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/seq_file.h>
17#include <linux/debugfs.h>
18#include <linux/slab.h>
19#include <linux/hash.h>
20
21#define ODEBUG_HASH_BITS	14
22#define ODEBUG_HASH_SIZE	(1 << ODEBUG_HASH_BITS)
23
24#define ODEBUG_POOL_SIZE	512
25#define ODEBUG_POOL_MIN_LEVEL	256
26
27#define ODEBUG_CHUNK_SHIFT	PAGE_SHIFT
28#define ODEBUG_CHUNK_SIZE	(1 << ODEBUG_CHUNK_SHIFT)
29#define ODEBUG_CHUNK_MASK	(~(ODEBUG_CHUNK_SIZE - 1))
30
31struct debug_bucket {
32	struct hlist_head	list;
33	raw_spinlock_t		lock;
34};
35
36static struct debug_bucket	obj_hash[ODEBUG_HASH_SIZE];
37
38static struct debug_obj		obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
39
40static DEFINE_RAW_SPINLOCK(pool_lock);
41
42static HLIST_HEAD(obj_pool);
43
44static int			obj_pool_min_free = ODEBUG_POOL_SIZE;
45static int			obj_pool_free = ODEBUG_POOL_SIZE;
46static int			obj_pool_used;
47static int			obj_pool_max_used;
48static struct kmem_cache	*obj_cache;
49
50static int			debug_objects_maxchain __read_mostly;
51static int			debug_objects_fixups __read_mostly;
52static int			debug_objects_warnings __read_mostly;
53static int			debug_objects_enabled __read_mostly
54				= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
55
56static struct debug_obj_descr	*descr_test  __read_mostly;
57
58static void free_obj_work(struct work_struct *work);
59static DECLARE_WORK(debug_obj_work, free_obj_work);
60
61static int __init enable_object_debug(char *str)
62{
63	debug_objects_enabled = 1;
64	return 0;
65}
66
67static int __init disable_object_debug(char *str)
68{
69	debug_objects_enabled = 0;
70	return 0;
71}
72
73early_param("debug_objects", enable_object_debug);
74early_param("no_debug_objects", disable_object_debug);
75
76static const char *obj_states[ODEBUG_STATE_MAX] = {
77	[ODEBUG_STATE_NONE]		= "none",
78	[ODEBUG_STATE_INIT]		= "initialized",
79	[ODEBUG_STATE_INACTIVE]		= "inactive",
80	[ODEBUG_STATE_ACTIVE]		= "active",
81	[ODEBUG_STATE_DESTROYED]	= "destroyed",
82	[ODEBUG_STATE_NOTAVAILABLE]	= "not available",
83};
84
85static void fill_pool(void)
86{
87	gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
88	struct debug_obj *new;
89	unsigned long flags;
90
91	if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
92		return;
93
94	if (unlikely(!obj_cache))
95		return;
96
97	while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
98
99		new = kmem_cache_zalloc(obj_cache, gfp);
100		if (!new)
101			return;
102
103		raw_spin_lock_irqsave(&pool_lock, flags);
104		hlist_add_head(&new->node, &obj_pool);
105		obj_pool_free++;
106		raw_spin_unlock_irqrestore(&pool_lock, flags);
107	}
108}
109
110/*
111 * Lookup an object in the hash bucket.
112 */
113static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
114{
115	struct debug_obj *obj;
116	int cnt = 0;
117
118	hlist_for_each_entry(obj, &b->list, node) {
119		cnt++;
120		if (obj->object == addr)
121			return obj;
122	}
123	if (cnt > debug_objects_maxchain)
124		debug_objects_maxchain = cnt;
125
126	return NULL;
127}
128
129/*
130 * Allocate a new object. If the pool is empty, switch off the debugger.
131 * Must be called with interrupts disabled.
132 */
133static struct debug_obj *
134alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
135{
136	struct debug_obj *obj = NULL;
137
138	raw_spin_lock(&pool_lock);
139	if (obj_pool.first) {
140		obj	    = hlist_entry(obj_pool.first, typeof(*obj), node);
141
142		obj->object = addr;
143		obj->descr  = descr;
144		obj->state  = ODEBUG_STATE_NONE;
145		obj->astate = 0;
146		hlist_del(&obj->node);
147
148		hlist_add_head(&obj->node, &b->list);
149
150		obj_pool_used++;
151		if (obj_pool_used > obj_pool_max_used)
152			obj_pool_max_used = obj_pool_used;
153
154		obj_pool_free--;
155		if (obj_pool_free < obj_pool_min_free)
156			obj_pool_min_free = obj_pool_free;
157	}
158	raw_spin_unlock(&pool_lock);
159
160	return obj;
161}
162
163/*
164 * workqueue function to free objects.
165 */
166static void free_obj_work(struct work_struct *work)
167{
168	struct debug_obj *obj;
169	unsigned long flags;
170
171	raw_spin_lock_irqsave(&pool_lock, flags);
172	while (obj_pool_free > ODEBUG_POOL_SIZE) {
173		obj = hlist_entry(obj_pool.first, typeof(*obj), node);
174		hlist_del(&obj->node);
175		obj_pool_free--;
176		/*
177		 * We release pool_lock across kmem_cache_free() to
178		 * avoid contention on pool_lock.
179		 */
180		raw_spin_unlock_irqrestore(&pool_lock, flags);
181		kmem_cache_free(obj_cache, obj);
182		raw_spin_lock_irqsave(&pool_lock, flags);
183	}
184	raw_spin_unlock_irqrestore(&pool_lock, flags);
185}
186
187/*
188 * Put the object back into the pool and schedule work to free objects
189 * if necessary.
190 */
191static void free_object(struct debug_obj *obj)
192{
193	unsigned long flags;
194	int sched = 0;
195
196	raw_spin_lock_irqsave(&pool_lock, flags);
197	/*
198	 * schedule work when the pool is filled and the cache is
199	 * initialized:
200	 */
201	if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
202		sched = keventd_up();
203	hlist_add_head(&obj->node, &obj_pool);
204	obj_pool_free++;
205	obj_pool_used--;
206	raw_spin_unlock_irqrestore(&pool_lock, flags);
207	if (sched)
208		schedule_work(&debug_obj_work);
209}
210
211/*
212 * We run out of memory. That means we probably have tons of objects
213 * allocated.
214 */
215static void debug_objects_oom(void)
216{
217	struct debug_bucket *db = obj_hash;
218	struct hlist_node *tmp;
219	HLIST_HEAD(freelist);
220	struct debug_obj *obj;
221	unsigned long flags;
222	int i;
223
224	pr_warn("Out of memory. ODEBUG disabled\n");
225
226	for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
227		raw_spin_lock_irqsave(&db->lock, flags);
228		hlist_move_list(&db->list, &freelist);
229		raw_spin_unlock_irqrestore(&db->lock, flags);
230
231		/* Now free them */
232		hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
233			hlist_del(&obj->node);
234			free_object(obj);
235		}
236	}
237}
238
239/*
240 * We use the pfn of the address for the hash. That way we can check
241 * for freed objects simply by checking the affected bucket.
242 */
243static struct debug_bucket *get_bucket(unsigned long addr)
244{
245	unsigned long hash;
246
247	hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
248	return &obj_hash[hash];
249}
250
251static void debug_print_object(struct debug_obj *obj, char *msg)
252{
253	struct debug_obj_descr *descr = obj->descr;
254	static int limit;
255
256	if (limit < 5 && descr != descr_test) {
257		void *hint = descr->debug_hint ?
258			descr->debug_hint(obj->object) : NULL;
259		limit++;
260		WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
261				 "object type: %s hint: %pS\n",
262			msg, obj_states[obj->state], obj->astate,
263			descr->name, hint);
264	}
265	debug_objects_warnings++;
266}
267
268/*
269 * Try to repair the damage, so we have a better chance to get useful
270 * debug output.
271 */
272static int
273debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
274		   void * addr, enum debug_obj_state state)
275{
276	int fixed = 0;
277
278	if (fixup)
279		fixed = fixup(addr, state);
280	debug_objects_fixups += fixed;
281	return fixed;
282}
283
284static void debug_object_is_on_stack(void *addr, int onstack)
285{
286	int is_on_stack;
287	static int limit;
288
289	if (limit > 4)
290		return;
291
292	is_on_stack = object_is_on_stack(addr);
293	if (is_on_stack == onstack)
294		return;
295
296	limit++;
297	if (is_on_stack)
298		pr_warn("object is on stack, but not annotated\n");
299	else
300		pr_warn("object is not on stack, but annotated\n");
301	WARN_ON(1);
302}
303
304static void
305__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
306{
307	enum debug_obj_state state;
308	struct debug_bucket *db;
309	struct debug_obj *obj;
310	unsigned long flags;
311
312	fill_pool();
313
314	db = get_bucket((unsigned long) addr);
315
316	raw_spin_lock_irqsave(&db->lock, flags);
317
318	obj = lookup_object(addr, db);
319	if (!obj) {
320		obj = alloc_object(addr, db, descr);
321		if (!obj) {
322			debug_objects_enabled = 0;
323			raw_spin_unlock_irqrestore(&db->lock, flags);
324			debug_objects_oom();
325			return;
326		}
327		debug_object_is_on_stack(addr, onstack);
328	}
329
330	switch (obj->state) {
331	case ODEBUG_STATE_NONE:
332	case ODEBUG_STATE_INIT:
333	case ODEBUG_STATE_INACTIVE:
334		obj->state = ODEBUG_STATE_INIT;
335		break;
336
337	case ODEBUG_STATE_ACTIVE:
338		debug_print_object(obj, "init");
339		state = obj->state;
340		raw_spin_unlock_irqrestore(&db->lock, flags);
341		debug_object_fixup(descr->fixup_init, addr, state);
342		return;
343
344	case ODEBUG_STATE_DESTROYED:
345		debug_print_object(obj, "init");
346		break;
347	default:
348		break;
349	}
350
351	raw_spin_unlock_irqrestore(&db->lock, flags);
352}
353
354/**
355 * debug_object_init - debug checks when an object is initialized
356 * @addr:	address of the object
357 * @descr:	pointer to an object specific debug description structure
358 */
359void debug_object_init(void *addr, struct debug_obj_descr *descr)
360{
361	if (!debug_objects_enabled)
362		return;
363
364	__debug_object_init(addr, descr, 0);
365}
366
367/**
368 * debug_object_init_on_stack - debug checks when an object on stack is
369 *				initialized
370 * @addr:	address of the object
371 * @descr:	pointer to an object specific debug description structure
372 */
373void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
374{
375	if (!debug_objects_enabled)
376		return;
377
378	__debug_object_init(addr, descr, 1);
379}
380
381/**
382 * debug_object_activate - debug checks when an object is activated
383 * @addr:	address of the object
384 * @descr:	pointer to an object specific debug description structure
385 * Returns 0 for success, -EINVAL for check failed.
386 */
387int debug_object_activate(void *addr, struct debug_obj_descr *descr)
388{
389	enum debug_obj_state state;
390	struct debug_bucket *db;
391	struct debug_obj *obj;
392	unsigned long flags;
393	int ret;
394	struct debug_obj o = { .object = addr,
395			       .state = ODEBUG_STATE_NOTAVAILABLE,
396			       .descr = descr };
397
398	if (!debug_objects_enabled)
399		return 0;
400
401	db = get_bucket((unsigned long) addr);
402
403	raw_spin_lock_irqsave(&db->lock, flags);
404
405	obj = lookup_object(addr, db);
406	if (obj) {
407		switch (obj->state) {
408		case ODEBUG_STATE_INIT:
409		case ODEBUG_STATE_INACTIVE:
410			obj->state = ODEBUG_STATE_ACTIVE;
411			ret = 0;
412			break;
413
414		case ODEBUG_STATE_ACTIVE:
415			debug_print_object(obj, "activate");
416			state = obj->state;
417			raw_spin_unlock_irqrestore(&db->lock, flags);
418			ret = debug_object_fixup(descr->fixup_activate, addr, state);
419			return ret ? -EINVAL : 0;
420
421		case ODEBUG_STATE_DESTROYED:
422			debug_print_object(obj, "activate");
423			ret = -EINVAL;
424			break;
425		default:
426			ret = 0;
427			break;
428		}
429		raw_spin_unlock_irqrestore(&db->lock, flags);
430		return ret;
431	}
432
433	raw_spin_unlock_irqrestore(&db->lock, flags);
434	/*
435	 * This happens when a static object is activated. We
436	 * let the type specific code decide whether this is
437	 * true or not.
438	 */
439	if (debug_object_fixup(descr->fixup_activate, addr,
440			   ODEBUG_STATE_NOTAVAILABLE)) {
441		debug_print_object(&o, "activate");
442		return -EINVAL;
443	}
444	return 0;
445}
446
447/**
448 * debug_object_deactivate - debug checks when an object is deactivated
449 * @addr:	address of the object
450 * @descr:	pointer to an object specific debug description structure
451 */
452void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
453{
454	struct debug_bucket *db;
455	struct debug_obj *obj;
456	unsigned long flags;
457
458	if (!debug_objects_enabled)
459		return;
460
461	db = get_bucket((unsigned long) addr);
462
463	raw_spin_lock_irqsave(&db->lock, flags);
464
465	obj = lookup_object(addr, db);
466	if (obj) {
467		switch (obj->state) {
468		case ODEBUG_STATE_INIT:
469		case ODEBUG_STATE_INACTIVE:
470		case ODEBUG_STATE_ACTIVE:
471			if (!obj->astate)
472				obj->state = ODEBUG_STATE_INACTIVE;
473			else
474				debug_print_object(obj, "deactivate");
475			break;
476
477		case ODEBUG_STATE_DESTROYED:
478			debug_print_object(obj, "deactivate");
479			break;
480		default:
481			break;
482		}
483	} else {
484		struct debug_obj o = { .object = addr,
485				       .state = ODEBUG_STATE_NOTAVAILABLE,
486				       .descr = descr };
487
488		debug_print_object(&o, "deactivate");
489	}
490
491	raw_spin_unlock_irqrestore(&db->lock, flags);
492}
493
494/**
495 * debug_object_destroy - debug checks when an object is destroyed
496 * @addr:	address of the object
497 * @descr:	pointer to an object specific debug description structure
498 */
499void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
500{
501	enum debug_obj_state state;
502	struct debug_bucket *db;
503	struct debug_obj *obj;
504	unsigned long flags;
505
506	if (!debug_objects_enabled)
507		return;
508
509	db = get_bucket((unsigned long) addr);
510
511	raw_spin_lock_irqsave(&db->lock, flags);
512
513	obj = lookup_object(addr, db);
514	if (!obj)
515		goto out_unlock;
516
517	switch (obj->state) {
518	case ODEBUG_STATE_NONE:
519	case ODEBUG_STATE_INIT:
520	case ODEBUG_STATE_INACTIVE:
521		obj->state = ODEBUG_STATE_DESTROYED;
522		break;
523	case ODEBUG_STATE_ACTIVE:
524		debug_print_object(obj, "destroy");
525		state = obj->state;
526		raw_spin_unlock_irqrestore(&db->lock, flags);
527		debug_object_fixup(descr->fixup_destroy, addr, state);
528		return;
529
530	case ODEBUG_STATE_DESTROYED:
531		debug_print_object(obj, "destroy");
532		break;
533	default:
534		break;
535	}
536out_unlock:
537	raw_spin_unlock_irqrestore(&db->lock, flags);
538}
539
540/**
541 * debug_object_free - debug checks when an object is freed
542 * @addr:	address of the object
543 * @descr:	pointer to an object specific debug description structure
544 */
545void debug_object_free(void *addr, struct debug_obj_descr *descr)
546{
547	enum debug_obj_state state;
548	struct debug_bucket *db;
549	struct debug_obj *obj;
550	unsigned long flags;
551
552	if (!debug_objects_enabled)
553		return;
554
555	db = get_bucket((unsigned long) addr);
556
557	raw_spin_lock_irqsave(&db->lock, flags);
558
559	obj = lookup_object(addr, db);
560	if (!obj)
561		goto out_unlock;
562
563	switch (obj->state) {
564	case ODEBUG_STATE_ACTIVE:
565		debug_print_object(obj, "free");
566		state = obj->state;
567		raw_spin_unlock_irqrestore(&db->lock, flags);
568		debug_object_fixup(descr->fixup_free, addr, state);
569		return;
570	default:
571		hlist_del(&obj->node);
572		raw_spin_unlock_irqrestore(&db->lock, flags);
573		free_object(obj);
574		return;
575	}
576out_unlock:
577	raw_spin_unlock_irqrestore(&db->lock, flags);
578}
579
580/**
581 * debug_object_assert_init - debug checks when object should be init-ed
582 * @addr:	address of the object
583 * @descr:	pointer to an object specific debug description structure
584 */
585void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
586{
587	struct debug_bucket *db;
588	struct debug_obj *obj;
589	unsigned long flags;
590
591	if (!debug_objects_enabled)
592		return;
593
594	db = get_bucket((unsigned long) addr);
595
596	raw_spin_lock_irqsave(&db->lock, flags);
597
598	obj = lookup_object(addr, db);
599	if (!obj) {
600		struct debug_obj o = { .object = addr,
601				       .state = ODEBUG_STATE_NOTAVAILABLE,
602				       .descr = descr };
603
604		raw_spin_unlock_irqrestore(&db->lock, flags);
605		/*
606		 * Maybe the object is static.  Let the type specific
607		 * code decide what to do.
608		 */
609		if (debug_object_fixup(descr->fixup_assert_init, addr,
610				       ODEBUG_STATE_NOTAVAILABLE))
611			debug_print_object(&o, "assert_init");
612		return;
613	}
614
615	raw_spin_unlock_irqrestore(&db->lock, flags);
616}
617
618/**
619 * debug_object_active_state - debug checks object usage state machine
620 * @addr:	address of the object
621 * @descr:	pointer to an object specific debug description structure
622 * @expect:	expected state
623 * @next:	state to move to if expected state is found
624 */
625void
626debug_object_active_state(void *addr, struct debug_obj_descr *descr,
627			  unsigned int expect, unsigned int next)
628{
629	struct debug_bucket *db;
630	struct debug_obj *obj;
631	unsigned long flags;
632
633	if (!debug_objects_enabled)
634		return;
635
636	db = get_bucket((unsigned long) addr);
637
638	raw_spin_lock_irqsave(&db->lock, flags);
639
640	obj = lookup_object(addr, db);
641	if (obj) {
642		switch (obj->state) {
643		case ODEBUG_STATE_ACTIVE:
644			if (obj->astate == expect)
645				obj->astate = next;
646			else
647				debug_print_object(obj, "active_state");
648			break;
649
650		default:
651			debug_print_object(obj, "active_state");
652			break;
653		}
654	} else {
655		struct debug_obj o = { .object = addr,
656				       .state = ODEBUG_STATE_NOTAVAILABLE,
657				       .descr = descr };
658
659		debug_print_object(&o, "active_state");
660	}
661
662	raw_spin_unlock_irqrestore(&db->lock, flags);
663}
664
665#ifdef CONFIG_DEBUG_OBJECTS_FREE
666static void __debug_check_no_obj_freed(const void *address, unsigned long size)
667{
668	unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
669	struct hlist_node *tmp;
670	HLIST_HEAD(freelist);
671	struct debug_obj_descr *descr;
672	enum debug_obj_state state;
673	struct debug_bucket *db;
674	struct debug_obj *obj;
675	int cnt;
676
677	saddr = (unsigned long) address;
678	eaddr = saddr + size;
679	paddr = saddr & ODEBUG_CHUNK_MASK;
680	chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
681	chunks >>= ODEBUG_CHUNK_SHIFT;
682
683	for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
684		db = get_bucket(paddr);
685
686repeat:
687		cnt = 0;
688		raw_spin_lock_irqsave(&db->lock, flags);
689		hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
690			cnt++;
691			oaddr = (unsigned long) obj->object;
692			if (oaddr < saddr || oaddr >= eaddr)
693				continue;
694
695			switch (obj->state) {
696			case ODEBUG_STATE_ACTIVE:
697				debug_print_object(obj, "free");
698				descr = obj->descr;
699				state = obj->state;
700				raw_spin_unlock_irqrestore(&db->lock, flags);
701				debug_object_fixup(descr->fixup_free,
702						   (void *) oaddr, state);
703				goto repeat;
704			default:
705				hlist_del(&obj->node);
706				hlist_add_head(&obj->node, &freelist);
707				break;
708			}
709		}
710		raw_spin_unlock_irqrestore(&db->lock, flags);
711
712		/* Now free them */
713		hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
714			hlist_del(&obj->node);
715			free_object(obj);
716		}
717
718		if (cnt > debug_objects_maxchain)
719			debug_objects_maxchain = cnt;
720	}
721}
722
723void debug_check_no_obj_freed(const void *address, unsigned long size)
724{
725	if (debug_objects_enabled)
726		__debug_check_no_obj_freed(address, size);
727}
728#endif
729
730#ifdef CONFIG_DEBUG_FS
731
732static int debug_stats_show(struct seq_file *m, void *v)
733{
734	seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
735	seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
736	seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
737	seq_printf(m, "pool_free     :%d\n", obj_pool_free);
738	seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
739	seq_printf(m, "pool_used     :%d\n", obj_pool_used);
740	seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
741	return 0;
742}
743
744static int debug_stats_open(struct inode *inode, struct file *filp)
745{
746	return single_open(filp, debug_stats_show, NULL);
747}
748
749static const struct file_operations debug_stats_fops = {
750	.open		= debug_stats_open,
751	.read		= seq_read,
752	.llseek		= seq_lseek,
753	.release	= single_release,
754};
755
756static int __init debug_objects_init_debugfs(void)
757{
758	struct dentry *dbgdir, *dbgstats;
759
760	if (!debug_objects_enabled)
761		return 0;
762
763	dbgdir = debugfs_create_dir("debug_objects", NULL);
764	if (!dbgdir)
765		return -ENOMEM;
766
767	dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
768				       &debug_stats_fops);
769	if (!dbgstats)
770		goto err;
771
772	return 0;
773
774err:
775	debugfs_remove(dbgdir);
776
777	return -ENOMEM;
778}
779__initcall(debug_objects_init_debugfs);
780
781#else
782static inline void debug_objects_init_debugfs(void) { }
783#endif
784
785#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
786
787/* Random data structure for the self test */
788struct self_test {
789	unsigned long	dummy1[6];
790	int		static_init;
791	unsigned long	dummy2[3];
792};
793
794static __initdata struct debug_obj_descr descr_type_test;
795
796/*
797 * fixup_init is called when:
798 * - an active object is initialized
799 */
800static int __init fixup_init(void *addr, enum debug_obj_state state)
801{
802	struct self_test *obj = addr;
803
804	switch (state) {
805	case ODEBUG_STATE_ACTIVE:
806		debug_object_deactivate(obj, &descr_type_test);
807		debug_object_init(obj, &descr_type_test);
808		return 1;
809	default:
810		return 0;
811	}
812}
813
814/*
815 * fixup_activate is called when:
816 * - an active object is activated
817 * - an unknown object is activated (might be a statically initialized object)
818 */
819static int __init fixup_activate(void *addr, enum debug_obj_state state)
820{
821	struct self_test *obj = addr;
822
823	switch (state) {
824	case ODEBUG_STATE_NOTAVAILABLE:
825		if (obj->static_init == 1) {
826			debug_object_init(obj, &descr_type_test);
827			debug_object_activate(obj, &descr_type_test);
828			return 0;
829		}
830		return 1;
831
832	case ODEBUG_STATE_ACTIVE:
833		debug_object_deactivate(obj, &descr_type_test);
834		debug_object_activate(obj, &descr_type_test);
835		return 1;
836
837	default:
838		return 0;
839	}
840}
841
842/*
843 * fixup_destroy is called when:
844 * - an active object is destroyed
845 */
846static int __init fixup_destroy(void *addr, enum debug_obj_state state)
847{
848	struct self_test *obj = addr;
849
850	switch (state) {
851	case ODEBUG_STATE_ACTIVE:
852		debug_object_deactivate(obj, &descr_type_test);
853		debug_object_destroy(obj, &descr_type_test);
854		return 1;
855	default:
856		return 0;
857	}
858}
859
860/*
861 * fixup_free is called when:
862 * - an active object is freed
863 */
864static int __init fixup_free(void *addr, enum debug_obj_state state)
865{
866	struct self_test *obj = addr;
867
868	switch (state) {
869	case ODEBUG_STATE_ACTIVE:
870		debug_object_deactivate(obj, &descr_type_test);
871		debug_object_free(obj, &descr_type_test);
872		return 1;
873	default:
874		return 0;
875	}
876}
877
878static int __init
879check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
880{
881	struct debug_bucket *db;
882	struct debug_obj *obj;
883	unsigned long flags;
884	int res = -EINVAL;
885
886	db = get_bucket((unsigned long) addr);
887
888	raw_spin_lock_irqsave(&db->lock, flags);
889
890	obj = lookup_object(addr, db);
891	if (!obj && state != ODEBUG_STATE_NONE) {
892		WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
893		goto out;
894	}
895	if (obj && obj->state != state) {
896		WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
897		       obj->state, state);
898		goto out;
899	}
900	if (fixups != debug_objects_fixups) {
901		WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
902		       fixups, debug_objects_fixups);
903		goto out;
904	}
905	if (warnings != debug_objects_warnings) {
906		WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
907		       warnings, debug_objects_warnings);
908		goto out;
909	}
910	res = 0;
911out:
912	raw_spin_unlock_irqrestore(&db->lock, flags);
913	if (res)
914		debug_objects_enabled = 0;
915	return res;
916}
917
918static __initdata struct debug_obj_descr descr_type_test = {
919	.name			= "selftest",
920	.fixup_init		= fixup_init,
921	.fixup_activate		= fixup_activate,
922	.fixup_destroy		= fixup_destroy,
923	.fixup_free		= fixup_free,
924};
925
926static __initdata struct self_test obj = { .static_init = 0 };
927
928static void __init debug_objects_selftest(void)
929{
930	int fixups, oldfixups, warnings, oldwarnings;
931	unsigned long flags;
932
933	local_irq_save(flags);
934
935	fixups = oldfixups = debug_objects_fixups;
936	warnings = oldwarnings = debug_objects_warnings;
937	descr_test = &descr_type_test;
938
939	debug_object_init(&obj, &descr_type_test);
940	if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
941		goto out;
942	debug_object_activate(&obj, &descr_type_test);
943	if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
944		goto out;
945	debug_object_activate(&obj, &descr_type_test);
946	if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
947		goto out;
948	debug_object_deactivate(&obj, &descr_type_test);
949	if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
950		goto out;
951	debug_object_destroy(&obj, &descr_type_test);
952	if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
953		goto out;
954	debug_object_init(&obj, &descr_type_test);
955	if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
956		goto out;
957	debug_object_activate(&obj, &descr_type_test);
958	if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
959		goto out;
960	debug_object_deactivate(&obj, &descr_type_test);
961	if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
962		goto out;
963	debug_object_free(&obj, &descr_type_test);
964	if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
965		goto out;
966
967	obj.static_init = 1;
968	debug_object_activate(&obj, &descr_type_test);
969	if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
970		goto out;
971	debug_object_init(&obj, &descr_type_test);
972	if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
973		goto out;
974	debug_object_free(&obj, &descr_type_test);
975	if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
976		goto out;
977
978#ifdef CONFIG_DEBUG_OBJECTS_FREE
979	debug_object_init(&obj, &descr_type_test);
980	if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
981		goto out;
982	debug_object_activate(&obj, &descr_type_test);
983	if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
984		goto out;
985	__debug_check_no_obj_freed(&obj, sizeof(obj));
986	if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
987		goto out;
988#endif
989	pr_info("selftest passed\n");
990
991out:
992	debug_objects_fixups = oldfixups;
993	debug_objects_warnings = oldwarnings;
994	descr_test = NULL;
995
996	local_irq_restore(flags);
997}
998#else
999static inline void debug_objects_selftest(void) { }
1000#endif
1001
1002/*
1003 * Called during early boot to initialize the hash buckets and link
1004 * the static object pool objects into the poll list. After this call
1005 * the object tracker is fully operational.
1006 */
1007void __init debug_objects_early_init(void)
1008{
1009	int i;
1010
1011	for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1012		raw_spin_lock_init(&obj_hash[i].lock);
1013
1014	for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1015		hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1016}
1017
1018/*
1019 * Convert the statically allocated objects to dynamic ones:
1020 */
1021static int __init debug_objects_replace_static_objects(void)
1022{
1023	struct debug_bucket *db = obj_hash;
1024	struct hlist_node *tmp;
1025	struct debug_obj *obj, *new;
1026	HLIST_HEAD(objects);
1027	int i, cnt = 0;
1028
1029	for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1030		obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1031		if (!obj)
1032			goto free;
1033		hlist_add_head(&obj->node, &objects);
1034	}
1035
1036	/*
1037	 * When debug_objects_mem_init() is called we know that only
1038	 * one CPU is up, so disabling interrupts is enough
1039	 * protection. This avoids the lockdep hell of lock ordering.
1040	 */
1041	local_irq_disable();
1042
1043	/* Remove the statically allocated objects from the pool */
1044	hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1045		hlist_del(&obj->node);
1046	/* Move the allocated objects to the pool */
1047	hlist_move_list(&objects, &obj_pool);
1048
1049	/* Replace the active object references */
1050	for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1051		hlist_move_list(&db->list, &objects);
1052
1053		hlist_for_each_entry(obj, &objects, node) {
1054			new = hlist_entry(obj_pool.first, typeof(*obj), node);
1055			hlist_del(&new->node);
1056			/* copy object data */
1057			*new = *obj;
1058			hlist_add_head(&new->node, &db->list);
1059			cnt++;
1060		}
1061	}
1062	local_irq_enable();
1063
1064	pr_debug("%d of %d active objects replaced\n",
1065		 cnt, obj_pool_used);
1066	return 0;
1067free:
1068	hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1069		hlist_del(&obj->node);
1070		kmem_cache_free(obj_cache, obj);
1071	}
1072	return -ENOMEM;
1073}
1074
1075/*
1076 * Called after the kmem_caches are functional to setup a dedicated
1077 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1078 * prevents that the debug code is called on kmem_cache_free() for the
1079 * debug tracker objects to avoid recursive calls.
1080 */
1081void __init debug_objects_mem_init(void)
1082{
1083	if (!debug_objects_enabled)
1084		return;
1085
1086	obj_cache = kmem_cache_create("debug_objects_cache",
1087				      sizeof (struct debug_obj), 0,
1088				      SLAB_DEBUG_OBJECTS, NULL);
1089
1090	if (!obj_cache || debug_objects_replace_static_objects()) {
1091		debug_objects_enabled = 0;
1092		if (obj_cache)
1093			kmem_cache_destroy(obj_cache);
1094		pr_warn("out of memory.\n");
1095	} else
1096		debug_objects_selftest();
1097}
1098