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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/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#include <linux/cpu.h>
23
24#define ODEBUG_HASH_BITS 14
25#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
26
27#define ODEBUG_POOL_SIZE 1024
28#define ODEBUG_POOL_MIN_LEVEL 256
29#define ODEBUG_POOL_PERCPU_SIZE 64
30#define ODEBUG_BATCH_SIZE 16
31
32#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
33#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
34#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
35
36/*
37 * We limit the freeing of debug objects via workqueue at a maximum
38 * frequency of 10Hz and about 1024 objects for each freeing operation.
39 * So it is freeing at most 10k debug objects per second.
40 */
41#define ODEBUG_FREE_WORK_MAX 1024
42#define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
43
44struct debug_bucket {
45 struct hlist_head list;
46 raw_spinlock_t lock;
47};
48
49/*
50 * Debug object percpu free list
51 * Access is protected by disabling irq
52 */
53struct debug_percpu_free {
54 struct hlist_head free_objs;
55 int obj_free;
56};
57
58static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
59
60static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
61
62static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
63
64static DEFINE_RAW_SPINLOCK(pool_lock);
65
66static HLIST_HEAD(obj_pool);
67static HLIST_HEAD(obj_to_free);
68
69/*
70 * Because of the presence of percpu free pools, obj_pool_free will
71 * under-count those in the percpu free pools. Similarly, obj_pool_used
72 * will over-count those in the percpu free pools. Adjustments will be
73 * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
74 * can be off.
75 */
76static int obj_pool_min_free = ODEBUG_POOL_SIZE;
77static int obj_pool_free = ODEBUG_POOL_SIZE;
78static int obj_pool_used;
79static int obj_pool_max_used;
80static bool obj_freeing;
81/* The number of objs on the global free list */
82static int obj_nr_tofree;
83
84static int debug_objects_maxchain __read_mostly;
85static int __maybe_unused debug_objects_maxchecked __read_mostly;
86static int debug_objects_fixups __read_mostly;
87static int debug_objects_warnings __read_mostly;
88static int debug_objects_enabled __read_mostly
89 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
90static int debug_objects_pool_size __read_mostly
91 = ODEBUG_POOL_SIZE;
92static int debug_objects_pool_min_level __read_mostly
93 = ODEBUG_POOL_MIN_LEVEL;
94static const struct debug_obj_descr *descr_test __read_mostly;
95static struct kmem_cache *obj_cache __read_mostly;
96
97/*
98 * Track numbers of kmem_cache_alloc()/free() calls done.
99 */
100static int debug_objects_allocated;
101static int debug_objects_freed;
102
103static void free_obj_work(struct work_struct *work);
104static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
105
106static int __init enable_object_debug(char *str)
107{
108 debug_objects_enabled = 1;
109 return 0;
110}
111
112static int __init disable_object_debug(char *str)
113{
114 debug_objects_enabled = 0;
115 return 0;
116}
117
118early_param("debug_objects", enable_object_debug);
119early_param("no_debug_objects", disable_object_debug);
120
121static const char *obj_states[ODEBUG_STATE_MAX] = {
122 [ODEBUG_STATE_NONE] = "none",
123 [ODEBUG_STATE_INIT] = "initialized",
124 [ODEBUG_STATE_INACTIVE] = "inactive",
125 [ODEBUG_STATE_ACTIVE] = "active",
126 [ODEBUG_STATE_DESTROYED] = "destroyed",
127 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
128};
129
130static void fill_pool(void)
131{
132 gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
133 struct debug_obj *obj;
134 unsigned long flags;
135
136 if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
137 return;
138
139 /*
140 * Reuse objs from the global free list; they will be reinitialized
141 * when allocating.
142 *
143 * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
144 * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
145 * sections.
146 */
147 while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
148 raw_spin_lock_irqsave(&pool_lock, flags);
149 /*
150 * Recheck with the lock held as the worker thread might have
151 * won the race and freed the global free list already.
152 */
153 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
154 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
155 hlist_del(&obj->node);
156 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
157 hlist_add_head(&obj->node, &obj_pool);
158 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
159 }
160 raw_spin_unlock_irqrestore(&pool_lock, flags);
161 }
162
163 if (unlikely(!obj_cache))
164 return;
165
166 while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
167 struct debug_obj *new[ODEBUG_BATCH_SIZE];
168 int cnt;
169
170 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
171 new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
172 if (!new[cnt])
173 break;
174 }
175 if (!cnt)
176 return;
177
178 raw_spin_lock_irqsave(&pool_lock, flags);
179 while (cnt) {
180 hlist_add_head(&new[--cnt]->node, &obj_pool);
181 debug_objects_allocated++;
182 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
183 }
184 raw_spin_unlock_irqrestore(&pool_lock, flags);
185 }
186}
187
188/*
189 * Lookup an object in the hash bucket.
190 */
191static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
192{
193 struct debug_obj *obj;
194 int cnt = 0;
195
196 hlist_for_each_entry(obj, &b->list, node) {
197 cnt++;
198 if (obj->object == addr)
199 return obj;
200 }
201 if (cnt > debug_objects_maxchain)
202 debug_objects_maxchain = cnt;
203
204 return NULL;
205}
206
207/*
208 * Allocate a new object from the hlist
209 */
210static struct debug_obj *__alloc_object(struct hlist_head *list)
211{
212 struct debug_obj *obj = NULL;
213
214 if (list->first) {
215 obj = hlist_entry(list->first, typeof(*obj), node);
216 hlist_del(&obj->node);
217 }
218
219 return obj;
220}
221
222/*
223 * Allocate a new object. If the pool is empty, switch off the debugger.
224 * Must be called with interrupts disabled.
225 */
226static struct debug_obj *
227alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
228{
229 struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
230 struct debug_obj *obj;
231
232 if (likely(obj_cache)) {
233 obj = __alloc_object(&percpu_pool->free_objs);
234 if (obj) {
235 percpu_pool->obj_free--;
236 goto init_obj;
237 }
238 }
239
240 raw_spin_lock(&pool_lock);
241 obj = __alloc_object(&obj_pool);
242 if (obj) {
243 obj_pool_used++;
244 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
245
246 /*
247 * Looking ahead, allocate one batch of debug objects and
248 * put them into the percpu free pool.
249 */
250 if (likely(obj_cache)) {
251 int i;
252
253 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
254 struct debug_obj *obj2;
255
256 obj2 = __alloc_object(&obj_pool);
257 if (!obj2)
258 break;
259 hlist_add_head(&obj2->node,
260 &percpu_pool->free_objs);
261 percpu_pool->obj_free++;
262 obj_pool_used++;
263 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
264 }
265 }
266
267 if (obj_pool_used > obj_pool_max_used)
268 obj_pool_max_used = obj_pool_used;
269
270 if (obj_pool_free < obj_pool_min_free)
271 obj_pool_min_free = obj_pool_free;
272 }
273 raw_spin_unlock(&pool_lock);
274
275init_obj:
276 if (obj) {
277 obj->object = addr;
278 obj->descr = descr;
279 obj->state = ODEBUG_STATE_NONE;
280 obj->astate = 0;
281 hlist_add_head(&obj->node, &b->list);
282 }
283 return obj;
284}
285
286/*
287 * workqueue function to free objects.
288 *
289 * To reduce contention on the global pool_lock, the actual freeing of
290 * debug objects will be delayed if the pool_lock is busy.
291 */
292static void free_obj_work(struct work_struct *work)
293{
294 struct hlist_node *tmp;
295 struct debug_obj *obj;
296 unsigned long flags;
297 HLIST_HEAD(tofree);
298
299 WRITE_ONCE(obj_freeing, false);
300 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
301 return;
302
303 if (obj_pool_free >= debug_objects_pool_size)
304 goto free_objs;
305
306 /*
307 * The objs on the pool list might be allocated before the work is
308 * run, so recheck if pool list it full or not, if not fill pool
309 * list from the global free list. As it is likely that a workload
310 * may be gearing up to use more and more objects, don't free any
311 * of them until the next round.
312 */
313 while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
314 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
315 hlist_del(&obj->node);
316 hlist_add_head(&obj->node, &obj_pool);
317 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
318 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
319 }
320 raw_spin_unlock_irqrestore(&pool_lock, flags);
321 return;
322
323free_objs:
324 /*
325 * Pool list is already full and there are still objs on the free
326 * list. Move remaining free objs to a temporary list to free the
327 * memory outside the pool_lock held region.
328 */
329 if (obj_nr_tofree) {
330 hlist_move_list(&obj_to_free, &tofree);
331 debug_objects_freed += obj_nr_tofree;
332 WRITE_ONCE(obj_nr_tofree, 0);
333 }
334 raw_spin_unlock_irqrestore(&pool_lock, flags);
335
336 hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
337 hlist_del(&obj->node);
338 kmem_cache_free(obj_cache, obj);
339 }
340}
341
342static void __free_object(struct debug_obj *obj)
343{
344 struct debug_obj *objs[ODEBUG_BATCH_SIZE];
345 struct debug_percpu_free *percpu_pool;
346 int lookahead_count = 0;
347 unsigned long flags;
348 bool work;
349
350 local_irq_save(flags);
351 if (!obj_cache)
352 goto free_to_obj_pool;
353
354 /*
355 * Try to free it into the percpu pool first.
356 */
357 percpu_pool = this_cpu_ptr(&percpu_obj_pool);
358 if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
359 hlist_add_head(&obj->node, &percpu_pool->free_objs);
360 percpu_pool->obj_free++;
361 local_irq_restore(flags);
362 return;
363 }
364
365 /*
366 * As the percpu pool is full, look ahead and pull out a batch
367 * of objects from the percpu pool and free them as well.
368 */
369 for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
370 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
371 if (!objs[lookahead_count])
372 break;
373 percpu_pool->obj_free--;
374 }
375
376free_to_obj_pool:
377 raw_spin_lock(&pool_lock);
378 work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
379 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
380 obj_pool_used--;
381
382 if (work) {
383 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
384 hlist_add_head(&obj->node, &obj_to_free);
385 if (lookahead_count) {
386 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
387 obj_pool_used -= lookahead_count;
388 while (lookahead_count) {
389 hlist_add_head(&objs[--lookahead_count]->node,
390 &obj_to_free);
391 }
392 }
393
394 if ((obj_pool_free > debug_objects_pool_size) &&
395 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
396 int i;
397
398 /*
399 * Free one more batch of objects from obj_pool.
400 */
401 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
402 obj = __alloc_object(&obj_pool);
403 hlist_add_head(&obj->node, &obj_to_free);
404 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
405 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
406 }
407 }
408 } else {
409 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
410 hlist_add_head(&obj->node, &obj_pool);
411 if (lookahead_count) {
412 WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
413 obj_pool_used -= lookahead_count;
414 while (lookahead_count) {
415 hlist_add_head(&objs[--lookahead_count]->node,
416 &obj_pool);
417 }
418 }
419 }
420 raw_spin_unlock(&pool_lock);
421 local_irq_restore(flags);
422}
423
424/*
425 * Put the object back into the pool and schedule work to free objects
426 * if necessary.
427 */
428static void free_object(struct debug_obj *obj)
429{
430 __free_object(obj);
431 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
432 WRITE_ONCE(obj_freeing, true);
433 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
434 }
435}
436
437#ifdef CONFIG_HOTPLUG_CPU
438static int object_cpu_offline(unsigned int cpu)
439{
440 struct debug_percpu_free *percpu_pool;
441 struct hlist_node *tmp;
442 struct debug_obj *obj;
443
444 /* Remote access is safe as the CPU is dead already */
445 percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
446 hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
447 hlist_del(&obj->node);
448 kmem_cache_free(obj_cache, obj);
449 }
450 percpu_pool->obj_free = 0;
451
452 return 0;
453}
454#endif
455
456/*
457 * We run out of memory. That means we probably have tons of objects
458 * allocated.
459 */
460static void debug_objects_oom(void)
461{
462 struct debug_bucket *db = obj_hash;
463 struct hlist_node *tmp;
464 HLIST_HEAD(freelist);
465 struct debug_obj *obj;
466 unsigned long flags;
467 int i;
468
469 pr_warn("Out of memory. ODEBUG disabled\n");
470
471 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
472 raw_spin_lock_irqsave(&db->lock, flags);
473 hlist_move_list(&db->list, &freelist);
474 raw_spin_unlock_irqrestore(&db->lock, flags);
475
476 /* Now free them */
477 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
478 hlist_del(&obj->node);
479 free_object(obj);
480 }
481 }
482}
483
484/*
485 * We use the pfn of the address for the hash. That way we can check
486 * for freed objects simply by checking the affected bucket.
487 */
488static struct debug_bucket *get_bucket(unsigned long addr)
489{
490 unsigned long hash;
491
492 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
493 return &obj_hash[hash];
494}
495
496static void debug_print_object(struct debug_obj *obj, char *msg)
497{
498 const struct debug_obj_descr *descr = obj->descr;
499 static int limit;
500
501 if (limit < 5 && descr != descr_test) {
502 void *hint = descr->debug_hint ?
503 descr->debug_hint(obj->object) : NULL;
504 limit++;
505 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
506 "object type: %s hint: %pS\n",
507 msg, obj_states[obj->state], obj->astate,
508 descr->name, hint);
509 }
510 debug_objects_warnings++;
511}
512
513/*
514 * Try to repair the damage, so we have a better chance to get useful
515 * debug output.
516 */
517static bool
518debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
519 void * addr, enum debug_obj_state state)
520{
521 if (fixup && fixup(addr, state)) {
522 debug_objects_fixups++;
523 return true;
524 }
525 return false;
526}
527
528static void debug_object_is_on_stack(void *addr, int onstack)
529{
530 int is_on_stack;
531 static int limit;
532
533 if (limit > 4)
534 return;
535
536 is_on_stack = object_is_on_stack(addr);
537 if (is_on_stack == onstack)
538 return;
539
540 limit++;
541 if (is_on_stack)
542 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
543 task_stack_page(current));
544 else
545 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
546 task_stack_page(current));
547
548 WARN_ON(1);
549}
550
551static void
552__debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
553{
554 enum debug_obj_state state;
555 bool check_stack = false;
556 struct debug_bucket *db;
557 struct debug_obj *obj;
558 unsigned long flags;
559
560 fill_pool();
561
562 db = get_bucket((unsigned long) addr);
563
564 raw_spin_lock_irqsave(&db->lock, flags);
565
566 obj = lookup_object(addr, db);
567 if (!obj) {
568 obj = alloc_object(addr, db, descr);
569 if (!obj) {
570 debug_objects_enabled = 0;
571 raw_spin_unlock_irqrestore(&db->lock, flags);
572 debug_objects_oom();
573 return;
574 }
575 check_stack = true;
576 }
577
578 switch (obj->state) {
579 case ODEBUG_STATE_NONE:
580 case ODEBUG_STATE_INIT:
581 case ODEBUG_STATE_INACTIVE:
582 obj->state = ODEBUG_STATE_INIT;
583 break;
584
585 case ODEBUG_STATE_ACTIVE:
586 state = obj->state;
587 raw_spin_unlock_irqrestore(&db->lock, flags);
588 debug_print_object(obj, "init");
589 debug_object_fixup(descr->fixup_init, addr, state);
590 return;
591
592 case ODEBUG_STATE_DESTROYED:
593 raw_spin_unlock_irqrestore(&db->lock, flags);
594 debug_print_object(obj, "init");
595 return;
596 default:
597 break;
598 }
599
600 raw_spin_unlock_irqrestore(&db->lock, flags);
601 if (check_stack)
602 debug_object_is_on_stack(addr, onstack);
603}
604
605/**
606 * debug_object_init - debug checks when an object is initialized
607 * @addr: address of the object
608 * @descr: pointer to an object specific debug description structure
609 */
610void debug_object_init(void *addr, const struct debug_obj_descr *descr)
611{
612 if (!debug_objects_enabled)
613 return;
614
615 __debug_object_init(addr, descr, 0);
616}
617EXPORT_SYMBOL_GPL(debug_object_init);
618
619/**
620 * debug_object_init_on_stack - debug checks when an object on stack is
621 * initialized
622 * @addr: address of the object
623 * @descr: pointer to an object specific debug description structure
624 */
625void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
626{
627 if (!debug_objects_enabled)
628 return;
629
630 __debug_object_init(addr, descr, 1);
631}
632EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
633
634/**
635 * debug_object_activate - debug checks when an object is activated
636 * @addr: address of the object
637 * @descr: pointer to an object specific debug description structure
638 * Returns 0 for success, -EINVAL for check failed.
639 */
640int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
641{
642 enum debug_obj_state state;
643 struct debug_bucket *db;
644 struct debug_obj *obj;
645 unsigned long flags;
646 int ret;
647 struct debug_obj o = { .object = addr,
648 .state = ODEBUG_STATE_NOTAVAILABLE,
649 .descr = descr };
650
651 if (!debug_objects_enabled)
652 return 0;
653
654 db = get_bucket((unsigned long) addr);
655
656 raw_spin_lock_irqsave(&db->lock, flags);
657
658 obj = lookup_object(addr, db);
659 if (obj) {
660 bool print_object = false;
661
662 switch (obj->state) {
663 case ODEBUG_STATE_INIT:
664 case ODEBUG_STATE_INACTIVE:
665 obj->state = ODEBUG_STATE_ACTIVE;
666 ret = 0;
667 break;
668
669 case ODEBUG_STATE_ACTIVE:
670 state = obj->state;
671 raw_spin_unlock_irqrestore(&db->lock, flags);
672 debug_print_object(obj, "activate");
673 ret = debug_object_fixup(descr->fixup_activate, addr, state);
674 return ret ? 0 : -EINVAL;
675
676 case ODEBUG_STATE_DESTROYED:
677 print_object = true;
678 ret = -EINVAL;
679 break;
680 default:
681 ret = 0;
682 break;
683 }
684 raw_spin_unlock_irqrestore(&db->lock, flags);
685 if (print_object)
686 debug_print_object(obj, "activate");
687 return ret;
688 }
689
690 raw_spin_unlock_irqrestore(&db->lock, flags);
691
692 /*
693 * We are here when a static object is activated. We
694 * let the type specific code confirm whether this is
695 * true or not. if true, we just make sure that the
696 * static object is tracked in the object tracker. If
697 * not, this must be a bug, so we try to fix it up.
698 */
699 if (descr->is_static_object && descr->is_static_object(addr)) {
700 /* track this static object */
701 debug_object_init(addr, descr);
702 debug_object_activate(addr, descr);
703 } else {
704 debug_print_object(&o, "activate");
705 ret = debug_object_fixup(descr->fixup_activate, addr,
706 ODEBUG_STATE_NOTAVAILABLE);
707 return ret ? 0 : -EINVAL;
708 }
709 return 0;
710}
711EXPORT_SYMBOL_GPL(debug_object_activate);
712
713/**
714 * debug_object_deactivate - debug checks when an object is deactivated
715 * @addr: address of the object
716 * @descr: pointer to an object specific debug description structure
717 */
718void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
719{
720 struct debug_bucket *db;
721 struct debug_obj *obj;
722 unsigned long flags;
723 bool print_object = false;
724
725 if (!debug_objects_enabled)
726 return;
727
728 db = get_bucket((unsigned long) addr);
729
730 raw_spin_lock_irqsave(&db->lock, flags);
731
732 obj = lookup_object(addr, db);
733 if (obj) {
734 switch (obj->state) {
735 case ODEBUG_STATE_INIT:
736 case ODEBUG_STATE_INACTIVE:
737 case ODEBUG_STATE_ACTIVE:
738 if (!obj->astate)
739 obj->state = ODEBUG_STATE_INACTIVE;
740 else
741 print_object = true;
742 break;
743
744 case ODEBUG_STATE_DESTROYED:
745 print_object = true;
746 break;
747 default:
748 break;
749 }
750 }
751
752 raw_spin_unlock_irqrestore(&db->lock, flags);
753 if (!obj) {
754 struct debug_obj o = { .object = addr,
755 .state = ODEBUG_STATE_NOTAVAILABLE,
756 .descr = descr };
757
758 debug_print_object(&o, "deactivate");
759 } else if (print_object) {
760 debug_print_object(obj, "deactivate");
761 }
762}
763EXPORT_SYMBOL_GPL(debug_object_deactivate);
764
765/**
766 * debug_object_destroy - debug checks when an object is destroyed
767 * @addr: address of the object
768 * @descr: pointer to an object specific debug description structure
769 */
770void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
771{
772 enum debug_obj_state state;
773 struct debug_bucket *db;
774 struct debug_obj *obj;
775 unsigned long flags;
776 bool print_object = false;
777
778 if (!debug_objects_enabled)
779 return;
780
781 db = get_bucket((unsigned long) addr);
782
783 raw_spin_lock_irqsave(&db->lock, flags);
784
785 obj = lookup_object(addr, db);
786 if (!obj)
787 goto out_unlock;
788
789 switch (obj->state) {
790 case ODEBUG_STATE_NONE:
791 case ODEBUG_STATE_INIT:
792 case ODEBUG_STATE_INACTIVE:
793 obj->state = ODEBUG_STATE_DESTROYED;
794 break;
795 case ODEBUG_STATE_ACTIVE:
796 state = obj->state;
797 raw_spin_unlock_irqrestore(&db->lock, flags);
798 debug_print_object(obj, "destroy");
799 debug_object_fixup(descr->fixup_destroy, addr, state);
800 return;
801
802 case ODEBUG_STATE_DESTROYED:
803 print_object = true;
804 break;
805 default:
806 break;
807 }
808out_unlock:
809 raw_spin_unlock_irqrestore(&db->lock, flags);
810 if (print_object)
811 debug_print_object(obj, "destroy");
812}
813EXPORT_SYMBOL_GPL(debug_object_destroy);
814
815/**
816 * debug_object_free - debug checks when an object is freed
817 * @addr: address of the object
818 * @descr: pointer to an object specific debug description structure
819 */
820void debug_object_free(void *addr, const struct debug_obj_descr *descr)
821{
822 enum debug_obj_state state;
823 struct debug_bucket *db;
824 struct debug_obj *obj;
825 unsigned long flags;
826
827 if (!debug_objects_enabled)
828 return;
829
830 db = get_bucket((unsigned long) addr);
831
832 raw_spin_lock_irqsave(&db->lock, flags);
833
834 obj = lookup_object(addr, db);
835 if (!obj)
836 goto out_unlock;
837
838 switch (obj->state) {
839 case ODEBUG_STATE_ACTIVE:
840 state = obj->state;
841 raw_spin_unlock_irqrestore(&db->lock, flags);
842 debug_print_object(obj, "free");
843 debug_object_fixup(descr->fixup_free, addr, state);
844 return;
845 default:
846 hlist_del(&obj->node);
847 raw_spin_unlock_irqrestore(&db->lock, flags);
848 free_object(obj);
849 return;
850 }
851out_unlock:
852 raw_spin_unlock_irqrestore(&db->lock, flags);
853}
854EXPORT_SYMBOL_GPL(debug_object_free);
855
856/**
857 * debug_object_assert_init - debug checks when object should be init-ed
858 * @addr: address of the object
859 * @descr: pointer to an object specific debug description structure
860 */
861void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
862{
863 struct debug_bucket *db;
864 struct debug_obj *obj;
865 unsigned long flags;
866
867 if (!debug_objects_enabled)
868 return;
869
870 db = get_bucket((unsigned long) addr);
871
872 raw_spin_lock_irqsave(&db->lock, flags);
873
874 obj = lookup_object(addr, db);
875 if (!obj) {
876 struct debug_obj o = { .object = addr,
877 .state = ODEBUG_STATE_NOTAVAILABLE,
878 .descr = descr };
879
880 raw_spin_unlock_irqrestore(&db->lock, flags);
881 /*
882 * Maybe the object is static, and we let the type specific
883 * code confirm. Track this static object if true, else invoke
884 * fixup.
885 */
886 if (descr->is_static_object && descr->is_static_object(addr)) {
887 /* Track this static object */
888 debug_object_init(addr, descr);
889 } else {
890 debug_print_object(&o, "assert_init");
891 debug_object_fixup(descr->fixup_assert_init, addr,
892 ODEBUG_STATE_NOTAVAILABLE);
893 }
894 return;
895 }
896
897 raw_spin_unlock_irqrestore(&db->lock, flags);
898}
899EXPORT_SYMBOL_GPL(debug_object_assert_init);
900
901/**
902 * debug_object_active_state - debug checks object usage state machine
903 * @addr: address of the object
904 * @descr: pointer to an object specific debug description structure
905 * @expect: expected state
906 * @next: state to move to if expected state is found
907 */
908void
909debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
910 unsigned int expect, unsigned int next)
911{
912 struct debug_bucket *db;
913 struct debug_obj *obj;
914 unsigned long flags;
915 bool print_object = false;
916
917 if (!debug_objects_enabled)
918 return;
919
920 db = get_bucket((unsigned long) addr);
921
922 raw_spin_lock_irqsave(&db->lock, flags);
923
924 obj = lookup_object(addr, db);
925 if (obj) {
926 switch (obj->state) {
927 case ODEBUG_STATE_ACTIVE:
928 if (obj->astate == expect)
929 obj->astate = next;
930 else
931 print_object = true;
932 break;
933
934 default:
935 print_object = true;
936 break;
937 }
938 }
939
940 raw_spin_unlock_irqrestore(&db->lock, flags);
941 if (!obj) {
942 struct debug_obj o = { .object = addr,
943 .state = ODEBUG_STATE_NOTAVAILABLE,
944 .descr = descr };
945
946 debug_print_object(&o, "active_state");
947 } else if (print_object) {
948 debug_print_object(obj, "active_state");
949 }
950}
951EXPORT_SYMBOL_GPL(debug_object_active_state);
952
953#ifdef CONFIG_DEBUG_OBJECTS_FREE
954static void __debug_check_no_obj_freed(const void *address, unsigned long size)
955{
956 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
957 const struct debug_obj_descr *descr;
958 enum debug_obj_state state;
959 struct debug_bucket *db;
960 struct hlist_node *tmp;
961 struct debug_obj *obj;
962 int cnt, objs_checked = 0;
963
964 saddr = (unsigned long) address;
965 eaddr = saddr + size;
966 paddr = saddr & ODEBUG_CHUNK_MASK;
967 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
968 chunks >>= ODEBUG_CHUNK_SHIFT;
969
970 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
971 db = get_bucket(paddr);
972
973repeat:
974 cnt = 0;
975 raw_spin_lock_irqsave(&db->lock, flags);
976 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
977 cnt++;
978 oaddr = (unsigned long) obj->object;
979 if (oaddr < saddr || oaddr >= eaddr)
980 continue;
981
982 switch (obj->state) {
983 case ODEBUG_STATE_ACTIVE:
984 descr = obj->descr;
985 state = obj->state;
986 raw_spin_unlock_irqrestore(&db->lock, flags);
987 debug_print_object(obj, "free");
988 debug_object_fixup(descr->fixup_free,
989 (void *) oaddr, state);
990 goto repeat;
991 default:
992 hlist_del(&obj->node);
993 __free_object(obj);
994 break;
995 }
996 }
997 raw_spin_unlock_irqrestore(&db->lock, flags);
998
999 if (cnt > debug_objects_maxchain)
1000 debug_objects_maxchain = cnt;
1001
1002 objs_checked += cnt;
1003 }
1004
1005 if (objs_checked > debug_objects_maxchecked)
1006 debug_objects_maxchecked = objs_checked;
1007
1008 /* Schedule work to actually kmem_cache_free() objects */
1009 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1010 WRITE_ONCE(obj_freeing, true);
1011 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1012 }
1013}
1014
1015void debug_check_no_obj_freed(const void *address, unsigned long size)
1016{
1017 if (debug_objects_enabled)
1018 __debug_check_no_obj_freed(address, size);
1019}
1020#endif
1021
1022#ifdef CONFIG_DEBUG_FS
1023
1024static int debug_stats_show(struct seq_file *m, void *v)
1025{
1026 int cpu, obj_percpu_free = 0;
1027
1028 for_each_possible_cpu(cpu)
1029 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1030
1031 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
1032 seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
1033 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
1034 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
1035 seq_printf(m, "pool_free :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1036 seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1037 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1038 seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
1039 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1040 seq_printf(m, "on_free_list :%d\n", READ_ONCE(obj_nr_tofree));
1041 seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1042 seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
1043 return 0;
1044}
1045DEFINE_SHOW_ATTRIBUTE(debug_stats);
1046
1047static int __init debug_objects_init_debugfs(void)
1048{
1049 struct dentry *dbgdir;
1050
1051 if (!debug_objects_enabled)
1052 return 0;
1053
1054 dbgdir = debugfs_create_dir("debug_objects", NULL);
1055
1056 debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1057
1058 return 0;
1059}
1060__initcall(debug_objects_init_debugfs);
1061
1062#else
1063static inline void debug_objects_init_debugfs(void) { }
1064#endif
1065
1066#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1067
1068/* Random data structure for the self test */
1069struct self_test {
1070 unsigned long dummy1[6];
1071 int static_init;
1072 unsigned long dummy2[3];
1073};
1074
1075static __initconst const struct debug_obj_descr descr_type_test;
1076
1077static bool __init is_static_object(void *addr)
1078{
1079 struct self_test *obj = addr;
1080
1081 return obj->static_init;
1082}
1083
1084/*
1085 * fixup_init is called when:
1086 * - an active object is initialized
1087 */
1088static bool __init fixup_init(void *addr, enum debug_obj_state state)
1089{
1090 struct self_test *obj = addr;
1091
1092 switch (state) {
1093 case ODEBUG_STATE_ACTIVE:
1094 debug_object_deactivate(obj, &descr_type_test);
1095 debug_object_init(obj, &descr_type_test);
1096 return true;
1097 default:
1098 return false;
1099 }
1100}
1101
1102/*
1103 * fixup_activate is called when:
1104 * - an active object is activated
1105 * - an unknown non-static object is activated
1106 */
1107static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1108{
1109 struct self_test *obj = addr;
1110
1111 switch (state) {
1112 case ODEBUG_STATE_NOTAVAILABLE:
1113 return true;
1114 case ODEBUG_STATE_ACTIVE:
1115 debug_object_deactivate(obj, &descr_type_test);
1116 debug_object_activate(obj, &descr_type_test);
1117 return true;
1118
1119 default:
1120 return false;
1121 }
1122}
1123
1124/*
1125 * fixup_destroy is called when:
1126 * - an active object is destroyed
1127 */
1128static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1129{
1130 struct self_test *obj = addr;
1131
1132 switch (state) {
1133 case ODEBUG_STATE_ACTIVE:
1134 debug_object_deactivate(obj, &descr_type_test);
1135 debug_object_destroy(obj, &descr_type_test);
1136 return true;
1137 default:
1138 return false;
1139 }
1140}
1141
1142/*
1143 * fixup_free is called when:
1144 * - an active object is freed
1145 */
1146static bool __init fixup_free(void *addr, enum debug_obj_state state)
1147{
1148 struct self_test *obj = addr;
1149
1150 switch (state) {
1151 case ODEBUG_STATE_ACTIVE:
1152 debug_object_deactivate(obj, &descr_type_test);
1153 debug_object_free(obj, &descr_type_test);
1154 return true;
1155 default:
1156 return false;
1157 }
1158}
1159
1160static int __init
1161check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1162{
1163 struct debug_bucket *db;
1164 struct debug_obj *obj;
1165 unsigned long flags;
1166 int res = -EINVAL;
1167
1168 db = get_bucket((unsigned long) addr);
1169
1170 raw_spin_lock_irqsave(&db->lock, flags);
1171
1172 obj = lookup_object(addr, db);
1173 if (!obj && state != ODEBUG_STATE_NONE) {
1174 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1175 goto out;
1176 }
1177 if (obj && obj->state != state) {
1178 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1179 obj->state, state);
1180 goto out;
1181 }
1182 if (fixups != debug_objects_fixups) {
1183 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1184 fixups, debug_objects_fixups);
1185 goto out;
1186 }
1187 if (warnings != debug_objects_warnings) {
1188 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1189 warnings, debug_objects_warnings);
1190 goto out;
1191 }
1192 res = 0;
1193out:
1194 raw_spin_unlock_irqrestore(&db->lock, flags);
1195 if (res)
1196 debug_objects_enabled = 0;
1197 return res;
1198}
1199
1200static __initconst const struct debug_obj_descr descr_type_test = {
1201 .name = "selftest",
1202 .is_static_object = is_static_object,
1203 .fixup_init = fixup_init,
1204 .fixup_activate = fixup_activate,
1205 .fixup_destroy = fixup_destroy,
1206 .fixup_free = fixup_free,
1207};
1208
1209static __initdata struct self_test obj = { .static_init = 0 };
1210
1211static void __init debug_objects_selftest(void)
1212{
1213 int fixups, oldfixups, warnings, oldwarnings;
1214 unsigned long flags;
1215
1216 local_irq_save(flags);
1217
1218 fixups = oldfixups = debug_objects_fixups;
1219 warnings = oldwarnings = debug_objects_warnings;
1220 descr_test = &descr_type_test;
1221
1222 debug_object_init(&obj, &descr_type_test);
1223 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1224 goto out;
1225 debug_object_activate(&obj, &descr_type_test);
1226 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1227 goto out;
1228 debug_object_activate(&obj, &descr_type_test);
1229 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1230 goto out;
1231 debug_object_deactivate(&obj, &descr_type_test);
1232 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1233 goto out;
1234 debug_object_destroy(&obj, &descr_type_test);
1235 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1236 goto out;
1237 debug_object_init(&obj, &descr_type_test);
1238 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1239 goto out;
1240 debug_object_activate(&obj, &descr_type_test);
1241 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1242 goto out;
1243 debug_object_deactivate(&obj, &descr_type_test);
1244 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1245 goto out;
1246 debug_object_free(&obj, &descr_type_test);
1247 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1248 goto out;
1249
1250 obj.static_init = 1;
1251 debug_object_activate(&obj, &descr_type_test);
1252 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1253 goto out;
1254 debug_object_init(&obj, &descr_type_test);
1255 if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1256 goto out;
1257 debug_object_free(&obj, &descr_type_test);
1258 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1259 goto out;
1260
1261#ifdef CONFIG_DEBUG_OBJECTS_FREE
1262 debug_object_init(&obj, &descr_type_test);
1263 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1264 goto out;
1265 debug_object_activate(&obj, &descr_type_test);
1266 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1267 goto out;
1268 __debug_check_no_obj_freed(&obj, sizeof(obj));
1269 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1270 goto out;
1271#endif
1272 pr_info("selftest passed\n");
1273
1274out:
1275 debug_objects_fixups = oldfixups;
1276 debug_objects_warnings = oldwarnings;
1277 descr_test = NULL;
1278
1279 local_irq_restore(flags);
1280}
1281#else
1282static inline void debug_objects_selftest(void) { }
1283#endif
1284
1285/*
1286 * Called during early boot to initialize the hash buckets and link
1287 * the static object pool objects into the poll list. After this call
1288 * the object tracker is fully operational.
1289 */
1290void __init debug_objects_early_init(void)
1291{
1292 int i;
1293
1294 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1295 raw_spin_lock_init(&obj_hash[i].lock);
1296
1297 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1298 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1299}
1300
1301/*
1302 * Convert the statically allocated objects to dynamic ones:
1303 */
1304static int __init debug_objects_replace_static_objects(void)
1305{
1306 struct debug_bucket *db = obj_hash;
1307 struct hlist_node *tmp;
1308 struct debug_obj *obj, *new;
1309 HLIST_HEAD(objects);
1310 int i, cnt = 0;
1311
1312 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1313 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1314 if (!obj)
1315 goto free;
1316 hlist_add_head(&obj->node, &objects);
1317 }
1318
1319 /*
1320 * debug_objects_mem_init() is now called early that only one CPU is up
1321 * and interrupts have been disabled, so it is safe to replace the
1322 * active object references.
1323 */
1324
1325 /* Remove the statically allocated objects from the pool */
1326 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1327 hlist_del(&obj->node);
1328 /* Move the allocated objects to the pool */
1329 hlist_move_list(&objects, &obj_pool);
1330
1331 /* Replace the active object references */
1332 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1333 hlist_move_list(&db->list, &objects);
1334
1335 hlist_for_each_entry(obj, &objects, node) {
1336 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1337 hlist_del(&new->node);
1338 /* copy object data */
1339 *new = *obj;
1340 hlist_add_head(&new->node, &db->list);
1341 cnt++;
1342 }
1343 }
1344
1345 pr_debug("%d of %d active objects replaced\n",
1346 cnt, obj_pool_used);
1347 return 0;
1348free:
1349 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1350 hlist_del(&obj->node);
1351 kmem_cache_free(obj_cache, obj);
1352 }
1353 return -ENOMEM;
1354}
1355
1356/*
1357 * Called after the kmem_caches are functional to setup a dedicated
1358 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1359 * prevents that the debug code is called on kmem_cache_free() for the
1360 * debug tracker objects to avoid recursive calls.
1361 */
1362void __init debug_objects_mem_init(void)
1363{
1364 int cpu, extras;
1365
1366 if (!debug_objects_enabled)
1367 return;
1368
1369 /*
1370 * Initialize the percpu object pools
1371 *
1372 * Initialization is not strictly necessary, but was done for
1373 * completeness.
1374 */
1375 for_each_possible_cpu(cpu)
1376 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1377
1378 obj_cache = kmem_cache_create("debug_objects_cache",
1379 sizeof (struct debug_obj), 0,
1380 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1381 NULL);
1382
1383 if (!obj_cache || debug_objects_replace_static_objects()) {
1384 debug_objects_enabled = 0;
1385 kmem_cache_destroy(obj_cache);
1386 pr_warn("out of memory.\n");
1387 } else
1388 debug_objects_selftest();
1389
1390#ifdef CONFIG_HOTPLUG_CPU
1391 cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1392 object_cpu_offline);
1393#endif
1394
1395 /*
1396 * Increase the thresholds for allocating and freeing objects
1397 * according to the number of possible CPUs available in the system.
1398 */
1399 extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1400 debug_objects_pool_size += extras;
1401 debug_objects_pool_min_level += extras;
1402}
1/*
2 * Generic infrastructure for lifetime debugging of objects.
3 *
4 * Started by Thomas Gleixner
5 *
6 * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
7 *
8 * For licencing details see kernel-base/COPYING
9 */
10#include <linux/debugobjects.h>
11#include <linux/interrupt.h>
12#include <linux/sched.h>
13#include <linux/seq_file.h>
14#include <linux/debugfs.h>
15#include <linux/slab.h>
16#include <linux/hash.h>
17
18#define ODEBUG_HASH_BITS 14
19#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
20
21#define ODEBUG_POOL_SIZE 512
22#define ODEBUG_POOL_MIN_LEVEL 256
23
24#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
25#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
26#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
27
28struct debug_bucket {
29 struct hlist_head list;
30 raw_spinlock_t lock;
31};
32
33static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
34
35static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
36
37static DEFINE_RAW_SPINLOCK(pool_lock);
38
39static HLIST_HEAD(obj_pool);
40
41static int obj_pool_min_free = ODEBUG_POOL_SIZE;
42static int obj_pool_free = ODEBUG_POOL_SIZE;
43static int obj_pool_used;
44static int obj_pool_max_used;
45static struct kmem_cache *obj_cache;
46
47static int debug_objects_maxchain __read_mostly;
48static int debug_objects_fixups __read_mostly;
49static int debug_objects_warnings __read_mostly;
50static int debug_objects_enabled __read_mostly
51 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
52
53static struct debug_obj_descr *descr_test __read_mostly;
54
55static void free_obj_work(struct work_struct *work);
56static DECLARE_WORK(debug_obj_work, free_obj_work);
57
58static int __init enable_object_debug(char *str)
59{
60 debug_objects_enabled = 1;
61 return 0;
62}
63
64static int __init disable_object_debug(char *str)
65{
66 debug_objects_enabled = 0;
67 return 0;
68}
69
70early_param("debug_objects", enable_object_debug);
71early_param("no_debug_objects", disable_object_debug);
72
73static const char *obj_states[ODEBUG_STATE_MAX] = {
74 [ODEBUG_STATE_NONE] = "none",
75 [ODEBUG_STATE_INIT] = "initialized",
76 [ODEBUG_STATE_INACTIVE] = "inactive",
77 [ODEBUG_STATE_ACTIVE] = "active",
78 [ODEBUG_STATE_DESTROYED] = "destroyed",
79 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
80};
81
82static void fill_pool(void)
83{
84 gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
85 struct debug_obj *new;
86 unsigned long flags;
87
88 if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
89 return;
90
91 if (unlikely(!obj_cache))
92 return;
93
94 while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
95
96 new = kmem_cache_zalloc(obj_cache, gfp);
97 if (!new)
98 return;
99
100 raw_spin_lock_irqsave(&pool_lock, flags);
101 hlist_add_head(&new->node, &obj_pool);
102 obj_pool_free++;
103 raw_spin_unlock_irqrestore(&pool_lock, flags);
104 }
105}
106
107/*
108 * Lookup an object in the hash bucket.
109 */
110static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
111{
112 struct hlist_node *node;
113 struct debug_obj *obj;
114 int cnt = 0;
115
116 hlist_for_each_entry(obj, node, &b->list, node) {
117 cnt++;
118 if (obj->object == addr)
119 return obj;
120 }
121 if (cnt > debug_objects_maxchain)
122 debug_objects_maxchain = cnt;
123
124 return NULL;
125}
126
127/*
128 * Allocate a new object. If the pool is empty, switch off the debugger.
129 * Must be called with interrupts disabled.
130 */
131static struct debug_obj *
132alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
133{
134 struct debug_obj *obj = NULL;
135
136 raw_spin_lock(&pool_lock);
137 if (obj_pool.first) {
138 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
139
140 obj->object = addr;
141 obj->descr = descr;
142 obj->state = ODEBUG_STATE_NONE;
143 obj->astate = 0;
144 hlist_del(&obj->node);
145
146 hlist_add_head(&obj->node, &b->list);
147
148 obj_pool_used++;
149 if (obj_pool_used > obj_pool_max_used)
150 obj_pool_max_used = obj_pool_used;
151
152 obj_pool_free--;
153 if (obj_pool_free < obj_pool_min_free)
154 obj_pool_min_free = obj_pool_free;
155 }
156 raw_spin_unlock(&pool_lock);
157
158 return obj;
159}
160
161/*
162 * workqueue function to free objects.
163 */
164static void free_obj_work(struct work_struct *work)
165{
166 struct debug_obj *obj;
167 unsigned long flags;
168
169 raw_spin_lock_irqsave(&pool_lock, flags);
170 while (obj_pool_free > ODEBUG_POOL_SIZE) {
171 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
172 hlist_del(&obj->node);
173 obj_pool_free--;
174 /*
175 * We release pool_lock across kmem_cache_free() to
176 * avoid contention on pool_lock.
177 */
178 raw_spin_unlock_irqrestore(&pool_lock, flags);
179 kmem_cache_free(obj_cache, obj);
180 raw_spin_lock_irqsave(&pool_lock, flags);
181 }
182 raw_spin_unlock_irqrestore(&pool_lock, flags);
183}
184
185/*
186 * Put the object back into the pool and schedule work to free objects
187 * if necessary.
188 */
189static void free_object(struct debug_obj *obj)
190{
191 unsigned long flags;
192 int sched = 0;
193
194 raw_spin_lock_irqsave(&pool_lock, flags);
195 /*
196 * schedule work when the pool is filled and the cache is
197 * initialized:
198 */
199 if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
200 sched = keventd_up() && !work_pending(&debug_obj_work);
201 hlist_add_head(&obj->node, &obj_pool);
202 obj_pool_free++;
203 obj_pool_used--;
204 raw_spin_unlock_irqrestore(&pool_lock, flags);
205 if (sched)
206 schedule_work(&debug_obj_work);
207}
208
209/*
210 * We run out of memory. That means we probably have tons of objects
211 * allocated.
212 */
213static void debug_objects_oom(void)
214{
215 struct debug_bucket *db = obj_hash;
216 struct hlist_node *node, *tmp;
217 HLIST_HEAD(freelist);
218 struct debug_obj *obj;
219 unsigned long flags;
220 int i;
221
222 printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
223
224 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
225 raw_spin_lock_irqsave(&db->lock, flags);
226 hlist_move_list(&db->list, &freelist);
227 raw_spin_unlock_irqrestore(&db->lock, flags);
228
229 /* Now free them */
230 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
231 hlist_del(&obj->node);
232 free_object(obj);
233 }
234 }
235}
236
237/*
238 * We use the pfn of the address for the hash. That way we can check
239 * for freed objects simply by checking the affected bucket.
240 */
241static struct debug_bucket *get_bucket(unsigned long addr)
242{
243 unsigned long hash;
244
245 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
246 return &obj_hash[hash];
247}
248
249static void debug_print_object(struct debug_obj *obj, char *msg)
250{
251 struct debug_obj_descr *descr = obj->descr;
252 static int limit;
253
254 if (limit < 5 && descr != descr_test) {
255 void *hint = descr->debug_hint ?
256 descr->debug_hint(obj->object) : NULL;
257 limit++;
258 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
259 "object type: %s hint: %pS\n",
260 msg, obj_states[obj->state], obj->astate,
261 descr->name, hint);
262 }
263 debug_objects_warnings++;
264}
265
266/*
267 * Try to repair the damage, so we have a better chance to get useful
268 * debug output.
269 */
270static int
271debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
272 void * addr, enum debug_obj_state state)
273{
274 int fixed = 0;
275
276 if (fixup)
277 fixed = fixup(addr, state);
278 debug_objects_fixups += fixed;
279 return fixed;
280}
281
282static void debug_object_is_on_stack(void *addr, int onstack)
283{
284 int is_on_stack;
285 static int limit;
286
287 if (limit > 4)
288 return;
289
290 is_on_stack = object_is_on_stack(addr);
291 if (is_on_stack == onstack)
292 return;
293
294 limit++;
295 if (is_on_stack)
296 printk(KERN_WARNING
297 "ODEBUG: object is on stack, but not annotated\n");
298 else
299 printk(KERN_WARNING
300 "ODEBUG: object is not on stack, but annotated\n");
301 WARN_ON(1);
302}
303
304static void
305__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
306{
307 enum debug_obj_state state;
308 struct debug_bucket *db;
309 struct debug_obj *obj;
310 unsigned long flags;
311
312 fill_pool();
313
314 db = get_bucket((unsigned long) addr);
315
316 raw_spin_lock_irqsave(&db->lock, flags);
317
318 obj = lookup_object(addr, db);
319 if (!obj) {
320 obj = alloc_object(addr, db, descr);
321 if (!obj) {
322 debug_objects_enabled = 0;
323 raw_spin_unlock_irqrestore(&db->lock, flags);
324 debug_objects_oom();
325 return;
326 }
327 debug_object_is_on_stack(addr, onstack);
328 }
329
330 switch (obj->state) {
331 case ODEBUG_STATE_NONE:
332 case ODEBUG_STATE_INIT:
333 case ODEBUG_STATE_INACTIVE:
334 obj->state = ODEBUG_STATE_INIT;
335 break;
336
337 case ODEBUG_STATE_ACTIVE:
338 debug_print_object(obj, "init");
339 state = obj->state;
340 raw_spin_unlock_irqrestore(&db->lock, flags);
341 debug_object_fixup(descr->fixup_init, addr, state);
342 return;
343
344 case ODEBUG_STATE_DESTROYED:
345 debug_print_object(obj, "init");
346 break;
347 default:
348 break;
349 }
350
351 raw_spin_unlock_irqrestore(&db->lock, flags);
352}
353
354/**
355 * debug_object_init - debug checks when an object is initialized
356 * @addr: address of the object
357 * @descr: pointer to an object specific debug description structure
358 */
359void debug_object_init(void *addr, struct debug_obj_descr *descr)
360{
361 if (!debug_objects_enabled)
362 return;
363
364 __debug_object_init(addr, descr, 0);
365}
366
367/**
368 * debug_object_init_on_stack - debug checks when an object on stack is
369 * initialized
370 * @addr: address of the object
371 * @descr: pointer to an object specific debug description structure
372 */
373void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
374{
375 if (!debug_objects_enabled)
376 return;
377
378 __debug_object_init(addr, descr, 1);
379}
380
381/**
382 * debug_object_activate - debug checks when an object is activated
383 * @addr: address of the object
384 * @descr: pointer to an object specific debug description structure
385 */
386void debug_object_activate(void *addr, struct debug_obj_descr *descr)
387{
388 enum debug_obj_state state;
389 struct debug_bucket *db;
390 struct debug_obj *obj;
391 unsigned long flags;
392 struct debug_obj o = { .object = addr,
393 .state = ODEBUG_STATE_NOTAVAILABLE,
394 .descr = descr };
395
396 if (!debug_objects_enabled)
397 return;
398
399 db = get_bucket((unsigned long) addr);
400
401 raw_spin_lock_irqsave(&db->lock, flags);
402
403 obj = lookup_object(addr, db);
404 if (obj) {
405 switch (obj->state) {
406 case ODEBUG_STATE_INIT:
407 case ODEBUG_STATE_INACTIVE:
408 obj->state = ODEBUG_STATE_ACTIVE;
409 break;
410
411 case ODEBUG_STATE_ACTIVE:
412 debug_print_object(obj, "activate");
413 state = obj->state;
414 raw_spin_unlock_irqrestore(&db->lock, flags);
415 debug_object_fixup(descr->fixup_activate, addr, state);
416 return;
417
418 case ODEBUG_STATE_DESTROYED:
419 debug_print_object(obj, "activate");
420 break;
421 default:
422 break;
423 }
424 raw_spin_unlock_irqrestore(&db->lock, flags);
425 return;
426 }
427
428 raw_spin_unlock_irqrestore(&db->lock, flags);
429 /*
430 * This happens when a static object is activated. We
431 * let the type specific code decide whether this is
432 * true or not.
433 */
434 if (debug_object_fixup(descr->fixup_activate, addr,
435 ODEBUG_STATE_NOTAVAILABLE))
436 debug_print_object(&o, "activate");
437}
438
439/**
440 * debug_object_deactivate - debug checks when an object is deactivated
441 * @addr: address of the object
442 * @descr: pointer to an object specific debug description structure
443 */
444void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
445{
446 struct debug_bucket *db;
447 struct debug_obj *obj;
448 unsigned long flags;
449
450 if (!debug_objects_enabled)
451 return;
452
453 db = get_bucket((unsigned long) addr);
454
455 raw_spin_lock_irqsave(&db->lock, flags);
456
457 obj = lookup_object(addr, db);
458 if (obj) {
459 switch (obj->state) {
460 case ODEBUG_STATE_INIT:
461 case ODEBUG_STATE_INACTIVE:
462 case ODEBUG_STATE_ACTIVE:
463 if (!obj->astate)
464 obj->state = ODEBUG_STATE_INACTIVE;
465 else
466 debug_print_object(obj, "deactivate");
467 break;
468
469 case ODEBUG_STATE_DESTROYED:
470 debug_print_object(obj, "deactivate");
471 break;
472 default:
473 break;
474 }
475 } else {
476 struct debug_obj o = { .object = addr,
477 .state = ODEBUG_STATE_NOTAVAILABLE,
478 .descr = descr };
479
480 debug_print_object(&o, "deactivate");
481 }
482
483 raw_spin_unlock_irqrestore(&db->lock, flags);
484}
485
486/**
487 * debug_object_destroy - debug checks when an object is destroyed
488 * @addr: address of the object
489 * @descr: pointer to an object specific debug description structure
490 */
491void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
492{
493 enum debug_obj_state state;
494 struct debug_bucket *db;
495 struct debug_obj *obj;
496 unsigned long flags;
497
498 if (!debug_objects_enabled)
499 return;
500
501 db = get_bucket((unsigned long) addr);
502
503 raw_spin_lock_irqsave(&db->lock, flags);
504
505 obj = lookup_object(addr, db);
506 if (!obj)
507 goto out_unlock;
508
509 switch (obj->state) {
510 case ODEBUG_STATE_NONE:
511 case ODEBUG_STATE_INIT:
512 case ODEBUG_STATE_INACTIVE:
513 obj->state = ODEBUG_STATE_DESTROYED;
514 break;
515 case ODEBUG_STATE_ACTIVE:
516 debug_print_object(obj, "destroy");
517 state = obj->state;
518 raw_spin_unlock_irqrestore(&db->lock, flags);
519 debug_object_fixup(descr->fixup_destroy, addr, state);
520 return;
521
522 case ODEBUG_STATE_DESTROYED:
523 debug_print_object(obj, "destroy");
524 break;
525 default:
526 break;
527 }
528out_unlock:
529 raw_spin_unlock_irqrestore(&db->lock, flags);
530}
531
532/**
533 * debug_object_free - debug checks when an object is freed
534 * @addr: address of the object
535 * @descr: pointer to an object specific debug description structure
536 */
537void debug_object_free(void *addr, struct debug_obj_descr *descr)
538{
539 enum debug_obj_state state;
540 struct debug_bucket *db;
541 struct debug_obj *obj;
542 unsigned long flags;
543
544 if (!debug_objects_enabled)
545 return;
546
547 db = get_bucket((unsigned long) addr);
548
549 raw_spin_lock_irqsave(&db->lock, flags);
550
551 obj = lookup_object(addr, db);
552 if (!obj)
553 goto out_unlock;
554
555 switch (obj->state) {
556 case ODEBUG_STATE_ACTIVE:
557 debug_print_object(obj, "free");
558 state = obj->state;
559 raw_spin_unlock_irqrestore(&db->lock, flags);
560 debug_object_fixup(descr->fixup_free, addr, state);
561 return;
562 default:
563 hlist_del(&obj->node);
564 raw_spin_unlock_irqrestore(&db->lock, flags);
565 free_object(obj);
566 return;
567 }
568out_unlock:
569 raw_spin_unlock_irqrestore(&db->lock, flags);
570}
571
572/**
573 * debug_object_assert_init - debug checks when object should be init-ed
574 * @addr: address of the object
575 * @descr: pointer to an object specific debug description structure
576 */
577void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
578{
579 struct debug_bucket *db;
580 struct debug_obj *obj;
581 unsigned long flags;
582
583 if (!debug_objects_enabled)
584 return;
585
586 db = get_bucket((unsigned long) addr);
587
588 raw_spin_lock_irqsave(&db->lock, flags);
589
590 obj = lookup_object(addr, db);
591 if (!obj) {
592 struct debug_obj o = { .object = addr,
593 .state = ODEBUG_STATE_NOTAVAILABLE,
594 .descr = descr };
595
596 raw_spin_unlock_irqrestore(&db->lock, flags);
597 /*
598 * Maybe the object is static. Let the type specific
599 * code decide what to do.
600 */
601 if (debug_object_fixup(descr->fixup_assert_init, addr,
602 ODEBUG_STATE_NOTAVAILABLE))
603 debug_print_object(&o, "assert_init");
604 return;
605 }
606
607 raw_spin_unlock_irqrestore(&db->lock, flags);
608}
609
610/**
611 * debug_object_active_state - debug checks object usage state machine
612 * @addr: address of the object
613 * @descr: pointer to an object specific debug description structure
614 * @expect: expected state
615 * @next: state to move to if expected state is found
616 */
617void
618debug_object_active_state(void *addr, struct debug_obj_descr *descr,
619 unsigned int expect, unsigned int next)
620{
621 struct debug_bucket *db;
622 struct debug_obj *obj;
623 unsigned long flags;
624
625 if (!debug_objects_enabled)
626 return;
627
628 db = get_bucket((unsigned long) addr);
629
630 raw_spin_lock_irqsave(&db->lock, flags);
631
632 obj = lookup_object(addr, db);
633 if (obj) {
634 switch (obj->state) {
635 case ODEBUG_STATE_ACTIVE:
636 if (obj->astate == expect)
637 obj->astate = next;
638 else
639 debug_print_object(obj, "active_state");
640 break;
641
642 default:
643 debug_print_object(obj, "active_state");
644 break;
645 }
646 } else {
647 struct debug_obj o = { .object = addr,
648 .state = ODEBUG_STATE_NOTAVAILABLE,
649 .descr = descr };
650
651 debug_print_object(&o, "active_state");
652 }
653
654 raw_spin_unlock_irqrestore(&db->lock, flags);
655}
656
657#ifdef CONFIG_DEBUG_OBJECTS_FREE
658static void __debug_check_no_obj_freed(const void *address, unsigned long size)
659{
660 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
661 struct hlist_node *node, *tmp;
662 HLIST_HEAD(freelist);
663 struct debug_obj_descr *descr;
664 enum debug_obj_state state;
665 struct debug_bucket *db;
666 struct debug_obj *obj;
667 int cnt;
668
669 saddr = (unsigned long) address;
670 eaddr = saddr + size;
671 paddr = saddr & ODEBUG_CHUNK_MASK;
672 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
673 chunks >>= ODEBUG_CHUNK_SHIFT;
674
675 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
676 db = get_bucket(paddr);
677
678repeat:
679 cnt = 0;
680 raw_spin_lock_irqsave(&db->lock, flags);
681 hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
682 cnt++;
683 oaddr = (unsigned long) obj->object;
684 if (oaddr < saddr || oaddr >= eaddr)
685 continue;
686
687 switch (obj->state) {
688 case ODEBUG_STATE_ACTIVE:
689 debug_print_object(obj, "free");
690 descr = obj->descr;
691 state = obj->state;
692 raw_spin_unlock_irqrestore(&db->lock, flags);
693 debug_object_fixup(descr->fixup_free,
694 (void *) oaddr, state);
695 goto repeat;
696 default:
697 hlist_del(&obj->node);
698 hlist_add_head(&obj->node, &freelist);
699 break;
700 }
701 }
702 raw_spin_unlock_irqrestore(&db->lock, flags);
703
704 /* Now free them */
705 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
706 hlist_del(&obj->node);
707 free_object(obj);
708 }
709
710 if (cnt > debug_objects_maxchain)
711 debug_objects_maxchain = cnt;
712 }
713}
714
715void debug_check_no_obj_freed(const void *address, unsigned long size)
716{
717 if (debug_objects_enabled)
718 __debug_check_no_obj_freed(address, size);
719}
720#endif
721
722#ifdef CONFIG_DEBUG_FS
723
724static int debug_stats_show(struct seq_file *m, void *v)
725{
726 seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
727 seq_printf(m, "warnings :%d\n", debug_objects_warnings);
728 seq_printf(m, "fixups :%d\n", debug_objects_fixups);
729 seq_printf(m, "pool_free :%d\n", obj_pool_free);
730 seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
731 seq_printf(m, "pool_used :%d\n", obj_pool_used);
732 seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
733 return 0;
734}
735
736static int debug_stats_open(struct inode *inode, struct file *filp)
737{
738 return single_open(filp, debug_stats_show, NULL);
739}
740
741static const struct file_operations debug_stats_fops = {
742 .open = debug_stats_open,
743 .read = seq_read,
744 .llseek = seq_lseek,
745 .release = single_release,
746};
747
748static int __init debug_objects_init_debugfs(void)
749{
750 struct dentry *dbgdir, *dbgstats;
751
752 if (!debug_objects_enabled)
753 return 0;
754
755 dbgdir = debugfs_create_dir("debug_objects", NULL);
756 if (!dbgdir)
757 return -ENOMEM;
758
759 dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
760 &debug_stats_fops);
761 if (!dbgstats)
762 goto err;
763
764 return 0;
765
766err:
767 debugfs_remove(dbgdir);
768
769 return -ENOMEM;
770}
771__initcall(debug_objects_init_debugfs);
772
773#else
774static inline void debug_objects_init_debugfs(void) { }
775#endif
776
777#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
778
779/* Random data structure for the self test */
780struct self_test {
781 unsigned long dummy1[6];
782 int static_init;
783 unsigned long dummy2[3];
784};
785
786static __initdata struct debug_obj_descr descr_type_test;
787
788/*
789 * fixup_init is called when:
790 * - an active object is initialized
791 */
792static int __init fixup_init(void *addr, enum debug_obj_state state)
793{
794 struct self_test *obj = addr;
795
796 switch (state) {
797 case ODEBUG_STATE_ACTIVE:
798 debug_object_deactivate(obj, &descr_type_test);
799 debug_object_init(obj, &descr_type_test);
800 return 1;
801 default:
802 return 0;
803 }
804}
805
806/*
807 * fixup_activate is called when:
808 * - an active object is activated
809 * - an unknown object is activated (might be a statically initialized object)
810 */
811static int __init fixup_activate(void *addr, enum debug_obj_state state)
812{
813 struct self_test *obj = addr;
814
815 switch (state) {
816 case ODEBUG_STATE_NOTAVAILABLE:
817 if (obj->static_init == 1) {
818 debug_object_init(obj, &descr_type_test);
819 debug_object_activate(obj, &descr_type_test);
820 return 0;
821 }
822 return 1;
823
824 case ODEBUG_STATE_ACTIVE:
825 debug_object_deactivate(obj, &descr_type_test);
826 debug_object_activate(obj, &descr_type_test);
827 return 1;
828
829 default:
830 return 0;
831 }
832}
833
834/*
835 * fixup_destroy is called when:
836 * - an active object is destroyed
837 */
838static int __init fixup_destroy(void *addr, enum debug_obj_state state)
839{
840 struct self_test *obj = addr;
841
842 switch (state) {
843 case ODEBUG_STATE_ACTIVE:
844 debug_object_deactivate(obj, &descr_type_test);
845 debug_object_destroy(obj, &descr_type_test);
846 return 1;
847 default:
848 return 0;
849 }
850}
851
852/*
853 * fixup_free is called when:
854 * - an active object is freed
855 */
856static int __init fixup_free(void *addr, enum debug_obj_state state)
857{
858 struct self_test *obj = addr;
859
860 switch (state) {
861 case ODEBUG_STATE_ACTIVE:
862 debug_object_deactivate(obj, &descr_type_test);
863 debug_object_free(obj, &descr_type_test);
864 return 1;
865 default:
866 return 0;
867 }
868}
869
870static int __init
871check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
872{
873 struct debug_bucket *db;
874 struct debug_obj *obj;
875 unsigned long flags;
876 int res = -EINVAL;
877
878 db = get_bucket((unsigned long) addr);
879
880 raw_spin_lock_irqsave(&db->lock, flags);
881
882 obj = lookup_object(addr, db);
883 if (!obj && state != ODEBUG_STATE_NONE) {
884 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
885 goto out;
886 }
887 if (obj && obj->state != state) {
888 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
889 obj->state, state);
890 goto out;
891 }
892 if (fixups != debug_objects_fixups) {
893 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
894 fixups, debug_objects_fixups);
895 goto out;
896 }
897 if (warnings != debug_objects_warnings) {
898 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
899 warnings, debug_objects_warnings);
900 goto out;
901 }
902 res = 0;
903out:
904 raw_spin_unlock_irqrestore(&db->lock, flags);
905 if (res)
906 debug_objects_enabled = 0;
907 return res;
908}
909
910static __initdata struct debug_obj_descr descr_type_test = {
911 .name = "selftest",
912 .fixup_init = fixup_init,
913 .fixup_activate = fixup_activate,
914 .fixup_destroy = fixup_destroy,
915 .fixup_free = fixup_free,
916};
917
918static __initdata struct self_test obj = { .static_init = 0 };
919
920static void __init debug_objects_selftest(void)
921{
922 int fixups, oldfixups, warnings, oldwarnings;
923 unsigned long flags;
924
925 local_irq_save(flags);
926
927 fixups = oldfixups = debug_objects_fixups;
928 warnings = oldwarnings = debug_objects_warnings;
929 descr_test = &descr_type_test;
930
931 debug_object_init(&obj, &descr_type_test);
932 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
933 goto out;
934 debug_object_activate(&obj, &descr_type_test);
935 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
936 goto out;
937 debug_object_activate(&obj, &descr_type_test);
938 if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
939 goto out;
940 debug_object_deactivate(&obj, &descr_type_test);
941 if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
942 goto out;
943 debug_object_destroy(&obj, &descr_type_test);
944 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
945 goto out;
946 debug_object_init(&obj, &descr_type_test);
947 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
948 goto out;
949 debug_object_activate(&obj, &descr_type_test);
950 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
951 goto out;
952 debug_object_deactivate(&obj, &descr_type_test);
953 if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
954 goto out;
955 debug_object_free(&obj, &descr_type_test);
956 if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
957 goto out;
958
959 obj.static_init = 1;
960 debug_object_activate(&obj, &descr_type_test);
961 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
962 goto out;
963 debug_object_init(&obj, &descr_type_test);
964 if (check_results(&obj, ODEBUG_STATE_INIT, ++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#ifdef CONFIG_DEBUG_OBJECTS_FREE
971 debug_object_init(&obj, &descr_type_test);
972 if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
973 goto out;
974 debug_object_activate(&obj, &descr_type_test);
975 if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
976 goto out;
977 __debug_check_no_obj_freed(&obj, sizeof(obj));
978 if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
979 goto out;
980#endif
981 printk(KERN_INFO "ODEBUG: selftest passed\n");
982
983out:
984 debug_objects_fixups = oldfixups;
985 debug_objects_warnings = oldwarnings;
986 descr_test = NULL;
987
988 local_irq_restore(flags);
989}
990#else
991static inline void debug_objects_selftest(void) { }
992#endif
993
994/*
995 * Called during early boot to initialize the hash buckets and link
996 * the static object pool objects into the poll list. After this call
997 * the object tracker is fully operational.
998 */
999void __init debug_objects_early_init(void)
1000{
1001 int i;
1002
1003 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1004 raw_spin_lock_init(&obj_hash[i].lock);
1005
1006 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1007 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1008}
1009
1010/*
1011 * Convert the statically allocated objects to dynamic ones:
1012 */
1013static int __init debug_objects_replace_static_objects(void)
1014{
1015 struct debug_bucket *db = obj_hash;
1016 struct hlist_node *node, *tmp;
1017 struct debug_obj *obj, *new;
1018 HLIST_HEAD(objects);
1019 int i, cnt = 0;
1020
1021 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1022 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1023 if (!obj)
1024 goto free;
1025 hlist_add_head(&obj->node, &objects);
1026 }
1027
1028 /*
1029 * When debug_objects_mem_init() is called we know that only
1030 * one CPU is up, so disabling interrupts is enough
1031 * protection. This avoids the lockdep hell of lock ordering.
1032 */
1033 local_irq_disable();
1034
1035 /* Remove the statically allocated objects from the pool */
1036 hlist_for_each_entry_safe(obj, node, tmp, &obj_pool, node)
1037 hlist_del(&obj->node);
1038 /* Move the allocated objects to the pool */
1039 hlist_move_list(&objects, &obj_pool);
1040
1041 /* Replace the active object references */
1042 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1043 hlist_move_list(&db->list, &objects);
1044
1045 hlist_for_each_entry(obj, node, &objects, node) {
1046 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1047 hlist_del(&new->node);
1048 /* copy object data */
1049 *new = *obj;
1050 hlist_add_head(&new->node, &db->list);
1051 cnt++;
1052 }
1053 }
1054 local_irq_enable();
1055
1056 printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
1057 obj_pool_used);
1058 return 0;
1059free:
1060 hlist_for_each_entry_safe(obj, node, tmp, &objects, node) {
1061 hlist_del(&obj->node);
1062 kmem_cache_free(obj_cache, obj);
1063 }
1064 return -ENOMEM;
1065}
1066
1067/*
1068 * Called after the kmem_caches are functional to setup a dedicated
1069 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1070 * prevents that the debug code is called on kmem_cache_free() for the
1071 * debug tracker objects to avoid recursive calls.
1072 */
1073void __init debug_objects_mem_init(void)
1074{
1075 if (!debug_objects_enabled)
1076 return;
1077
1078 obj_cache = kmem_cache_create("debug_objects_cache",
1079 sizeof (struct debug_obj), 0,
1080 SLAB_DEBUG_OBJECTS, NULL);
1081
1082 if (!obj_cache || debug_objects_replace_static_objects()) {
1083 debug_objects_enabled = 0;
1084 if (obj_cache)
1085 kmem_cache_destroy(obj_cache);
1086 printk(KERN_WARNING "ODEBUG: out of memory.\n");
1087 } else
1088 debug_objects_selftest();
1089}