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 UID: %u PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n", 58 log_lvl, raw_smp_processor_id(), 59 __kuid_val(current_real_cred()->euid), 60 current->pid, current->comm, 61 kexec_crash_loaded() ? "Kdump: loaded " : "", 62 print_tainted(), 63 init_utsname()->release, 64 (int)strcspn(init_utsname()->version, " "), 65 init_utsname()->version, BUILD_ID_VAL); 66 67 if (get_taint()) 68 printk("%s%s\n", log_lvl, print_tainted_verbose()); 69 70 if (dump_stack_arch_desc_str[0] != '\0') 71 printk("%sHardware name: %s\n", 72 log_lvl, dump_stack_arch_desc_str); 73 74 print_worker_info(log_lvl, current); 75 print_stop_info(log_lvl, current); 76 } 77 78 /** 79 * show_regs_print_info - print generic debug info for show_regs() 80 * @log_lvl: log level 81 * 82 * show_regs() implementations can use this function to print out generic 83 * debug information. 84 */ 85 void show_regs_print_info(const char *log_lvl) 86 { 87 dump_stack_print_info(log_lvl); 88 } 89 90 static void __dump_stack(const char *log_lvl) 91 { 92 dump_stack_print_info(log_lvl); 93 show_stack(NULL, NULL, log_lvl); 94 } 95 96 /** 97 * dump_stack_lvl - dump the current task information and its stack trace 98 * @log_lvl: log level 99 * 100 * Architectures can override this implementation by implementing its own. 101 */ 102 asmlinkage __visible void dump_stack_lvl(const char *log_lvl) 103 { 104 bool in_panic = this_cpu_in_panic(); 105 unsigned long flags; 106 107 /* 108 * Permit this cpu to perform nested stack dumps while serialising 109 * against other CPUs, unless this CPU is in panic. 110 * 111 * When in panic, non-panic CPUs are not permitted to store new 112 * printk messages so there is no need to synchronize the output. 113 * This avoids potential deadlock in panic() if another CPU is 114 * holding and unable to release the printk_cpu_sync. 115 */ 116 if (!in_panic) 117 printk_cpu_sync_get_irqsave(flags); 118 119 __dump_stack(log_lvl); 120 121 if (!in_panic) 122 printk_cpu_sync_put_irqrestore(flags); 123 } 124 EXPORT_SYMBOL(dump_stack_lvl); 125 126 asmlinkage __visible void dump_stack(void) 127 { 128 dump_stack_lvl(KERN_DEFAULT); 129 } 130 EXPORT_SYMBOL(dump_stack); 131