projects/linux·blob v5.9-rc5 · refs

1377 lines · 34.6 KiB

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