1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #include <sys/param.h> 33 #include <sys/kernel.h> 34 #ifdef KTR 35 #include <sys/ktr.h> 36 #endif 37 #include <sys/linker.h> 38 #include <sys/malloc.h> 39 #include <sys/sbuf.h> 40 #include <sys/stack.h> 41 #include <sys/systm.h> 42 #include <sys/sysctl.h> 43 44 FEATURE(stack, "Support for capturing kernel stack"); 45 46 MALLOC_DEFINE(M_STACK, "stack", "Stack Traces"); 47 48 static int stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, 49 long *offset, int flags); 50 static int stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset); 51 52 struct stack * 53 stack_create(int flags) 54 { 55 struct stack *st; 56 57 st = malloc(sizeof(*st), M_STACK, flags | M_ZERO); 58 return (st); 59 } 60 61 void 62 stack_destroy(struct stack *st) 63 { 64 65 free(st, M_STACK); 66 } 67 68 int 69 stack_put(struct stack *st, vm_offset_t pc) 70 { 71 72 if (st->depth < STACK_MAX) { 73 st->pcs[st->depth++] = pc; 74 return (0); 75 } else 76 return (-1); 77 } 78 79 void 80 stack_copy(const struct stack *src, struct stack *dst) 81 { 82 83 *dst = *src; 84 } 85 86 void 87 stack_zero(struct stack *st) 88 { 89 90 bzero(st, sizeof *st); 91 } 92 93 void 94 stack_print(const struct stack *st) 95 { 96 char namebuf[64]; 97 long offset; 98 int i; 99 100 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 101 for (i = 0; i < st->depth; i++) { 102 (void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf), 103 &offset, M_WAITOK); 104 printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i], 105 namebuf, offset); 106 } 107 } 108 109 void 110 stack_print_short(const struct stack *st) 111 { 112 char namebuf[64]; 113 long offset; 114 int i; 115 116 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 117 for (i = 0; i < st->depth; i++) { 118 if (i > 0) 119 printf(" "); 120 if (stack_symbol(st->pcs[i], namebuf, sizeof(namebuf), 121 &offset, M_WAITOK) == 0) 122 printf("%s+%#lx", namebuf, offset); 123 else 124 printf("%p", (void *)st->pcs[i]); 125 } 126 printf("\n"); 127 } 128 129 void 130 stack_print_ddb(const struct stack *st) 131 { 132 const char *name; 133 long offset; 134 int i; 135 136 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 137 for (i = 0; i < st->depth; i++) { 138 stack_symbol_ddb(st->pcs[i], &name, &offset); 139 printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i], 140 name, offset); 141 } 142 } 143 144 #if defined(DDB) || defined(WITNESS) 145 void 146 stack_print_short_ddb(const struct stack *st) 147 { 148 const char *name; 149 long offset; 150 int i; 151 152 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 153 for (i = 0; i < st->depth; i++) { 154 if (i > 0) 155 printf(" "); 156 if (stack_symbol_ddb(st->pcs[i], &name, &offset) == 0) 157 printf("%s+%#lx", name, offset); 158 else 159 printf("%p", (void *)st->pcs[i]); 160 } 161 printf("\n"); 162 } 163 #endif 164 165 /* 166 * Format stack into sbuf from live kernel. 167 * 168 * flags - M_WAITOK or M_NOWAIT (EWOULDBLOCK). 169 */ 170 int 171 stack_sbuf_print_flags(struct sbuf *sb, const struct stack *st, int flags, 172 enum stack_sbuf_fmt format) 173 { 174 char namebuf[64]; 175 long offset; 176 int i, error; 177 178 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 179 for (i = 0; i < st->depth; i++) { 180 error = stack_symbol(st->pcs[i], namebuf, sizeof(namebuf), 181 &offset, flags); 182 if (error == EWOULDBLOCK) 183 return (error); 184 switch (format) { 185 case STACK_SBUF_FMT_LONG: 186 sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, 187 (void *)st->pcs[i], namebuf, offset); 188 break; 189 case STACK_SBUF_FMT_COMPACT: 190 sbuf_printf(sb, "%s+%#lx ", namebuf, offset); 191 break; 192 default: 193 __assert_unreachable(); 194 } 195 } 196 sbuf_nl_terminate(sb); 197 return (0); 198 } 199 200 void 201 stack_sbuf_print(struct sbuf *sb, const struct stack *st) 202 { 203 204 (void)stack_sbuf_print_flags(sb, st, M_WAITOK, STACK_SBUF_FMT_LONG); 205 } 206 207 #if defined(DDB) || defined(WITNESS) 208 void 209 stack_sbuf_print_ddb(struct sbuf *sb, const struct stack *st) 210 { 211 const char *name; 212 long offset; 213 int i; 214 215 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 216 for (i = 0; i < st->depth; i++) { 217 (void)stack_symbol_ddb(st->pcs[i], &name, &offset); 218 sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i], 219 name, offset); 220 } 221 } 222 #endif 223 224 #ifdef KTR 225 void 226 stack_ktr(u_int mask, const char *file, int line, const struct stack *st, 227 u_int depth) 228 { 229 #ifdef DDB 230 const char *name; 231 long offset; 232 int i; 233 #endif 234 235 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 236 #ifdef DDB 237 if (depth == 0 || st->depth < depth) 238 depth = st->depth; 239 for (i = 0; i < depth; i++) { 240 (void)stack_symbol_ddb(st->pcs[i], &name, &offset); 241 ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx", 242 i, st->pcs[i], (u_long)name, offset, 0, 0); 243 } 244 #endif 245 } 246 #endif 247 248 /* 249 * Two variants of stack symbol lookup -- one that uses the DDB interfaces 250 * and bypasses linker locking, and the other that doesn't. 251 */ 252 static int 253 stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset, 254 int flags) 255 { 256 int error; 257 258 error = linker_search_symbol_name_flags((caddr_t)pc, namebuf, buflen, 259 offset, flags); 260 if (error == 0 || error == EWOULDBLOCK) 261 return (error); 262 263 *offset = 0; 264 strlcpy(namebuf, "??", buflen); 265 return (ENOENT); 266 } 267 268 static int 269 stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset) 270 { 271 linker_symval_t symval; 272 c_linker_sym_t sym; 273 274 if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0) 275 goto out; 276 if (linker_ddb_symbol_values(sym, &symval) != 0) 277 goto out; 278 if (symval.name != NULL) { 279 *name = symval.name; 280 return (0); 281 } 282 out: 283 *offset = 0; 284 *name = "??"; 285 return (ENOENT); 286 } 287