uma_dbg.c revision 252040 
1/*-
2 * Copyright (c) 2002, 2003, 2004, 2005 Jeffrey Roberson <jeff@FreeBSD.org>
3 * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice unmodified, this list of conditions, and the following
11 *    disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28/*
29 * uma_dbg.c	Debugging features for UMA users
30 *
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/sys/vm/uma_dbg.c 252040 2013-06-20 19:08:12Z jeff $");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/bitset.h>
39#include <sys/kernel.h>
40#include <sys/types.h>
41#include <sys/queue.h>
42#include <sys/lock.h>
43#include <sys/mutex.h>
44#include <sys/malloc.h>
45
46#include <vm/vm.h>
47#include <vm/vm_object.h>
48#include <vm/vm_page.h>
49#include <vm/uma.h>
50#include <vm/uma_int.h>
51#include <vm/uma_dbg.h>
52
53static const uint32_t uma_junk = 0xdeadc0de;
54
55/*
56 * Checks an item to make sure it hasn't been overwritten since it was freed,
57 * prior to subsequent reallocation.
58 *
59 * Complies with standard ctor arg/return
60 *
61 */
62int
63trash_ctor(void *mem, int size, void *arg, int flags)
64{
65	int cnt;
66	uint32_t *p;
67
68	cnt = size / sizeof(uma_junk);
69
70	for (p = mem; cnt > 0; cnt--, p++)
71		if (*p != uma_junk) {
72			printf("Memory modified after free %p(%d) val=%x @ %p\n",
73			    mem, size, *p, p);
74			return (0);
75		}
76	return (0);
77}
78
79/*
80 * Fills an item with predictable garbage
81 *
82 * Complies with standard dtor arg/return
83 *
84 */
85void
86trash_dtor(void *mem, int size, void *arg)
87{
88	int cnt;
89	uint32_t *p;
90
91	cnt = size / sizeof(uma_junk);
92
93	for (p = mem; cnt > 0; cnt--, p++)
94		*p = uma_junk;
95}
96
97/*
98 * Fills an item with predictable garbage
99 *
100 * Complies with standard init arg/return
101 *
102 */
103int
104trash_init(void *mem, int size, int flags)
105{
106	trash_dtor(mem, size, NULL);
107	return (0);
108}
109
110/*
111 * Checks an item to make sure it hasn't been overwritten since it was freed.
112 *
113 * Complies with standard fini arg/return
114 *
115 */
116void
117trash_fini(void *mem, int size)
118{
119	(void)trash_ctor(mem, size, NULL, 0);
120}
121
122int
123mtrash_ctor(void *mem, int size, void *arg, int flags)
124{
125	struct malloc_type **ksp;
126	uint32_t *p = mem;
127	int cnt;
128
129	size -= sizeof(struct malloc_type *);
130	ksp = (struct malloc_type **)mem;
131	ksp += size / sizeof(struct malloc_type *);
132	cnt = size / sizeof(uma_junk);
133
134	for (p = mem; cnt > 0; cnt--, p++)
135		if (*p != uma_junk) {
136			printf("Memory modified after free %p(%d) val=%x @ %p\n",
137			    mem, size, *p, p);
138			panic("Most recently used by %s\n", (*ksp == NULL)?
139			    "none" : (*ksp)->ks_shortdesc);
140		}
141	return (0);
142}
143
144/*
145 * Fills an item with predictable garbage
146 *
147 * Complies with standard dtor arg/return
148 *
149 */
150void
151mtrash_dtor(void *mem, int size, void *arg)
152{
153	int cnt;
154	uint32_t *p;
155
156	size -= sizeof(struct malloc_type *);
157	cnt = size / sizeof(uma_junk);
158
159	for (p = mem; cnt > 0; cnt--, p++)
160		*p = uma_junk;
161}
162
163/*
164 * Fills an item with predictable garbage
165 *
166 * Complies with standard init arg/return
167 *
168 */
169int
170mtrash_init(void *mem, int size, int flags)
171{
172	struct malloc_type **ksp;
173
174	mtrash_dtor(mem, size, NULL);
175
176	ksp = (struct malloc_type **)mem;
177	ksp += (size / sizeof(struct malloc_type *)) - 1;
178	*ksp = NULL;
179	return (0);
180}
181
182/*
183 * Checks an item to make sure it hasn't been overwritten since it was freed,
184 * prior to freeing it back to available memory.
185 *
186 * Complies with standard fini arg/return
187 *
188 */
189void
190mtrash_fini(void *mem, int size)
191{
192	(void)mtrash_ctor(mem, size, NULL, 0);
193}
194
195#ifdef INVARIANTS
196static uma_slab_t
197uma_dbg_getslab(uma_zone_t zone, void *item)
198{
199	uma_slab_t slab;
200	uma_keg_t keg;
201	uint8_t *mem;
202
203	mem = (uint8_t *)((uintptr_t)item & (~UMA_SLAB_MASK));
204	if (zone->uz_flags & UMA_ZONE_VTOSLAB) {
205		slab = vtoslab((vm_offset_t)mem);
206	} else {
207		/*
208		 * It is safe to return the slab here even though the
209		 * zone is unlocked because the item's allocation state
210		 * essentially holds a reference.
211		 */
212		ZONE_LOCK(zone);
213		keg = LIST_FIRST(&zone->uz_kegs)->kl_keg;
214		if (keg->uk_flags & UMA_ZONE_HASH)
215			slab = hash_sfind(&keg->uk_hash, mem);
216		else
217			slab = (uma_slab_t)(mem + keg->uk_pgoff);
218		ZONE_UNLOCK(zone);
219	}
220
221	return (slab);
222}
223
224/*
225 * Set up the slab's freei data such that uma_dbg_free can function.
226 *
227 */
228void
229uma_dbg_alloc(uma_zone_t zone, uma_slab_t slab, void *item)
230{
231	uma_keg_t keg;
232	int freei;
233
234	if (zone_first_keg(zone) == NULL)
235		return;
236	if (slab == NULL) {
237		slab = uma_dbg_getslab(zone, item);
238		if (slab == NULL)
239			panic("uma: item %p did not belong to zone %s\n",
240			    item, zone->uz_name);
241	}
242	keg = slab->us_keg;
243	freei = ((uintptr_t)item - (uintptr_t)slab->us_data) / keg->uk_rsize;
244
245	if (BIT_ISSET(SLAB_SETSIZE, freei, &slab->us_debugfree))
246		panic("Duplicate alloc of %p from zone %p(%s) slab %p(%d)\n",
247		    item, zone, zone->uz_name, slab, freei);
248	BIT_SET_ATOMIC(SLAB_SETSIZE, freei, &slab->us_debugfree);
249
250	return;
251}
252
253/*
254 * Verifies freed addresses.  Checks for alignment, valid slab membership
255 * and duplicate frees.
256 *
257 */
258void
259uma_dbg_free(uma_zone_t zone, uma_slab_t slab, void *item)
260{
261	uma_keg_t keg;
262	int freei;
263
264	if (zone_first_keg(zone) == NULL)
265		return;
266	if (slab == NULL) {
267		slab = uma_dbg_getslab(zone, item);
268		if (slab == NULL)
269			panic("uma: Freed item %p did not belong to zone %s\n",
270			    item, zone->uz_name);
271	}
272	keg = slab->us_keg;
273	freei = ((uintptr_t)item - (uintptr_t)slab->us_data) / keg->uk_rsize;
274
275	if (freei >= keg->uk_ipers)
276		panic("Invalid free of %p from zone %p(%s) slab %p(%d)\n",
277		    item, zone, zone->uz_name, slab, freei);
278
279	if (((freei * keg->uk_rsize) + slab->us_data) != item)
280		panic("Unaligned free of %p from zone %p(%s) slab %p(%d)\n",
281		    item, zone, zone->uz_name, slab, freei);
282
283	if (!BIT_ISSET(SLAB_SETSIZE, freei, &slab->us_debugfree))
284		panic("Duplicate free of %p from zone %p(%s) slab %p(%d)\n",
285		    item, zone, zone->uz_name, slab, freei);
286
287	BIT_CLR_ATOMIC(SLAB_SETSIZE, freei, &slab->us_debugfree);
288}
289
290#endif /* INVARIANTS */
291