diff options
Diffstat (limited to 'kernel/panic.c')
| -rw-r--r-- | kernel/panic.c | 338 |
1 files changed, 235 insertions, 103 deletions
diff --git a/kernel/panic.c b/kernel/panic.c index 2a2ff36ff44..62e16cef9cc 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -8,42 +8,57 @@ * 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/sched.h> -#include <linux/delay.h> +#include <linux/random.h> +#include <linux/ftrace.h> #include <linux/reboot.h> -#include <linux/notifier.h> -#include <linux/init.h> +#include <linux/delay.h> +#include <linux/kexec.h> +#include <linux/sched.h> #include <linux/sysrq.h> -#include <linux/interrupt.h> +#include <linux/init.h> #include <linux/nmi.h> -#include <linux/kexec.h> -#include <linux/debug_locks.h> -#include <linux/random.h> -#include <linux/kallsyms.h> -#include <linux/dmi.h> -int panic_on_oops; +#define PANIC_TIMER_STEP 100 +#define PANIC_BLINK_SPD 18 + +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); EXPORT_SYMBOL(panic_notifier_list); -static long no_blink(long time) +static long no_blink(int state) { return 0; } /* Returns how long it waited in ms */ -long (*panic_blink)(long time); +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 @@ -52,66 +67,108 @@ EXPORT_SYMBOL(panic_blink); * * This function never returns. */ - -NORET_TYPE void panic(const char * fmt, ...) +void panic(const char *fmt, ...) { - long i; + static DEFINE_SPINLOCK(panic_lock); static char buf[1024]; va_list args; -#if defined(CONFIG_S390) - unsigned long caller = (unsigned long) __builtin_return_address(0); -#endif + long i, i_next = 0; + int state = 0; /* - * It's possible to come here directly from a panic-assertion and not - * have preempt disabled. Some functions called from here want + * 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); - bust_spinlocks(0); + pr_emerg("Kernel panic - not syncing: %s\n", buf); +#ifdef CONFIG_DEBUG_BUGVERBOSE + /* + * 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); + if (!crash_kexec_post_notifiers) + crash_kexec(NULL); -#ifdef CONFIG_SMP /* * 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(); -#endif + /* + * 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) panic_blink = no_blink; 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*1000; ) { + * Delay timeout seconds before rebooting the machine. + * We can't use the "normal" timers since we just panicked. + */ + pr_emerg("Rebooting in %d seconds..", panic_timeout); + + for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { touch_nmi_watchdog(); - i += panic_blink(i); - mdelay(1); - i++; + if (i >= i_next) { + i += panic_blink(state ^= 1); + i_next = i + 3600 / PANIC_BLINK_SPD; + } + mdelay(PANIC_TIMER_STEP); } - /* 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. + } + if (panic_timeout != 0) { + /* + * 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(); } @@ -120,18 +177,26 @@ 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) - disabled_wait(caller); + { + unsigned long caller; + + caller = (unsigned long)__builtin_return_address(0); + disabled_wait(caller); + } #endif + pr_emerg("---[ end Kernel panic - not syncing: %s\n", buf); local_irq_enable(); - for (i = 0;;) { + for (i = 0; ; i += PANIC_TIMER_STEP) { touch_softlockup_watchdog(); - i += panic_blink(i); - mdelay(1); - i++; + if (i >= i_next) { + i += panic_blink(state ^= 1); + i_next = i + 3600 / PANIC_BLINK_SPD; + } + mdelay(PANIC_TIMER_STEP); } } @@ -139,23 +204,26 @@ EXPORT_SYMBOL(panic); struct tnt { - u8 bit; - char true; - char false; + 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_PROPRIETARY_MODULE, 'P', 'G' }, + { TAINT_FORCED_MODULE, 'F', ' ' }, + { TAINT_CPU_OUT_OF_SPEC, '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', ' ' }, + { TAINT_OOT_MODULE, 'O', ' ' }, + { TAINT_UNSIGNED_MODULE, 'E', ' ' }, }; /** @@ -172,12 +240,15 @@ static const struct tnt tnts[] = { * 'A' - ACPI table overridden. * '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_taint(). + * 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; @@ -192,7 +263,8 @@ const char *print_tainted(void) *s = 0; } else snprintf(buf, sizeof(buf), "Not tainted"); - return(buf); + + return buf; } int test_taint(unsigned flag) @@ -206,9 +278,19 @@ 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) { - debug_locks = 0; /* can't trust the integrity of the kernel anymore */ + if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) + pr_warn("Disabling lock debugging due to kernel taint\n"); + set_bit(flag, &tainted_mask); } EXPORT_SYMBOL(add_taint); @@ -263,8 +345,8 @@ static void do_oops_enter_exit(void) } /* - * Return true if the calling CPU is allowed to print oops-related info. This - * is a bit racy.. + * Return true if the calling CPU is allowed to print oops-related info. + * This is a bit racy.. */ int oops_may_print(void) { @@ -273,20 +355,23 @@ int oops_may_print(void) /* * 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. + * 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. + * 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(). + * 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) { - debug_locks_off(); /* can't trust the integrity of the kernel anymore */ + tracing_off(); + /* can't trust the integrity of the kernel anymore: */ + debug_locks_off(); do_oops_enter_exit(); } @@ -306,11 +391,10 @@ static int init_oops_id(void) } late_initcall(init_oops_id); -static void print_oops_end_marker(void) +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); } /* @@ -321,50 +405,98 @@ void oops_exit(void) { do_oops_enter_exit(); print_oops_end_marker(); + kmsg_dump(KMSG_DUMP_OOPS); } #ifdef WANT_WARN_ON_SLOWPATH -void warn_slowpath(const char *file, int line, const char *fmt, ...) -{ +struct slowpath_args { + const char *fmt; va_list args; - char function[KSYM_SYMBOL_LEN]; - unsigned long caller = (unsigned long)__builtin_return_address(0); - const char *board; - - sprint_symbol(function, caller); - - printk(KERN_WARNING "------------[ cut here ]------------\n"); - printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, - line, function); - board = dmi_get_system_info(DMI_PRODUCT_NAME); - if (board) - printk(KERN_WARNING "Hardware name: %s\n", board); - - if (fmt) { - va_start(args, fmt); - vprintk(fmt, args); - va_end(args); - } +}; + +static void warn_slowpath_common(const char *file, int line, void *caller, + unsigned taint, struct slowpath_args *args) +{ + disable_trace_on_warning(); + + 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); print_modules(); dump_stack(); print_oops_end_marker(); - add_taint(TAINT_WARN); + /* 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, ...) +{ + 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); +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) +__visible void __stack_chk_fail(void) { - panic("stack-protector: Kernel stack is corrupted"); + 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); + +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); |