slub.c 128 KB
Newer Older
Christoph Lameter's avatar
Christoph Lameter committed
1
2
3
4
/*
 * SLUB: A slab allocator that limits cache line use instead of queuing
 * objects in per cpu and per node lists.
 *
5
6
 * The allocator synchronizes using per slab locks or atomic operatios
 * and only uses a centralized lock to manage a pool of partial slabs.
Christoph Lameter's avatar
Christoph Lameter committed
7
 *
Christoph Lameter's avatar
Christoph Lameter committed
8
 * (C) 2007 SGI, Christoph Lameter
9
 * (C) 2011 Linux Foundation, Christoph Lameter
Christoph Lameter's avatar
Christoph Lameter committed
10
11
12
 */

#include <linux/mm.h>
Nick Piggin's avatar
Nick Piggin committed
13
#include <linux/swap.h> /* struct reclaim_state */
Christoph Lameter's avatar
Christoph Lameter committed
14
15
16
17
18
#include <linux/module.h>
#include <linux/bit_spinlock.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/slab.h>
19
#include <linux/proc_fs.h>
Christoph Lameter's avatar
Christoph Lameter committed
20
#include <linux/seq_file.h>
Vegard Nossum's avatar
Vegard Nossum committed
21
#include <linux/kmemcheck.h>
Christoph Lameter's avatar
Christoph Lameter committed
22
23
24
25
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/mempolicy.h>
#include <linux/ctype.h>
26
#include <linux/debugobjects.h>
Christoph Lameter's avatar
Christoph Lameter committed
27
#include <linux/kallsyms.h>
28
#include <linux/memory.h>
Roman Zippel's avatar
Roman Zippel committed
29
#include <linux/math64.h>
Akinobu Mita's avatar
Akinobu Mita committed
30
#include <linux/fault-inject.h>
31
#include <linux/stacktrace.h>
Christoph Lameter's avatar
Christoph Lameter committed
32

33
34
#include <trace/events/kmem.h>

Christoph Lameter's avatar
Christoph Lameter committed
35
36
/*
 * Lock order:
37
38
39
 *   1. slub_lock (Global Semaphore)
 *   2. node->list_lock
 *   3. slab_lock(page) (Only on some arches and for debugging)
Christoph Lameter's avatar
Christoph Lameter committed
40
 *
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
 *   slub_lock
 *
 *   The role of the slub_lock is to protect the list of all the slabs
 *   and to synchronize major metadata changes to slab cache structures.
 *
 *   The slab_lock is only used for debugging and on arches that do not
 *   have the ability to do a cmpxchg_double. It only protects the second
 *   double word in the page struct. Meaning
 *	A. page->freelist	-> List of object free in a page
 *	B. page->counters	-> Counters of objects
 *	C. page->frozen		-> frozen state
 *
 *   If a slab is frozen then it is exempt from list management. It is not
 *   on any list. The processor that froze the slab is the one who can
 *   perform list operations on the page. Other processors may put objects
 *   onto the freelist but the processor that froze the slab is the only
 *   one that can retrieve the objects from the page's freelist.
Christoph Lameter's avatar
Christoph Lameter committed
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
 *
 *   The list_lock protects the partial and full list on each node and
 *   the partial slab counter. If taken then no new slabs may be added or
 *   removed from the lists nor make the number of partial slabs be modified.
 *   (Note that the total number of slabs is an atomic value that may be
 *   modified without taking the list lock).
 *
 *   The list_lock is a centralized lock and thus we avoid taking it as
 *   much as possible. As long as SLUB does not have to handle partial
 *   slabs, operations can continue without any centralized lock. F.e.
 *   allocating a long series of objects that fill up slabs does not require
 *   the list lock.
 *   Interrupts are disabled during allocation and deallocation in order to
 *   make the slab allocator safe to use in the context of an irq. In addition
 *   interrupts are disabled to ensure that the processor does not change
 *   while handling per_cpu slabs, due to kernel preemption.
 *
 * SLUB assigns one slab for allocation to each processor.
 * Allocations only occur from these slabs called cpu slabs.
 *
Christoph Lameter's avatar
Christoph Lameter committed
78
79
 * Slabs with free elements are kept on a partial list and during regular
 * operations no list for full slabs is used. If an object in a full slab is
Christoph Lameter's avatar
Christoph Lameter committed
80
 * freed then the slab will show up again on the partial lists.
Christoph Lameter's avatar
Christoph Lameter committed
81
82
 * We track full slabs for debugging purposes though because otherwise we
 * cannot scan all objects.
Christoph Lameter's avatar
Christoph Lameter committed
83
84
85
86
87
88
89
 *
 * Slabs are freed when they become empty. Teardown and setup is
 * minimal so we rely on the page allocators per cpu caches for
 * fast frees and allocs.
 *
 * Overloading of page flags that are otherwise used for LRU management.
 *
90
91
92
93
94
95
96
97
98
99
100
101
 * PageActive 		The slab is frozen and exempt from list processing.
 * 			This means that the slab is dedicated to a purpose
 * 			such as satisfying allocations for a specific
 * 			processor. Objects may be freed in the slab while
 * 			it is frozen but slab_free will then skip the usual
 * 			list operations. It is up to the processor holding
 * 			the slab to integrate the slab into the slab lists
 * 			when the slab is no longer needed.
 *
 * 			One use of this flag is to mark slabs that are
 * 			used for allocations. Then such a slab becomes a cpu
 * 			slab. The cpu slab may be equipped with an additional
102
 * 			freelist that allows lockless access to
103
104
 * 			free objects in addition to the regular freelist
 * 			that requires the slab lock.
Christoph Lameter's avatar
Christoph Lameter committed
105
106
107
 *
 * PageError		Slab requires special handling due to debug
 * 			options set. This moves	slab handling out of
108
 * 			the fast path and disables lockless freelists.
Christoph Lameter's avatar
Christoph Lameter committed
109
110
 */

111
112
113
114
115
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
		SLAB_TRACE | SLAB_DEBUG_FREE)

static inline int kmem_cache_debug(struct kmem_cache *s)
{
116
#ifdef CONFIG_SLUB_DEBUG
117
	return unlikely(s->flags & SLAB_DEBUG_FLAGS);
118
#else
119
	return 0;
120
#endif
121
}
122

Christoph Lameter's avatar
Christoph Lameter committed
123
124
125
126
127
128
129
130
131
132
133
/*
 * Issues still to be resolved:
 *
 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
 *
 * - Variable sizing of the per node arrays
 */

/* Enable to test recovery from slab corruption on boot */
#undef SLUB_RESILIENCY_TEST

134
135
136
/* Enable to log cmpxchg failures */
#undef SLUB_DEBUG_CMPXCHG

137
138
139
140
/*
 * Mininum number of partial slabs. These will be left on the partial
 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 */
141
#define MIN_PARTIAL 5
Christoph Lameter's avatar
Christoph Lameter committed
142

143
144
145
146
147
148
149
/*
 * Maximum number of desirable partial slabs.
 * The existence of more partial slabs makes kmem_cache_shrink
 * sort the partial list by the number of objects in the.
 */
#define MAX_PARTIAL 10

Christoph Lameter's avatar
Christoph Lameter committed
150
151
#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
				SLAB_POISON | SLAB_STORE_USER)
Christoph Lameter's avatar
Christoph Lameter committed
152

153
/*
154
155
156
 * Debugging flags that require metadata to be stored in the slab.  These get
 * disabled when slub_debug=O is used and a cache's min order increases with
 * metadata.
157
 */
158
#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
159

Christoph Lameter's avatar
Christoph Lameter committed
160
161
162
163
/*
 * Set of flags that will prevent slab merging
 */
#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
164
165
		SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
		SLAB_FAILSLAB)
Christoph Lameter's avatar
Christoph Lameter committed
166
167

#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
Vegard Nossum's avatar
Vegard Nossum committed
168
		SLAB_CACHE_DMA | SLAB_NOTRACK)
Christoph Lameter's avatar
Christoph Lameter committed
169

170
171
#define OO_SHIFT	16
#define OO_MASK		((1 << OO_SHIFT) - 1)
172
#define MAX_OBJS_PER_PAGE	32767 /* since page.objects is u15 */
173

Christoph Lameter's avatar
Christoph Lameter committed
174
/* Internal SLUB flags */
Christoph Lameter's avatar
Christoph Lameter committed
175
#define __OBJECT_POISON		0x80000000UL /* Poison object */
176
#define __CMPXCHG_DOUBLE	0x40000000UL /* Use cmpxchg_double */
Christoph Lameter's avatar
Christoph Lameter committed
177
178
179
180
181
182
183
184
185

static int kmem_size = sizeof(struct kmem_cache);

#ifdef CONFIG_SMP
static struct notifier_block slab_notifier;
#endif

static enum {
	DOWN,		/* No slab functionality available */
186
	PARTIAL,	/* Kmem_cache_node works */
Christoph Lameter's avatar
Christoph Lameter committed
187
	UP,		/* Everything works but does not show up in sysfs */
Christoph Lameter's avatar
Christoph Lameter committed
188
189
190
191
192
	SYSFS		/* Sysfs up */
} slab_state = DOWN;

/* A list of all slab caches on the system */
static DECLARE_RWSEM(slub_lock);
Adrian Bunk's avatar
Adrian Bunk committed
193
static LIST_HEAD(slab_caches);
Christoph Lameter's avatar
Christoph Lameter committed
194

195
196
197
/*
 * Tracking user of a slab.
 */
198
#define TRACK_ADDRS_COUNT 16
199
struct track {
200
	unsigned long addr;	/* Called from address */
201
202
203
#ifdef CONFIG_STACKTRACE
	unsigned long addrs[TRACK_ADDRS_COUNT];	/* Called from address */
#endif
204
205
206
207
208
209
210
	int cpu;		/* Was running on cpu */
	int pid;		/* Pid context */
	unsigned long when;	/* When did the operation occur */
};

enum track_item { TRACK_ALLOC, TRACK_FREE };

211
#ifdef CONFIG_SYSFS
Christoph Lameter's avatar
Christoph Lameter committed
212
213
214
static int sysfs_slab_add(struct kmem_cache *);
static int sysfs_slab_alias(struct kmem_cache *, const char *);
static void sysfs_slab_remove(struct kmem_cache *);
215

Christoph Lameter's avatar
Christoph Lameter committed
216
#else
217
218
219
static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
							{ return 0; }
220
221
static inline void sysfs_slab_remove(struct kmem_cache *s)
{
222
	kfree(s->name);
223
224
	kfree(s);
}
225

Christoph Lameter's avatar
Christoph Lameter committed
226
227
#endif

228
static inline void stat(const struct kmem_cache *s, enum stat_item si)
229
230
{
#ifdef CONFIG_SLUB_STATS
231
	__this_cpu_inc(s->cpu_slab->stat[si]);
232
233
234
#endif
}

Christoph Lameter's avatar
Christoph Lameter committed
235
236
237
238
239
240
241
242
243
244
245
246
247
248
/********************************************************************
 * 			Core slab cache functions
 *******************************************************************/

int slab_is_available(void)
{
	return slab_state >= UP;
}

static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
{
	return s->node[node];
}

Christoph Lameter's avatar
Christoph Lameter committed
249
/* Verify that a pointer has an address that is valid within a slab page */
250
251
252
253
254
static inline int check_valid_pointer(struct kmem_cache *s,
				struct page *page, const void *object)
{
	void *base;

255
	if (!object)
256
257
		return 1;

258
	base = page_address(page);
259
	if (object < base || object >= base + page->objects * s->size ||
260
261
262
263
264
265
266
		(object - base) % s->size) {
		return 0;
	}

	return 1;
}

267
268
269
270
271
static inline void *get_freepointer(struct kmem_cache *s, void *object)
{
	return *(void **)(object + s->offset);
}

272
273
274
275
276
277
278
279
280
281
282
283
static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
{
	void *p;

#ifdef CONFIG_DEBUG_PAGEALLOC
	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
#else
	p = get_freepointer(s, object);
#endif
	return p;
}

284
285
286
287
288
289
static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
{
	*(void **)(object + s->offset) = fp;
}

/* Loop over all objects in a slab */
290
291
#define for_each_object(__p, __s, __addr, __objects) \
	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
292
293
294
295
296
297
298
299
			__p += (__s)->size)

/* Determine object index from a given position */
static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
{
	return (p - addr) / s->size;
}

300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
static inline size_t slab_ksize(const struct kmem_cache *s)
{
#ifdef CONFIG_SLUB_DEBUG
	/*
	 * Debugging requires use of the padding between object
	 * and whatever may come after it.
	 */
	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
		return s->objsize;

#endif
	/*
	 * If we have the need to store the freelist pointer
	 * back there or track user information then we can
	 * only use the space before that information.
	 */
	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
		return s->inuse;
	/*
	 * Else we can use all the padding etc for the allocation
	 */
	return s->size;
}

324
325
326
327
328
static inline int order_objects(int order, unsigned long size, int reserved)
{
	return ((PAGE_SIZE << order) - reserved) / size;
}

329
static inline struct kmem_cache_order_objects oo_make(int order,
330
		unsigned long size, int reserved)
331
332
{
	struct kmem_cache_order_objects x = {
333
		(order << OO_SHIFT) + order_objects(order, size, reserved)
334
335
336
337
338
339
340
	};

	return x;
}

static inline int oo_order(struct kmem_cache_order_objects x)
{
341
	return x.x >> OO_SHIFT;
342
343
344
345
}

static inline int oo_objects(struct kmem_cache_order_objects x)
{
346
	return x.x & OO_MASK;
347
348
}

349
350
351
352
353
354
355
356
357
358
359
360
361
/*
 * Per slab locking using the pagelock
 */
static __always_inline void slab_lock(struct page *page)
{
	bit_spin_lock(PG_locked, &page->flags);
}

static __always_inline void slab_unlock(struct page *page)
{
	__bit_spin_unlock(PG_locked, &page->flags);
}

362
363
364
365
366
367
368
/* Interrupts must be disabled (for the fallback code to work right) */
static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
		void *freelist_old, unsigned long counters_old,
		void *freelist_new, unsigned long counters_new,
		const char *n)
{
	VM_BUG_ON(!irqs_disabled());
369
370
#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
371
	if (s->flags & __CMPXCHG_DOUBLE) {
372
		if (cmpxchg_double(&page->freelist, &page->counters,
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
			freelist_old, counters_old,
			freelist_new, counters_new))
		return 1;
	} else
#endif
	{
		slab_lock(page);
		if (page->freelist == freelist_old && page->counters == counters_old) {
			page->freelist = freelist_new;
			page->counters = counters_new;
			slab_unlock(page);
			return 1;
		}
		slab_unlock(page);
	}

	cpu_relax();
	stat(s, CMPXCHG_DOUBLE_FAIL);

#ifdef SLUB_DEBUG_CMPXCHG
	printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
#endif

	return 0;
}

399
400
401
402
403
static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
		void *freelist_old, unsigned long counters_old,
		void *freelist_new, unsigned long counters_new,
		const char *n)
{
404
405
#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
406
	if (s->flags & __CMPXCHG_DOUBLE) {
407
		if (cmpxchg_double(&page->freelist, &page->counters,
408
409
410
411
412
413
			freelist_old, counters_old,
			freelist_new, counters_new))
		return 1;
	} else
#endif
	{
414
415
416
		unsigned long flags;

		local_irq_save(flags);
417
		slab_lock(page);
418
419
420
		if (page->freelist == freelist_old && page->counters == counters_old) {
			page->freelist = freelist_new;
			page->counters = counters_new;
421
			slab_unlock(page);
422
			local_irq_restore(flags);
423
424
			return 1;
		}
425
		slab_unlock(page);
426
		local_irq_restore(flags);
427
428
429
430
431
432
433
434
435
436
437
438
	}

	cpu_relax();
	stat(s, CMPXCHG_DOUBLE_FAIL);

#ifdef SLUB_DEBUG_CMPXCHG
	printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
#endif

	return 0;
}

439
#ifdef CONFIG_SLUB_DEBUG
440
441
442
/*
 * Determine a map of object in use on a page.
 *
443
 * Node listlock must be held to guarantee that the page does
444
445
446
447
448
449
450
451
452
453
454
 * not vanish from under us.
 */
static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
{
	void *p;
	void *addr = page_address(page);

	for (p = page->freelist; p; p = get_freepointer(s, p))
		set_bit(slab_index(p, s, addr), map);
}

455
456
457
/*
 * Debug settings:
 */
458
459
460
#ifdef CONFIG_SLUB_DEBUG_ON
static int slub_debug = DEBUG_DEFAULT_FLAGS;
#else
461
static int slub_debug;
462
#endif
463
464

static char *slub_debug_slabs;
465
static int disable_higher_order_debug;
466

Christoph Lameter's avatar
Christoph Lameter committed
467
468
469
470
471
/*
 * Object debugging
 */
static void print_section(char *text, u8 *addr, unsigned int length)
{
472
473
	print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
			length, 1);
Christoph Lameter's avatar
Christoph Lameter committed
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
}

static struct track *get_track(struct kmem_cache *s, void *object,
	enum track_item alloc)
{
	struct track *p;

	if (s->offset)
		p = object + s->offset + sizeof(void *);
	else
		p = object + s->inuse;

	return p + alloc;
}

static void set_track(struct kmem_cache *s, void *object,
490
			enum track_item alloc, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
491
{
Akinobu Mita's avatar
Akinobu Mita committed
492
	struct track *p = get_track(s, object, alloc);
Christoph Lameter's avatar
Christoph Lameter committed
493
494

	if (addr) {
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
#ifdef CONFIG_STACKTRACE
		struct stack_trace trace;
		int i;

		trace.nr_entries = 0;
		trace.max_entries = TRACK_ADDRS_COUNT;
		trace.entries = p->addrs;
		trace.skip = 3;
		save_stack_trace(&trace);

		/* See rant in lockdep.c */
		if (trace.nr_entries != 0 &&
		    trace.entries[trace.nr_entries - 1] == ULONG_MAX)
			trace.nr_entries--;

		for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
			p->addrs[i] = 0;
#endif
Christoph Lameter's avatar
Christoph Lameter committed
513
514
		p->addr = addr;
		p->cpu = smp_processor_id();
515
		p->pid = current->pid;
Christoph Lameter's avatar
Christoph Lameter committed
516
517
518
519
520
521
522
		p->when = jiffies;
	} else
		memset(p, 0, sizeof(struct track));
}

static void init_tracking(struct kmem_cache *s, void *object)
{
523
524
525
	if (!(s->flags & SLAB_STORE_USER))
		return;

526
527
	set_track(s, object, TRACK_FREE, 0UL);
	set_track(s, object, TRACK_ALLOC, 0UL);
Christoph Lameter's avatar
Christoph Lameter committed
528
529
530
531
532
533
534
}

static void print_track(const char *s, struct track *t)
{
	if (!t->addr)
		return;

535
	printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
536
		s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
537
538
539
540
541
542
543
544
545
546
#ifdef CONFIG_STACKTRACE
	{
		int i;
		for (i = 0; i < TRACK_ADDRS_COUNT; i++)
			if (t->addrs[i])
				printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
			else
				break;
	}
#endif
547
548
549
550
551
552
553
554
555
556
557
558
559
}

static void print_tracking(struct kmem_cache *s, void *object)
{
	if (!(s->flags & SLAB_STORE_USER))
		return;

	print_track("Allocated", get_track(s, object, TRACK_ALLOC));
	print_track("Freed", get_track(s, object, TRACK_FREE));
}

static void print_page_info(struct page *page)
{
560
561
	printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
		page, page->objects, page->inuse, page->freelist, page->flags);
562
563
564
565
566
567
568
569
570
571
572
573
574

}

static void slab_bug(struct kmem_cache *s, char *fmt, ...)
{
	va_list args;
	char buf[100];

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	printk(KERN_ERR "========================================"
			"=====================================\n");
575
	printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
576
577
	printk(KERN_ERR "----------------------------------------"
			"-------------------------------------\n\n");
Christoph Lameter's avatar
Christoph Lameter committed
578
579
}

580
581
582
583
584
585
586
587
588
589
590
591
static void slab_fix(struct kmem_cache *s, char *fmt, ...)
{
	va_list args;
	char buf[100];

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
}

static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
Christoph Lameter's avatar
Christoph Lameter committed
592
593
{
	unsigned int off;	/* Offset of last byte */
594
	u8 *addr = page_address(page);
595
596
597
598
599
600
601
602
603

	print_tracking(s, p);

	print_page_info(page);

	printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
			p, p - addr, get_freepointer(s, p));

	if (p > addr + 16)
604
		print_section("Bytes b4 ", p - 16, 16);
Christoph Lameter's avatar
Christoph Lameter committed
605

606
607
	print_section("Object ", p, min_t(unsigned long, s->objsize,
				PAGE_SIZE));
Christoph Lameter's avatar
Christoph Lameter committed
608
	if (s->flags & SLAB_RED_ZONE)
609
		print_section("Redzone ", p + s->objsize,
Christoph Lameter's avatar
Christoph Lameter committed
610
611
612
613
614
615
616
			s->inuse - s->objsize);

	if (s->offset)
		off = s->offset + sizeof(void *);
	else
		off = s->inuse;

617
	if (s->flags & SLAB_STORE_USER)
Christoph Lameter's avatar
Christoph Lameter committed
618
619
620
621
		off += 2 * sizeof(struct track);

	if (off != s->size)
		/* Beginning of the filler is the free pointer */
622
		print_section("Padding ", p + off, s->size - off);
623
624

	dump_stack();
Christoph Lameter's avatar
Christoph Lameter committed
625
626
627
628
629
}

static void object_err(struct kmem_cache *s, struct page *page,
			u8 *object, char *reason)
{
630
	slab_bug(s, "%s", reason);
631
	print_trailer(s, page, object);
Christoph Lameter's avatar
Christoph Lameter committed
632
633
}

634
static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
Christoph Lameter's avatar
Christoph Lameter committed
635
636
637
638
{
	va_list args;
	char buf[100];

639
640
	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
Christoph Lameter's avatar
Christoph Lameter committed
641
	va_end(args);
642
	slab_bug(s, "%s", buf);
643
	print_page_info(page);
Christoph Lameter's avatar
Christoph Lameter committed
644
645
646
	dump_stack();
}

647
static void init_object(struct kmem_cache *s, void *object, u8 val)
Christoph Lameter's avatar
Christoph Lameter committed
648
649
650
651
652
{
	u8 *p = object;

	if (s->flags & __OBJECT_POISON) {
		memset(p, POISON_FREE, s->objsize - 1);
653
		p[s->objsize - 1] = POISON_END;
Christoph Lameter's avatar
Christoph Lameter committed
654
655
656
	}

	if (s->flags & SLAB_RED_ZONE)
657
		memset(p + s->objsize, val, s->inuse - s->objsize);
Christoph Lameter's avatar
Christoph Lameter committed
658
659
}

660
661
662
663
664
665
666
667
668
static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
						void *from, void *to)
{
	slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
	memset(from, data, to - from);
}

static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
			u8 *object, char *what,
669
			u8 *start, unsigned int value, unsigned int bytes)
670
671
672
673
{
	u8 *fault;
	u8 *end;

674
	fault = memchr_inv(start, value, bytes);
675
676
677
678
679
680
681
682
683
684
685
686
687
688
	if (!fault)
		return 1;

	end = start + bytes;
	while (end > fault && end[-1] == value)
		end--;

	slab_bug(s, "%s overwritten", what);
	printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
					fault, end - 1, fault[0], value);
	print_trailer(s, page, object);

	restore_bytes(s, what, value, fault, end);
	return 0;
Christoph Lameter's avatar
Christoph Lameter committed
689
690
691
692
693
694
695
696
697
}

/*
 * Object layout:
 *
 * object address
 * 	Bytes of the object to be managed.
 * 	If the freepointer may overlay the object then the free
 * 	pointer is the first word of the object.
Christoph Lameter's avatar
Christoph Lameter committed
698
 *
Christoph Lameter's avatar
Christoph Lameter committed
699
700
701
702
703
 * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
 * 	0xa5 (POISON_END)
 *
 * object + s->objsize
 * 	Padding to reach word boundary. This is also used for Redzoning.
Christoph Lameter's avatar
Christoph Lameter committed
704
705
706
 * 	Padding is extended by another word if Redzoning is enabled and
 * 	objsize == inuse.
 *
Christoph Lameter's avatar
Christoph Lameter committed
707
708
709
710
 * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
 * 	0xcc (RED_ACTIVE) for objects in use.
 *
 * object + s->inuse
Christoph Lameter's avatar
Christoph Lameter committed
711
712
 * 	Meta data starts here.
 *
Christoph Lameter's avatar
Christoph Lameter committed
713
714
 * 	A. Free pointer (if we cannot overwrite object on free)
 * 	B. Tracking data for SLAB_STORE_USER
Christoph Lameter's avatar
Christoph Lameter committed
715
 * 	C. Padding to reach required alignment boundary or at mininum
Christoph Lameter's avatar
Christoph Lameter committed
716
 * 		one word if debugging is on to be able to detect writes
Christoph Lameter's avatar
Christoph Lameter committed
717
718
719
 * 		before the word boundary.
 *
 *	Padding is done using 0x5a (POISON_INUSE)
Christoph Lameter's avatar
Christoph Lameter committed
720
721
 *
 * object + s->size
Christoph Lameter's avatar
Christoph Lameter committed
722
 * 	Nothing is used beyond s->size.
Christoph Lameter's avatar
Christoph Lameter committed
723
 *
Christoph Lameter's avatar
Christoph Lameter committed
724
725
 * If slabcaches are merged then the objsize and inuse boundaries are mostly
 * ignored. And therefore no slab options that rely on these boundaries
Christoph Lameter's avatar
Christoph Lameter committed
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
 * may be used with merged slabcaches.
 */

static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
{
	unsigned long off = s->inuse;	/* The end of info */

	if (s->offset)
		/* Freepointer is placed after the object. */
		off += sizeof(void *);

	if (s->flags & SLAB_STORE_USER)
		/* We also have user information there */
		off += 2 * sizeof(struct track);

	if (s->size == off)
		return 1;

744
745
	return check_bytes_and_report(s, page, p, "Object padding",
				p + off, POISON_INUSE, s->size - off);
Christoph Lameter's avatar
Christoph Lameter committed
746
747
}

748
/* Check the pad bytes at the end of a slab page */
Christoph Lameter's avatar
Christoph Lameter committed
749
750
static int slab_pad_check(struct kmem_cache *s, struct page *page)
{
751
752
753
754
755
	u8 *start;
	u8 *fault;
	u8 *end;
	int length;
	int remainder;
Christoph Lameter's avatar
Christoph Lameter committed
756
757
758
759

	if (!(s->flags & SLAB_POISON))
		return 1;

760
	start = page_address(page);
761
	length = (PAGE_SIZE << compound_order(page)) - s->reserved;
762
763
	end = start + length;
	remainder = length % s->size;
Christoph Lameter's avatar
Christoph Lameter committed
764
765
766
	if (!remainder)
		return 1;

767
	fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
768
769
770
771
772
773
	if (!fault)
		return 1;
	while (end > fault && end[-1] == POISON_INUSE)
		end--;

	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
774
	print_section("Padding ", end - remainder, remainder);
775

Eric Dumazet's avatar
Eric Dumazet committed
776
	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
777
	return 0;
Christoph Lameter's avatar
Christoph Lameter committed
778
779
780
}

static int check_object(struct kmem_cache *s, struct page *page,
781
					void *object, u8 val)
Christoph Lameter's avatar
Christoph Lameter committed
782
783
784
785
786
{
	u8 *p = object;
	u8 *endobject = object + s->objsize;

	if (s->flags & SLAB_RED_ZONE) {
787
		if (!check_bytes_and_report(s, page, object, "Redzone",
788
			endobject, val, s->inuse - s->objsize))
Christoph Lameter's avatar
Christoph Lameter committed
789
790
			return 0;
	} else {
Ingo Molnar's avatar
Ingo Molnar committed
791
792
793
794
		if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
			check_bytes_and_report(s, page, p, "Alignment padding",
				endobject, POISON_INUSE, s->inuse - s->objsize);
		}
Christoph Lameter's avatar
Christoph Lameter committed
795
796
797
	}

	if (s->flags & SLAB_POISON) {
798
		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
799
800
801
			(!check_bytes_and_report(s, page, p, "Poison", p,
					POISON_FREE, s->objsize - 1) ||
			 !check_bytes_and_report(s, page, p, "Poison",
802
				p + s->objsize - 1, POISON_END, 1)))
Christoph Lameter's avatar
Christoph Lameter committed
803
804
805
806
807
808
809
			return 0;
		/*
		 * check_pad_bytes cleans up on its own.
		 */
		check_pad_bytes(s, page, p);
	}

810
	if (!s->offset && val == SLUB_RED_ACTIVE)
Christoph Lameter's avatar
Christoph Lameter committed
811
812
813
814
815
816
817
818
819
820
		/*
		 * Object and freepointer overlap. Cannot check
		 * freepointer while object is allocated.
		 */
		return 1;

	/* Check free pointer validity */
	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
		object_err(s, page, p, "Freepointer corrupt");
		/*
Nick Andrew's avatar
Nick Andrew committed
821
		 * No choice but to zap it and thus lose the remainder
Christoph Lameter's avatar
Christoph Lameter committed
822
		 * of the free objects in this slab. May cause
Christoph Lameter's avatar
Christoph Lameter committed
823
		 * another error because the object count is now wrong.
Christoph Lameter's avatar
Christoph Lameter committed
824
		 */
825
		set_freepointer(s, p, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
826
827
828
829
830
831
832
		return 0;
	}
	return 1;
}

static int check_slab(struct kmem_cache *s, struct page *page)
{
833
834
	int maxobj;

Christoph Lameter's avatar
Christoph Lameter committed
835
836
837
	VM_BUG_ON(!irqs_disabled());

	if (!PageSlab(page)) {
838
		slab_err(s, page, "Not a valid slab page");
Christoph Lameter's avatar
Christoph Lameter committed
839
840
		return 0;
	}
841

842
	maxobj = order_objects(compound_order(page), s->size, s->reserved);
843
844
845
846
847
848
	if (page->objects > maxobj) {
		slab_err(s, page, "objects %u > max %u",
			s->name, page->objects, maxobj);
		return 0;
	}
	if (page->inuse > page->objects) {
849
		slab_err(s, page, "inuse %u > max %u",
850
			s->name, page->inuse, page->objects);
Christoph Lameter's avatar
Christoph Lameter committed
851
852
853
854
855
856
857
858
		return 0;
	}
	/* Slab_pad_check fixes things up after itself */
	slab_pad_check(s, page);
	return 1;
}

/*
Christoph Lameter's avatar
Christoph Lameter committed
859
860
 * Determine if a certain object on a page is on the freelist. Must hold the
 * slab lock to guarantee that the chains are in a consistent state.
Christoph Lameter's avatar
Christoph Lameter committed
861
862
863
864
 */
static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
{
	int nr = 0;
865
	void *fp;
Christoph Lameter's avatar
Christoph Lameter committed
866
	void *object = NULL;
867
	unsigned long max_objects;
Christoph Lameter's avatar
Christoph Lameter committed
868

869
	fp = page->freelist;
870
	while (fp && nr <= page->objects) {
Christoph Lameter's avatar
Christoph Lameter committed
871
872
873
874
875
876
		if (fp == search)
			return 1;
		if (!check_valid_pointer(s, page, fp)) {
			if (object) {
				object_err(s, page, object,
					"Freechain corrupt");
877
				set_freepointer(s, object, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
878
879
				break;
			} else {
880
				slab_err(s, page, "Freepointer corrupt");
881
				page->freelist = NULL;
882
				page->inuse = page->objects;
883
				slab_fix(s, "Freelist cleared");
Christoph Lameter's avatar
Christoph Lameter committed
884
885
886
887
888
889
890
891
892
				return 0;
			}
			break;
		}
		object = fp;
		fp = get_freepointer(s, object);
		nr++;
	}

893
	max_objects = order_objects(compound_order(page), s->size, s->reserved);
894
895
	if (max_objects > MAX_OBJS_PER_PAGE)
		max_objects = MAX_OBJS_PER_PAGE;
896
897
898
899
900
901
902

	if (page->objects != max_objects) {
		slab_err(s, page, "Wrong number of objects. Found %d but "
			"should be %d", page->objects, max_objects);
		page->objects = max_objects;
		slab_fix(s, "Number of objects adjusted.");
	}
903
	if (page->inuse != page->objects - nr) {
904
		slab_err(s, page, "Wrong object count. Counter is %d but "
905
906
			"counted were %d", page->inuse, page->objects - nr);
		page->inuse = page->objects - nr;
907
		slab_fix(s, "Object count adjusted.");
Christoph Lameter's avatar
Christoph Lameter committed
908
909
910
911
	}
	return search == NULL;
}

912
913
static void trace(struct kmem_cache *s, struct page *page, void *object,
								int alloc)
Christoph Lameter's avatar
Christoph Lameter committed
914
915
916
917
918
919
920
921
922
{
	if (s->flags & SLAB_TRACE) {
		printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
			s->name,
			alloc ? "alloc" : "free",
			object, page->inuse,
			page->freelist);

		if (!alloc)
923
			print_section("Object ", (void *)object, s->objsize);
Christoph Lameter's avatar
Christoph Lameter committed
924
925
926
927
928

		dump_stack();
	}
}

929
930
931
932
933
934
/*
 * Hooks for other subsystems that check memory allocations. In a typical
 * production configuration these hooks all should produce no code at all.
 */
static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
{
935
	flags &= gfp_allowed_mask;
936
937
938
939
940
941
942
943
	lockdep_trace_alloc(flags);
	might_sleep_if(flags & __GFP_WAIT);

	return should_failslab(s->objsize, flags, s->flags);
}

static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
{
944
	flags &= gfp_allowed_mask;
945
	kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
946
947
948
949
950
951
952
	kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
}

static inline void slab_free_hook(struct kmem_cache *s, void *x)
{
	kmemleak_free_recursive(x, s->flags);

953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
	/*
	 * Trouble is that we may no longer disable interupts in the fast path
	 * So in order to make the debug calls that expect irqs to be
	 * disabled we need to disable interrupts temporarily.
	 */
#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
	{
		unsigned long flags;

		local_irq_save(flags);
		kmemcheck_slab_free(s, x, s->objsize);
		debug_check_no_locks_freed(x, s->objsize);
		local_irq_restore(flags);
	}
#endif
968
969
	if (!(s->flags & SLAB_DEBUG_OBJECTS))
		debug_check_no_obj_freed(x, s->objsize);
970
971
}

972
/*
Christoph Lameter's avatar
Christoph Lameter committed
973
 * Tracking of fully allocated slabs for debugging purposes.
974
975
 *
 * list_lock must be held.
976
 */
977
978
static void add_full(struct kmem_cache *s,
	struct kmem_cache_node *n, struct page *page)
979
{
980
981
982
	if (!(s->flags & SLAB_STORE_USER))
		return;

983
984
985
	list_add(&page->lru, &n->full);
}

986
987
988
/*
 * list_lock must be held.
 */
989
990
991
992
993
994
995
996
static void remove_full(struct kmem_cache *s, struct page *page)
{
	if (!(s->flags & SLAB_STORE_USER))
		return;

	list_del(&page->lru);
}

997
998
999
1000
1001
1002
1003
1004
/* Tracking of the number of slabs for debugging purposes */
static inline unsigned long slabs_node(struct kmem_cache *s, int node)
{
	struct kmem_cache_node *n = get_node(s, node);

	return atomic_long_read(&n->nr_slabs);
}

1005
1006
1007
1008
1009
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
{
	return atomic_long_read(&n->nr_slabs);
}

1010
static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1011
1012
1013
1014
1015
1016
1017
1018
1019
{
	struct kmem_cache_node *n = get_node(s, node);

	/*
	 * May be called early in order to allocate a slab for the
	 * kmem_cache_node structure. Solve the chicken-egg
	 * dilemma by deferring the increment of the count during
	 * bootstrap (see early_kmem_cache_node_alloc).
	 */
1020
	if (n) {
1021
		atomic_long_inc(&n->nr_slabs);
1022
1023
		atomic_long_add(objects, &n->total_objects);
	}
1024
}
1025
static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1026
1027
1028
1029
{
	struct kmem_cache_node *n = get_node(s, node);

	atomic_long_dec(&n->nr_slabs);
1030
	atomic_long_sub(objects, &n->total_objects);
1031
1032
1033
}

/* Object debug checks for alloc/free paths */
Christoph Lameter's avatar
Christoph Lameter committed
1034
1035
1036
1037
1038
1039
static void setup_object_debug(struct kmem_cache *s, struct page *page,
								void *object)
{
	if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
		return;

1040
	init_object(s, object, SLUB_RED_INACTIVE);
Christoph Lameter's avatar
Christoph Lameter committed
1041
1042
1043
	init_tracking(s, object);
}

1044
static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1045
					void *object, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
1046
1047
1048
1049
1050
1051
{
	if (!check_slab(s, page))
		goto bad;

	if (!check_valid_pointer(s, page, object)) {
		object_err(s, page, object, "Freelist Pointer check fails");
1052
		goto bad;
Christoph Lameter's avatar
Christoph Lameter committed
1053
1054
	}

1055
	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
Christoph Lameter's avatar
Christoph Lameter committed
1056
1057
		goto bad;

Christoph Lameter's avatar
Christoph Lameter committed
1058
1059
1060
1061
	/* Success perform special debug activities for allocs */
	if (s->flags & SLAB_STORE_USER)
		set_track(s, object, TRACK_ALLOC, addr);
	trace(s, page, object, 1);
1062
	init_object(s, object, SLUB_RED_ACTIVE);
Christoph Lameter's avatar
Christoph Lameter committed
1063
	return 1;
Christoph Lameter's avatar
Christoph Lameter committed
1064

Christoph Lameter's avatar
Christoph Lameter committed
1065
1066
1067
1068
1069
bad:
	if (PageSlab(page)) {
		/*
		 * If this is a slab page then lets do the best we can
		 * to avoid issues in the future. Marking all objects
Christoph Lameter's avatar
Christoph Lameter committed
1070
		 * as used avoids touching the remaining objects.
Christoph Lameter's avatar
Christoph Lameter committed
1071
		 */
1072
		slab_fix(s, "Marking all objects used");
1073
		page->inuse = page->objects;
1074
		page->freelist = NULL;
Christoph Lameter's avatar
Christoph Lameter committed
1075
1076
1077
1078
	}
	return 0;
}

1079
1080
static noinline int free_debug_processing(struct kmem_cache *s,
		 struct page *page, void *object, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
1081
{
1082
1083
1084
1085
	unsigned long flags;
	int rc = 0;

	local_irq_save(flags);
1086
1087
	slab_lock(page);

Christoph Lameter's avatar
Christoph Lameter committed
1088
1089
1090
1091
	if (!check_slab(s, page))
		goto fail;

	if (!check_valid_pointer(s, page, object)) {
1092
		slab_err(s, page, "Invalid object pointer 0x%p", object);
Christoph Lameter's avatar
Christoph Lameter committed
1093
1094
1095
1096
		goto fail;
	}

	if (on_freelist(s, page, object)) {
1097
		object_err(s, page, object, "Object already free");
Christoph Lameter's avatar
Christoph Lameter committed
1098
1099
1100
		goto fail;
	}

1101
	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1102
		goto out;
Christoph Lameter's avatar
Christoph Lameter committed
1103
1104

	if (unlikely(s != page->slab)) {
Ingo Molnar's avatar
Ingo Molnar committed
1105
		if (!PageSlab(page)) {
1106
1107
			slab_err(s, page, "Attempt to free object(0x%p) "
				"outside of slab", object);
Ingo Molnar's avatar
Ingo Molnar committed
1108
		} else if (!page->slab) {
Christoph Lameter's avatar
Christoph Lameter committed
1109
			printk(KERN_ERR
1110
				"SLUB <none>: no slab for object 0x%p.\n",
Christoph Lameter's avatar
Christoph Lameter committed
1111
						object);
1112
			dump_stack();
1113
		} else
1114
1115
			object_err(s, page, object,
					"page slab pointer corrupt.");
Christoph Lameter's avatar
Christoph Lameter committed
1116
1117
		goto fail;
	}
Christoph Lameter's avatar
Christoph Lameter committed
1118
1119
1120
1121

	if (s->flags & SLAB_STORE_USER)
		set_track(s, object, TRACK_FREE, addr);
	trace(s, page, object, 0);
1122
	init_object(s, object, SLUB_RED_INACTIVE);
1123
1124
	rc = 1;
out:
1125
	slab_unlock(page);
1126
1127
	local_irq_restore(flags);
	return rc;
Christoph Lameter's avatar
Christoph Lameter committed
1128

Christoph Lameter's avatar
Christoph Lameter committed
1129
fail:
1130
	slab_fix(s, "Object at 0x%p not freed", object);
1131
	goto out;
Christoph Lameter's avatar
Christoph Lameter committed
1132
1133
}

1134
1135
static int __init setup_slub_debug(char *str)
{
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
	slub_debug = DEBUG_DEFAULT_FLAGS;
	if (*str++ != '=' || !*str)
		/*
		 * No options specified. Switch on full debugging.
		 */
		goto out;

	if (*str == ',')
		/*
		 * No options but restriction on slabs. This means full
		 * debugging for slabs matching a pattern.
		 */
		goto check_slabs;

1150
1151
1152
1153
1154
1155
1156
1157
1158
	if (tolower(*str) == 'o') {
		/*
		 * Avoid enabling debugging on caches if its minimum order
		 * would increase as a result.
		 */
		disable_higher_order_debug = 1;
		goto out;
	}

1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
	slub_debug = 0;
	if (*str == '-')
		/*
		 * Switch off all debugging measures.
		 */
		goto out;

	/*
	 * Determine which debug features should be switched on
	 */
1169
	for (; *str && *str != ','; str++) {
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
		switch (tolower(*str)) {
		case 'f':
			slub_debug |= SLAB_DEBUG_FREE;
			break;
		case 'z':
			slub_debug |= SLAB_RED_ZONE;
			break;
		case 'p':
			slub_debug |= SLAB_POISON;
			break;
		case 'u':
			slub_debug |= SLAB_STORE_USER;
			break;
		case 't':
			slub_debug |= SLAB_TRACE;
			break;
1186
1187
1188
		case 'a':
			slub_debug |= SLAB_FAILSLAB;
			break;
1189
1190
		default:
			printk(KERN_ERR "slub_debug option '%c' "
1191
				"unknown. skipped\n", *str);
1192
		}
1193
1194
	}

1195
check_slabs:
1196
1197
	if (*str == ',')
		slub_debug_slabs = str + 1;
1198
out:
1199
1200
1201
1202
1203
	return 1;
}

__setup("slub_debug", setup_slub_debug);

1204
1205
static unsigned long kmem_cache_flags(unsigned long objsize,
	unsigned long flags, const char *name,
1206
	void (*ctor)(void *))
1207
1208
{
	/*
1209
	 * Enable debugging if selected on the kernel commandline.
1210
	 */
1211
	if (slub_debug && (!slub_debug_slabs ||
1212
1213
		!strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
		flags |= slub_debug;
1214
1215

	return flags;
1216
1217
}
#else
Christoph Lameter's avatar
Christoph Lameter committed
1218
1219
static inline void setup_object_debug(struct kmem_cache *s,
			struct page *page, void *object) {}
1220

Christoph Lameter's avatar
Christoph Lameter committed
1221
static inline int alloc_debug_processing(struct kmem_cache *s,
1222
	struct page *page, void *object, unsigned long addr) { return 0; }
1223

Christoph Lameter's avatar
Christoph Lameter committed
1224
static inline int free_debug_processing(struct kmem_cache *s,
1225