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