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Diffstat (limited to 'kernel/debug/kdb/kdb_bt.c')
| -rw-r--r-- | kernel/debug/kdb/kdb_bt.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c new file mode 100644 index 000000000..10b454554 --- /dev/null +++ b/kernel/debug/kdb/kdb_bt.c @@ -0,0 +1,221 @@ +/* + * Kernel Debugger Architecture Independent Stack Traceback + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved. + * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. + */ + +#include <linux/ctype.h> +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/sched/signal.h> +#include <linux/sched/debug.h> +#include <linux/kdb.h> +#include <linux/nmi.h> +#include "kdb_private.h" + + +static void kdb_show_stack(struct task_struct *p, void *addr) +{ + kdb_trap_printk++; + + if (!addr && kdb_task_has_cpu(p)) { + int old_lvl = console_loglevel; + + console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; + kdb_dump_stack_on_cpu(kdb_process_cpu(p)); + console_loglevel = old_lvl; + } else { + show_stack(p, addr, KERN_EMERG); + } + + kdb_trap_printk--; +} + +/* + * kdb_bt + * + * This function implements the 'bt' command. Print a stack + * traceback. + * + * bt [<address-expression>] (addr-exp is for alternate stacks) + * btp <pid> Kernel stack for <pid> + * btt <address-expression> Kernel stack for task structure at + * <address-expression> + * bta [state_chars>|A] All useful processes, optionally + * filtered by state + * btc [<cpu>] The current process on one cpu, + * default is all cpus + * + * bt <address-expression> refers to a address on the stack, that location + * is assumed to contain a return address. + * + * btt <address-expression> refers to the address of a struct task. + * + * Inputs: + * argc argument count + * argv argument vector + * Outputs: + * None. + * Returns: + * zero for success, a kdb diagnostic if error + * Locking: + * none. + * Remarks: + * Backtrack works best when the code uses frame pointers. But even + * without frame pointers we should get a reasonable trace. + * + * mds comes in handy when examining the stack to do a manual traceback or + * to get a starting point for bt <address-expression>. + */ + +static int +kdb_bt1(struct task_struct *p, const char *mask, bool btaprompt) +{ + char ch; + + if (kdb_getarea(ch, (unsigned long)p) || + kdb_getarea(ch, (unsigned long)(p+1)-1)) + return KDB_BADADDR; + if (!kdb_task_state(p, mask)) + return 0; + kdb_printf("Stack traceback for pid %d\n", p->pid); + kdb_ps1(p); + kdb_show_stack(p, NULL); + if (btaprompt) { + kdb_printf("Enter <q> to end, <cr> or <space> to continue:"); + do { + ch = kdb_getchar(); + } while (!strchr("\r\n q", ch)); + kdb_printf("\n"); + + /* reset the pager */ + kdb_nextline = 1; + + if (ch == 'q') + return 1; + } + touch_nmi_watchdog(); + return 0; +} + +static void +kdb_bt_cpu(unsigned long cpu) +{ + struct task_struct *kdb_tsk; + + if (cpu >= num_possible_cpus() || !cpu_online(cpu)) { + kdb_printf("WARNING: no process for cpu %ld\n", cpu); + return; + } + + /* If a CPU failed to round up we could be here */ + kdb_tsk = KDB_TSK(cpu); + if (!kdb_tsk) { + kdb_printf("WARNING: no task for cpu %ld\n", cpu); + return; + } + + kdb_bt1(kdb_tsk, "A", false); +} + +int +kdb_bt(int argc, const char **argv) +{ + int diag; + int btaprompt = 1; + int nextarg; + unsigned long addr; + long offset; + + /* Prompt after each proc in bta */ + kdbgetintenv("BTAPROMPT", &btaprompt); + + if (strcmp(argv[0], "bta") == 0) { + struct task_struct *g, *p; + unsigned long cpu; + const char *mask = argc ? argv[1] : kdbgetenv("PS"); + + if (argc == 0) + kdb_ps_suppressed(); + /* Run the active tasks first */ + for_each_online_cpu(cpu) { + p = kdb_curr_task(cpu); + if (kdb_bt1(p, mask, btaprompt)) + return 0; + } + /* Now the inactive tasks */ + for_each_process_thread(g, p) { + if (KDB_FLAG(CMD_INTERRUPT)) + return 0; + if (task_curr(p)) + continue; + if (kdb_bt1(p, mask, btaprompt)) + return 0; + } + } else if (strcmp(argv[0], "btp") == 0) { + struct task_struct *p; + unsigned long pid; + if (argc != 1) + return KDB_ARGCOUNT; + diag = kdbgetularg((char *)argv[1], &pid); + if (diag) + return diag; + p = find_task_by_pid_ns(pid, &init_pid_ns); + if (p) + return kdb_bt1(p, "A", false); + kdb_printf("No process with pid == %ld found\n", pid); + return 0; + } else if (strcmp(argv[0], "btt") == 0) { + if (argc != 1) + return KDB_ARGCOUNT; + diag = kdbgetularg((char *)argv[1], &addr); + if (diag) + return diag; + return kdb_bt1((struct task_struct *)addr, "A", false); + } else if (strcmp(argv[0], "btc") == 0) { + unsigned long cpu = ~0; + if (argc > 1) + return KDB_ARGCOUNT; + if (argc == 1) { + diag = kdbgetularg((char *)argv[1], &cpu); + if (diag) + return diag; + } + if (cpu != ~0) { + kdb_bt_cpu(cpu); + } else { + /* + * Recursive use of kdb_parse, do not use argv after + * this point. + */ + argv = NULL; + kdb_printf("btc: cpu status: "); + kdb_parse("cpu\n"); + for_each_online_cpu(cpu) { + kdb_bt_cpu(cpu); + touch_nmi_watchdog(); + } + } + return 0; + } else { + if (argc) { + nextarg = 1; + diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, + &offset, NULL); + if (diag) + return diag; + kdb_show_stack(kdb_current_task, (void *)addr); + return 0; + } else { + return kdb_bt1(kdb_current_task, "A", false); + } + } + + /* NOTREACHED */ + return 0; +} |