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/sched/task_stack.h>
17 #include <linux/seq_file.h>
18 #include <linux/debugfs.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/kmemleak.h>
22
23 #define ODEBUG_HASH_BITS 14
24 #define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
25
26 #define ODEBUG_POOL_SIZE 1024
27 #define ODEBUG_POOL_MIN_LEVEL 256
28
29 #define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
30 #define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
31 #define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
32
33 struct debug_bucket {
34 struct hlist_head list;
35 raw_spinlock_t lock;
36 };
37
38 static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
39
40 static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
41
42 static DEFINE_RAW_SPINLOCK(pool_lock);
43
44 static HLIST_HEAD(obj_pool);
45
46 static int obj_pool_min_free = ODEBUG_POOL_SIZE;
47 static int obj_pool_free = ODEBUG_POOL_SIZE;
48 static int obj_pool_used;
49 static int obj_pool_max_used;
50 static struct kmem_cache *obj_cache;
51
52 static int debug_objects_maxchain __read_mostly;
53 static int debug_objects_fixups __read_mostly;
54 static int debug_objects_warnings __read_mostly;
55 static int debug_objects_enabled __read_mostly
56 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
57 static int debug_objects_pool_size __read_mostly
58 = ODEBUG_POOL_SIZE;
59 static int debug_objects_pool_min_level __read_mostly
60 = ODEBUG_POOL_MIN_LEVEL;
61 static struct debug_obj_descr *descr_test __read_mostly;
62
63 /*
64 * Track numbers of kmem_cache_alloc()/free() calls done.
65 */
66 static int debug_objects_allocated;
67 static int debug_objects_freed;
68
69 static void free_obj_work(struct work_struct *work);
70 static DECLARE_WORK(debug_obj_work, free_obj_work);
71
enable_object_debug(char * str)72 static int __init enable_object_debug(char *str)
73 {
74 debug_objects_enabled = 1;
75 return 0;
76 }
77
disable_object_debug(char * str)78 static int __init disable_object_debug(char *str)
79 {
80 debug_objects_enabled = 0;
81 return 0;
82 }
83
84 early_param("debug_objects", enable_object_debug);
85 early_param("no_debug_objects", disable_object_debug);
86
87 static const char *obj_states[ODEBUG_STATE_MAX] = {
88 [ODEBUG_STATE_NONE] = "none",
89 [ODEBUG_STATE_INIT] = "initialized",
90 [ODEBUG_STATE_INACTIVE] = "inactive",
91 [ODEBUG_STATE_ACTIVE] = "active",
92 [ODEBUG_STATE_DESTROYED] = "destroyed",
93 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
94 };
95
fill_pool(void)96 static void fill_pool(void)
97 {
98 gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
99 struct debug_obj *new;
100 unsigned long flags;
101
102 if (likely(obj_pool_free >= debug_objects_pool_min_level))
103 return;
104
105 if (unlikely(!obj_cache))
106 return;
107
108 while (obj_pool_free < debug_objects_pool_min_level) {
109
110 new = kmem_cache_zalloc(obj_cache, gfp);
111 if (!new)
112 return;
113
114 raw_spin_lock_irqsave(&pool_lock, flags);
115 hlist_add_head(&new->node, &obj_pool);
116 debug_objects_allocated++;
117 obj_pool_free++;
118 raw_spin_unlock_irqrestore(&pool_lock, flags);
119 }
120 }
121
122 /*
123 * Lookup an object in the hash bucket.
124 */
lookup_object(void * addr,struct debug_bucket * b)125 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
126 {
127 struct debug_obj *obj;
128 int cnt = 0;
129
130 hlist_for_each_entry(obj, &b->list, node) {
131 cnt++;
132 if (obj->object == addr)
133 return obj;
134 }
135 if (cnt > debug_objects_maxchain)
136 debug_objects_maxchain = cnt;
137
138 return NULL;
139 }
140
141 /*
142 * Allocate a new object. If the pool is empty, switch off the debugger.
143 * Must be called with interrupts disabled.
144 */
145 static struct debug_obj *
alloc_object(void * addr,struct debug_bucket * b,struct debug_obj_descr * descr)146 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
147 {
148 struct debug_obj *obj = NULL;
149
150 raw_spin_lock(&pool_lock);
151 if (obj_pool.first) {
152 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
153
154 obj->object = addr;
155 obj->descr = descr;
156 obj->state = ODEBUG_STATE_NONE;
157 obj->astate = 0;
158 hlist_del(&obj->node);
159
160 hlist_add_head(&obj->node, &b->list);
161
162 obj_pool_used++;
163 if (obj_pool_used > obj_pool_max_used)
164 obj_pool_max_used = obj_pool_used;
165
166 obj_pool_free--;
167 if (obj_pool_free < obj_pool_min_free)
168 obj_pool_min_free = obj_pool_free;
169 }
170 raw_spin_unlock(&pool_lock);
171
172 return obj;
173 }
174
175 /*
176 * workqueue function to free objects.
177 *
178 * To reduce contention on the global pool_lock, the actual freeing of
179 * debug objects will be delayed if the pool_lock is busy. We also free
180 * the objects in a batch of 4 for each lock/unlock cycle.
181 */
182 #define ODEBUG_FREE_BATCH 4
183
free_obj_work(struct work_struct * work)184 static void free_obj_work(struct work_struct *work)
185 {
186 struct debug_obj *objs[ODEBUG_FREE_BATCH];
187 unsigned long flags;
188 int i;
189
190 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
191 return;
192 while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
193 for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
194 objs[i] = hlist_entry(obj_pool.first,
195 typeof(*objs[0]), node);
196 hlist_del(&objs[i]->node);
197 }
198
199 obj_pool_free -= ODEBUG_FREE_BATCH;
200 debug_objects_freed += ODEBUG_FREE_BATCH;
201 /*
202 * We release pool_lock across kmem_cache_free() to
203 * avoid contention on pool_lock.
204 */
205 raw_spin_unlock_irqrestore(&pool_lock, flags);
206 for (i = 0; i < ODEBUG_FREE_BATCH; i++)
207 kmem_cache_free(obj_cache, objs[i]);
208 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
209 return;
210 }
211 raw_spin_unlock_irqrestore(&pool_lock, flags);
212 }
213
214 /*
215 * Put the object back into the pool and schedule work to free objects
216 * if necessary.
217 */
free_object(struct debug_obj * obj)218 static void free_object(struct debug_obj *obj)
219 {
220 unsigned long flags;
221 int sched = 0;
222
223 raw_spin_lock_irqsave(&pool_lock, flags);
224 /*
225 * schedule work when the pool is filled and the cache is
226 * initialized:
227 */
228 if (obj_pool_free > debug_objects_pool_size && obj_cache)
229 sched = 1;
230 hlist_add_head(&obj->node, &obj_pool);
231 obj_pool_free++;
232 obj_pool_used--;
233 raw_spin_unlock_irqrestore(&pool_lock, flags);
234 if (sched)
235 schedule_work(&debug_obj_work);
236 }
237
238 /*
239 * We run out of memory. That means we probably have tons of objects
240 * allocated.
241 */
debug_objects_oom(void)242 static void debug_objects_oom(void)
243 {
244 struct debug_bucket *db = obj_hash;
245 struct hlist_node *tmp;
246 HLIST_HEAD(freelist);
247 struct debug_obj *obj;
248 unsigned long flags;
249 int i;
250
251 pr_warn("Out of memory. ODEBUG disabled\n");
252
253 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
254 raw_spin_lock_irqsave(&db->lock, flags);
255 hlist_move_list(&db->list, &freelist);
256 raw_spin_unlock_irqrestore(&db->lock, flags);
257
258 /* Now free them */
259 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
260 hlist_del(&obj->node);
261 free_object(obj);
262 }
263 }
264 }
265
266 /*
267 * We use the pfn of the address for the hash. That way we can check
268 * for freed objects simply by checking the affected bucket.
269 */
get_bucket(unsigned long addr)270 static struct debug_bucket *get_bucket(unsigned long addr)
271 {
272 unsigned long hash;
273
274 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
275 return &obj_hash[hash];
276 }
277
debug_print_object(struct debug_obj * obj,char * msg)278 static void debug_print_object(struct debug_obj *obj, char *msg)
279 {
280 struct debug_obj_descr *descr = obj->descr;
281 static int limit;
282
283 if (limit < 5 && descr != descr_test) {
284 void *hint = descr->debug_hint ?
285 descr->debug_hint(obj->object) : NULL;
286 limit++;
287 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
288 "object type: %s hint: %pS\n",
289 msg, obj_states[obj->state], obj->astate,
290 descr->name, hint);
291 }
292 debug_objects_warnings++;
293 }
294
295 /*
296 * Try to repair the damage, so we have a better chance to get useful
297 * debug output.
298 */
299 static bool
debug_object_fixup(bool (* fixup)(void * addr,enum debug_obj_state state),void * addr,enum debug_obj_state state)300 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
301 void * addr, enum debug_obj_state state)
302 {
303 if (fixup && fixup(addr, state)) {
304 debug_objects_fixups++;
305 return true;
306 }
307 return false;
308 }
309
debug_object_is_on_stack(void * addr,int onstack)310 static void debug_object_is_on_stack(void *addr, int onstack)
311 {
312 int is_on_stack;
313 static int limit;
314
315 if (limit > 4)
316 return;
317
318 is_on_stack = object_is_on_stack(addr);
319 if (is_on_stack == onstack)
320 return;
321
322 limit++;
323 if (is_on_stack)
324 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
325 task_stack_page(current));
326 else
327 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
328 task_stack_page(current));
329
330 WARN_ON(1);
331 }
332
333 static void
__debug_object_init(void * addr,struct debug_obj_descr * descr,int onstack)334 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
335 {
336 enum debug_obj_state state;
337 struct debug_bucket *db;
338 struct debug_obj *obj;
339 unsigned long flags;
340
341 fill_pool();
342
343 db = get_bucket((unsigned long) addr);
344
345 raw_spin_lock_irqsave(&db->lock, flags);
346
347 obj = lookup_object(addr, db);
348 if (!obj) {
349 obj = alloc_object(addr, db, descr);
350 if (!obj) {
351 debug_objects_enabled = 0;
352 raw_spin_unlock_irqrestore(&db->lock, flags);
353 debug_objects_oom();
354 return;
355 }
356 debug_object_is_on_stack(addr, onstack);
357 }
358
359 switch (obj->state) {
360 case ODEBUG_STATE_NONE:
361 case ODEBUG_STATE_INIT:
362 case ODEBUG_STATE_INACTIVE:
363 obj->state = ODEBUG_STATE_INIT;
364 break;
365
366 case ODEBUG_STATE_ACTIVE:
367 debug_print_object(obj, "init");
368 state = obj->state;
369 raw_spin_unlock_irqrestore(&db->lock, flags);
370 debug_object_fixup(descr->fixup_init, addr, state);
371 return;
372
373 case ODEBUG_STATE_DESTROYED:
374 debug_print_object(obj, "init");
375 break;
376 default:
377 break;
378 }
379
380 raw_spin_unlock_irqrestore(&db->lock, flags);
381 }
382
383 /**
384 * debug_object_init - debug checks when an object is initialized
385 * @addr: address of the object
386 * @descr: pointer to an object specific debug description structure
387 */
debug_object_init(void * addr,struct debug_obj_descr * descr)388 void debug_object_init(void *addr, struct debug_obj_descr *descr)
389 {
390 if (!debug_objects_enabled)
391 return;
392
393 __debug_object_init(addr, descr, 0);
394 }
395 EXPORT_SYMBOL_GPL(debug_object_init);
396
397 /**
398 * debug_object_init_on_stack - debug checks when an object on stack is
399 * initialized
400 * @addr: address of the object
401 * @descr: pointer to an object specific debug description structure
402 */
debug_object_init_on_stack(void * addr,struct debug_obj_descr * descr)403 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
404 {
405 if (!debug_objects_enabled)
406 return;
407
408 __debug_object_init(addr, descr, 1);
409 }
410 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
411
412 /**
413 * debug_object_activate - debug checks when an object is activated
414 * @addr: address of the object
415 * @descr: pointer to an object specific debug description structure
416 * Returns 0 for success, -EINVAL for check failed.
417 */
debug_object_activate(void * addr,struct debug_obj_descr * descr)418 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
419 {
420 enum debug_obj_state state;
421 struct debug_bucket *db;
422 struct debug_obj *obj;
423 unsigned long flags;
424 int ret;
425 struct debug_obj o = { .object = addr,
426 .state = ODEBUG_STATE_NOTAVAILABLE,
427 .descr = descr };
428
429 if (!debug_objects_enabled)
430 return 0;
431
432 db = get_bucket((unsigned long) addr);
433
434 raw_spin_lock_irqsave(&db->lock, flags);
435
436 obj = lookup_object(addr, db);
437 if (obj) {
438 switch (obj->state) {
439 case ODEBUG_STATE_INIT:
440 case ODEBUG_STATE_INACTIVE:
441 obj->state = ODEBUG_STATE_ACTIVE;
442 ret = 0;
443 break;
444
445 case ODEBUG_STATE_ACTIVE:
446 debug_print_object(obj, "activate");
447 state = obj->state;
448 raw_spin_unlock_irqrestore(&db->lock, flags);
449 ret = debug_object_fixup(descr->fixup_activate, addr, state);
450 return ret ? 0 : -EINVAL;
451
452 case ODEBUG_STATE_DESTROYED:
453 debug_print_object(obj, "activate");
454 ret = -EINVAL;
455 break;
456 default:
457 ret = 0;
458 break;
459 }
460 raw_spin_unlock_irqrestore(&db->lock, flags);
461 return ret;
462 }
463
464 raw_spin_unlock_irqrestore(&db->lock, flags);
465 /*
466 * We are here when a static object is activated. We
467 * let the type specific code confirm whether this is
468 * true or not. if true, we just make sure that the
469 * static object is tracked in the object tracker. If
470 * not, this must be a bug, so we try to fix it up.
471 */
472 if (descr->is_static_object && descr->is_static_object(addr)) {
473 /* track this static object */
474 debug_object_init(addr, descr);
475 debug_object_activate(addr, descr);
476 } else {
477 debug_print_object(&o, "activate");
478 ret = debug_object_fixup(descr->fixup_activate, addr,
479 ODEBUG_STATE_NOTAVAILABLE);
480 return ret ? 0 : -EINVAL;
481 }
482 return 0;
483 }
484 EXPORT_SYMBOL_GPL(debug_object_activate);
485
486 /**
487 * debug_object_deactivate - debug checks when an object is deactivated
488 * @addr: address of the object
489 * @descr: pointer to an object specific debug description structure
490 */
debug_object_deactivate(void * addr,struct debug_obj_descr * descr)491 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
492 {
493 struct debug_bucket *db;
494 struct debug_obj *obj;
495 unsigned long flags;
496
497 if (!debug_objects_enabled)
498 return;
499
500 db = get_bucket((unsigned long) addr);
501
502 raw_spin_lock_irqsave(&db->lock, flags);
503
504 obj = lookup_object(addr, db);
505 if (obj) {
506 switch (obj->state) {
507 case ODEBUG_STATE_INIT:
508 case ODEBUG_STATE_INACTIVE:
509 case ODEBUG_STATE_ACTIVE:
510 if (!obj->astate)
511 obj->state = ODEBUG_STATE_INACTIVE;
512 else
513 debug_print_object(obj, "deactivate");
514 break;
515
516 case ODEBUG_STATE_DESTROYED:
517 debug_print_object(obj, "deactivate");
518 break;
519 default:
520 break;
521 }
522 } else {
523 struct debug_obj o = { .object = addr,
524 .state = ODEBUG_STATE_NOTAVAILABLE,
525 .descr = descr };
526
527 debug_print_object(&o, "deactivate");
528 }
529
530 raw_spin_unlock_irqrestore(&db->lock, flags);
531 }
532 EXPORT_SYMBOL_GPL(debug_object_deactivate);
533
534 /**
535 * debug_object_destroy - debug checks when an object is destroyed
536 * @addr: address of the object
537 * @descr: pointer to an object specific debug description structure
538 */
debug_object_destroy(void * addr,struct debug_obj_descr * descr)539 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
540 {
541 enum debug_obj_state state;
542 struct debug_bucket *db;
543 struct debug_obj *obj;
544 unsigned long flags;
545
546 if (!debug_objects_enabled)
547 return;
548
549 db = get_bucket((unsigned long) addr);
550
551 raw_spin_lock_irqsave(&db->lock, flags);
552
553 obj = lookup_object(addr, db);
554 if (!obj)
555 goto out_unlock;
556
557 switch (obj->state) {
558 case ODEBUG_STATE_NONE:
559 case ODEBUG_STATE_INIT:
560 case ODEBUG_STATE_INACTIVE:
561 obj->state = ODEBUG_STATE_DESTROYED;
562 break;
563 case ODEBUG_STATE_ACTIVE:
564 debug_print_object(obj, "destroy");
565 state = obj->state;
566 raw_spin_unlock_irqrestore(&db->lock, flags);
567 debug_object_fixup(descr->fixup_destroy, addr, state);
568 return;
569
570 case ODEBUG_STATE_DESTROYED:
571 debug_print_object(obj, "destroy");
572 break;
573 default:
574 break;
575 }
576 out_unlock:
577 raw_spin_unlock_irqrestore(&db->lock, flags);
578 }
579 EXPORT_SYMBOL_GPL(debug_object_destroy);
580
581 /**
582 * debug_object_free - debug checks when an object is freed
583 * @addr: address of the object
584 * @descr: pointer to an object specific debug description structure
585 */
debug_object_free(void * addr,struct debug_obj_descr * descr)586 void debug_object_free(void *addr, struct debug_obj_descr *descr)
587 {
588 enum debug_obj_state state;
589 struct debug_bucket *db;
590 struct debug_obj *obj;
591 unsigned long flags;
592
593 if (!debug_objects_enabled)
594 return;
595
596 db = get_bucket((unsigned long) addr);
597
598 raw_spin_lock_irqsave(&db->lock, flags);
599
600 obj = lookup_object(addr, db);
601 if (!obj)
602 goto out_unlock;
603
604 switch (obj->state) {
605 case ODEBUG_STATE_ACTIVE:
606 debug_print_object(obj, "free");
607 state = obj->state;
608 raw_spin_unlock_irqrestore(&db->lock, flags);
609 debug_object_fixup(descr->fixup_free, addr, state);
610 return;
611 default:
612 hlist_del(&obj->node);
613 raw_spin_unlock_irqrestore(&db->lock, flags);
614 free_object(obj);
615 return;
616 }
617 out_unlock:
618 raw_spin_unlock_irqrestore(&db->lock, flags);
619 }
620 EXPORT_SYMBOL_GPL(debug_object_free);
621
622 /**
623 * debug_object_assert_init - debug checks when object should be init-ed
624 * @addr: address of the object
625 * @descr: pointer to an object specific debug description structure
626 */
debug_object_assert_init(void * addr,struct debug_obj_descr * descr)627 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
628 {
629 struct debug_bucket *db;
630 struct debug_obj *obj;
631 unsigned long flags;
632
633 if (!debug_objects_enabled)
634 return;
635
636 db = get_bucket((unsigned long) addr);
637
638 raw_spin_lock_irqsave(&db->lock, flags);
639
640 obj = lookup_object(addr, db);
641 if (!obj) {
642 struct debug_obj o = { .object = addr,
643 .state = ODEBUG_STATE_NOTAVAILABLE,
644 .descr = descr };
645
646 raw_spin_unlock_irqrestore(&db->lock, flags);
647 /*
648 * Maybe the object is static, and we let the type specific
649 * code confirm. Track this static object if true, else invoke
650 * fixup.
651 */
652 if (descr->is_static_object && descr->is_static_object(addr)) {
653 /* Track this static object */
654 debug_object_init(addr, descr);
655 } else {
656 debug_print_object(&o, "assert_init");
657 debug_object_fixup(descr->fixup_assert_init, addr,
658 ODEBUG_STATE_NOTAVAILABLE);
659 }
660 return;
661 }
662
663 raw_spin_unlock_irqrestore(&db->lock, flags);
664 }
665 EXPORT_SYMBOL_GPL(debug_object_assert_init);
666
667 /**
668 * debug_object_active_state - debug checks object usage state machine
669 * @addr: address of the object
670 * @descr: pointer to an object specific debug description structure
671 * @expect: expected state
672 * @next: state to move to if expected state is found
673 */
674 void
debug_object_active_state(void * addr,struct debug_obj_descr * descr,unsigned int expect,unsigned int next)675 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
676 unsigned int expect, unsigned int next)
677 {
678 struct debug_bucket *db;
679 struct debug_obj *obj;
680 unsigned long flags;
681
682 if (!debug_objects_enabled)
683 return;
684
685 db = get_bucket((unsigned long) addr);
686
687 raw_spin_lock_irqsave(&db->lock, flags);
688
689 obj = lookup_object(addr, db);
690 if (obj) {
691 switch (obj->state) {
692 case ODEBUG_STATE_ACTIVE:
693 if (obj->astate == expect)
694 obj->astate = next;
695 else
696 debug_print_object(obj, "active_state");
697 break;
698
699 default:
700 debug_print_object(obj, "active_state");
701 break;
702 }
703 } else {
704 struct debug_obj o = { .object = addr,
705 .state = ODEBUG_STATE_NOTAVAILABLE,
706 .descr = descr };
707
708 debug_print_object(&o, "active_state");
709 }
710
711 raw_spin_unlock_irqrestore(&db->lock, flags);
712 }
713 EXPORT_SYMBOL_GPL(debug_object_active_state);
714
715 #ifdef CONFIG_DEBUG_OBJECTS_FREE
__debug_check_no_obj_freed(const void * address,unsigned long size)716 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
717 {
718 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
719 struct hlist_node *tmp;
720 HLIST_HEAD(freelist);
721 struct debug_obj_descr *descr;
722 enum debug_obj_state state;
723 struct debug_bucket *db;
724 struct debug_obj *obj;
725 int cnt;
726
727 saddr = (unsigned long) address;
728 eaddr = saddr + size;
729 paddr = saddr & ODEBUG_CHUNK_MASK;
730 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
731 chunks >>= ODEBUG_CHUNK_SHIFT;
732
733 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
734 db = get_bucket(paddr);
735
736 repeat:
737 cnt = 0;
738 raw_spin_lock_irqsave(&db->lock, flags);
739 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
740 cnt++;
741 oaddr = (unsigned long) obj->object;
742 if (oaddr < saddr || oaddr >= eaddr)
743 continue;
744
745 switch (obj->state) {
746 case ODEBUG_STATE_ACTIVE:
747 debug_print_object(obj, "free");
748 descr = obj->descr;
749 state = obj->state;
750 raw_spin_unlock_irqrestore(&db->lock, flags);
751 debug_object_fixup(descr->fixup_free,
752 (void *) oaddr, state);
753 goto repeat;
754 default:
755 hlist_del(&obj->node);
756 hlist_add_head(&obj->node, &freelist);
757 break;
758 }
759 }
760 raw_spin_unlock_irqrestore(&db->lock, flags);
761
762 /* Now free them */
763 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
764 hlist_del(&obj->node);
765 free_object(obj);
766 }
767
768 if (cnt > debug_objects_maxchain)
769 debug_objects_maxchain = cnt;
770 }
771 }
772
debug_check_no_obj_freed(const void * address,unsigned long size)773 void debug_check_no_obj_freed(const void *address, unsigned long size)
774 {
775 if (debug_objects_enabled)
776 __debug_check_no_obj_freed(address, size);
777 }
778 #endif
779
780 #ifdef CONFIG_DEBUG_FS
781
debug_stats_show(struct seq_file * m,void * v)782 static int debug_stats_show(struct seq_file *m, void *v)
783 {
784 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
785 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
786 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
787 seq_printf(m, "pool_free :%d\n", obj_pool_free);
788 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
789 seq_printf(m, "pool_used :%d\n", obj_pool_used);
790 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
791 seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
792 seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
793 return 0;
794 }
795
debug_stats_open(struct inode * inode,struct file * filp)796 static int debug_stats_open(struct inode *inode, struct file *filp)
797 {
798 return single_open(filp, debug_stats_show, NULL);
799 }
800
801 static const struct file_operations debug_stats_fops = {
802 .open = debug_stats_open,
803 .read = seq_read,
804 .llseek = seq_lseek,
805 .release = single_release,
806 };
807
debug_objects_init_debugfs(void)808 static int __init debug_objects_init_debugfs(void)
809 {
810 struct dentry *dbgdir, *dbgstats;
811
812 if (!debug_objects_enabled)
813 return 0;
814
815 dbgdir = debugfs_create_dir("debug_objects", NULL);
816 if (!dbgdir)
817 return -ENOMEM;
818
819 dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
820 &debug_stats_fops);
821 if (!dbgstats)
822 goto err;
823
824 return 0;
825
826 err:
827 debugfs_remove(dbgdir);
828
829 return -ENOMEM;
830 }
831 __initcall(debug_objects_init_debugfs);
832
833 #else
debug_objects_init_debugfs(void)834 static inline void debug_objects_init_debugfs(void) { }
835 #endif
836
837 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
838
839 /* Random data structure for the self test */
840 struct self_test {
841 unsigned long dummy1[6];
842 int static_init;
843 unsigned long dummy2[3];
844 };
845
846 static __initdata struct debug_obj_descr descr_type_test;
847
is_static_object(void * addr)848 static bool __init is_static_object(void *addr)
849 {
850 struct self_test *obj = addr;
851
852 return obj->static_init;
853 }
854
855 /*
856 * fixup_init is called when:
857 * - an active object is initialized
858 */
fixup_init(void * addr,enum debug_obj_state state)859 static bool __init fixup_init(void *addr, enum debug_obj_state state)
860 {
861 struct self_test *obj = addr;
862
863 switch (state) {
864 case ODEBUG_STATE_ACTIVE:
865 debug_object_deactivate(obj, &descr_type_test);
866 debug_object_init(obj, &descr_type_test);
867 return true;
868 default:
869 return false;
870 }
871 }
872
873 /*
874 * fixup_activate is called when:
875 * - an active object is activated
876 * - an unknown non-static object is activated
877 */
fixup_activate(void * addr,enum debug_obj_state state)878 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
879 {
880 struct self_test *obj = addr;
881
882 switch (state) {
883 case ODEBUG_STATE_NOTAVAILABLE:
884 return true;
885 case ODEBUG_STATE_ACTIVE:
886 debug_object_deactivate(obj, &descr_type_test);
887 debug_object_activate(obj, &descr_type_test);
888 return true;
889
890 default:
891 return false;
892 }
893 }
894
895 /*
896 * fixup_destroy is called when:
897 * - an active object is destroyed
898 */
fixup_destroy(void * addr,enum debug_obj_state state)899 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
900 {
901 struct self_test *obj = addr;
902
903 switch (state) {
904 case ODEBUG_STATE_ACTIVE:
905 debug_object_deactivate(obj, &descr_type_test);
906 debug_object_destroy(obj, &descr_type_test);
907 return true;
908 default:
909 return false;
910 }
911 }
912
913 /*
914 * fixup_free is called when:
915 * - an active object is freed
916 */
fixup_free(void * addr,enum debug_obj_state state)917 static bool __init fixup_free(void *addr, enum debug_obj_state state)
918 {
919 struct self_test *obj = addr;
920
921 switch (state) {
922 case ODEBUG_STATE_ACTIVE:
923 debug_object_deactivate(obj, &descr_type_test);
924 debug_object_free(obj, &descr_type_test);
925 return true;
926 default:
927 return false;
928 }
929 }
930
931 static int __init
check_results(void * addr,enum debug_obj_state state,int fixups,int warnings)932 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
933 {
934 struct debug_bucket *db;
935 struct debug_obj *obj;
936 unsigned long flags;
937 int res = -EINVAL;
938
939 db = get_bucket((unsigned long) addr);
940
941 raw_spin_lock_irqsave(&db->lock, flags);
942
943 obj = lookup_object(addr, db);
944 if (!obj && state != ODEBUG_STATE_NONE) {
945 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
946 goto out;
947 }
948 if (obj && obj->state != state) {
949 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
950 obj->state, state);
951 goto out;
952 }
953 if (fixups != debug_objects_fixups) {
954 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
955 fixups, debug_objects_fixups);
956 goto out;
957 }
958 if (warnings != debug_objects_warnings) {
959 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
960 warnings, debug_objects_warnings);
961 goto out;
962 }
963 res = 0;
964 out:
965 raw_spin_unlock_irqrestore(&db->lock, flags);
966 if (res)
967 debug_objects_enabled = 0;
968 return res;
969 }
970
971 static __initdata struct debug_obj_descr descr_type_test = {
972 .name = "selftest",
973 .is_static_object = is_static_object,
974 .fixup_init = fixup_init,
975 .fixup_activate = fixup_activate,
976 .fixup_destroy = fixup_destroy,
977 .fixup_free = fixup_free,
978 };
979
980 static __initdata struct self_test obj = { .static_init = 0 };
981
debug_objects_selftest(void)982 static void __init debug_objects_selftest(void)
983 {
984 int fixups, oldfixups, warnings, oldwarnings;
985 unsigned long flags;
986
987 local_irq_save(flags);
988
989 fixups = oldfixups = debug_objects_fixups;
990 warnings = oldwarnings = debug_objects_warnings;
991 descr_test = &descr_type_test;
992
993 debug_object_init(&obj, &descr_type_test);
994 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
995 goto out;
996 debug_object_activate(&obj, &descr_type_test);
997 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
998 goto out;
999 debug_object_activate(&obj, &descr_type_test);
1000 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1001 goto out;
1002 debug_object_deactivate(&obj, &descr_type_test);
1003 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1004 goto out;
1005 debug_object_destroy(&obj, &descr_type_test);
1006 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1007 goto out;
1008 debug_object_init(&obj, &descr_type_test);
1009 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1010 goto out;
1011 debug_object_activate(&obj, &descr_type_test);
1012 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1013 goto out;
1014 debug_object_deactivate(&obj, &descr_type_test);
1015 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1016 goto out;
1017 debug_object_free(&obj, &descr_type_test);
1018 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1019 goto out;
1020
1021 obj.static_init = 1;
1022 debug_object_activate(&obj, &descr_type_test);
1023 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1024 goto out;
1025 debug_object_init(&obj, &descr_type_test);
1026 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1027 goto out;
1028 debug_object_free(&obj, &descr_type_test);
1029 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1030 goto out;
1031
1032 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1033 debug_object_init(&obj, &descr_type_test);
1034 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1035 goto out;
1036 debug_object_activate(&obj, &descr_type_test);
1037 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1038 goto out;
1039 __debug_check_no_obj_freed(&obj, sizeof(obj));
1040 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1041 goto out;
1042 #endif
1043 pr_info("selftest passed\n");
1044
1045 out:
1046 debug_objects_fixups = oldfixups;
1047 debug_objects_warnings = oldwarnings;
1048 descr_test = NULL;
1049
1050 local_irq_restore(flags);
1051 }
1052 #else
debug_objects_selftest(void)1053 static inline void debug_objects_selftest(void) { }
1054 #endif
1055
1056 /*
1057 * Called during early boot to initialize the hash buckets and link
1058 * the static object pool objects into the poll list. After this call
1059 * the object tracker is fully operational.
1060 */
debug_objects_early_init(void)1061 void __init debug_objects_early_init(void)
1062 {
1063 int i;
1064
1065 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1066 raw_spin_lock_init(&obj_hash[i].lock);
1067
1068 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1069 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1070 }
1071
1072 /*
1073 * Convert the statically allocated objects to dynamic ones:
1074 */
debug_objects_replace_static_objects(void)1075 static int __init debug_objects_replace_static_objects(void)
1076 {
1077 struct debug_bucket *db = obj_hash;
1078 struct hlist_node *tmp;
1079 struct debug_obj *obj, *new;
1080 HLIST_HEAD(objects);
1081 int i, cnt = 0;
1082
1083 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1084 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1085 if (!obj)
1086 goto free;
1087 hlist_add_head(&obj->node, &objects);
1088 }
1089
1090 /*
1091 * When debug_objects_mem_init() is called we know that only
1092 * one CPU is up, so disabling interrupts is enough
1093 * protection. This avoids the lockdep hell of lock ordering.
1094 */
1095 local_irq_disable();
1096
1097 /* Remove the statically allocated objects from the pool */
1098 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1099 hlist_del(&obj->node);
1100 /* Move the allocated objects to the pool */
1101 hlist_move_list(&objects, &obj_pool);
1102
1103 /* Replace the active object references */
1104 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1105 hlist_move_list(&db->list, &objects);
1106
1107 hlist_for_each_entry(obj, &objects, node) {
1108 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1109 hlist_del(&new->node);
1110 /* copy object data */
1111 *new = *obj;
1112 hlist_add_head(&new->node, &db->list);
1113 cnt++;
1114 }
1115 }
1116 local_irq_enable();
1117
1118 pr_debug("%d of %d active objects replaced\n",
1119 cnt, obj_pool_used);
1120 return 0;
1121 free:
1122 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1123 hlist_del(&obj->node);
1124 kmem_cache_free(obj_cache, obj);
1125 }
1126 return -ENOMEM;
1127 }
1128
1129 /*
1130 * Called after the kmem_caches are functional to setup a dedicated
1131 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1132 * prevents that the debug code is called on kmem_cache_free() for the
1133 * debug tracker objects to avoid recursive calls.
1134 */
debug_objects_mem_init(void)1135 void __init debug_objects_mem_init(void)
1136 {
1137 if (!debug_objects_enabled)
1138 return;
1139
1140 obj_cache = kmem_cache_create("debug_objects_cache",
1141 sizeof (struct debug_obj), 0,
1142 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1143 NULL);
1144
1145 if (!obj_cache || debug_objects_replace_static_objects()) {
1146 debug_objects_enabled = 0;
1147 if (obj_cache)
1148 kmem_cache_destroy(obj_cache);
1149 pr_warn("out of memory.\n");
1150 } else
1151 debug_objects_selftest();
1152
1153 /*
1154 * Increase the thresholds for allocating and freeing objects
1155 * according to the number of possible CPUs available in the system.
1156 */
1157 debug_objects_pool_size += num_possible_cpus() * 32;
1158 debug_objects_pool_min_level += num_possible_cpus() * 4;
1159 }
1160