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

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