/* * 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/ftrace.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/console.h>#include <linux/bug.h> #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);bool crash_kexec_post_notifiers;int panic_on_warn __read_mostly; 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(int state){ return 0;} /* Returns how long it waited in ms */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();} /* * Stop ourselves in NMI context if another CPU has already panicked. Arch code * may override this to prepare for crash dumping, e.g. save regs info. */void __weak nmi_panic_self_stop(struct pt_regs *regs){ panic_smp_self_stop();} /* * Stop other CPUs in panic. Architecture dependent code may override this * with more suitable version. For example, if the architecture supports * crash dump, it should save registers of each stopped CPU and disable * per-CPU features such as virtualization extensions. */void __weak crash_smp_send_stop(void){ static int cpus_stopped; /* * This function can be called twice in panic path, but obviously * we execute this only once. */ if (cpus_stopped) return; /* * 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(); cpus_stopped = 1;} atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); /* * A variant of panic() called from NMI context. We return if we've already * panicked on this CPU. If another CPU already panicked, loop in * nmi_panic_self_stop() which can provide architecture dependent code such * as saving register state for crash dump. */void nmi_panic(struct pt_regs *regs, const char *msg){ int old_cpu, cpu; cpu = raw_smp_processor_id(); old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); if (old_cpu == PANIC_CPU_INVALID) panic("%s", msg); else if (old_cpu != cpu) nmi_panic_self_stop(regs);}EXPORT_SYMBOL(nmi_panic); /** * 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; 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); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); 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_nmi_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_nmi_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); bust_spinlocks(0); /* * 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(); 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..", 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) 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); }} EXPORT_SYMBOL(panic); /* * TAINT_FORCED_RMMOD could be a per-module flag but the module * is being removed anyway. */const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { { 'P', 'G', true }, /* TAINT_PROPRIETARY_MODULE */ { 'F', ' ', true }, /* TAINT_FORCED_MODULE */ { 'S', ' ', false }, /* TAINT_CPU_OUT_OF_SPEC */ { 'R', ' ', false }, /* TAINT_FORCED_RMMOD */ { 'M', ' ', false }, /* TAINT_MACHINE_CHECK */ { 'B', ' ', false }, /* TAINT_BAD_PAGE */ { 'U', ' ', false }, /* TAINT_USER */ { 'D', ' ', false }, /* TAINT_DIE */ { 'A', ' ', false }, /* TAINT_OVERRIDDEN_ACPI_TABLE */ { 'W', ' ', false }, /* TAINT_WARN */ { 'C', ' ', true }, /* TAINT_CRAP */ { 'I', ' ', false }, /* TAINT_FIRMWARE_WORKAROUND */ { 'O', ' ', true }, /* TAINT_OOT_MODULE */ { 'E', ' ', true }, /* TAINT_UNSIGNED_MODULE */ { 'L', ' ', false }, /* TAINT_SOFTLOCKUP */ { 'K', ' ', true }, /* TAINT_LIVEPATCH */}; /** * 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. * 'O' - Out-of-tree module has been loaded. * 'E' - Unsigned module has been loaded. * 'L' - A soft lockup has previously occurred. * 'K' - Kernel has been live patched. * * The string is overwritten by the next call to print_tainted(). */const char *print_tainted(void){ static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; if (tainted_mask) { char *s; int i; s = buf + sprintf(buf, "Tainted: "); for (i = 0; i < TAINT_FLAGS_COUNT; i++) { const struct taint_flag *t = &taint_flags[i]; *s++ = test_bit(i, &tainted_mask) ? t->c_true : t->c_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;} /** * 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){ 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); 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); void print_oops_end_marker(void){ init_oops_id(); pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);} /* * Called when the architecture exits its oops handler, after printing * everything. */Lines 1–500 of 615. Load more
/* * 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/ftrace.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/console.h> #include <linux/bug.h> #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); bool crash_kexec_post_notifiers; int panic_on_warn __read_mostly; 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(int state) { return 0; } /* Returns how long it waited in ms */ 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(); } /* * Stop ourselves in NMI context if another CPU has already panicked. Arch code * may override this to prepare for crash dumping, e.g. save regs info. */ void __weak nmi_panic_self_stop(struct pt_regs *regs) { panic_smp_self_stop(); } /* * Stop other CPUs in panic. Architecture dependent code may override this * with more suitable version. For example, if the architecture supports * crash dump, it should save registers of each stopped CPU and disable * per-CPU features such as virtualization extensions. */ void __weak crash_smp_send_stop(void) { static int cpus_stopped; /* * This function can be called twice in panic path, but obviously * we execute this only once. */ if (cpus_stopped) return; /* * 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(); cpus_stopped = 1; } atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); /* * A variant of panic() called from NMI context. We return if we've already * panicked on this CPU. If another CPU already panicked, loop in * nmi_panic_self_stop() which can provide architecture dependent code such * as saving register state for crash dump. */ void nmi_panic(struct pt_regs *regs, const char *msg) { int old_cpu, cpu; cpu = raw_smp_processor_id(); old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); if (old_cpu == PANIC_CPU_INVALID) panic("%s", msg); else if (old_cpu != cpu) nmi_panic_self_stop(regs); } EXPORT_SYMBOL(nmi_panic); /** * 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; 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); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); 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_nmi_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_nmi_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); bust_spinlocks(0); /* * 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(); 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..", 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) 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); } } EXPORT_SYMBOL(panic); /* * TAINT_FORCED_RMMOD could be a per-module flag but the module * is being removed anyway. */ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { { 'P', 'G', true }, /* TAINT_PROPRIETARY_MODULE */ { 'F', ' ', true }, /* TAINT_FORCED_MODULE */ { 'S', ' ', false }, /* TAINT_CPU_OUT_OF_SPEC */ { 'R', ' ', false }, /* TAINT_FORCED_RMMOD */ { 'M', ' ', false }, /* TAINT_MACHINE_CHECK */ { 'B', ' ', false }, /* TAINT_BAD_PAGE */ { 'U', ' ', false }, /* TAINT_USER */ { 'D', ' ', false }, /* TAINT_DIE */ { 'A', ' ', false }, /* TAINT_OVERRIDDEN_ACPI_TABLE */ { 'W', ' ', false }, /* TAINT_WARN */ { 'C', ' ', true }, /* TAINT_CRAP */ { 'I', ' ', false }, /* TAINT_FIRMWARE_WORKAROUND */ { 'O', ' ', true }, /* TAINT_OOT_MODULE */ { 'E', ' ', true }, /* TAINT_UNSIGNED_MODULE */ { 'L', ' ', false }, /* TAINT_SOFTLOCKUP */ { 'K', ' ', true }, /* TAINT_LIVEPATCH */ }; /** * 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. * 'O' - Out-of-tree module has been loaded. * 'E' - Unsigned module has been loaded. * 'L' - A soft lockup has previously occurred. * 'K' - Kernel has been live patched. * * The string is overwritten by the next call to print_tainted(). */ const char *print_tainted(void) { static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; if (tainted_mask) { char *s; int i; s = buf + sprintf(buf, "Tainted: "); for (i = 0; i < TAINT_FLAGS_COUNT; i++) { const struct taint_flag *t = &taint_flags[i]; *s++ = test_bit(i, &tainted_mask) ? t->c_true : t->c_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; } /** * 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) { 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); 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); void print_oops_end_marker(void) { init_oops_id(); pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id); } /* * Called when the architecture exits its oops handler, after printing * everything. */