uma_dbg.c revision 147615 
1/*-
2 * Copyright (c) 2004, 2005,
3 *     Bosko Milekic <bmilekic@FreeBSD.org>.  All rights reserved.
4 * Copyright (c) 2002, 2003, 2004, 2005,
5 *     Jeffrey Roberson <jeff@FreeBSD.org>.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice unmodified, this list of conditions, and the following
12 *    disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * uma_dbg.c	Debugging features for UMA users
31 *
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: head/sys/vm/uma_dbg.c 147615 2005-06-26 23:44:07Z silby $");
36
37#include <sys/param.h>
38#include <sys/systm.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 u_int32_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	u_int32_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	u_int32_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	u_int32_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	u_int32_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
195static uma_slab_t
196uma_dbg_getslab(uma_zone_t zone, void *item)
197{
198	uma_slab_t slab;
199	uma_keg_t keg;
200	u_int8_t *mem;
201
202	keg = zone->uz_keg;
203	mem = (u_int8_t *)((unsigned long)item & (~UMA_SLAB_MASK));
204	if (keg->uk_flags & UMA_ZONE_MALLOC) {
205		slab = vtoslab((vm_offset_t)mem);
206	} else if (keg->uk_flags & UMA_ZONE_HASH) {
207		slab = hash_sfind(&keg->uk_hash, mem);
208	} else {
209		mem += keg->uk_pgoff;
210		slab = (uma_slab_t)mem;
211	}
212
213	return (slab);
214}
215
216/*
217 * Set up the slab's freei data such that uma_dbg_free can function.
218 *
219 */
220
221void
222uma_dbg_alloc(uma_zone_t zone, uma_slab_t slab, void *item)
223{
224	uma_keg_t keg;
225	uma_slabrefcnt_t slabref;
226	int freei;
227
228	keg = zone->uz_keg;
229	if (slab == NULL) {
230		slab = uma_dbg_getslab(zone, item);
231		if (slab == NULL)
232			panic("uma: item %p did not belong to zone %s\n",
233			    item, zone->uz_name);
234	}
235
236	freei = ((unsigned long)item - (unsigned long)slab->us_data)
237	    / keg->uk_rsize;
238
239	if (keg->uk_flags & UMA_ZONE_REFCNT) {
240		slabref = (uma_slabrefcnt_t)slab;
241		slabref->us_freelist[freei].us_item = 255;
242	} else {
243		slab->us_freelist[freei].us_item = 255;
244	}
245
246	return;
247}
248
249/*
250 * Verifies freed addresses.  Checks for alignment, valid slab membership
251 * and duplicate frees.
252 *
253 */
254
255void
256uma_dbg_free(uma_zone_t zone, uma_slab_t slab, void *item)
257{
258	uma_keg_t keg;
259	uma_slabrefcnt_t slabref;
260	int freei;
261
262	keg = zone->uz_keg;
263	if (slab == NULL) {
264		slab = uma_dbg_getslab(zone, item);
265		if (slab == NULL)
266			panic("uma: Freed item %p did not belong to zone %s\n",
267			    item, zone->uz_name);
268	}
269
270	freei = ((unsigned long)item - (unsigned long)slab->us_data)
271	    / keg->uk_rsize;
272
273	if (freei >= keg->uk_ipers)
274		panic("zone: %s(%p) slab %p freelist %d out of range 0-%d\n",
275		    zone->uz_name, zone, slab, freei, keg->uk_ipers-1);
276
277	if (((freei * keg->uk_rsize) + slab->us_data) != item) {
278		printf("zone: %s(%p) slab %p freed address %p unaligned.\n",
279		    zone->uz_name, zone, slab, item);
280		panic("should be %p\n",
281		    (freei * keg->uk_rsize) + slab->us_data);
282	}
283
284	if (keg->uk_flags & UMA_ZONE_REFCNT) {
285		slabref = (uma_slabrefcnt_t)slab;
286		if (slabref->us_freelist[freei].us_item != 255) {
287			printf("Slab at %p, freei %d = %d.\n",
288			    slab, freei, slabref->us_freelist[freei].us_item);
289			panic("Duplicate free of item %p from zone %p(%s)\n",
290			    item, zone, zone->uz_name);
291		}
292
293		/*
294		 * When this is actually linked into the slab this will change.
295		 * Until then the count of valid slabs will make sure we don't
296		 * accidentally follow this and assume it's a valid index.
297		 */
298		slabref->us_freelist[freei].us_item = 0;
299	} else {
300		if (slab->us_freelist[freei].us_item != 255) {
301			printf("Slab at %p, freei %d = %d.\n",
302			    slab, freei, slab->us_freelist[freei].us_item);
303			panic("Duplicate free of item %p from zone %p(%s)\n",
304			    item, zone, zone->uz_name);
305		}
306
307		/*
308		 * When this is actually linked into the slab this will change.
309		 * Until then the count of valid slabs will make sure we don't
310		 * accidentally follow this and assume it's a valid index.
311		 */
312		slab->us_freelist[freei].us_item = 0;
313	}
314}
315