288 lines
6.7 KiB
C
288 lines
6.7 KiB
C
/*
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* linux/kernel/panic.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* This function is used through-out the kernel (including mm and fs)
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* to indicate a major problem.
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/notifier.h>
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#include <linux/init.h>
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#include <linux/sysrq.h>
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#include <linux/interrupt.h>
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#include <linux/nmi.h>
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#include <linux/kexec.h>
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#include <linux/debug_locks.h>
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int panic_on_oops;
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int tainted;
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static int pause_on_oops;
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static int pause_on_oops_flag;
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static DEFINE_SPINLOCK(pause_on_oops_lock);
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int panic_timeout;
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ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
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EXPORT_SYMBOL(panic_notifier_list);
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static int __init panic_setup(char *str)
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{
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panic_timeout = simple_strtoul(str, NULL, 0);
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return 1;
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}
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__setup("panic=", panic_setup);
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static long no_blink(long time)
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{
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return 0;
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}
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/* Returns how long it waited in ms */
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long (*panic_blink)(long time);
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EXPORT_SYMBOL(panic_blink);
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/**
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* panic - halt the system
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* @fmt: The text string to print
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*
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* Display a message, then perform cleanups.
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*
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* This function never returns.
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*/
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NORET_TYPE void panic(const char * fmt, ...)
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{
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long i;
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static char buf[1024];
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va_list args;
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#if defined(CONFIG_S390)
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unsigned long caller = (unsigned long) __builtin_return_address(0);
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#endif
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/*
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* It's possible to come here directly from a panic-assertion and not
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* have preempt disabled. Some functions called from here want
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* preempt to be disabled. No point enabling it later though...
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*/
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preempt_disable();
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bust_spinlocks(1);
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va_start(args, fmt);
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vsnprintf(buf, sizeof(buf), fmt, args);
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va_end(args);
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printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
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bust_spinlocks(0);
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/*
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* If we have crashed and we have a crash kernel loaded let it handle
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* everything else.
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* Do we want to call this before we try to display a message?
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*/
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crash_kexec(NULL);
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#ifdef CONFIG_SMP
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/*
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* Note smp_send_stop is the usual smp shutdown function, which
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* unfortunately means it may not be hardened to work in a panic
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* situation.
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*/
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smp_send_stop();
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#endif
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atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
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if (!panic_blink)
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panic_blink = no_blink;
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if (panic_timeout > 0) {
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/*
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* Delay timeout seconds before rebooting the machine.
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* We can't use the "normal" timers since we just panicked..
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*/
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printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
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for (i = 0; i < panic_timeout*1000; ) {
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touch_nmi_watchdog();
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i += panic_blink(i);
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mdelay(1);
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i++;
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}
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/* This will not be a clean reboot, with everything
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* shutting down. But if there is a chance of
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* rebooting the system it will be rebooted.
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*/
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emergency_restart();
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}
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#ifdef __sparc__
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{
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extern int stop_a_enabled;
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/* Make sure the user can actually press Stop-A (L1-A) */
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stop_a_enabled = 1;
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printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
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}
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#endif
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#if defined(CONFIG_S390)
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disabled_wait(caller);
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#endif
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local_irq_enable();
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for (i = 0;;) {
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touch_softlockup_watchdog();
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i += panic_blink(i);
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mdelay(1);
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i++;
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}
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}
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EXPORT_SYMBOL(panic);
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/**
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* print_tainted - return a string to represent the kernel taint state.
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*
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* 'P' - Proprietary module has been loaded.
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* 'F' - Module has been forcibly loaded.
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* 'S' - SMP with CPUs not designed for SMP.
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* 'R' - User forced a module unload.
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* 'M' - Machine had a machine check experience.
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* 'B' - System has hit bad_page.
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* 'U' - Userspace-defined naughtiness.
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*
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* The string is overwritten by the next call to print_taint().
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*/
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const char *print_tainted(void)
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{
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static char buf[20];
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if (tainted) {
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snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c",
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tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
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tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
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tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
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tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
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tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
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tainted & TAINT_BAD_PAGE ? 'B' : ' ',
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tainted & TAINT_USER ? 'U' : ' ',
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tainted & TAINT_DIE ? 'D' : ' ');
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}
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else
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snprintf(buf, sizeof(buf), "Not tainted");
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return(buf);
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}
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void add_taint(unsigned flag)
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{
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debug_locks = 0; /* can't trust the integrity of the kernel anymore */
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tainted |= flag;
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}
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EXPORT_SYMBOL(add_taint);
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static int __init pause_on_oops_setup(char *str)
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{
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pause_on_oops = simple_strtoul(str, NULL, 0);
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return 1;
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}
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__setup("pause_on_oops=", pause_on_oops_setup);
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static void spin_msec(int msecs)
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{
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int i;
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for (i = 0; i < msecs; i++) {
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touch_nmi_watchdog();
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mdelay(1);
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}
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}
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/*
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* It just happens that oops_enter() and oops_exit() are identically
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* implemented...
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*/
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static void do_oops_enter_exit(void)
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{
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unsigned long flags;
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static int spin_counter;
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if (!pause_on_oops)
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return;
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spin_lock_irqsave(&pause_on_oops_lock, flags);
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if (pause_on_oops_flag == 0) {
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/* This CPU may now print the oops message */
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pause_on_oops_flag = 1;
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} else {
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/* We need to stall this CPU */
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if (!spin_counter) {
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/* This CPU gets to do the counting */
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spin_counter = pause_on_oops;
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do {
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spin_unlock(&pause_on_oops_lock);
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spin_msec(MSEC_PER_SEC);
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spin_lock(&pause_on_oops_lock);
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} while (--spin_counter);
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pause_on_oops_flag = 0;
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} else {
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/* This CPU waits for a different one */
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while (spin_counter) {
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spin_unlock(&pause_on_oops_lock);
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spin_msec(1);
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spin_lock(&pause_on_oops_lock);
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}
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}
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}
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spin_unlock_irqrestore(&pause_on_oops_lock, flags);
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}
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/*
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* Return true if the calling CPU is allowed to print oops-related info. This
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* is a bit racy..
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*/
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int oops_may_print(void)
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{
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return pause_on_oops_flag == 0;
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}
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/*
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* Called when the architecture enters its oops handler, before it prints
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* anything. If this is the first CPU to oops, and it's oopsing the first time
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* then let it proceed.
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*
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* This is all enabled by the pause_on_oops kernel boot option. We do all this
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* to ensure that oopses don't scroll off the screen. It has the side-effect
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* of preventing later-oopsing CPUs from mucking up the display, too.
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*
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* It turns out that the CPU which is allowed to print ends up pausing for the
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* right duration, whereas all the other CPUs pause for twice as long: once in
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* oops_enter(), once in oops_exit().
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*/
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void oops_enter(void)
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{
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debug_locks_off(); /* can't trust the integrity of the kernel anymore */
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do_oops_enter_exit();
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}
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/*
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* Called when the architecture exits its oops handler, after printing
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* everything.
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*/
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void oops_exit(void)
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{
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do_oops_enter_exit();
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}
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#ifdef CONFIG_CC_STACKPROTECTOR
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/*
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* Called when gcc's -fstack-protector feature is used, and
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* gcc detects corruption of the on-stack canary value
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*/
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void __stack_chk_fail(void)
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{
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panic("stack-protector: Kernel stack is corrupted");
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}
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EXPORT_SYMBOL(__stack_chk_fail);
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#endif
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