Root/lib/debugobjects.c

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

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