| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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/sched/debug.h> |
| #include <linux/interrupt.h> |
| #include <linux/kgdb.h> |
| #include <linux/kmsg_dump.h> |
| #include <linux/kallsyms.h> |
| #include <linux/notifier.h> |
| #include <linux/vt_kern.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/panic_notifier.h> |
| #include <linux/sched.h> |
| #include <linux/string_helpers.h> |
| #include <linux/sysrq.h> |
| #include <linux/init.h> |
| #include <linux/nmi.h> |
| #include <linux/console.h> |
| #include <linux/bug.h> |
| #include <linux/ratelimit.h> |
| #include <linux/debugfs.h> |
| #include <linux/sysfs.h> |
| #include <linux/context_tracking.h> |
| #include <linux/seq_buf.h> |
| #include <trace/events/error_report.h> |
| #include <asm/sections.h> |
| |
| #define PANIC_TIMER_STEP 100 |
| #define PANIC_BLINK_SPD 18 |
| |
| #ifdef CONFIG_SMP |
| /* |
| * Should we dump all CPUs backtraces in an oops event? |
| * Defaults to 0, can be changed via sysctl. |
| */ |
| static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; |
| #else |
| #define sysctl_oops_all_cpu_backtrace 0 |
| #endif /* CONFIG_SMP */ |
| |
| int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
| static unsigned long tainted_mask = |
| IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; |
| 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; |
| unsigned long panic_on_taint; |
| bool panic_on_taint_nousertaint = false; |
| static unsigned int warn_limit __read_mostly; |
| |
| int panic_timeout = CONFIG_PANIC_TIMEOUT; |
| EXPORT_SYMBOL_GPL(panic_timeout); |
| |
| #define PANIC_PRINT_TASK_INFO 0x00000001 |
| #define PANIC_PRINT_MEM_INFO 0x00000002 |
| #define PANIC_PRINT_TIMER_INFO 0x00000004 |
| #define PANIC_PRINT_LOCK_INFO 0x00000008 |
| #define PANIC_PRINT_FTRACE_INFO 0x00000010 |
| #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 |
| #define PANIC_PRINT_ALL_CPU_BT 0x00000040 |
| #define PANIC_PRINT_BLOCKED_TASKS 0x00000080 |
| unsigned long panic_print; |
| |
| ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
| |
| EXPORT_SYMBOL(panic_notifier_list); |
| |
| #ifdef CONFIG_SYSCTL |
| static struct ctl_table kern_panic_table[] = { |
| #ifdef CONFIG_SMP |
| { |
| .procname = "oops_all_cpu_backtrace", |
| .data = &sysctl_oops_all_cpu_backtrace, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = SYSCTL_ZERO, |
| .extra2 = SYSCTL_ONE, |
| }, |
| #endif |
| { |
| .procname = "warn_limit", |
| .data = &warn_limit, |
| .maxlen = sizeof(warn_limit), |
| .mode = 0644, |
| .proc_handler = proc_douintvec, |
| }, |
| }; |
| |
| static __init int kernel_panic_sysctls_init(void) |
| { |
| register_sysctl_init("kernel", kern_panic_table); |
| return 0; |
| } |
| late_initcall(kernel_panic_sysctls_init); |
| #endif |
| |
| static atomic_t warn_count = ATOMIC_INIT(0); |
| |
| #ifdef CONFIG_SYSFS |
| static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr, |
| char *page) |
| { |
| return sysfs_emit(page, "%d\n", atomic_read(&warn_count)); |
| } |
| |
| static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count); |
| |
| static __init int kernel_panic_sysfs_init(void) |
| { |
| sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL); |
| return 0; |
| } |
| late_initcall(kernel_panic_sysfs_init); |
| #endif |
| |
| 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 __noreturn 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 __noreturn 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, this_cpu; |
| |
| old_cpu = PANIC_CPU_INVALID; |
| this_cpu = raw_smp_processor_id(); |
| |
| /* atomic_try_cmpxchg updates old_cpu on failure */ |
| if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) |
| panic("%s", msg); |
| else if (old_cpu != this_cpu) |
| nmi_panic_self_stop(regs); |
| } |
| EXPORT_SYMBOL(nmi_panic); |
| |
| static void panic_print_sys_info(bool console_flush) |
| { |
| if (console_flush) { |
| if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) |
| console_flush_on_panic(CONSOLE_REPLAY_ALL); |
| return; |
| } |
| |
| if (panic_print & PANIC_PRINT_TASK_INFO) |
| show_state(); |
| |
| if (panic_print & PANIC_PRINT_MEM_INFO) |
| show_mem(); |
| |
| if (panic_print & PANIC_PRINT_TIMER_INFO) |
| sysrq_timer_list_show(); |
| |
| if (panic_print & PANIC_PRINT_LOCK_INFO) |
| debug_show_all_locks(); |
| |
| if (panic_print & PANIC_PRINT_FTRACE_INFO) |
| ftrace_dump(DUMP_ALL); |
| |
| if (panic_print & PANIC_PRINT_BLOCKED_TASKS) |
| show_state_filter(TASK_UNINTERRUPTIBLE); |
| } |
| |
| void check_panic_on_warn(const char *origin) |
| { |
| unsigned int limit; |
| |
| if (panic_on_warn) |
| panic("%s: panic_on_warn set ...\n", origin); |
| |
| limit = READ_ONCE(warn_limit); |
| if (atomic_inc_return(&warn_count) >= limit && limit) |
| panic("%s: system warned too often (kernel.warn_limit is %d)", |
| origin, limit); |
| } |
| |
| /* |
| * Helper that triggers the NMI backtrace (if set in panic_print) |
| * and then performs the secondary CPUs shutdown - we cannot have |
| * the NMI backtrace after the CPUs are off! |
| */ |
| static void panic_other_cpus_shutdown(bool crash_kexec) |
| { |
| if (panic_print & PANIC_PRINT_ALL_CPU_BT) |
| trigger_all_cpu_backtrace(); |
| |
| /* |
| * Note that smp_send_stop() is the usual SMP shutdown function, |
| * which unfortunately may not be hardened to work in a panic |
| * situation. If we want to do crash dump after notifier calls |
| * and kmsg_dump, we will need architecture dependent extra |
| * bits in addition to stopping other CPUs, hence we rely on |
| * crash_smp_send_stop() for that. |
| */ |
| if (!crash_kexec) |
| smp_send_stop(); |
| else |
| crash_smp_send_stop(); |
| } |
| |
| /** |
| * 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; |
| |
| if (panic_on_warn) { |
| /* |
| * This thread may hit another WARN() in the panic path. |
| * Resetting this prevents additional WARN() from panicking the |
| * system on this thread. Other threads are blocked by the |
| * panic_mutex in panic(). |
| */ |
| panic_on_warn = 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 setting panic_cpu) from invoking panic() again. |
| */ |
| local_irq_disable(); |
| preempt_disable_notrace(); |
| |
| /* |
| * 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(). |
| * |
| * cmpxchg success 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. |
| */ |
| old_cpu = PANIC_CPU_INVALID; |
| this_cpu = raw_smp_processor_id(); |
| |
| /* atomic_try_cmpxchg updates old_cpu on failure */ |
| if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) { |
| /* go ahead */ |
| } else if (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 kgdb is enabled, give it a chance to run before we stop all |
| * the other CPUs or else we won't be able to debug processes left |
| * running on them. |
| */ |
| kgdb_panic(buf); |
| |
| /* |
| * 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) |
| __crash_kexec(NULL); |
| |
| panic_other_cpus_shutdown(_crash_kexec_post_notifiers); |
| |
| /* |
| * 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); |
| |
| panic_print_sys_info(false); |
| |
| 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); |
| |
| 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(CONSOLE_FLUSH_PENDING); |
| |
| panic_print_sys_info(true); |
| |
| 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. |
| */ |
| if (panic_reboot_mode != REBOOT_UNDEFINED) |
| reboot_mode = panic_reboot_mode; |
| 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) |
| disabled_wait(); |
| #endif |
| pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); |
| |
| /* Do not scroll important messages printed above */ |
| suppress_printk = 1; |
| |
| /* |
| * The final messages may not have been printed if in a context that |
| * defers printing (such as NMI) and irq_work is not available. |
| * Explicitly flush the kernel log buffer one last time. |
| */ |
| console_flush_on_panic(CONSOLE_FLUSH_PENDING); |
| |
| 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); |
| |
| #define TAINT_FLAG(taint, _c_true, _c_false, _module) \ |
| [ TAINT_##taint ] = { \ |
| .c_true = _c_true, .c_false = _c_false, \ |
| .module = _module, \ |
| .desc = #taint, \ |
| } |
| |
| /* |
| * 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] = { |
| TAINT_FLAG(PROPRIETARY_MODULE, 'P', 'G', true), |
| TAINT_FLAG(FORCED_MODULE, 'F', ' ', true), |
| TAINT_FLAG(CPU_OUT_OF_SPEC, 'S', ' ', false), |
| TAINT_FLAG(FORCED_RMMOD, 'R', ' ', false), |
| TAINT_FLAG(MACHINE_CHECK, 'M', ' ', false), |
| TAINT_FLAG(BAD_PAGE, 'B', ' ', false), |
| TAINT_FLAG(USER, 'U', ' ', false), |
| TAINT_FLAG(DIE, 'D', ' ', false), |
| TAINT_FLAG(OVERRIDDEN_ACPI_TABLE, 'A', ' ', false), |
| TAINT_FLAG(WARN, 'W', ' ', false), |
| TAINT_FLAG(CRAP, 'C', ' ', true), |
| TAINT_FLAG(FIRMWARE_WORKAROUND, 'I', ' ', false), |
| TAINT_FLAG(OOT_MODULE, 'O', ' ', true), |
| TAINT_FLAG(UNSIGNED_MODULE, 'E', ' ', true), |
| TAINT_FLAG(SOFTLOCKUP, 'L', ' ', false), |
| TAINT_FLAG(LIVEPATCH, 'K', ' ', true), |
| TAINT_FLAG(AUX, 'X', ' ', true), |
| TAINT_FLAG(RANDSTRUCT, 'T', ' ', true), |
| TAINT_FLAG(TEST, 'N', ' ', true), |
| }; |
| |
| #undef TAINT_FLAG |
| |
| static void print_tainted_seq(struct seq_buf *s, bool verbose) |
| { |
| const char *sep = ""; |
| int i; |
| |
| if (!tainted_mask) { |
| seq_buf_puts(s, "Not tainted"); |
| return; |
| } |
| |
| seq_buf_printf(s, "Tainted: "); |
| for (i = 0; i < TAINT_FLAGS_COUNT; i++) { |
| const struct taint_flag *t = &taint_flags[i]; |
| bool is_set = test_bit(i, &tainted_mask); |
| char c = is_set ? t->c_true : t->c_false; |
| |
| if (verbose) { |
| if (is_set) { |
| seq_buf_printf(s, "%s[%c]=%s", sep, c, t->desc); |
| sep = ", "; |
| } |
| } else { |
| seq_buf_putc(s, c); |
| } |
| } |
| } |
| |
| static const char *_print_tainted(bool verbose) |
| { |
| /* FIXME: what should the size be? */ |
| static char buf[sizeof(taint_flags)]; |
| struct seq_buf s; |
| |
| BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); |
| |
| seq_buf_init(&s, buf, sizeof(buf)); |
| |
| print_tainted_seq(&s, verbose); |
| |
| return seq_buf_str(&s); |
| } |
| |
| /** |
| * print_tainted - return a string to represent the kernel taint state. |
| * |
| * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst |
| * |
| * The string is overwritten by the next call to print_tainted(), |
| * but is always NULL terminated. |
| */ |
| const char *print_tainted(void) |
| { |
| return _print_tainted(false); |
| } |
| |
| /** |
| * print_tainted_verbose - A more verbose version of print_tainted() |
| */ |
| const char *print_tainted_verbose(void) |
| { |
| return _print_tainted(true); |
| } |
| |
| 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); |
| |
| if (tainted_mask & panic_on_taint) { |
| panic_on_taint = 0; |
| panic("panic_on_taint set ..."); |
| } |
| } |
| 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.. |
| */ |
| bool 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(); |
| |
| if (sysctl_oops_all_cpu_backtrace) |
| trigger_all_cpu_backtrace(); |
| } |
| |
| static void print_oops_end_marker(void) |
| { |
| pr_warn("---[ end trace %016llx ]---\n", 0ULL); |
| } |
| |
| /* |
| * 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); |
| } |
| |
| struct warn_args { |
| const char *fmt; |
| va_list args; |
| }; |
| |
| void __warn(const char *file, int line, void *caller, unsigned taint, |
| struct pt_regs *regs, struct warn_args *args) |
| { |
| disable_trace_on_warning(); |
| |
| if (file) |
| pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", |
| raw_smp_processor_id(), current->pid, file, line, |
| caller); |
| else |
| pr_warn("WARNING: CPU: %d PID: %d at %pS\n", |
| raw_smp_processor_id(), current->pid, caller); |
| |
| #pragma GCC diagnostic push |
| #ifndef __clang__ |
| #pragma GCC diagnostic ignored "-Wsuggest-attribute=format" |
| #endif |
| if (args) |
| vprintk(args->fmt, args->args); |
| #pragma GCC diagnostic pop |
| |
| print_modules(); |
| |
| if (regs) |
| show_regs(regs); |
| |
| check_panic_on_warn("kernel"); |
| |
| if (!regs) |
| dump_stack(); |
| |
| print_irqtrace_events(current); |
| |
| print_oops_end_marker(); |
| trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); |
| |
| /* Just a warning, don't kill lockdep. */ |
| add_taint(taint, LOCKDEP_STILL_OK); |
| } |
| |
| #ifdef CONFIG_BUG |
| #ifndef __WARN_FLAGS |
| void warn_slowpath_fmt(const char *file, int line, unsigned taint, |
| const char *fmt, ...) |
| { |
| bool rcu = warn_rcu_enter(); |
| struct warn_args args; |
| |
| pr_warn(CUT_HERE); |
| |
| if (!fmt) { |
| __warn(file, line, __builtin_return_address(0), taint, |
| NULL, NULL); |
| warn_rcu_exit(rcu); |
| return; |
| } |
| |
| args.fmt = fmt; |
| va_start(args.args, fmt); |
| __warn(file, line, __builtin_return_address(0), taint, NULL, &args); |
| va_end(args.args); |
| warn_rcu_exit(rcu); |
| } |
| EXPORT_SYMBOL(warn_slowpath_fmt); |
| #else |
| void __warn_printk(const char *fmt, ...) |
| { |
| bool rcu = warn_rcu_enter(); |
| va_list args; |
| |
| pr_warn(CUT_HERE); |
| |
| va_start(args, fmt); |
| vprintk(fmt, args); |
| va_end(args); |
| warn_rcu_exit(rcu); |
| } |
| EXPORT_SYMBOL(__warn_printk); |
| #endif |
| |
| /* Support resetting WARN*_ONCE state */ |
| |
| static int clear_warn_once_set(void *data, u64 val) |
| { |
| generic_bug_clear_once(); |
| memset(__start_once, 0, __end_once - __start_once); |
| return 0; |
| } |
| |
| DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, |
| "%lld\n"); |
| |
| static __init int register_warn_debugfs(void) |
| { |
| /* Don't care about failure */ |
| debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, |
| &clear_warn_once_fops); |
| return 0; |
| } |
| |
| device_initcall(register_warn_debugfs); |
| #endif |
| |
| #ifdef CONFIG_STACKPROTECTOR |
| |
| /* |
| * Called when gcc's -fstack-protector feature is used, and |
| * gcc detects corruption of the on-stack canary value |
| */ |
| __visible noinstr void __stack_chk_fail(void) |
| { |
| instrumentation_begin(); |
| panic("stack-protector: Kernel stack is corrupted in: %pB", |
| __builtin_return_address(0)); |
| instrumentation_end(); |
| } |
| EXPORT_SYMBOL(__stack_chk_fail); |
| |
| #endif |
| |
| core_param(panic, panic_timeout, int, 0644); |
| core_param(panic_print, panic_print, ulong, 0644); |
| core_param(pause_on_oops, pause_on_oops, int, 0644); |
| core_param(panic_on_warn, panic_on_warn, int, 0644); |
| core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); |
| |
| 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); |
| |
| static int __init panic_on_taint_setup(char *s) |
| { |
| char *taint_str; |
| |
| if (!s) |
| return -EINVAL; |
| |
| taint_str = strsep(&s, ","); |
| if (kstrtoul(taint_str, 16, &panic_on_taint)) |
| return -EINVAL; |
| |
| /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ |
| panic_on_taint &= TAINT_FLAGS_MAX; |
| |
| if (!panic_on_taint) |
| return -EINVAL; |
| |
| if (s && !strcmp(s, "nousertaint")) |
| panic_on_taint_nousertaint = true; |
| |
| pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n", |
| panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint)); |
| |
| return 0; |
| } |
| early_param("panic_on_taint", panic_on_taint_setup); |