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