subr_stack.c revision 291059
1/*- 2 * Copyright (c) 2005 Antoine Brodin 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include "opt_ddb.h" 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: head/sys/kern/subr_stack.c 291059 2015-11-19 05:56:59Z markj $"); 31 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 44FEATURE(stack, "Support for capturing kernel stack"); 45 46static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces"); 47 48static int stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, 49 long *offset); 50static int stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset); 51 52struct stack * 53stack_create(void) 54{ 55 struct stack *st; 56 57 st = malloc(sizeof *st, M_STACK, M_WAITOK | M_ZERO); 58 return (st); 59} 60 61void 62stack_destroy(struct stack *st) 63{ 64 65 free(st, M_STACK); 66} 67 68int 69stack_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 79void 80stack_copy(const struct stack *src, struct stack *dst) 81{ 82 83 *dst = *src; 84} 85 86void 87stack_zero(struct stack *st) 88{ 89 90 bzero(st, sizeof *st); 91} 92 93void 94stack_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); 104 printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i], 105 namebuf, offset); 106 } 107} 108 109void 110stack_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) == 0) 122 printf("%s+%#lx", namebuf, offset); 123 else 124 printf("%p", (void *)st->pcs[i]); 125 } 126 printf("\n"); 127} 128 129void 130stack_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) 145void 146stack_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 * Two print routines -- one for use from DDB and DDB-like contexts, the 167 * other for use in the live kernel. 168 */ 169void 170stack_sbuf_print(struct sbuf *sb, const struct stack *st) 171{ 172 char namebuf[64]; 173 long offset; 174 int i; 175 176 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 177 for (i = 0; i < st->depth; i++) { 178 (void)stack_symbol(st->pcs[i], namebuf, sizeof(namebuf), 179 &offset); 180 sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i], 181 namebuf, offset); 182 } 183} 184 185#if defined(DDB) || defined(WITNESS) 186void 187stack_sbuf_print_ddb(struct sbuf *sb, const struct stack *st) 188{ 189 const char *name; 190 long offset; 191 int i; 192 193 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 194 for (i = 0; i < st->depth; i++) { 195 (void)stack_symbol_ddb(st->pcs[i], &name, &offset); 196 sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i], 197 name, offset); 198 } 199} 200#endif 201 202#ifdef KTR 203void 204stack_ktr(u_int mask, const char *file, int line, const struct stack *st, 205 u_int depth, int cheap) 206{ 207#ifdef DDB 208 const char *name; 209 long offset; 210 int i; 211#endif 212 213 KASSERT(st->depth <= STACK_MAX, ("bogus stack")); 214 if (cheap) { 215 ktr_tracepoint(mask, file, line, "#0 %p %p %p %p %p %p", 216 st->pcs[0], st->pcs[1], st->pcs[2], st->pcs[3], 217 st->pcs[4], st->pcs[5]); 218 if (st->depth <= 6) 219 return; 220 ktr_tracepoint(mask, file, line, "#1 %p %p %p %p %p %p", 221 st->pcs[6], st->pcs[7], st->pcs[8], st->pcs[9], 222 st->pcs[10], st->pcs[11]); 223 if (st->depth <= 12) 224 return; 225 ktr_tracepoint(mask, file, line, "#2 %p %p %p %p %p %p", 226 st->pcs[12], st->pcs[13], st->pcs[14], st->pcs[15], 227 st->pcs[16], st->pcs[17]); 228#ifdef DDB 229 } else { 230 if (depth == 0 || st->depth < depth) 231 depth = st->depth; 232 for (i = 0; i < depth; i++) { 233 (void)stack_symbol_ddb(st->pcs[i], &name, &offset); 234 ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx", 235 i, st->pcs[i], (u_long)name, offset, 0, 0); 236 } 237#endif 238 } 239} 240#endif 241 242/* 243 * Two variants of stack symbol lookup -- one that uses the DDB interfaces 244 * and bypasses linker locking, and the other that doesn't. 245 */ 246static int 247stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset) 248{ 249 250 if (linker_search_symbol_name((caddr_t)pc, namebuf, buflen, 251 offset) != 0) { 252 *offset = 0; 253 strlcpy(namebuf, "??", buflen); 254 return (ENOENT); 255 } else 256 return (0); 257} 258 259static int 260stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset) 261{ 262 linker_symval_t symval; 263 c_linker_sym_t sym; 264 265 if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0) 266 goto out; 267 if (linker_ddb_symbol_values(sym, &symval) != 0) 268 goto out; 269 if (symval.name != NULL) { 270 *name = symval.name; 271 return (0); 272 } 273 out: 274 *offset = 0; 275 *name = "??"; 276 return (ENOENT); 277} 278