diff options
Diffstat (limited to 'kernel/panic.c')
| -rw-r--r-- | kernel/panic.c | 138 |
1 files changed, 103 insertions, 35 deletions
diff --git a/kernel/panic.c b/kernel/panic.c index 4c13b1a88eb..62e16cef9cc 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -15,6 +15,7 @@ #include <linux/notifier.h> #include <linux/module.h> #include <linux/random.h> +#include <linux/ftrace.h> #include <linux/reboot.h> #include <linux/delay.h> #include <linux/kexec.h> @@ -22,18 +23,19 @@ #include <linux/sysrq.h> #include <linux/init.h> #include <linux/nmi.h> -#include <linux/dmi.h> #define PANIC_TIMER_STEP 100 #define PANIC_BLINK_SPD 18 -int panic_on_oops; +int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; static unsigned long tainted_mask; static int pause_on_oops; static int pause_on_oops_flag; static DEFINE_SPINLOCK(pause_on_oops_lock); +static bool crash_kexec_post_notifiers; -int panic_timeout; +int panic_timeout = CONFIG_PANIC_TIMEOUT; +EXPORT_SYMBOL_GPL(panic_timeout); ATOMIC_NOTIFIER_HEAD(panic_notifier_list); @@ -48,6 +50,15 @@ static long no_blink(int state) long (*panic_blink)(int state); EXPORT_SYMBOL(panic_blink); +/* + * Stop ourself in panic -- architecture code may override this + */ +void __weak panic_smp_self_stop(void) +{ + while (1) + cpu_relax(); +} + /** * panic - halt the system * @fmt: The text string to print @@ -56,38 +67,57 @@ EXPORT_SYMBOL(panic_blink); * * This function never returns. */ -NORET_TYPE void panic(const char * fmt, ...) +void panic(const char *fmt, ...) { + static DEFINE_SPINLOCK(panic_lock); static char buf[1024]; va_list args; long i, i_next = 0; int state = 0; /* + * Disable local interrupts. This will prevent panic_smp_self_stop + * from deadlocking the first cpu that invokes the panic, since + * there is nothing to prevent an interrupt handler (that runs + * after the panic_lock is acquired) from invoking panic again. + */ + local_irq_disable(); + + /* * 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... + * + * Only one CPU is allowed to execute the panic code from here. For + * multiple parallel invocations of panic, all other CPUs either + * stop themself or will wait until they are stopped by the 1st CPU + * with smp_send_stop(). */ - preempt_disable(); + if (!spin_trylock(&panic_lock)) + panic_smp_self_stop(); 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); + pr_emerg("Kernel panic - not syncing: %s\n", buf); #ifdef CONFIG_DEBUG_BUGVERBOSE - dump_stack(); + /* + * Avoid nested stack-dumping if a panic occurs during oops processing + */ + if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) + 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? + * If we want to run this after calling panic_notifiers, pass + * the "crash_kexec_post_notifiers" option to the kernel. */ - crash_kexec(NULL); - - kmsg_dump(KMSG_DUMP_PANIC); + if (!crash_kexec_post_notifiers) + crash_kexec(NULL); /* * Note smp_send_stop is the usual smp shutdown function, which @@ -96,8 +126,23 @@ NORET_TYPE void panic(const char * fmt, ...) */ smp_send_stop(); + /* + * Run any panic handlers, including those that might need to + * add information to the kmsg dump output. + */ atomic_notifier_call_chain(&panic_notifier_list, 0, buf); + kmsg_dump(KMSG_DUMP_PANIC); + + /* + * If you doubt kdump always works fine in any situation, + * "crash_kexec_post_notifiers" offers you a chance to run + * panic_notifiers and dumping kmsg before kdump. + * Note: since some panic_notifiers can make crashed kernel + * more unstable, it can increase risks of the kdump failure too. + */ + crash_kexec(NULL); + bust_spinlocks(0); if (!panic_blink) @@ -108,7 +153,7 @@ NORET_TYPE void panic(const char * fmt, ...) * 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); + pr_emerg("Rebooting in %d seconds..", panic_timeout); for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { touch_nmi_watchdog(); @@ -118,6 +163,8 @@ NORET_TYPE void panic(const char * fmt, ...) } mdelay(PANIC_TIMER_STEP); } + } + if (panic_timeout != 0) { /* * This will not be a clean reboot, with everything * shutting down. But if there is a chance of @@ -130,7 +177,7 @@ NORET_TYPE void panic(const char * fmt, ...) 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"); + pr_emerg("Press Stop-A (L1-A) to return to the boot prom\n"); } #endif #if defined(CONFIG_S390) @@ -141,6 +188,7 @@ NORET_TYPE void panic(const char * fmt, ...) disabled_wait(caller); } #endif + pr_emerg("---[ end Kernel panic - not syncing: %s\n", buf); local_irq_enable(); for (i = 0; ; i += PANIC_TIMER_STEP) { touch_softlockup_watchdog(); @@ -164,7 +212,7 @@ struct tnt { static const struct tnt tnts[] = { { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, { TAINT_FORCED_MODULE, 'F', ' ' }, - { TAINT_UNSAFE_SMP, 'S', ' ' }, + { TAINT_CPU_OUT_OF_SPEC, 'S', ' ' }, { TAINT_FORCED_RMMOD, 'R', ' ' }, { TAINT_MACHINE_CHECK, 'M', ' ' }, { TAINT_BAD_PAGE, 'B', ' ' }, @@ -174,6 +222,8 @@ static const struct tnt tnts[] = { { TAINT_WARN, 'W', ' ' }, { TAINT_CRAP, 'C', ' ' }, { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' }, + { TAINT_OOT_MODULE, 'O', ' ' }, + { TAINT_UNSIGNED_MODULE, 'E', ' ' }, }; /** @@ -191,12 +241,14 @@ static const struct tnt tnts[] = { * 'W' - Taint on warning. * 'C' - modules from drivers/staging are loaded. * 'I' - Working around severe firmware bug. + * 'O' - Out-of-tree module has been loaded. + * 'E' - Unsigned module has been loaded. * * 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]; + static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ")]; if (tainted_mask) { char *s; @@ -226,17 +278,18 @@ unsigned long get_taint(void) return tainted_mask; } -void add_taint(unsigned flag) +/** + * add_taint: add a taint flag if not already set. + * @flag: one of the TAINT_* constants. + * @lockdep_ok: whether lock debugging is still OK. + * + * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for + * some notewortht-but-not-corrupting cases, it can be set to true. + */ +void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) { - /* - * 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"); + if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) + pr_warn("Disabling lock debugging due to kernel taint\n"); set_bit(flag, &tainted_mask); } @@ -341,8 +394,7 @@ late_initcall(init_oops_id); void print_oops_end_marker(void) { init_oops_id(); - printk(KERN_WARNING "---[ end trace %016llx ]---\n", - (unsigned long long)oops_id); + pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id); } /* @@ -365,13 +417,11 @@ struct slowpath_args { static void warn_slowpath_common(const char *file, int line, void *caller, unsigned taint, struct slowpath_args *args) { - const char *board; + disable_trace_on_warning(); - 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); + pr_warn("------------[ cut here ]------------\n"); + pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS()\n", + raw_smp_processor_id(), current->pid, file, line, caller); if (args) vprintk(args->fmt, args->args); @@ -379,7 +429,8 @@ static void warn_slowpath_common(const char *file, int line, void *caller, print_modules(); dump_stack(); print_oops_end_marker(); - add_taint(taint); + /* Just a warning, don't kill lockdep. */ + add_taint(taint, LOCKDEP_STILL_OK); } void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) @@ -421,7 +472,7 @@ EXPORT_SYMBOL(warn_slowpath_null); * Called when gcc's -fstack-protector feature is used, and * gcc detects corruption of the on-stack canary value */ -void __stack_chk_fail(void) +__visible void __stack_chk_fail(void) { panic("stack-protector: Kernel stack is corrupted in: %p\n", __builtin_return_address(0)); @@ -432,3 +483,20 @@ EXPORT_SYMBOL(__stack_chk_fail); core_param(panic, panic_timeout, int, 0644); core_param(pause_on_oops, pause_on_oops, int, 0644); + +static int __init setup_crash_kexec_post_notifiers(char *s) +{ + crash_kexec_post_notifiers = true; + return 0; +} +early_param("crash_kexec_post_notifiers", setup_crash_kexec_post_notifiers); + +static int __init oops_setup(char *s) +{ + if (!s) + return -EINVAL; + if (!strcmp(s, "panic")) + panic_on_oops = 1; + return 0; +} +early_param("oops", oops_setup); |