uma_dbg.c revision 187681 
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 187681 2009-01-25 09:11:24Z jeff $");
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/kernel.h>
39#include <sys/types.h>
40#include <sys/queue.h>
41#include <sys/lock.h>
42#include <sys/mutex.h>
43#include <sys/malloc.h>
44
45#include <vm/vm.h>
46#include <vm/vm_object.h>
47#include <vm/vm_page.h>
48#include <vm/uma.h>
49#include <vm/uma_int.h>
50#include <vm/uma_dbg.h>
51
52static const u_int32_t uma_junk = 0xdeadc0de;
53
54/*
55 * Checks an item to make sure it hasn't been overwritten since it was freed,
56 * prior to subsequent reallocation.
57 *
58 * Complies with standard ctor arg/return
59 *
60 */
61int
62trash_ctor(void *mem, int size, void *arg, int flags)
63{
64	int cnt;
65	u_int32_t *p;
66
67	cnt = size / sizeof(uma_junk);
68
69	for (p = mem; cnt > 0; cnt--, p++)
70		if (*p != uma_junk) {
71			printf("Memory modified after free %p(%d) val=%x @ %p\n",
72			    mem, size, *p, p);
73			return (0);
74		}
75	return (0);
76}
77
78/*
79 * Fills an item with predictable garbage
80 *
81 * Complies with standard dtor arg/return
82 *
83 */
84void
85trash_dtor(void *mem, int size, void *arg)
86{
87	int cnt;
88	u_int32_t *p;
89
90	cnt = size / sizeof(uma_junk);
91
92	for (p = mem; cnt > 0; cnt--, p++)
93		*p = uma_junk;
94}
95
96/*
97 * Fills an item with predictable garbage
98 *
99 * Complies with standard init arg/return
100 *
101 */
102int
103trash_init(void *mem, int size, int flags)
104{
105	trash_dtor(mem, size, NULL);
106	return (0);
107}
108
109/*
110 * Checks an item to make sure it hasn't been overwritten since it was freed.
111 *
112 * Complies with standard fini arg/return
113 *
114 */
115void
116trash_fini(void *mem, int size)
117{
118	(void)trash_ctor(mem, size, NULL, 0);
119}
120
121int
122mtrash_ctor(void *mem, int size, void *arg, int flags)
123{
124	struct malloc_type **ksp;
125	u_int32_t *p = mem;
126	int cnt;
127
128	size -= sizeof(struct malloc_type *);
129	ksp = (struct malloc_type **)mem;
130	ksp += size / sizeof(struct malloc_type *);
131	cnt = size / sizeof(uma_junk);
132
133	for (p = mem; cnt > 0; cnt--, p++)
134		if (*p != uma_junk) {
135			printf("Memory modified after free %p(%d) val=%x @ %p\n",
136			    mem, size, *p, p);
137			panic("Most recently used by %s\n", (*ksp == NULL)?
138			    "none" : (*ksp)->ks_shortdesc);
139		}
140	return (0);
141}
142
143/*
144 * Fills an item with predictable garbage
145 *
146 * Complies with standard dtor arg/return
147 *
148 */
149void
150mtrash_dtor(void *mem, int size, void *arg)
151{
152	int cnt;
153	u_int32_t *p;
154
155	size -= sizeof(struct malloc_type *);
156	cnt = size / sizeof(uma_junk);
157
158	for (p = mem; cnt > 0; cnt--, p++)
159		*p = uma_junk;
160}
161
162/*
163 * Fills an item with predictable garbage
164 *
165 * Complies with standard init arg/return
166 *
167 */
168int
169mtrash_init(void *mem, int size, int flags)
170{
171	struct malloc_type **ksp;
172
173	mtrash_dtor(mem, size, NULL);
174
175	ksp = (struct malloc_type **)mem;
176	ksp += (size / sizeof(struct malloc_type *)) - 1;
177	*ksp = NULL;
178	return (0);
179}
180
181/*
182 * Checks an item to make sure it hasn't been overwritten since it was freed,
183 * prior to freeing it back to available memory.
184 *
185 * Complies with standard fini arg/return
186 *
187 */
188void
189mtrash_fini(void *mem, int size)
190{
191	(void)mtrash_ctor(mem, size, NULL, 0);
192}
193
194static uma_slab_t
195uma_dbg_getslab(uma_zone_t zone, void *item)
196{
197	uma_slab_t slab;
198	uma_keg_t keg;
199	u_int8_t *mem;
200
201	mem = (u_int8_t *)((unsigned long)item & (~UMA_SLAB_MASK));
202	if (zone->uz_flags & UMA_ZONE_VTOSLAB) {
203		slab = vtoslab((vm_offset_t)mem);
204	} else {
205		keg = LIST_FIRST(&zone->uz_kegs)->kl_keg;
206		if (keg->uk_flags & UMA_ZONE_HASH)
207			slab = hash_sfind(&keg->uk_hash, mem);
208		else
209			slab = (uma_slab_t)(mem + keg->uk_pgoff);
210	}
211
212	return (slab);
213}
214
215/*
216 * Set up the slab's freei data such that uma_dbg_free can function.
217 *
218 */
219
220void
221uma_dbg_alloc(uma_zone_t zone, uma_slab_t slab, void *item)
222{
223	uma_keg_t keg;
224	uma_slabrefcnt_t slabref;
225	int freei;
226
227	if (slab == NULL) {
228		slab = uma_dbg_getslab(zone, item);
229		if (slab == NULL)
230			panic("uma: item %p did not belong to zone %s\n",
231			    item, zone->uz_name);
232	}
233	keg = slab->us_keg;
234
235	freei = ((unsigned long)item - (unsigned long)slab->us_data)
236	    / keg->uk_rsize;
237
238	if (keg->uk_flags & UMA_ZONE_REFCNT) {
239		slabref = (uma_slabrefcnt_t)slab;
240		slabref->us_freelist[freei].us_item = 255;
241	} else {
242		slab->us_freelist[freei].us_item = 255;
243	}
244
245	return;
246}
247
248/*
249 * Verifies freed addresses.  Checks for alignment, valid slab membership
250 * and duplicate frees.
251 *
252 */
253
254void
255uma_dbg_free(uma_zone_t zone, uma_slab_t slab, void *item)
256{
257	uma_keg_t keg;
258	uma_slabrefcnt_t slabref;
259	int freei;
260
261	if (slab == NULL) {
262		slab = uma_dbg_getslab(zone, item);
263		if (slab == NULL)
264			panic("uma: Freed item %p did not belong to zone %s\n",
265			    item, zone->uz_name);
266	}
267	keg = slab->us_keg;
268
269	freei = ((unsigned long)item - (unsigned long)slab->us_data)
270	    / keg->uk_rsize;
271
272	if (freei >= keg->uk_ipers)
273		panic("zone: %s(%p) slab %p freelist %d out of range 0-%d\n",
274		    zone->uz_name, zone, slab, freei, keg->uk_ipers-1);
275
276	if (((freei * keg->uk_rsize) + slab->us_data) != item) {
277		printf("zone: %s(%p) slab %p freed address %p unaligned.\n",
278		    zone->uz_name, zone, slab, item);
279		panic("should be %p\n",
280		    (freei * keg->uk_rsize) + slab->us_data);
281	}
282
283	if (keg->uk_flags & UMA_ZONE_REFCNT) {
284		slabref = (uma_slabrefcnt_t)slab;
285		if (slabref->us_freelist[freei].us_item != 255) {
286			printf("Slab at %p, freei %d = %d.\n",
287			    slab, freei, slabref->us_freelist[freei].us_item);
288			panic("Duplicate free of item %p from zone %p(%s)\n",
289			    item, zone, zone->uz_name);
290		}
291
292		/*
293		 * When this is actually linked into the slab this will change.
294		 * Until then the count of valid slabs will make sure we don't
295		 * accidentally follow this and assume it's a valid index.
296		 */
297		slabref->us_freelist[freei].us_item = 0;
298	} else {
299		if (slab->us_freelist[freei].us_item != 255) {
300			printf("Slab at %p, freei %d = %d.\n",
301			    slab, freei, slab->us_freelist[freei].us_item);
302			panic("Duplicate free of item %p from zone %p(%s)\n",
303			    item, zone, zone->uz_name);
304		}
305
306		/*
307		 * When this is actually linked into the slab this will change.
308		 * Until then the count of valid slabs will make sure we don't
309		 * accidentally follow this and assume it's a valid index.
310		 */
311		slab->us_freelist[freei].us_item = 0;
312	}
313}
314