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path: root/lib/debugobjects.c (plain)
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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
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 1024
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
31struct debug_bucket {
32 struct hlist_head list;
33 raw_spinlock_t lock;
34};
35
36static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
37
38static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
39
40static DEFINE_RAW_SPINLOCK(pool_lock);
41
42static HLIST_HEAD(obj_pool);
43
44static int obj_pool_min_free = ODEBUG_POOL_SIZE;
45static int obj_pool_free = ODEBUG_POOL_SIZE;
46static int obj_pool_used;
47static int obj_pool_max_used;
48static struct kmem_cache *obj_cache;
49
50static int debug_objects_maxchain __read_mostly;
51static int debug_objects_fixups __read_mostly;
52static int debug_objects_warnings __read_mostly;
53static int debug_objects_enabled __read_mostly
54 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
55
56static struct debug_obj_descr *descr_test __read_mostly;
57
58static void free_obj_work(struct work_struct *work);
59static DECLARE_WORK(debug_obj_work, free_obj_work);
60
61static int __init enable_object_debug(char *str)
62{
63 debug_objects_enabled = 1;
64 return 0;
65}
66
67static int __init disable_object_debug(char *str)
68{
69 debug_objects_enabled = 0;
70 return 0;
71}
72
73early_param("debug_objects", enable_object_debug);
74early_param("no_debug_objects", disable_object_debug);
75
76static 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
85static 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 */
113static 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 */
133static struct debug_obj *
134alloc_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 */
166static 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 */
191static 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 */
215static 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 */
243static 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
251static 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 */
272static bool
273debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
274 void * addr, enum debug_obj_state state)
275{
276 if (fixup && fixup(addr, state)) {
277 debug_objects_fixups++;
278 return true;
279 }
280 return false;
281}
282
283static void debug_object_is_on_stack(void *addr, int onstack)
284{
285 int is_on_stack;
286 static int limit;
287
288 if (limit > 4)
289 return;
290
291 is_on_stack = object_is_on_stack(addr);
292 if (is_on_stack == onstack)
293 return;
294
295 limit++;
296 if (is_on_stack)
297 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
298 task_stack_page(current));
299 else
300 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
301 task_stack_page(current));
302
303 WARN_ON(1);
304}
305
306static void
307__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
308{
309 enum debug_obj_state state;
310 struct debug_bucket *db;
311 struct debug_obj *obj;
312 unsigned long flags;
313
314 fill_pool();
315
316 db = get_bucket((unsigned long) addr);
317
318 raw_spin_lock_irqsave(&db->lock, flags);
319
320 obj = lookup_object(addr, db);
321 if (!obj) {
322 obj = alloc_object(addr, db, descr);
323 if (!obj) {
324 debug_objects_enabled = 0;
325 raw_spin_unlock_irqrestore(&db->lock, flags);
326 debug_objects_oom();
327 return;
328 }
329 debug_object_is_on_stack(addr, onstack);
330 }
331
332 switch (obj->state) {
333 case ODEBUG_STATE_NONE:
334 case ODEBUG_STATE_INIT:
335 case ODEBUG_STATE_INACTIVE:
336 obj->state = ODEBUG_STATE_INIT;
337 break;
338
339 case ODEBUG_STATE_ACTIVE:
340 debug_print_object(obj, "init");
341 state = obj->state;
342 raw_spin_unlock_irqrestore(&db->lock, flags);
343 debug_object_fixup(descr->fixup_init, addr, state);
344 return;
345
346 case ODEBUG_STATE_DESTROYED:
347 debug_print_object(obj, "init");
348 break;
349 default:
350 break;
351 }
352
353 raw_spin_unlock_irqrestore(&db->lock, flags);
354}
355
356/**
357 * debug_object_init - debug checks when an object is initialized
358 * @addr: address of the object
359 * @descr: pointer to an object specific debug description structure
360 */
361void debug_object_init(void *addr, struct debug_obj_descr *descr)
362{
363 if (!debug_objects_enabled)
364 return;
365
366 __debug_object_init(addr, descr, 0);
367}
368EXPORT_SYMBOL_GPL(debug_object_init);
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 */
376void 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}
383EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
384
385/**
386 * debug_object_activate - debug checks when an object is activated
387 * @addr: address of the object
388 * @descr: pointer to an object specific debug description structure
389 * Returns 0 for success, -EINVAL for check failed.
390 */
391int debug_object_activate(void *addr, struct debug_obj_descr *descr)
392{
393 enum debug_obj_state state;
394 struct debug_bucket *db;
395 struct debug_obj *obj;
396 unsigned long flags;
397 int ret;
398 struct debug_obj o = { .object = addr,
399 .state = ODEBUG_STATE_NOTAVAILABLE,
400 .descr = descr };
401
402 if (!debug_objects_enabled)
403 return 0;
404
405 db = get_bucket((unsigned long) addr);
406
407 raw_spin_lock_irqsave(&db->lock, flags);
408
409 obj = lookup_object(addr, db);
410 if (obj) {
411 switch (obj->state) {
412 case ODEBUG_STATE_INIT:
413 case ODEBUG_STATE_INACTIVE:
414 obj->state = ODEBUG_STATE_ACTIVE;
415 ret = 0;
416 break;
417
418 case ODEBUG_STATE_ACTIVE:
419 debug_print_object(obj, "activate");
420 state = obj->state;
421 raw_spin_unlock_irqrestore(&db->lock, flags);
422 ret = debug_object_fixup(descr->fixup_activate, addr, state);
423 return ret ? 0 : -EINVAL;
424
425 case ODEBUG_STATE_DESTROYED:
426 debug_print_object(obj, "activate");
427 ret = -EINVAL;
428 break;
429 default:
430 ret = 0;
431 break;
432 }
433 raw_spin_unlock_irqrestore(&db->lock, flags);
434 return ret;
435 }
436
437 raw_spin_unlock_irqrestore(&db->lock, flags);
438 /*
439 * We are here when a static object is activated. We
440 * let the type specific code confirm whether this is
441 * true or not. if true, we just make sure that the
442 * static object is tracked in the object tracker. If
443 * not, this must be a bug, so we try to fix it up.
444 */
445 if (descr->is_static_object && descr->is_static_object(addr)) {
446 /* track this static object */
447 debug_object_init(addr, descr);
448 debug_object_activate(addr, descr);
449 } else {
450 debug_print_object(&o, "activate");
451 ret = debug_object_fixup(descr->fixup_activate, addr,
452 ODEBUG_STATE_NOTAVAILABLE);
453 return ret ? 0 : -EINVAL;
454 }
455 return 0;
456}
457EXPORT_SYMBOL_GPL(debug_object_activate);
458
459/**
460 * debug_object_deactivate - debug checks when an object is deactivated
461 * @addr: address of the object
462 * @descr: pointer to an object specific debug description structure
463 */
464void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
465{
466 struct debug_bucket *db;
467 struct debug_obj *obj;
468 unsigned long flags;
469
470 if (!debug_objects_enabled)
471 return;
472
473 db = get_bucket((unsigned long) addr);
474
475 raw_spin_lock_irqsave(&db->lock, flags);
476
477 obj = lookup_object(addr, db);
478 if (obj) {
479 switch (obj->state) {
480 case ODEBUG_STATE_INIT:
481 case ODEBUG_STATE_INACTIVE:
482 case ODEBUG_STATE_ACTIVE:
483 if (!obj->astate)
484 obj->state = ODEBUG_STATE_INACTIVE;
485 else
486 debug_print_object(obj, "deactivate");
487 break;
488
489 case ODEBUG_STATE_DESTROYED:
490 debug_print_object(obj, "deactivate");
491 break;
492 default:
493 break;
494 }
495 } else {
496 struct debug_obj o = { .object = addr,
497 .state = ODEBUG_STATE_NOTAVAILABLE,
498 .descr = descr };
499
500 debug_print_object(&o, "deactivate");
501 }
502
503 raw_spin_unlock_irqrestore(&db->lock, flags);
504}
505EXPORT_SYMBOL_GPL(debug_object_deactivate);
506
507/**
508 * debug_object_destroy - debug checks when an object is destroyed
509 * @addr: address of the object
510 * @descr: pointer to an object specific debug description structure
511 */
512void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
513{
514 enum debug_obj_state state;
515 struct debug_bucket *db;
516 struct debug_obj *obj;
517 unsigned long flags;
518
519 if (!debug_objects_enabled)
520 return;
521
522 db = get_bucket((unsigned long) addr);
523
524 raw_spin_lock_irqsave(&db->lock, flags);
525
526 obj = lookup_object(addr, db);
527 if (!obj)
528 goto out_unlock;
529
530 switch (obj->state) {
531 case ODEBUG_STATE_NONE:
532 case ODEBUG_STATE_INIT:
533 case ODEBUG_STATE_INACTIVE:
534 obj->state = ODEBUG_STATE_DESTROYED;
535 break;
536 case ODEBUG_STATE_ACTIVE:
537 debug_print_object(obj, "destroy");
538 state = obj->state;
539 raw_spin_unlock_irqrestore(&db->lock, flags);
540 debug_object_fixup(descr->fixup_destroy, addr, state);
541 return;
542
543 case ODEBUG_STATE_DESTROYED:
544 debug_print_object(obj, "destroy");
545 break;
546 default:
547 break;
548 }
549out_unlock:
550 raw_spin_unlock_irqrestore(&db->lock, flags);
551}
552EXPORT_SYMBOL_GPL(debug_object_destroy);
553
554/**
555 * debug_object_free - debug checks when an object is freed
556 * @addr: address of the object
557 * @descr: pointer to an object specific debug description structure
558 */
559void debug_object_free(void *addr, struct debug_obj_descr *descr)
560{
561 enum debug_obj_state state;
562 struct debug_bucket *db;
563 struct debug_obj *obj;
564 unsigned long flags;
565
566 if (!debug_objects_enabled)
567 return;
568
569 db = get_bucket((unsigned long) addr);
570
571 raw_spin_lock_irqsave(&db->lock, flags);
572
573 obj = lookup_object(addr, db);
574 if (!obj)
575 goto out_unlock;
576
577 switch (obj->state) {
578 case ODEBUG_STATE_ACTIVE:
579 debug_print_object(obj, "free");
580 state = obj->state;
581 raw_spin_unlock_irqrestore(&db->lock, flags);
582 debug_object_fixup(descr->fixup_free, addr, state);
583 return;
584 default:
585 hlist_del(&obj->node);
586 raw_spin_unlock_irqrestore(&db->lock, flags);
587 free_object(obj);
588 return;
589 }
590out_unlock:
591 raw_spin_unlock_irqrestore(&db->lock, flags);
592}
593EXPORT_SYMBOL_GPL(debug_object_free);
594
595/**
596 * debug_object_assert_init - debug checks when object should be init-ed
597 * @addr: address of the object
598 * @descr: pointer to an object specific debug description structure
599 */
600void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
601{
602 struct debug_bucket *db;
603 struct debug_obj *obj;
604 unsigned long flags;
605
606 if (!debug_objects_enabled)
607 return;
608
609 db = get_bucket((unsigned long) addr);
610
611 raw_spin_lock_irqsave(&db->lock, flags);
612
613 obj = lookup_object(addr, db);
614 if (!obj) {
615 struct debug_obj o = { .object = addr,
616 .state = ODEBUG_STATE_NOTAVAILABLE,
617 .descr = descr };
618
619 raw_spin_unlock_irqrestore(&db->lock, flags);
620 /*
621 * Maybe the object is static, and we let the type specific
622 * code confirm. Track this static object if true, else invoke
623 * fixup.
624 */
625 if (descr->is_static_object && descr->is_static_object(addr)) {
626 /* Track this static object */
627 debug_object_init(addr, descr);
628 } else {
629 debug_print_object(&o, "assert_init");
630 debug_object_fixup(descr->fixup_assert_init, addr,
631 ODEBUG_STATE_NOTAVAILABLE);
632 }
633 return;
634 }
635
636 raw_spin_unlock_irqrestore(&db->lock, flags);
637}
638EXPORT_SYMBOL_GPL(debug_object_assert_init);
639
640/**
641 * debug_object_active_state - debug checks object usage state machine
642 * @addr: address of the object
643 * @descr: pointer to an object specific debug description structure
644 * @expect: expected state
645 * @next: state to move to if expected state is found
646 */
647void
648debug_object_active_state(void *addr, struct debug_obj_descr *descr,
649 unsigned int expect, unsigned int next)
650{
651 struct debug_bucket *db;
652 struct debug_obj *obj;
653 unsigned long flags;
654
655 if (!debug_objects_enabled)
656 return;
657
658 db = get_bucket((unsigned long) addr);
659
660 raw_spin_lock_irqsave(&db->lock, flags);
661
662 obj = lookup_object(addr, db);
663 if (obj) {
664 switch (obj->state) {
665 case ODEBUG_STATE_ACTIVE:
666 if (obj->astate == expect)
667 obj->astate = next;
668 else
669 debug_print_object(obj, "active_state");
670 break;
671
672 default:
673 debug_print_object(obj, "active_state");
674 break;
675 }
676 } else {
677 struct debug_obj o = { .object = addr,
678 .state = ODEBUG_STATE_NOTAVAILABLE,
679 .descr = descr };
680
681 debug_print_object(&o, "active_state");
682 }
683
684 raw_spin_unlock_irqrestore(&db->lock, flags);
685}
686EXPORT_SYMBOL_GPL(debug_object_active_state);
687
688#ifdef CONFIG_DEBUG_OBJECTS_FREE
689static void __debug_check_no_obj_freed(const void *address, unsigned long size)
690{
691 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
692 struct hlist_node *tmp;
693 HLIST_HEAD(freelist);
694 struct debug_obj_descr *descr;
695 enum debug_obj_state state;
696 struct debug_bucket *db;
697 struct debug_obj *obj;
698 int cnt;
699
700 saddr = (unsigned long) address;
701 eaddr = saddr + size;
702 paddr = saddr & ODEBUG_CHUNK_MASK;
703 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
704 chunks >>= ODEBUG_CHUNK_SHIFT;
705
706 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
707 db = get_bucket(paddr);
708
709repeat:
710 cnt = 0;
711 raw_spin_lock_irqsave(&db->lock, flags);
712 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
713 cnt++;
714 oaddr = (unsigned long) obj->object;
715 if (oaddr < saddr || oaddr >= eaddr)
716 continue;
717
718 switch (obj->state) {
719 case ODEBUG_STATE_ACTIVE:
720 debug_print_object(obj, "free");
721 descr = obj->descr;
722 state = obj->state;
723 raw_spin_unlock_irqrestore(&db->lock, flags);
724 debug_object_fixup(descr->fixup_free,
725 (void *) oaddr, state);
726 goto repeat;
727 default:
728 hlist_del(&obj->node);
729 hlist_add_head(&obj->node, &freelist);
730 break;
731 }
732 }
733 raw_spin_unlock_irqrestore(&db->lock, flags);
734
735 /* Now free them */
736 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
737 hlist_del(&obj->node);
738 free_object(obj);
739 }
740
741 if (cnt > debug_objects_maxchain)
742 debug_objects_maxchain = cnt;
743 }
744}
745
746void debug_check_no_obj_freed(const void *address, unsigned long size)
747{
748 if (debug_objects_enabled)
749 __debug_check_no_obj_freed(address, size);
750}
751#endif
752
753#ifdef CONFIG_DEBUG_FS
754
755static int debug_stats_show(struct seq_file *m, void *v)
756{
757 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
758 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
759 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
760 seq_printf(m, "pool_free :%d\n", obj_pool_free);
761 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
762 seq_printf(m, "pool_used :%d\n", obj_pool_used);
763 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
764 return 0;
765}
766
767static int debug_stats_open(struct inode *inode, struct file *filp)
768{
769 return single_open(filp, debug_stats_show, NULL);
770}
771
772static const struct file_operations debug_stats_fops = {
773 .open = debug_stats_open,
774 .read = seq_read,
775 .llseek = seq_lseek,
776 .release = single_release,
777};
778
779static int __init debug_objects_init_debugfs(void)
780{
781 struct dentry *dbgdir, *dbgstats;
782
783 if (!debug_objects_enabled)
784 return 0;
785
786 dbgdir = debugfs_create_dir("debug_objects", NULL);
787 if (!dbgdir)
788 return -ENOMEM;
789
790 dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
791 &debug_stats_fops);
792 if (!dbgstats)
793 goto err;
794
795 return 0;
796
797err:
798 debugfs_remove(dbgdir);
799
800 return -ENOMEM;
801}
802__initcall(debug_objects_init_debugfs);
803
804#else
805static inline void debug_objects_init_debugfs(void) { }
806#endif
807
808#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
809
810/* Random data structure for the self test */
811struct self_test {
812 unsigned long dummy1[6];
813 int static_init;
814 unsigned long dummy2[3];
815};
816
817static __initdata struct debug_obj_descr descr_type_test;
818
819static bool __init is_static_object(void *addr)
820{
821 struct self_test *obj = addr;
822
823 return obj->static_init;
824}
825
826/*
827 * fixup_init is called when:
828 * - an active object is initialized
829 */
830static bool __init fixup_init(void *addr, enum debug_obj_state state)
831{
832 struct self_test *obj = addr;
833
834 switch (state) {
835 case ODEBUG_STATE_ACTIVE:
836 debug_object_deactivate(obj, &descr_type_test);
837 debug_object_init(obj, &descr_type_test);
838 return true;
839 default:
840 return false;
841 }
842}
843
844/*
845 * fixup_activate is called when:
846 * - an active object is activated
847 * - an unknown non-static object is activated
848 */
849static bool __init fixup_activate(void *addr, enum debug_obj_state state)
850{
851 struct self_test *obj = addr;
852
853 switch (state) {
854 case ODEBUG_STATE_NOTAVAILABLE:
855 return true;
856 case ODEBUG_STATE_ACTIVE:
857 debug_object_deactivate(obj, &descr_type_test);
858 debug_object_activate(obj, &descr_type_test);
859 return true;
860
861 default:
862 return false;
863 }
864}
865
866/*
867 * fixup_destroy is called when:
868 * - an active object is destroyed
869 */
870static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
871{
872 struct self_test *obj = addr;
873
874 switch (state) {
875 case ODEBUG_STATE_ACTIVE:
876 debug_object_deactivate(obj, &descr_type_test);
877 debug_object_destroy(obj, &descr_type_test);
878 return true;
879 default:
880 return false;
881 }
882}
883
884/*
885 * fixup_free is called when:
886 * - an active object is freed
887 */
888static bool __init fixup_free(void *addr, enum debug_obj_state state)
889{
890 struct self_test *obj = addr;
891
892 switch (state) {
893 case ODEBUG_STATE_ACTIVE:
894 debug_object_deactivate(obj, &descr_type_test);
895 debug_object_free(obj, &descr_type_test);
896 return true;
897 default:
898 return false;
899 }
900}
901
902static int __init
903check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
904{
905 struct debug_bucket *db;
906 struct debug_obj *obj;
907 unsigned long flags;
908 int res = -EINVAL;
909
910 db = get_bucket((unsigned long) addr);
911
912 raw_spin_lock_irqsave(&db->lock, flags);
913
914 obj = lookup_object(addr, db);
915 if (!obj && state != ODEBUG_STATE_NONE) {
916 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
917 goto out;
918 }
919 if (obj && obj->state != state) {
920 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
921 obj->state, state);
922 goto out;
923 }
924 if (fixups != debug_objects_fixups) {
925 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
926 fixups, debug_objects_fixups);
927 goto out;
928 }
929 if (warnings != debug_objects_warnings) {
930 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
931 warnings, debug_objects_warnings);
932 goto out;
933 }
934 res = 0;
935out:
936 raw_spin_unlock_irqrestore(&db->lock, flags);
937 if (res)
938 debug_objects_enabled = 0;
939 return res;
940}
941
942static __initdata struct debug_obj_descr descr_type_test = {
943 .name = "selftest",
944 .is_static_object = is_static_object,
945 .fixup_init = fixup_init,
946 .fixup_activate = fixup_activate,
947 .fixup_destroy = fixup_destroy,
948 .fixup_free = fixup_free,
949};
950
951static __initdata struct self_test obj = { .static_init = 0 };
952
953static void __init debug_objects_selftest(void)
954{
955 int fixups, oldfixups, warnings, oldwarnings;
956 unsigned long flags;
957
958 local_irq_save(flags);
959
960 fixups = oldfixups = debug_objects_fixups;
961 warnings = oldwarnings = debug_objects_warnings;
962 descr_test = &descr_type_test;
963
964 debug_object_init(&obj, &descr_type_test);
965 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
966 goto out;
967 debug_object_activate(&obj, &descr_type_test);
968 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
969 goto out;
970 debug_object_activate(&obj, &descr_type_test);
971 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
972 goto out;
973 debug_object_deactivate(&obj, &descr_type_test);
974 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
975 goto out;
976 debug_object_destroy(&obj, &descr_type_test);
977 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
978 goto out;
979 debug_object_init(&obj, &descr_type_test);
980 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
981 goto out;
982 debug_object_activate(&obj, &descr_type_test);
983 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
984 goto out;
985 debug_object_deactivate(&obj, &descr_type_test);
986 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
987 goto out;
988 debug_object_free(&obj, &descr_type_test);
989 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
990 goto out;
991
992 obj.static_init = 1;
993 debug_object_activate(&obj, &descr_type_test);
994 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
995 goto out;
996 debug_object_init(&obj, &descr_type_test);
997 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
998 goto out;
999 debug_object_free(&obj, &descr_type_test);
1000 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1001 goto out;
1002
1003#ifdef CONFIG_DEBUG_OBJECTS_FREE
1004 debug_object_init(&obj, &descr_type_test);
1005 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1006 goto out;
1007 debug_object_activate(&obj, &descr_type_test);
1008 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1009 goto out;
1010 __debug_check_no_obj_freed(&obj, sizeof(obj));
1011 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1012 goto out;
1013#endif
1014 pr_info("selftest passed\n");
1015
1016out:
1017 debug_objects_fixups = oldfixups;
1018 debug_objects_warnings = oldwarnings;
1019 descr_test = NULL;
1020
1021 local_irq_restore(flags);
1022}
1023#else
1024static inline void debug_objects_selftest(void) { }
1025#endif
1026
1027/*
1028 * Called during early boot to initialize the hash buckets and link
1029 * the static object pool objects into the poll list. After this call
1030 * the object tracker is fully operational.
1031 */
1032void __init debug_objects_early_init(void)
1033{
1034 int i;
1035
1036 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1037 raw_spin_lock_init(&obj_hash[i].lock);
1038
1039 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1040 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1041}
1042
1043/*
1044 * Convert the statically allocated objects to dynamic ones:
1045 */
1046static int __init debug_objects_replace_static_objects(void)
1047{
1048 struct debug_bucket *db = obj_hash;
1049 struct hlist_node *tmp;
1050 struct debug_obj *obj, *new;
1051 HLIST_HEAD(objects);
1052 int i, cnt = 0;
1053
1054 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1055 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1056 if (!obj)
1057 goto free;
1058 hlist_add_head(&obj->node, &objects);
1059 }
1060
1061 /*
1062 * When debug_objects_mem_init() is called we know that only
1063 * one CPU is up, so disabling interrupts is enough
1064 * protection. This avoids the lockdep hell of lock ordering.
1065 */
1066 local_irq_disable();
1067
1068 /* Remove the statically allocated objects from the pool */
1069 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1070 hlist_del(&obj->node);
1071 /* Move the allocated objects to the pool */
1072 hlist_move_list(&objects, &obj_pool);
1073
1074 /* Replace the active object references */
1075 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1076 hlist_move_list(&db->list, &objects);
1077
1078 hlist_for_each_entry(obj, &objects, node) {
1079 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1080 hlist_del(&new->node);
1081 /* copy object data */
1082 *new = *obj;
1083 hlist_add_head(&new->node, &db->list);
1084 cnt++;
1085 }
1086 }
1087 local_irq_enable();
1088
1089 pr_debug("%d of %d active objects replaced\n",
1090 cnt, obj_pool_used);
1091 return 0;
1092free:
1093 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1094 hlist_del(&obj->node);
1095 kmem_cache_free(obj_cache, obj);
1096 }
1097 return -ENOMEM;
1098}
1099
1100/*
1101 * Called after the kmem_caches are functional to setup a dedicated
1102 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1103 * prevents that the debug code is called on kmem_cache_free() for the
1104 * debug tracker objects to avoid recursive calls.
1105 */
1106void __init debug_objects_mem_init(void)
1107{
1108 if (!debug_objects_enabled)
1109 return;
1110
1111 obj_cache = kmem_cache_create("debug_objects_cache",
1112 sizeof (struct debug_obj), 0,
1113 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1114 NULL);
1115
1116 if (!obj_cache || debug_objects_replace_static_objects()) {
1117 debug_objects_enabled = 0;
1118 if (obj_cache)
1119 kmem_cache_destroy(obj_cache);
1120 pr_warn("out of memory.\n");
1121 } else
1122 debug_objects_selftest();
1123}
1124
generated by cgit at 2024-05-18 14:16:49 (GMT)