lib/dump_stack.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Provide a default dump_stack() function for architectures
   4  * which don't implement their own.
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/buildid.h>
   9 #include <linux/export.h>
  10 #include <linux/sched.h>
  11 #include <linux/sched/debug.h>
  12 #include <linux/smp.h>
  13 #include <linux/atomic.h>
  14 #include <linux/kexec.h>
  15 #include <linux/utsname.h>
  16 #include <linux/stop_machine.h>
  17
  18 static char dump_stack_arch_desc_str[128];
  19
  20 /**
  21  * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
  22  * @fmt: printf-style format string
  23  * @...: arguments for the format string
  24  *
  25  * The configured string will be printed right after utsname during task
  26  * dumps.  Usually used to add arch-specific system identifiers.  If an
  27  * arch wants to make use of such an ID string, it should initialize this
  28  * as soon as possible during boot.
  29  */
  30 void __init dump_stack_set_arch_desc(const char *fmt, ...)
  31 {
  32         va_list args;
  33
  34         va_start(args, fmt);
  35         vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
  36                   fmt, args);
  37         va_end(args);
  38 }
  39
  40 #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
  41 #define BUILD_ID_FMT " %20phN"
  42 #define BUILD_ID_VAL vmlinux_build_id
  43 #else
  44 #define BUILD_ID_FMT "%s"
  45 #define BUILD_ID_VAL ""
  46 #endif
  47
  48 /**
  49  * dump_stack_print_info - print generic debug info for dump_stack()
  50  * @log_lvl: log level
  51  *
  52  * Arch-specific dump_stack() implementations can use this function to
  53  * print out the same debug information as the generic dump_stack().
  54  */
  55 void dump_stack_print_info(const char *log_lvl)
  56 {
  57         printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
  58                log_lvl, raw_smp_processor_id(), current->pid, current->comm,
  59                kexec_crash_loaded() ? "Kdump: loaded " : "",
  60                print_tainted(),
  61                init_utsname()->release,
  62                (int)strcspn(init_utsname()->version, " "),
  63                init_utsname()->version, BUILD_ID_VAL);
  64
  65         if (dump_stack_arch_desc_str[0] != '\0')
  66                 printk("%sHardware name: %s\n",
  67                        log_lvl, dump_stack_arch_desc_str);
  68
  69         print_worker_info(log_lvl, current);
  70         print_stop_info(log_lvl, current);
  71 }
  72
  73 /**
  74  * show_regs_print_info - print generic debug info for show_regs()
  75  * @log_lvl: log level
  76  *
  77  * show_regs() implementations can use this function to print out generic
  78  * debug information.
  79  */
  80 void show_regs_print_info(const char *log_lvl)
  81 {
  82         dump_stack_print_info(log_lvl);
  83 }
  84
  85 static void __dump_stack(const char *log_lvl)
  86 {
  87         dump_stack_print_info(log_lvl);
  88         show_stack(NULL, NULL, log_lvl);
  89 }
  90
  91 /**
  92  * dump_stack_lvl - dump the current task information and its stack trace
  93  * @log_lvl: log level
  94  *
  95  * Architectures can override this implementation by implementing its own.
  96  */
  97 asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
  98 {
  99         unsigned long flags;
 100
 101         /*
 102          * Permit this cpu to perform nested stack dumps while serialising
 103          * against other CPUs
 104          */
 105         printk_cpu_sync_get_irqsave(flags);
 106         __dump_stack(log_lvl);
 107         printk_cpu_sync_put_irqrestore(flags);
 108 }
 109 EXPORT_SYMBOL(dump_stack_lvl);
 110
 111 asmlinkage __visible void dump_stack(void)
 112 {
 113         dump_stack_lvl(KERN_DEFAULT);
 114 }
 115 EXPORT_SYMBOL(dump_stack);