| /* |
| * linux/kernel/panic.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| /* |
| * This function is used through-out the kernel (including mm and fs) |
| * to indicate a major problem. |
| */ |
| #include <linux/debug_locks.h> |
| #include <linux/interrupt.h> |
| #include <linux/kmsg_dump.h> |
| #include <linux/kallsyms.h> |
| #include <linux/notifier.h> |
| #include <linux/module.h> |
| #include <linux/random.h> |
| #include <linux/reboot.h> |
| #include <linux/delay.h> |
| #include <linux/kexec.h> |
| #include <linux/sched.h> |
| #include <linux/sysrq.h> |
| #include <linux/init.h> |
| #include <linux/nmi.h> |
| #include <linux/dmi.h> |
| |
| int panic_on_oops; |
| static unsigned long tainted_mask; |
| static int pause_on_oops; |
| static int pause_on_oops_flag; |
| static DEFINE_SPINLOCK(pause_on_oops_lock); |
| |
| int panic_timeout; |
| |
| ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
| |
| EXPORT_SYMBOL(panic_notifier_list); |
| |
| /* Returns how long it waited in ms */ |
| long (*panic_blink)(long time); |
| EXPORT_SYMBOL(panic_blink); |
| |
| static void panic_blink_one_second(void) |
| { |
| static long i = 0, end; |
| |
| if (panic_blink) { |
| end = i + MSEC_PER_SEC; |
| |
| while (i < end) { |
| i += panic_blink(i); |
| mdelay(1); |
| i++; |
| } |
| } else { |
| /* |
| * When running under a hypervisor a small mdelay may get |
| * rounded up to the hypervisor timeslice. For example, with |
| * a 1ms in 10ms hypervisor timeslice we might inflate a |
| * mdelay(1) loop by 10x. |
| * |
| * If we have nothing to blink, spin on 1 second calls to |
| * mdelay to avoid this. |
| */ |
| mdelay(MSEC_PER_SEC); |
| } |
| } |
| |
| /** |
| * panic - halt the system |
| * @fmt: The text string to print |
| * |
| * Display a message, then perform cleanups. |
| * |
| * This function never returns. |
| */ |
| NORET_TYPE void panic(const char * fmt, ...) |
| { |
| static char buf[1024]; |
| va_list args; |
| long i; |
| |
| /* |
| * It's possible to come here directly from a panic-assertion and |
| * not have preempt disabled. Some functions called from here want |
| * preempt to be disabled. No point enabling it later though... |
| */ |
| preempt_disable(); |
| |
| console_verbose(); |
| bust_spinlocks(1); |
| va_start(args, fmt); |
| vsnprintf(buf, sizeof(buf), fmt, args); |
| va_end(args); |
| printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); |
| #ifdef CONFIG_DEBUG_BUGVERBOSE |
| dump_stack(); |
| #endif |
| |
| /* |
| * If we have crashed and we have a crash kernel loaded let it handle |
| * everything else. |
| * Do we want to call this before we try to display a message? |
| */ |
| crash_kexec(NULL); |
| |
| kmsg_dump(KMSG_DUMP_PANIC); |
| |
| /* |
| * Note smp_send_stop is the usual smp shutdown function, which |
| * unfortunately means it may not be hardened to work in a panic |
| * situation. |
| */ |
| smp_send_stop(); |
| |
| atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
| |
| bust_spinlocks(0); |
| |
| if (panic_timeout > 0) { |
| /* |
| * Delay timeout seconds before rebooting the machine. |
| * We can't use the "normal" timers since we just panicked. |
| */ |
| printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout); |
| |
| for (i = 0; i < panic_timeout; i++) { |
| touch_nmi_watchdog(); |
| panic_blink_one_second(); |
| } |
| /* |
| * This will not be a clean reboot, with everything |
| * shutting down. But if there is a chance of |
| * rebooting the system it will be rebooted. |
| */ |
| emergency_restart(); |
| } |
| #ifdef __sparc__ |
| { |
| extern int stop_a_enabled; |
| /* Make sure the user can actually press Stop-A (L1-A) */ |
| stop_a_enabled = 1; |
| printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
| } |
| #endif |
| #if defined(CONFIG_S390) |
| { |
| unsigned long caller; |
| |
| caller = (unsigned long)__builtin_return_address(0); |
| disabled_wait(caller); |
| } |
| #endif |
| local_irq_enable(); |
| while (1) { |
| touch_softlockup_watchdog(); |
| panic_blink_one_second(); |
| } |
| } |
| |
| EXPORT_SYMBOL(panic); |
| |
| |
| struct tnt { |
| u8 bit; |
| char true; |
| char false; |
| }; |
| |
| static const struct tnt tnts[] = { |
| { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, |
| { TAINT_FORCED_MODULE, 'F', ' ' }, |
| { TAINT_UNSAFE_SMP, 'S', ' ' }, |
| { TAINT_FORCED_RMMOD, 'R', ' ' }, |
| { TAINT_MACHINE_CHECK, 'M', ' ' }, |
| { TAINT_BAD_PAGE, 'B', ' ' }, |
| { TAINT_USER, 'U', ' ' }, |
| { TAINT_DIE, 'D', ' ' }, |
| { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, |
| { TAINT_WARN, 'W', ' ' }, |
| { TAINT_CRAP, 'C', ' ' }, |
| { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' }, |
| }; |
| |
| /** |
| * print_tainted - return a string to represent the kernel taint state. |
| * |
| * 'P' - Proprietary module has been loaded. |
| * 'F' - Module has been forcibly loaded. |
| * 'S' - SMP with CPUs not designed for SMP. |
| * 'R' - User forced a module unload. |
| * 'M' - System experienced a machine check exception. |
| * 'B' - System has hit bad_page. |
| * 'U' - Userspace-defined naughtiness. |
| * 'D' - Kernel has oopsed before |
| * 'A' - ACPI table overridden. |
| * 'W' - Taint on warning. |
| * 'C' - modules from drivers/staging are loaded. |
| * 'I' - Working around severe firmware bug. |
| * |
| * The string is overwritten by the next call to print_tainted(). |
| */ |
| const char *print_tainted(void) |
| { |
| static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
| |
| if (tainted_mask) { |
| char *s; |
| int i; |
| |
| s = buf + sprintf(buf, "Tainted: "); |
| for (i = 0; i < ARRAY_SIZE(tnts); i++) { |
| const struct tnt *t = &tnts[i]; |
| *s++ = test_bit(t->bit, &tainted_mask) ? |
| t->true : t->false; |
| } |
| *s = 0; |
| } else |
| snprintf(buf, sizeof(buf), "Not tainted"); |
| |
| return buf; |
| } |
| |
| int test_taint(unsigned flag) |
| { |
| return test_bit(flag, &tainted_mask); |
| } |
| EXPORT_SYMBOL(test_taint); |
| |
| unsigned long get_taint(void) |
| { |
| return tainted_mask; |
| } |
| |
| void add_taint(unsigned flag) |
| { |
| /* |
| * Can't trust the integrity of the kernel anymore. |
| * We don't call directly debug_locks_off() because the issue |
| * is not necessarily serious enough to set oops_in_progress to 1 |
| * Also we want to keep up lockdep for staging development and |
| * post-warning case. |
| */ |
| if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off()) |
| printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n"); |
| |
| set_bit(flag, &tainted_mask); |
| } |
| EXPORT_SYMBOL(add_taint); |
| |
| static void spin_msec(int msecs) |
| { |
| int i; |
| |
| for (i = 0; i < msecs; i++) { |
| touch_nmi_watchdog(); |
| mdelay(1); |
| } |
| } |
| |
| /* |
| * It just happens that oops_enter() and oops_exit() are identically |
| * implemented... |
| */ |
| static void do_oops_enter_exit(void) |
| { |
| unsigned long flags; |
| static int spin_counter; |
| |
| if (!pause_on_oops) |
| return; |
| |
| spin_lock_irqsave(&pause_on_oops_lock, flags); |
| if (pause_on_oops_flag == 0) { |
| /* This CPU may now print the oops message */ |
| pause_on_oops_flag = 1; |
| } else { |
| /* We need to stall this CPU */ |
| if (!spin_counter) { |
| /* This CPU gets to do the counting */ |
| spin_counter = pause_on_oops; |
| do { |
| spin_unlock(&pause_on_oops_lock); |
| spin_msec(MSEC_PER_SEC); |
| spin_lock(&pause_on_oops_lock); |
| } while (--spin_counter); |
| pause_on_oops_flag = 0; |
| } else { |
| /* This CPU waits for a different one */ |
| while (spin_counter) { |
| spin_unlock(&pause_on_oops_lock); |
| spin_msec(1); |
| spin_lock(&pause_on_oops_lock); |
| } |
| } |
| } |
| spin_unlock_irqrestore(&pause_on_oops_lock, flags); |
| } |
| |
| /* |
| * Return true if the calling CPU is allowed to print oops-related info. |
| * This is a bit racy.. |
| */ |
| int oops_may_print(void) |
| { |
| return pause_on_oops_flag == 0; |
| } |
| |
| /* |
| * Called when the architecture enters its oops handler, before it prints |
| * anything. If this is the first CPU to oops, and it's oopsing the first |
| * time then let it proceed. |
| * |
| * This is all enabled by the pause_on_oops kernel boot option. We do all |
| * this to ensure that oopses don't scroll off the screen. It has the |
| * side-effect of preventing later-oopsing CPUs from mucking up the display, |
| * too. |
| * |
| * It turns out that the CPU which is allowed to print ends up pausing for |
| * the right duration, whereas all the other CPUs pause for twice as long: |
| * once in oops_enter(), once in oops_exit(). |
| */ |
| void oops_enter(void) |
| { |
| tracing_off(); |
| /* can't trust the integrity of the kernel anymore: */ |
| debug_locks_off(); |
| do_oops_enter_exit(); |
| } |
| |
| /* |
| * 64-bit random ID for oopses: |
| */ |
| static u64 oops_id; |
| |
| static int init_oops_id(void) |
| { |
| if (!oops_id) |
| get_random_bytes(&oops_id, sizeof(oops_id)); |
| else |
| oops_id++; |
| |
| return 0; |
| } |
| late_initcall(init_oops_id); |
| |
| static void print_oops_end_marker(void) |
| { |
| init_oops_id(); |
| printk(KERN_WARNING "---[ end trace %016llx ]---\n", |
| (unsigned long long)oops_id); |
| } |
| |
| /* |
| * Called when the architecture exits its oops handler, after printing |
| * everything. |
| */ |
| void oops_exit(void) |
| { |
| do_oops_enter_exit(); |
| print_oops_end_marker(); |
| kmsg_dump(KMSG_DUMP_OOPS); |
| } |
| |
| #ifdef WANT_WARN_ON_SLOWPATH |
| struct slowpath_args { |
| const char *fmt; |
| va_list args; |
| }; |
| |
| static void warn_slowpath_common(const char *file, int line, void *caller, |
| unsigned taint, struct slowpath_args *args) |
| { |
| const char *board; |
| |
| printk(KERN_WARNING "------------[ cut here ]------------\n"); |
| printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller); |
| board = dmi_get_system_info(DMI_PRODUCT_NAME); |
| if (board) |
| printk(KERN_WARNING "Hardware name: %s\n", board); |
| |
| if (args) |
| vprintk(args->fmt, args->args); |
| |
| print_modules(); |
| dump_stack(); |
| print_oops_end_marker(); |
| add_taint(taint); |
| } |
| |
| void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) |
| { |
| struct slowpath_args args; |
| |
| args.fmt = fmt; |
| va_start(args.args, fmt); |
| warn_slowpath_common(file, line, __builtin_return_address(0), |
| TAINT_WARN, &args); |
| va_end(args.args); |
| } |
| EXPORT_SYMBOL(warn_slowpath_fmt); |
| |
| void warn_slowpath_fmt_taint(const char *file, int line, |
| unsigned taint, const char *fmt, ...) |
| { |
| struct slowpath_args args; |
| |
| args.fmt = fmt; |
| va_start(args.args, fmt); |
| warn_slowpath_common(file, line, __builtin_return_address(0), |
| taint, &args); |
| va_end(args.args); |
| } |
| EXPORT_SYMBOL(warn_slowpath_fmt_taint); |
| |
| void warn_slowpath_null(const char *file, int line) |
| { |
| warn_slowpath_common(file, line, __builtin_return_address(0), |
| TAINT_WARN, NULL); |
| } |
| EXPORT_SYMBOL(warn_slowpath_null); |
| #endif |
| |
| #ifdef CONFIG_CC_STACKPROTECTOR |
| |
| /* |
| * Called when gcc's -fstack-protector feature is used, and |
| * gcc detects corruption of the on-stack canary value |
| */ |
| void __stack_chk_fail(void) |
| { |
| panic("stack-protector: Kernel stack is corrupted in: %p\n", |
| __builtin_return_address(0)); |
| } |
| EXPORT_SYMBOL(__stack_chk_fail); |
| |
| #endif |
| |
| core_param(panic, panic_timeout, int, 0644); |
| core_param(pause_on_oops, pause_on_oops, int, 0644); |