1/* 2 * Kernel Debugger Architecture Independent Stack Traceback 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved. 9 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. 10 */ 11 12#include <linux/ctype.h> 13#include <linux/string.h> 14#include <linux/kernel.h> 15#include <linux/sched.h> 16#include <linux/kdb.h> 17#include <linux/nmi.h> 18#include <asm/system.h> 19#include "kdb_private.h" 20 21 22static void kdb_show_stack(struct task_struct *p, void *addr) 23{ 24 int old_lvl = console_loglevel; 25 console_loglevel = 15; 26 kdb_trap_printk++; 27 kdb_set_current_task(p); 28 if (addr) { 29 show_stack((struct task_struct *)p, addr); 30 } else if (kdb_current_regs) { 31#ifdef CONFIG_X86 32 show_stack(p, &kdb_current_regs->sp); 33#else 34 show_stack(p, NULL); 35#endif 36 } else { 37 show_stack(p, NULL); 38 } 39 console_loglevel = old_lvl; 40 kdb_trap_printk--; 41} 42 43/* 44 * kdb_bt 45 * 46 * This function implements the 'bt' command. Print a stack 47 * traceback. 48 * 49 * bt [<address-expression>] (addr-exp is for alternate stacks) 50 * btp <pid> Kernel stack for <pid> 51 * btt <address-expression> Kernel stack for task structure at 52 * <address-expression> 53 * bta [DRSTCZEUIMA] All useful processes, optionally 54 * filtered by state 55 * btc [<cpu>] The current process on one cpu, 56 * default is all cpus 57 * 58 * bt <address-expression> refers to a address on the stack, that location 59 * is assumed to contain a return address. 60 * 61 * btt <address-expression> refers to the address of a struct task. 62 * 63 * Inputs: 64 * argc argument count 65 * argv argument vector 66 * Outputs: 67 * None. 68 * Returns: 69 * zero for success, a kdb diagnostic if error 70 * Locking: 71 * none. 72 * Remarks: 73 * Backtrack works best when the code uses frame pointers. But even 74 * without frame pointers we should get a reasonable trace. 75 * 76 * mds comes in handy when examining the stack to do a manual traceback or 77 * to get a starting point for bt <address-expression>. 78 */ 79 80static int 81kdb_bt1(struct task_struct *p, unsigned long mask, 82 int argcount, int btaprompt) 83{ 84 char buffer[2]; 85 if (kdb_getarea(buffer[0], (unsigned long)p) || 86 kdb_getarea(buffer[0], (unsigned long)(p+1)-1)) 87 return KDB_BADADDR; 88 if (!kdb_task_state(p, mask)) 89 return 0; 90 kdb_printf("Stack traceback for pid %d\n", p->pid); 91 kdb_ps1(p); 92 kdb_show_stack(p, NULL); 93 if (btaprompt) { 94 kdb_getstr(buffer, sizeof(buffer), 95 "Enter <q> to end, <cr> to continue:"); 96 if (buffer[0] == 'q') { 97 kdb_printf("\n"); 98 return 1; 99 } 100 } 101 touch_nmi_watchdog(); 102 return 0; 103} 104 105int 106kdb_bt(int argc, const char **argv) 107{ 108 int diag; 109 int argcount = 5; 110 int btaprompt = 1; 111 int nextarg; 112 unsigned long addr; 113 long offset; 114 115 kdbgetintenv("BTARGS", &argcount); /* Arguments to print */ 116 kdbgetintenv("BTAPROMPT", &btaprompt); /* Prompt after each 117 * proc in bta */ 118 119 if (strcmp(argv[0], "bta") == 0) { 120 struct task_struct *g, *p; 121 unsigned long cpu; 122 unsigned long mask = kdb_task_state_string(argc ? argv[1] : 123 NULL); 124 if (argc == 0) 125 kdb_ps_suppressed(); 126 /* Run the active tasks first */ 127 for_each_online_cpu(cpu) { 128 p = kdb_curr_task(cpu); 129 if (kdb_bt1(p, mask, argcount, btaprompt)) 130 return 0; 131 } 132 /* Now the inactive tasks */ 133 kdb_do_each_thread(g, p) { 134 if (task_curr(p)) 135 continue; 136 if (kdb_bt1(p, mask, argcount, btaprompt)) 137 return 0; 138 } kdb_while_each_thread(g, p); 139 } else if (strcmp(argv[0], "btp") == 0) { 140 struct task_struct *p; 141 unsigned long pid; 142 if (argc != 1) 143 return KDB_ARGCOUNT; 144 diag = kdbgetularg((char *)argv[1], &pid); 145 if (diag) 146 return diag; 147 p = find_task_by_pid_ns(pid, &init_pid_ns); 148 if (p) { 149 kdb_set_current_task(p); 150 return kdb_bt1(p, ~0UL, argcount, 0); 151 } 152 kdb_printf("No process with pid == %ld found\n", pid); 153 return 0; 154 } else if (strcmp(argv[0], "btt") == 0) { 155 if (argc != 1) 156 return KDB_ARGCOUNT; 157 diag = kdbgetularg((char *)argv[1], &addr); 158 if (diag) 159 return diag; 160 kdb_set_current_task((struct task_struct *)addr); 161 return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0); 162 } else if (strcmp(argv[0], "btc") == 0) { 163 unsigned long cpu = ~0; 164 struct task_struct *save_current_task = kdb_current_task; 165 char buf[80]; 166 if (argc > 1) 167 return KDB_ARGCOUNT; 168 if (argc == 1) { 169 diag = kdbgetularg((char *)argv[1], &cpu); 170 if (diag) 171 return diag; 172 } 173 /* Recursive use of kdb_parse, do not use argv after 174 * this point */ 175 argv = NULL; 176 if (cpu != ~0) { 177 if (cpu >= num_possible_cpus() || !cpu_online(cpu)) { 178 kdb_printf("no process for cpu %ld\n", cpu); 179 return 0; 180 } 181 sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu)); 182 kdb_parse(buf); 183 return 0; 184 } 185 kdb_printf("btc: cpu status: "); 186 kdb_parse("cpu\n"); 187 for_each_online_cpu(cpu) { 188 sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu)); 189 kdb_parse(buf); 190 touch_nmi_watchdog(); 191 } 192 kdb_set_current_task(save_current_task); 193 return 0; 194 } else { 195 if (argc) { 196 nextarg = 1; 197 diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, 198 &offset, NULL); 199 if (diag) 200 return diag; 201 kdb_show_stack(kdb_current_task, (void *)addr); 202 return 0; 203 } else { 204 return kdb_bt1(kdb_current_task, ~0UL, argcount, 0); 205 } 206 } 207 208 /* NOTREACHED */ 209 return 0; 210} 211