FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_stack.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2005 Antoine Brodin
5 * 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, this list of conditions and the following 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 AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include "opt_ddb.h"
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #ifdef KTR
37 #include <sys/ktr.h>
38 #endif
39 #include <sys/linker.h>
40 #include <sys/malloc.h>
41 #include <sys/sbuf.h>
42 #include <sys/stack.h>
43 #include <sys/systm.h>
44 #include <sys/sysctl.h>
45
46 FEATURE(stack, "Support for capturing kernel stack");
47
48 MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
49
50 static int stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
51 long *offset, int flags);
52 static int stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset);
53
54 struct stack *
55 stack_create(int flags)
56 {
57 struct stack *st;
58
59 st = malloc(sizeof(*st), M_STACK, flags | M_ZERO);
60 return (st);
61 }
62
63 void
64 stack_destroy(struct stack *st)
65 {
66
67 free(st, M_STACK);
68 }
69
70 int
71 stack_put(struct stack *st, vm_offset_t pc)
72 {
73
74 if (st->depth < STACK_MAX) {
75 st->pcs[st->depth++] = pc;
76 return (0);
77 } else
78 return (-1);
79 }
80
81 void
82 stack_copy(const struct stack *src, struct stack *dst)
83 {
84
85 *dst = *src;
86 }
87
88 void
89 stack_zero(struct stack *st)
90 {
91
92 bzero(st, sizeof *st);
93 }
94
95 void
96 stack_print(const struct stack *st)
97 {
98 char namebuf[64];
99 long offset;
100 int i;
101
102 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
103 for (i = 0; i < st->depth; i++) {
104 (void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
105 &offset, M_WAITOK);
106 printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
107 namebuf, offset);
108 }
109 }
110
111 void
112 stack_print_short(const struct stack *st)
113 {
114 char namebuf[64];
115 long offset;
116 int i;
117
118 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
119 for (i = 0; i < st->depth; i++) {
120 if (i > 0)
121 printf(" ");
122 if (stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
123 &offset, M_WAITOK) == 0)
124 printf("%s+%#lx", namebuf, offset);
125 else
126 printf("%p", (void *)st->pcs[i]);
127 }
128 printf("\n");
129 }
130
131 void
132 stack_print_ddb(const struct stack *st)
133 {
134 const char *name;
135 long offset;
136 int i;
137
138 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
139 for (i = 0; i < st->depth; i++) {
140 stack_symbol_ddb(st->pcs[i], &name, &offset);
141 printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
142 name, offset);
143 }
144 }
145
146 #if defined(DDB) || defined(WITNESS)
147 void
148 stack_print_short_ddb(const struct stack *st)
149 {
150 const char *name;
151 long offset;
152 int i;
153
154 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
155 for (i = 0; i < st->depth; i++) {
156 if (i > 0)
157 printf(" ");
158 if (stack_symbol_ddb(st->pcs[i], &name, &offset) == 0)
159 printf("%s+%#lx", name, offset);
160 else
161 printf("%p", (void *)st->pcs[i]);
162 }
163 printf("\n");
164 }
165 #endif
166
167 /*
168 * Format stack into sbuf from live kernel.
169 *
170 * flags - M_WAITOK or M_NOWAIT (EWOULDBLOCK).
171 */
172 int
173 stack_sbuf_print_flags(struct sbuf *sb, const struct stack *st, int flags,
174 enum stack_sbuf_fmt format)
175 {
176 char namebuf[64];
177 long offset;
178 int i, error;
179
180 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
181 for (i = 0; i < st->depth; i++) {
182 error = stack_symbol(st->pcs[i], namebuf, sizeof(namebuf),
183 &offset, flags);
184 if (error == EWOULDBLOCK)
185 return (error);
186 switch (format) {
187 case STACK_SBUF_FMT_LONG:
188 sbuf_printf(sb, "#%d %p at %s+%#lx\n", i,
189 (void *)st->pcs[i], namebuf, offset);
190 break;
191 case STACK_SBUF_FMT_COMPACT:
192 sbuf_printf(sb, "%s+%#lx ", namebuf, offset);
193 break;
194 default:
195 __assert_unreachable();
196 }
197 }
198 sbuf_nl_terminate(sb);
199 return (0);
200 }
201
202 void
203 stack_sbuf_print(struct sbuf *sb, const struct stack *st)
204 {
205
206 (void)stack_sbuf_print_flags(sb, st, M_WAITOK, STACK_SBUF_FMT_LONG);
207 }
208
209 #if defined(DDB) || defined(WITNESS)
210 void
211 stack_sbuf_print_ddb(struct sbuf *sb, const struct stack *st)
212 {
213 const char *name;
214 long offset;
215 int i;
216
217 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
218 for (i = 0; i < st->depth; i++) {
219 (void)stack_symbol_ddb(st->pcs[i], &name, &offset);
220 sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
221 name, offset);
222 }
223 }
224 #endif
225
226 #ifdef KTR
227 void
228 stack_ktr(u_int mask, const char *file, int line, const struct stack *st,
229 u_int depth)
230 {
231 #ifdef DDB
232 const char *name;
233 long offset;
234 int i;
235 #endif
236
237 KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
238 #ifdef DDB
239 if (depth == 0 || st->depth < depth)
240 depth = st->depth;
241 for (i = 0; i < depth; i++) {
242 (void)stack_symbol_ddb(st->pcs[i], &name, &offset);
243 ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx",
244 i, st->pcs[i], (u_long)name, offset, 0, 0);
245 }
246 #endif
247 }
248 #endif
249
250 /*
251 * Two variants of stack symbol lookup -- one that uses the DDB interfaces
252 * and bypasses linker locking, and the other that doesn't.
253 */
254 static int
255 stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset,
256 int flags)
257 {
258 int error;
259
260 error = linker_search_symbol_name_flags((caddr_t)pc, namebuf, buflen,
261 offset, flags);
262 if (error == 0 || error == EWOULDBLOCK)
263 return (error);
264
265 *offset = 0;
266 strlcpy(namebuf, "??", buflen);
267 return (ENOENT);
268 }
269
270 static int
271 stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset)
272 {
273 linker_symval_t symval;
274 c_linker_sym_t sym;
275
276 if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0)
277 goto out;
278 if (linker_ddb_symbol_values(sym, &symval) != 0)
279 goto out;
280 if (symval.name != NULL) {
281 *name = symval.name;
282 return (0);
283 }
284 out:
285 *offset = 0;
286 *name = "??";
287 return (ENOENT);
288 }
Cache object: e73ea7b73f462ea641b7f324e5eac26f
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