Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/panic.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * This function is used through-out the kernel (including mm and fs) |
| 9 | * to indicate a major problem. |
| 10 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/module.h> |
| 12 | #include <linux/sched.h> |
| 13 | #include <linux/delay.h> |
| 14 | #include <linux/reboot.h> |
| 15 | #include <linux/notifier.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/sysrq.h> |
| 18 | #include <linux/interrupt.h> |
| 19 | #include <linux/nmi.h> |
Eric W. Biederman | dc009d9 | 2005-06-25 14:57:52 -0700 | [diff] [blame] | 20 | #include <linux/kexec.h> |
Andrew Morton | 657b301 | 2006-08-13 23:24:19 -0700 | [diff] [blame] | 21 | #include <linux/debug_locks.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | int panic_on_oops; |
| 24 | int tainted; |
Andrew Morton | dd28779 | 2006-03-23 03:00:57 -0800 | [diff] [blame] | 25 | static int pause_on_oops; |
| 26 | static int pause_on_oops_flag; |
| 27 | static DEFINE_SPINLOCK(pause_on_oops_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | |
Andrew Morton | dd28779 | 2006-03-23 03:00:57 -0800 | [diff] [blame] | 29 | int panic_timeout; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
Alan Stern | e041c68 | 2006-03-27 01:16:30 -0800 | [diff] [blame] | 31 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
| 33 | EXPORT_SYMBOL(panic_notifier_list); |
| 34 | |
| 35 | static int __init panic_setup(char *str) |
| 36 | { |
| 37 | panic_timeout = simple_strtoul(str, NULL, 0); |
| 38 | return 1; |
| 39 | } |
| 40 | __setup("panic=", panic_setup); |
| 41 | |
| 42 | static long no_blink(long time) |
| 43 | { |
| 44 | return 0; |
| 45 | } |
| 46 | |
| 47 | /* Returns how long it waited in ms */ |
| 48 | long (*panic_blink)(long time); |
| 49 | EXPORT_SYMBOL(panic_blink); |
| 50 | |
| 51 | /** |
| 52 | * panic - halt the system |
| 53 | * @fmt: The text string to print |
| 54 | * |
| 55 | * Display a message, then perform cleanups. |
| 56 | * |
| 57 | * This function never returns. |
| 58 | */ |
| 59 | |
| 60 | NORET_TYPE void panic(const char * fmt, ...) |
| 61 | { |
| 62 | long i; |
| 63 | static char buf[1024]; |
| 64 | va_list args; |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 65 | #if defined(CONFIG_S390) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | unsigned long caller = (unsigned long) __builtin_return_address(0); |
| 67 | #endif |
| 68 | |
Eric W. Biederman | dc009d9 | 2005-06-25 14:57:52 -0700 | [diff] [blame] | 69 | /* |
| 70 | * It's possible to come here directly from a panic-assertion and not |
| 71 | * have preempt disabled. Some functions called from here want |
| 72 | * preempt to be disabled. No point enabling it later though... |
| 73 | */ |
| 74 | preempt_disable(); |
| 75 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | bust_spinlocks(1); |
| 77 | va_start(args, fmt); |
| 78 | vsnprintf(buf, sizeof(buf), fmt, args); |
| 79 | va_end(args); |
| 80 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); |
| 81 | bust_spinlocks(0); |
| 82 | |
Eric W. Biederman | dc009d9 | 2005-06-25 14:57:52 -0700 | [diff] [blame] | 83 | /* |
| 84 | * If we have crashed and we have a crash kernel loaded let it handle |
| 85 | * everything else. |
| 86 | * Do we want to call this before we try to display a message? |
| 87 | */ |
Alexander Nyberg | 6e274d1 | 2005-06-25 14:58:26 -0700 | [diff] [blame] | 88 | crash_kexec(NULL); |
Eric W. Biederman | dc009d9 | 2005-06-25 14:57:52 -0700 | [diff] [blame] | 89 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | #ifdef CONFIG_SMP |
Eric W. Biederman | dc009d9 | 2005-06-25 14:57:52 -0700 | [diff] [blame] | 91 | /* |
| 92 | * Note smp_send_stop is the usual smp shutdown function, which |
| 93 | * unfortunately means it may not be hardened to work in a panic |
| 94 | * situation. |
| 95 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | smp_send_stop(); |
| 97 | #endif |
| 98 | |
Alan Stern | e041c68 | 2006-03-27 01:16:30 -0800 | [diff] [blame] | 99 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | |
| 101 | if (!panic_blink) |
| 102 | panic_blink = no_blink; |
| 103 | |
Eric W. Biederman | dc009d9 | 2005-06-25 14:57:52 -0700 | [diff] [blame] | 104 | if (panic_timeout > 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 105 | /* |
| 106 | * Delay timeout seconds before rebooting the machine. |
| 107 | * We can't use the "normal" timers since we just panicked.. |
| 108 | */ |
| 109 | printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout); |
| 110 | for (i = 0; i < panic_timeout*1000; ) { |
| 111 | touch_nmi_watchdog(); |
| 112 | i += panic_blink(i); |
| 113 | mdelay(1); |
| 114 | i++; |
| 115 | } |
Eric W. Biederman | 2f048ea | 2005-07-26 11:49:23 -0600 | [diff] [blame] | 116 | /* This will not be a clean reboot, with everything |
| 117 | * shutting down. But if there is a chance of |
| 118 | * rebooting the system it will be rebooted. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | */ |
Eric W. Biederman | 2f048ea | 2005-07-26 11:49:23 -0600 | [diff] [blame] | 120 | emergency_restart(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | } |
| 122 | #ifdef __sparc__ |
| 123 | { |
| 124 | extern int stop_a_enabled; |
Tom 'spot' Callaway | a271c24 | 2005-04-24 20:38:02 -0700 | [diff] [blame] | 125 | /* Make sure the user can actually press Stop-A (L1-A) */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | stop_a_enabled = 1; |
Tom 'spot' Callaway | a271c24 | 2005-04-24 20:38:02 -0700 | [diff] [blame] | 127 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | } |
| 129 | #endif |
Martin Schwidefsky | 347a8dc | 2006-01-06 00:19:28 -0800 | [diff] [blame] | 130 | #if defined(CONFIG_S390) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | disabled_wait(caller); |
| 132 | #endif |
| 133 | local_irq_enable(); |
| 134 | for (i = 0;;) { |
Jan Beulich | c22db94 | 2006-02-10 01:51:11 -0800 | [diff] [blame] | 135 | touch_softlockup_watchdog(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | i += panic_blink(i); |
| 137 | mdelay(1); |
| 138 | i++; |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | EXPORT_SYMBOL(panic); |
| 143 | |
| 144 | /** |
| 145 | * print_tainted - return a string to represent the kernel taint state. |
| 146 | * |
| 147 | * 'P' - Proprietary module has been loaded. |
| 148 | * 'F' - Module has been forcibly loaded. |
| 149 | * 'S' - SMP with CPUs not designed for SMP. |
| 150 | * 'R' - User forced a module unload. |
| 151 | * 'M' - Machine had a machine check experience. |
| 152 | * 'B' - System has hit bad_page. |
Theodore Ts'o | 34f5a39 | 2007-02-10 01:45:24 -0800 | [diff] [blame] | 153 | * 'U' - Userspace-defined naughtiness. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | * |
| 155 | * The string is overwritten by the next call to print_taint(). |
| 156 | */ |
| 157 | |
| 158 | const char *print_tainted(void) |
| 159 | { |
| 160 | static char buf[20]; |
| 161 | if (tainted) { |
Theodore Ts'o | 34f5a39 | 2007-02-10 01:45:24 -0800 | [diff] [blame] | 162 | snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G', |
| 164 | tainted & TAINT_FORCED_MODULE ? 'F' : ' ', |
| 165 | tainted & TAINT_UNSAFE_SMP ? 'S' : ' ', |
| 166 | tainted & TAINT_FORCED_RMMOD ? 'R' : ' ', |
| 167 | tainted & TAINT_MACHINE_CHECK ? 'M' : ' ', |
Theodore Ts'o | 34f5a39 | 2007-02-10 01:45:24 -0800 | [diff] [blame] | 168 | tainted & TAINT_BAD_PAGE ? 'B' : ' ', |
| 169 | tainted & TAINT_USER ? 'U' : ' '); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } |
| 171 | else |
| 172 | snprintf(buf, sizeof(buf), "Not tainted"); |
| 173 | return(buf); |
| 174 | } |
| 175 | |
| 176 | void add_taint(unsigned flag) |
| 177 | { |
Ingo Molnar | 068c457 | 2006-09-06 00:03:44 -0700 | [diff] [blame] | 178 | debug_locks = 0; /* can't trust the integrity of the kernel anymore */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | tainted |= flag; |
| 180 | } |
| 181 | EXPORT_SYMBOL(add_taint); |
Andrew Morton | dd28779 | 2006-03-23 03:00:57 -0800 | [diff] [blame] | 182 | |
| 183 | static int __init pause_on_oops_setup(char *str) |
| 184 | { |
| 185 | pause_on_oops = simple_strtoul(str, NULL, 0); |
| 186 | return 1; |
| 187 | } |
| 188 | __setup("pause_on_oops=", pause_on_oops_setup); |
| 189 | |
| 190 | static void spin_msec(int msecs) |
| 191 | { |
| 192 | int i; |
| 193 | |
| 194 | for (i = 0; i < msecs; i++) { |
| 195 | touch_nmi_watchdog(); |
| 196 | mdelay(1); |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * It just happens that oops_enter() and oops_exit() are identically |
| 202 | * implemented... |
| 203 | */ |
| 204 | static void do_oops_enter_exit(void) |
| 205 | { |
| 206 | unsigned long flags; |
| 207 | static int spin_counter; |
| 208 | |
| 209 | if (!pause_on_oops) |
| 210 | return; |
| 211 | |
| 212 | spin_lock_irqsave(&pause_on_oops_lock, flags); |
| 213 | if (pause_on_oops_flag == 0) { |
| 214 | /* This CPU may now print the oops message */ |
| 215 | pause_on_oops_flag = 1; |
| 216 | } else { |
| 217 | /* We need to stall this CPU */ |
| 218 | if (!spin_counter) { |
| 219 | /* This CPU gets to do the counting */ |
| 220 | spin_counter = pause_on_oops; |
| 221 | do { |
| 222 | spin_unlock(&pause_on_oops_lock); |
| 223 | spin_msec(MSEC_PER_SEC); |
| 224 | spin_lock(&pause_on_oops_lock); |
| 225 | } while (--spin_counter); |
| 226 | pause_on_oops_flag = 0; |
| 227 | } else { |
| 228 | /* This CPU waits for a different one */ |
| 229 | while (spin_counter) { |
| 230 | spin_unlock(&pause_on_oops_lock); |
| 231 | spin_msec(1); |
| 232 | spin_lock(&pause_on_oops_lock); |
| 233 | } |
| 234 | } |
| 235 | } |
| 236 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); |
| 237 | } |
| 238 | |
| 239 | /* |
| 240 | * Return true if the calling CPU is allowed to print oops-related info. This |
| 241 | * is a bit racy.. |
| 242 | */ |
| 243 | int oops_may_print(void) |
| 244 | { |
| 245 | return pause_on_oops_flag == 0; |
| 246 | } |
| 247 | |
| 248 | /* |
| 249 | * Called when the architecture enters its oops handler, before it prints |
| 250 | * anything. If this is the first CPU to oops, and it's oopsing the first time |
| 251 | * then let it proceed. |
| 252 | * |
| 253 | * This is all enabled by the pause_on_oops kernel boot option. We do all this |
| 254 | * to ensure that oopses don't scroll off the screen. It has the side-effect |
| 255 | * of preventing later-oopsing CPUs from mucking up the display, too. |
| 256 | * |
| 257 | * It turns out that the CPU which is allowed to print ends up pausing for the |
| 258 | * right duration, whereas all the other CPUs pause for twice as long: once in |
| 259 | * oops_enter(), once in oops_exit(). |
| 260 | */ |
| 261 | void oops_enter(void) |
| 262 | { |
Arjan van de Ven | 2c16e9c | 2006-07-10 04:45:42 -0700 | [diff] [blame] | 263 | debug_locks_off(); /* can't trust the integrity of the kernel anymore */ |
Andrew Morton | dd28779 | 2006-03-23 03:00:57 -0800 | [diff] [blame] | 264 | do_oops_enter_exit(); |
| 265 | } |
| 266 | |
| 267 | /* |
| 268 | * Called when the architecture exits its oops handler, after printing |
| 269 | * everything. |
| 270 | */ |
| 271 | void oops_exit(void) |
| 272 | { |
| 273 | do_oops_enter_exit(); |
| 274 | } |
Arjan van de Ven | 3162f75 | 2006-09-26 10:52:39 +0200 | [diff] [blame] | 275 | |
| 276 | #ifdef CONFIG_CC_STACKPROTECTOR |
| 277 | /* |
| 278 | * Called when gcc's -fstack-protector feature is used, and |
| 279 | * gcc detects corruption of the on-stack canary value |
| 280 | */ |
| 281 | void __stack_chk_fail(void) |
| 282 | { |
| 283 | panic("stack-protector: Kernel stack is corrupted"); |
| 284 | } |
| 285 | EXPORT_SYMBOL(__stack_chk_fail); |
| 286 | #endif |