void machine_power_off(void) { if (!in_interrupt() || oops_in_progress) /* * Only unblank the console if we are called in enabled * context or a bust_spinlocks cleared the way for us. */ console_unblank(); _machine_power_off(); }
void machine_restart(char *command) { if ((!in_interrupt() && !in_atomic()) || oops_in_progress) /* * Only unblank the console if we are called in enabled * context or a bust_spinlocks cleared the way for us. */ console_unblank(); _machine_restart(command); }
void __attribute__((weak)) bust_spinlocks(int yes) { if (yes) { ++oops_in_progress; } else { #ifdef CONFIG_VT unblank_screen(); #endif console_unblank(); if (--oops_in_progress == 0) wake_up_klogd(); } }
void bust_spinlocks(int yes) { if (yes) { oops_in_progress = 1; } else { int loglevel_save = console_loglevel; console_unblank(); oops_in_progress = 0; console_loglevel = 15; printk(" "); console_loglevel = loglevel_save; } }
/* * Unlock any spinlocks which will prevent us from getting the * message out. */ void bust_spinlocks(int yes) { if (yes) { oops_in_progress = 1; } else { int loglevel_save = console_loglevel; console_unblank(); oops_in_progress = 0; /* * OK, the message is on the console. Now we call printk() * without oops_in_progress set so that printk will give klogd * a poke. Hold onto your hats... */ console_loglevel = 15; printk(" "); console_loglevel = loglevel_save; } }
/** * panic - halt the system * @fmt: The text string to print * * Display a message, then perform cleanups. * * This function never returns. */ void panic(const char *fmt, ...) { static char buf[1024]; va_list args; long i, i_next = 0, len; int state = 0; int old_cpu, this_cpu; bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; /* * 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 setting panic_cpu) 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(). * * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which * comes here, so go ahead. * `old_cpu == this_cpu' means we came from nmi_panic() which sets * panic_cpu to this CPU. In this case, this is also the 1st CPU. */ this_cpu = raw_smp_processor_id(); old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) panic_smp_self_stop(); console_verbose(); bust_spinlocks(1); va_start(args, fmt); len = vscnprintf(buf, sizeof(buf), fmt, args); va_end(args); if (len && buf[len - 1] == '\n') buf[len - 1] = '\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. * If we want to run this after calling panic_notifiers, pass * the "crash_kexec_post_notifiers" option to the kernel. * * Bypass the panic_cpu check and call __crash_kexec directly. */ if (!_crash_kexec_post_notifiers) { printk_safe_flush_on_panic(); __crash_kexec(NULL); /* * 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(); } else { /* * If we want to do crash dump after notifier calls and * kmsg_dump, we will need architecture dependent extra * works in addition to stopping other CPUs. */ crash_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); /* Call flush even twice. It tries harder with a single online CPU */ printk_safe_flush_on_panic(); 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. * * Bypass the panic_cpu check and call __crash_kexec directly. */ if (_crash_kexec_post_notifiers) __crash_kexec(NULL); #ifdef CONFIG_VT unblank_screen(); #endif console_unblank(); /* * We may have ended up stopping the CPU holding the lock (in * smp_send_stop()) while still having some valuable data in the console * buffer. Try to acquire the lock then release it regardless of the * result. The release will also print the buffers out. Locks debug * should be disabled to avoid reporting bad unlock balance when * panic() is not being callled from OOPS. */ debug_locks_off(); console_flush_on_panic(); panic_print_sys_info(); 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. */ pr_emerg("Rebooting in %d seconds..\n", panic_timeout); for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { touch_nmi_watchdog(); if (i >= i_next) { i += panic_blink(state ^= 1); i_next = i + 3600 / PANIC_BLINK_SPD; } 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 * 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; pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" "twice on console 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 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); local_irq_enable(); for (i = 0; ; i += PANIC_TIMER_STEP) { touch_softlockup_watchdog(); if (i >= i_next) { i += panic_blink(state ^= 1); i_next = i + 3600 / PANIC_BLINK_SPD; } mdelay(PANIC_TIMER_STEP); } }