore(&db->lock, flags);
433 return ret;
434 }
435
436 raw_spin_unlock_irqrestore(&db->lock, flags);
437 /*
438 * This happens when a static object is activated. We
439 * let the type specific code decide whether this is
440 * true or not.
441 */
442 if (debug_object_fixup(descr->fixup_activate, addr,
443 ODEBUG_STATE_NOTAVAILABLE)) {
444 debug_print_object(&o, "activate");
445 return -EINVAL;
446 }
447 return 0;
448 }
449
450 /**
451 * debug_object_deactivate - debug checks when an object is deactivated
452 * @addr: address of the object
453 * @descr: pointer to an object specific debug description structure
454 */
debug_object_deactivate(void * addr,struct debug_obj_descr * descr)455 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
456 {
457 struct debug_bucket *db;
458 struct debug_obj *obj;
459 unsigned long flags;
460
461 if (!debug_objects_enabled)
462 return;
463
464 db = get_bucket((unsigned long) addr);
465
466 raw_spin_lock_irqsave(&db->lock, flags);
467
468 obj = lookup_object(addr, db);
469 if (obj) {
470 switch (obj->state) {
471 case ODEBUG_STATE_INIT:
472 case ODEBUG_STATE_INACTIVE:
473 case ODEBUG_STATE_ACTIVE:
474 if (!obj->astate)
475 obj->state = ODEBUG_STATE_INACTIVE;
476 else
477 debug_print_object(obj, "deactivate");
478 break;
479
480 case ODEBUG_STATE_DESTROYED:
481 debug_print_object(obj, "deactivate");
482 break;
483 default:
484 break;
485 }
486 } else {
487 struct debug_obj o = { .object = addr,
488 .state = ODEBUG_STATE_NOTAVAILABLE,
489 .descr = descr };
490
491 debug_print_object(&o, "deactivate");
492 }
493
494 raw_spin_unlock_irqrestore(&db->lock, flags);
495 }
496
497 /**
498 * debug_object_destroy - debug checks when an object is destroyed
499 * @addr: address of the object
500 * @descr: pointer to an object specific debug description structure
501 */
debug_object_destroy(void * addr,struct debug_obj_descr * descr)502 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
503 {
504 enum debug_obj_state state;
505 struct debug_bucket *db;
506 struct debug_obj *obj;
507 unsigned long flags;
508
509 if (!debug_objects_enabled)
510 return;
511
512 db = get_bucket((unsigned long) addr);
513
514 raw_spin_lock_irqsave(&db->lock, flags);
515
516 obj = lookup_object(addr, db);
517 if (!obj)
518 goto out_unlock;
519
520 switch (obj->state) {
521 case ODEBUG_STATE_NONE:
522 case ODEBUG_STATE_INIT:
523 case ODEBUG_STATE_INACTIVE:
524 obj->state = ODEBUG_STATE_DESTROYED;
525 break;
526 case ODEBUG_STATE_ACTIVE:
527 debug_print_object(obj, "destroy");
528 state = obj->state;
529 raw_spin_unlock_irqrestore(&db->lock, flags);
530 debug_object_fixup(descr->fixup_destroy, addr, state);
531 return;
532
533 case ODEBUG_STATE_DESTROYED:
534 debug_print_object(obj, "destroy");
535 break;
536 default:
537 break;
538 }
539 out_unlock:
540 raw_spin_unlock_irqrestore(&db->lock, flags);
541 }
542
543 /**
544 * debug_object_free - debug checks when an object is freed
545 * @addr: address of the object
546 * @descr: pointer to an object specific debug description structure
547 */
debug_object_free(void * addr,struct debug_obj_descr * descr)548 void debug_object_free(void *addr, struct debug_obj_descr *descr)
549 {
550 enum debug_obj_state state;
551 struct debug_bucket *db;
552 struct debug_obj *obj;
553 unsigned long flags;
554
555 if (!debug_objects_enabled)
556 return;
557
558 db = get_bucket((unsigned long) addr);
559
560 raw_spin_lock_irqsave(&db->lock, flags);
561
562 obj = lookup_object(addr, db);
563 if (!obj)
564 goto out_unlock;
565
566 switch (obj->state) {
567 case ODEBUG_STATE_ACTIVE:
568 debug_print_object(obj, "free");
569 state = obj->state;
570 raw_spin_unlock_irqrestore(&db->lock, flags);
571 debug_object_fixup(descr->fixup_free, addr, state);
572 return;
573 default:
574 hlist_del(&obj->node);
575 raw_spin_unlock_irqrestore(&db->lock, flags);
576 free_object(obj);
577 return;
578 }
579 out_unlock:
580 raw_spin_unlock_irqrestore(&db->lock, flags);
581 }
582
583 /**
584 * debug_object_assert_init - debug checks when object should be init-ed
585 * @addr: address of the object
586 * @descr: pointer to an object specific debug description structure
587 */
debug_object_assert_init(void * addr,struct debug_obj_descr * descr)588 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
589 {
590 struct debug_bucket *db;
591 struct debug_obj *obj;
592 unsigned long flags;
593
594 if (!debug_objects_enabled)
595 return;
596
597 db = get_bucket((unsigned long) addr);
598
599 raw_spin_lock_irqsave(&db->lock, flags);
600
601 obj = lookup_object(addr, db);
602 if (!obj) {
603 struct debug_obj o = { .object = addr,
604 .state = ODEBUG_STATE_NOTAVAILABLE,
605 .descr = descr };
606
607 raw_spin_unlock_irqrestore(&db->lock, flags);
608 /*
609 * Maybe the object is static. Let the type specific
610 * code decide what to do.
611 */
612 if (debug_object_fixup(descr->fixup_assert_init, addr,
613 ODEBUG_STATE_NOTAVAILABLE))
614 debug_print_object(&o, "assert_init");
615 return;
616 }
617
618 raw_spin_unlock_irqrestore(&db->lock, flags);
619 }
620
621 /**
622 * debug_object_active_state - debug checks object usage state machine
623 * @addr: address of the object
624 * @descr: pointer to an object specific debug description structure
625 * @expect: expected state
626 * @next: state to move to if expected state is found
627 */
628 void
debug_object_active_state(void * addr,struct debug_obj_descr * descr,unsigned int expect,unsigned int next)629 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
630 unsigned int expect, unsigned int next)
631 {
632 struct debug_bucket *db;
633 struct debug_obj *obj;
634 unsigned long flags;
635
636 if (!debug_objects_enabled)
637 return;
638
639 db = get_bucket((unsigned long) addr);
640
641 raw_spin_lock_irqsave(&db->lock, flags);
642
643 obj = lookup_object(addr, db);
644 if (obj) {
645 switch (obj->state) {
646 case ODEBUG_STATE_ACTIVE:
647 if (obj->astate == expect)
648 obj->astate = next;
649 else
650 debug_print_object(obj, "active_state");
651 break;
652
653 default:
654 debug_print_object(obj, "active_state");
655 break;
656 }
657 } else {
658 struct debug_obj o = { .object = addr,
659 .state = ODEBUG_STATE_NOTAVAILABLE,
660 .descr = descr };
661
662 debug_print_object(&o, "active_state");
663 }
664
665 raw_spin_unlock_irqrestore(&db->lock, flags);
666 }
667
668 #ifdef CONFIG_DEBUG_OBJECTS_FREE
__debug_check_no_obj_freed(const void * address,unsigned long size)669 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
670 {
671 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
672 struct hlist_node *tmp;
673 HLIST_HEAD(freelist);
674 struct debug_obj_descr *descr;
675 enum debug_obj_state state;
676 struct debug_bucket *db;
677 struct debug_obj *obj;
678 int cnt;
679
680 saddr = (unsigned long) address;
681 eaddr = saddr + size;
682 paddr = saddr & ODEBUG_CHUNK_MASK;
683 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
684 chunks >>= ODEBUG_CHUNK_SHIFT;
685
686 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
687 db = get_bucket(paddr);
688
689 repeat:
690 cnt = 0;
691 raw_spin_lock_irqsave(&db->lock, flags);
692 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
693 cnt++;
694 oaddr = (unsigned long) obj->object;
695 if (oaddr < saddr || oaddr >= eaddr)
696 continue;
697
698 switch (obj->state) {
699 case ODEBUG_STATE_ACTIVE:
700 debug_print_object(obj, "free");
701 descr = obj->descr;
702 state = obj->state;
703 raw_spin_unlock_irqrestore(&db->lock, flags);
704 debug_object_fixup(descr->fixup_free,
705 (void *) oaddr, state);
706 goto repeat;
707 default:
708 hlist_del(&obj->node);
709 hlist_add_head(&obj->node, &freelist);
710 break;
711 }
712 }
713 raw_spin_unlock_irqrestore(&db->lock, flags);
714
715 /* Now free them */
716 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
717 hlist_del(&obj->node);
718 free_object(obj);
719 }
720
721 if (cnt > debug_objects_maxchain)
722 debug_objects_maxchain = cnt;
723 }
724 }
725
debug_check_no_obj_freed(const void * address,unsigned long size)726 void debug_check_no_obj_freed(const void *address, unsigned long size)
727 {
728 if (debug_objects_enabled)
729 __debug_check_no_obj_freed(address, size);
730 }
731 #endif
732
733 #ifdef CONFIG_DEBUG_FS
734
debug_stats_show(struct seq_file * m,void * v)735 static int debug_stats_show(struct seq_file *m, void *v)
736 {
737 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
738 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
739 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
740 seq_printf(m, "pool_free :%d\n", obj_pool_free);
741 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
742 seq_printf(m, "pool_used :%d\n", obj_pool_used);
743 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
744 return 0;
745 }
746
debug_stats_open(struct inode * inode,struct file * filp)747 static int debug_stats_open(struct inode *inode, struct file *filp)
748 {
749 return single_open(filp, debug_stats_show, NULL);
750 }
751
752 static const struct file_operations debug_stats_fops = {
753 .open = debug_stats_open,
754 .read = seq_read,
755 .llseek = seq_lseek,
756 .release = single_release,
757 };
758
debug_objects_init_debugfs(void)759 static int __init debug_objects_init_debugfs(void)
760 {
761 struct dentry *dbgdir, *dbgstats;
762
763 if (!debug_objects_enabled)
764 return 0;
765
766 dbgdir = debugfs_create_dir("debug_objects", NULL);
767 if (!dbgdir)
768 return -ENOMEM;
769
770 dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
771 &debug_stats_fops);
772 if (!dbgstats)
773 goto err;
774
775 return 0;
776
777 err:
778 debugfs_remove(dbgdir);
779
780 return -ENOMEM;
781 }
782 __initcall(debug_objects_init_debugfs);
783
784 #else
debug_objects_init_debugfs(void)785 static inline void debug_objects_init_debugfs(void) { }
786 #endif
787
788 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
789
790 /* Random data structure for the self test */
791 struct self_test {
792 unsigned long dummy1[6];
793 int static_init;
794 unsigned long dummy2[3];
795 };
796
797 static __initdata struct debug_obj_descr descr_type_test;
798
799 /*
800 * fixup_init is called when:
801 * - an active object is initialized
802 */
fixup_init(void * addr,enum debug_obj_state state)803 static int __init fixup_init(void *addr, enum debug_obj_state state)
804 {
805 struct self_test *obj = addr;
806
807 switch (state) {
808 case ODEBUG_STATE_ACTIVE:
809 debug_object_deactivate(obj, &descr_type_test);
810 debug_object_init(obj, &descr_type_test);
811 return 1;
812 default:
813 return 0;
814 }
815 }
816
817 /*
818 * fixup_activate is called when:
819 * - an active object is activated
820 * - an unknown object is activated (might be a statically initialized object)
821 */
fixup_activate(void * addr,enum debug_obj_state state)822 static int __init fixup_activate(void *addr, enum debug_obj_state state)
823 {
824 struct self_test *obj = addr;
825
826 switch (state) {
827 case ODEBUG_STATE_NOTAVAILABLE:
828 if (obj->static_init == 1) {
829 debug_object_init(obj, &descr_type_test);
830 debug_object_activate(obj, &descr_type_test);
831 return 0;
832 }
833 return 1;
834
835 case ODEBUG_STATE_ACTIVE:
836 debug_object_deactivate(obj, &descr_type_test);
837 debug_object_activate(obj, &descr_type_test);
838 return 1;
839
840 default:
841 return 0;
842 }
843 }
844
845 /*
846 * fixup_destroy is called when:
847 * - an active object is destroyed
848 */
fixup_destroy(void * addr,enum debug_obj_state state)849 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
850 {
851 struct self_test *obj = addr;
852
853 switch (state) {
854 case ODEBUG_STATE_ACTIVE:
855 debug_object_deactivate(obj, &descr_type_test);
856 debug_object_destroy(obj, &descr_type_test);
857 return 1;
858 default:
859 return 0;
860 }
861 }
862
863 /*
864 * fixup_free is called when:
865 * - an active object is freed
866 */
fixup_free(void * addr,enum debug_obj_state state)867 static int __init fixup_free(void *addr, enum debug_obj_state state)
868 {
869 struct self_test *obj = addr;
870
871 switch (state) {
872 case ODEBUG_STATE_ACTIVE:
873 debug_object_deactivate(obj, &descr_type_test);
874 debug_object_free(obj, &descr_type_test);
875 return 1;
876 default:
877 return 0;
878 }
879 }
880
881 static int __init
check_results(void * addr,enum debug_obj_state state,int fixups,int warnings)882 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
883 {
884 struct debug_bucket *db;
885 struct debug_obj *obj;
886 unsigned long flags;
887 int res = -EINVAL;
888
889 db = get_bucket((unsigned long) addr);
890
891 raw_spin_lock_irqsave(&db->lock, flags);
892
893 obj = lookup_object(addr, db);
894 if (!obj && state != ODEBUG_STATE_NONE) {
895 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
896 goto out;
897 }
898 if (obj && obj->state != state) {
899 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
900 obj->state, state);
901 goto out;
902 }
903 if (fixups != debug_objects_fixups) {
904 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
905 fixups, debug_objects_fixups);
906 goto out;
907 }
908 if (warnings != debug_objects_warnings) {
909 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
910 warnings, debug_objects_warnings);
911 goto out;
912 }
913 res = 0;
914 out:
915 raw_spin_unlock_irqrestore(&db->lock, flags);
916 if (res)
917 debug_objects_enabled = 0;
918 return res;
919 }
920
921 static __initdata struct debug_obj_descr descr_type_test = {
922 .name = "selftest",
923 .fixup_init = fixup_init,
924 .fixup_activate = fixup_activate,
925 .fixup_destroy = fixup_destroy,
926 .fixup_free = fixup_free,
927 };
928
929 static __initdata struct self_test obj = { .static_init = 0 };
930
debug_objects_selftest(void)931 static void __init debug_objects_selftest(void)
932 {
933 int fixups, oldfixups, warnings, oldwarnings;
934 unsigned long flags;
935
936 local_irq_save(flags);
937
938 fixups = oldfixups = debug_objects_fixups;
939 warnings = oldwarnings = debug_objects_warnings;
940 descr_test = &descr_type_test;
941
942 debug_object_init(&obj, &descr_type_test);
943 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
944 goto out;
945 debug_object_activate(&obj, &descr_type_test);
946 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
947 goto out;
948 debug_object_activate(&obj, &descr_type_test);
949 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
950 goto out;
951 debug_object_deactivate(&obj, &descr_type_test);
952 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
953 goto out;
954 debug_object_destroy(&obj, &descr_type_test);
955 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
956 goto out;
957 debug_object_init(&obj, &descr_type_test);
958 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
959 goto out;
960 debug_object_activate(&obj, &descr_type_test);
961 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
962 goto out;
963 debug_object_deactivate(&obj, &descr_type_test);
964 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
965 goto out;
966 debug_object_free(&obj, &descr_type_test);
967 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
968 goto out;
969
970 obj.static_init = 1;
971 debug_object_activate(&obj, &descr_type_test);
972 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
973 goto out;
974 debug_object_init(&obj, &descr_type_test);
975 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
976 goto out;
977 debug_object_free(&obj, &descr_type_test);
978 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
979 goto out;
980
981 #ifdef CONFIG_DEBUG_OBJECTS_FREE
982 debug_object_init(&obj, &descr_type_test);
983 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
984 goto out;
985 debug_object_activate(&obj, &descr_type_test);
986 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
987 goto out;
988 __debug_check_no_obj_freed(&obj, sizeof(obj));
989 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
990 goto out;
991 #endif
992 pr_info("selftest passed\n");
993
994 out:
995 debug_objects_fixups = oldfixups;
996 debug_objects_warnings = oldwarnings;
997 descr_test = NULL;
998
999 local_irq_restore(flags);
1000 }
1001 #else
debug_objects_selftest(void)1002 static inline void debug_objects_selftest(void) { }
1003 #endif
1004
1005 /*
1006 * Called during early boot to initialize the hash buckets and link
1007 * the static object pool objects into the poll list. After this call
1008 * the object tracker is fully operational.
1009 */
debug_objects_early_init(void)1010 void __init debug_objects_early_init(void)
1011 {
1012 int i;
1013
1014 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1015 raw_spin_lock_init(&obj_hash[i].lock);
1016
1017 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1018 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1019 }
1020
1021 /*
1022 * Convert the statically allocated objects to dynamic ones:
1023 */
debug_objects_replace_static_objects(void)1024 static int __init debug_objects_replace_static_objects(void)
1025 {
1026 struct debug_bucket *db = obj_hash;
1027 struct hlist_node *tmp;
1028 struct debug_obj *obj, *new;
1029 HLIST_HEAD(objects);
1030 int i, cnt = 0;
1031
1032 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1033 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1034 if (!obj)
1035 goto free;
1036 hlist_add_head(&obj->node, &objects);
1037 }
1038
1039 /*
1040 * When debug_objects_mem_init() is called we know that only
1041 * one CPU is up, so disabling interrupts is enough
1042 * protection. This avoids the lockdep hell of lock ordering.
1043 */
1044 local_irq_disable();
1045
1046 /* Remove the statically allocated objects from the pool */
1047 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1048 hlist_del(&obj->node);
1049 /* Move the allocated objects to the pool */
1050 hlist_move_list(&objects, &obj_pool);
1051
1052 /* Replace the active object references */
1053 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1054 hlist_move_list(&db->list, &objects);
1055
1056 hlist_for_each_entry(obj, &objects, node) {
1057 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1058 hlist_del(&new->node);
1059 /* copy object data */
1060 *new = *obj;
1061 hlist_add_head(&new->node, &db->list);
1062 cnt++;
1063 }
1064 }
1065 local_irq_enable();
1066
1067 pr_debug("%d of %d active objects replaced\n",
1068 cnt, obj_pool_used);
1069 return 0;
1070 free:
1071 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1072 hlist_del(&obj->node);
1073 kmem_cache_free(obj_cache, obj);
1074 }
1075 return -ENOMEM;
1076 }
1077
1078 /*
1079 * Called after the kmem_caches are functional to setup a dedicated
1080 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1081 * prevents that the debug code is called on kmem_cache_free() for the
1082 * debug tracker objects to avoid recursive calls.
1083 */
debug_objects_mem_init(void)1084 void __init debug_objects_mem_init(void)
1085 {
1086 if (!debug_objects_enabled)
1087 return;
1088
1089 obj_cache = kmem_cache_create("debug_objects_cache",
1090 sizeof (struct debug_obj), 0,
1091 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1092 NULL);
1093
1094 if (!obj_cache || debug_objects_replace_static_objects()) {
1095 debug_objects_enabled = 0;
1096 if (obj_cache)
1097 kmem_cache_destroy(obj_cache);
1098 pr_warn("out of memory.\n");
1099 } else
1100 debug_objects_selftest();
1101 }
1102