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_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 */
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 /*
223 * Allocate a new object. If the pool is empty, switch off the debugger.
224 * Must be called with interrupts disabled.
225 */
226 static struct debug_obj *
alloc_object(void * addr,struct debug_bucket * b,const struct debug_obj_descr * descr)227 alloc_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
275 init_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 */
free_obj_work(struct work_struct * work)292 static 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
323 free_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
__free_object(struct debug_obj * obj)342 static 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
376 free_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 */
free_object(struct debug_obj * obj)428 static 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
object_cpu_offline(unsigned int cpu)438 static 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 */
debug_objects_oom(void)460 static 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 */
get_bucket(unsigned long addr)488 static 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
debug_print_object(struct debug_obj * obj,char * msg)496 static 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 */
517 static bool
debug_object_fixup(bool (* fixup)(void * addr,enum debug_obj_state state),void * addr,enum debug_obj_state state)518 debug_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
debug_object_is_on_stack(void * addr,int onstack)528 static 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
551 static void
__debug_object_init(void * addr,const struct debug_obj_descr * descr,int onstack)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 */
debug_object_init(void * addr,const struct debug_obj_descr * descr)610 void 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 }
617 EXPORT_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 */
debug_object_init_on_stack(void * addr,const struct debug_obj_descr * descr)625 void 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 }
632 EXPORT_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 */
debug_object_activate(void * addr,const struct debug_obj_descr * descr)640 int 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 }
711 EXPORT_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 */
debug_object_deactivate(void * addr,const struct debug_obj_descr * descr)718 void 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 }
763 EXPORT_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 */
debug_object_destroy(void * addr,const struct debug_obj_descr * descr)770 void 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 }
808 out_unlock:
809 raw_spin_unlock_irqrestore(&db->lock, flags);
810 if (print_object)
811 debug_print_object(obj, "destroy");
812 }
813 EXPORT_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 */
debug_object_free(void * addr,const struct debug_obj_descr * descr)820 void 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 }
851 out_unlock:
852 raw_spin_unlock_irqrestore(&db->lock, flags);
853 }
854 EXPORT_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 */
debug_object_assert_init(void * addr,const struct debug_obj_descr * descr)861 void 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 }
899 EXPORT_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 */
908 void
debug_object_active_state(void * addr,const struct debug_obj_descr * descr,unsigned int expect,unsigned int next)909 debug_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 }
951 EXPORT_SYMBOL_GPL(debug_object_active_state);
952
953 #ifdef CONFIG_DEBUG_OBJECTS_FREE
__debug_check_no_obj_freed(const void * address,unsigned long size)954 static 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
973 repeat:
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
debug_check_no_obj_freed(const void * address,unsigned long size)1015 void 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
debug_stats_show(struct seq_file * m,void * v)1024 static 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 }
1045 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1046
debug_objects_init_debugfs(void)1047 static 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
debug_objects_init_debugfs(void)1063 static 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 */
1069 struct self_test {
1070 unsigned long dummy1[6];
1071 int static_init;
1072 unsigned long dummy2[3];
1073 };
1074
1075 static __initconst const struct debug_obj_descr descr_type_test;
1076
is_static_object(void * addr)1077 static 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 */
fixup_init(void * addr,enum debug_obj_state state)1088 static 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 */
fixup_activate(void * addr,enum debug_obj_state state)1107 static 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 */
fixup_destroy(void * addr,enum debug_obj_state state)1128 static 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 */
fixup_free(void * addr,enum debug_obj_state state)1146 static 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
1160 static int __init
check_results(void * addr,enum debug_obj_state state,int fixups,int warnings)1161 check_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;
1193 out:
1194 raw_spin_unlock_irqrestore(&db->lock, flags);
1195 if (res)
1196 debug_objects_enabled = 0;
1197 return res;
1198 }
1199
1200 static __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
1209 static __initdata struct self_test obj = { .static_init = 0 };
1210
debug_objects_selftest(void)1211 static 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
1274 out:
1275 debug_objects_fixups = oldfixups;
1276 debug_objects_warnings = oldwarnings;
1277 descr_test = NULL;
1278
1279 local_irq_restore(flags);
1280 }
1281 #else
debug_objects_selftest(void)1282 static 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 */
debug_objects_early_init(void)1290 void __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 */
debug_objects_replace_static_objects(void)1304 static 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;
1348 free:
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 */
debug_objects_mem_init(void)1362 void __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 }
1403
