4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * This function is used through-out the kernel (including mm and fs)
9 * to indicate a major problem.
11 #include <linux/debug_locks.h>
12 #include <linux/interrupt.h>
13 #include <linux/kmsg_dump.h>
14 #include <linux/kallsyms.h>
15 #include <linux/notifier.h>
16 #include <linux/module.h>
17 #include <linux/random.h>
18 #include <linux/reboot.h>
19 #include <linux/delay.h>
20 #include <linux/kexec.h>
21 #include <linux/sched.h>
22 #include <linux/sysrq.h>
23 #include <linux/init.h>
24 #include <linux/nmi.h>
25 #include <linux/dmi.h>
27 #define PANIC_TIMER_STEP 100
28 #define PANIC_BLINK_SPD 18
31 static unsigned long tainted_mask;
32 static int pause_on_oops;
33 static int pause_on_oops_flag;
34 static DEFINE_SPINLOCK(pause_on_oops_lock);
36 #ifndef CONFIG_PANIC_TIMEOUT
37 #define CONFIG_PANIC_TIMEOUT 0
39 int panic_timeout = CONFIG_PANIC_TIMEOUT;
40 EXPORT_SYMBOL_GPL(panic_timeout);
42 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
44 EXPORT_SYMBOL(panic_notifier_list);
46 static long no_blink(int state)
51 /* Returns how long it waited in ms */
52 long (*panic_blink)(int state);
53 EXPORT_SYMBOL(panic_blink);
56 * panic - halt the system
57 * @fmt: The text string to print
59 * Display a message, then perform cleanups.
61 * This function never returns.
63 NORET_TYPE void panic(const char * fmt, ...)
65 static char buf[1024];
71 * It's possible to come here directly from a panic-assertion and
72 * not have preempt disabled. Some functions called from here want
73 * preempt to be disabled. No point enabling it later though...
80 vsnprintf(buf, sizeof(buf), fmt, args);
82 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
83 #ifdef CONFIG_DEBUG_BUGVERBOSE
88 * If we have crashed and we have a crash kernel loaded let it handle
90 * Do we want to call this before we try to display a message?
94 kmsg_dump(KMSG_DUMP_PANIC);
97 * Note smp_send_stop is the usual smp shutdown function, which
98 * unfortunately means it may not be hardened to work in a panic
103 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
108 panic_blink = no_blink;
110 if (panic_timeout > 0) {
112 * Delay timeout seconds before rebooting the machine.
113 * We can't use the "normal" timers since we just panicked.
115 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
117 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
118 touch_nmi_watchdog();
120 i += panic_blink(state ^= 1);
121 i_next = i + 3600 / PANIC_BLINK_SPD;
123 mdelay(PANIC_TIMER_STEP);
126 * This will not be a clean reboot, with everything
127 * shutting down. But if there is a chance of
128 * rebooting the system it will be rebooted.
134 extern int stop_a_enabled;
135 /* Make sure the user can actually press Stop-A (L1-A) */
137 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
140 #if defined(CONFIG_S390)
142 unsigned long caller;
144 caller = (unsigned long)__builtin_return_address(0);
145 disabled_wait(caller);
149 for (i = 0; ; i += PANIC_TIMER_STEP) {
150 touch_softlockup_watchdog();
152 i += panic_blink(state ^= 1);
153 i_next = i + 3600 / PANIC_BLINK_SPD;
155 mdelay(PANIC_TIMER_STEP);
159 EXPORT_SYMBOL(panic);
168 static const struct tnt tnts[] = {
169 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
170 { TAINT_FORCED_MODULE, 'F', ' ' },
171 { TAINT_UNSAFE_SMP, 'S', ' ' },
172 { TAINT_FORCED_RMMOD, 'R', ' ' },
173 { TAINT_MACHINE_CHECK, 'M', ' ' },
174 { TAINT_BAD_PAGE, 'B', ' ' },
175 { TAINT_USER, 'U', ' ' },
176 { TAINT_DIE, 'D', ' ' },
177 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
178 { TAINT_WARN, 'W', ' ' },
179 { TAINT_CRAP, 'C', ' ' },
180 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
184 * print_tainted - return a string to represent the kernel taint state.
186 * 'P' - Proprietary module has been loaded.
187 * 'F' - Module has been forcibly loaded.
188 * 'S' - SMP with CPUs not designed for SMP.
189 * 'R' - User forced a module unload.
190 * 'M' - System experienced a machine check exception.
191 * 'B' - System has hit bad_page.
192 * 'U' - Userspace-defined naughtiness.
193 * 'D' - Kernel has oopsed before
194 * 'A' - ACPI table overridden.
195 * 'W' - Taint on warning.
196 * 'C' - modules from drivers/staging are loaded.
197 * 'I' - Working around severe firmware bug.
199 * The string is overwritten by the next call to print_tainted().
201 const char *print_tainted(void)
203 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
209 s = buf + sprintf(buf, "Tainted: ");
210 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
211 const struct tnt *t = &tnts[i];
212 *s++ = test_bit(t->bit, &tainted_mask) ?
217 snprintf(buf, sizeof(buf), "Not tainted");
222 int test_taint(unsigned flag)
224 return test_bit(flag, &tainted_mask);
226 EXPORT_SYMBOL(test_taint);
228 unsigned long get_taint(void)
233 void add_taint(unsigned flag)
236 * Can't trust the integrity of the kernel anymore.
237 * We don't call directly debug_locks_off() because the issue
238 * is not necessarily serious enough to set oops_in_progress to 1
239 * Also we want to keep up lockdep for staging development and
242 if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
243 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
245 set_bit(flag, &tainted_mask);
247 EXPORT_SYMBOL(add_taint);
249 static void spin_msec(int msecs)
253 for (i = 0; i < msecs; i++) {
254 touch_nmi_watchdog();
260 * It just happens that oops_enter() and oops_exit() are identically
263 static void do_oops_enter_exit(void)
266 static int spin_counter;
271 spin_lock_irqsave(&pause_on_oops_lock, flags);
272 if (pause_on_oops_flag == 0) {
273 /* This CPU may now print the oops message */
274 pause_on_oops_flag = 1;
276 /* We need to stall this CPU */
278 /* This CPU gets to do the counting */
279 spin_counter = pause_on_oops;
281 spin_unlock(&pause_on_oops_lock);
282 spin_msec(MSEC_PER_SEC);
283 spin_lock(&pause_on_oops_lock);
284 } while (--spin_counter);
285 pause_on_oops_flag = 0;
287 /* This CPU waits for a different one */
288 while (spin_counter) {
289 spin_unlock(&pause_on_oops_lock);
291 spin_lock(&pause_on_oops_lock);
295 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
299 * Return true if the calling CPU is allowed to print oops-related info.
300 * This is a bit racy..
302 int oops_may_print(void)
304 return pause_on_oops_flag == 0;
308 * Called when the architecture enters its oops handler, before it prints
309 * anything. If this is the first CPU to oops, and it's oopsing the first
310 * time then let it proceed.
312 * This is all enabled by the pause_on_oops kernel boot option. We do all
313 * this to ensure that oopses don't scroll off the screen. It has the
314 * side-effect of preventing later-oopsing CPUs from mucking up the display,
317 * It turns out that the CPU which is allowed to print ends up pausing for
318 * the right duration, whereas all the other CPUs pause for twice as long:
319 * once in oops_enter(), once in oops_exit().
321 void oops_enter(void)
324 /* can't trust the integrity of the kernel anymore: */
326 do_oops_enter_exit();
330 * 64-bit random ID for oopses:
334 static int init_oops_id(void)
337 get_random_bytes(&oops_id, sizeof(oops_id));
343 late_initcall(init_oops_id);
345 void print_oops_end_marker(void)
348 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
349 (unsigned long long)oops_id);
353 * Called when the architecture exits its oops handler, after printing
358 do_oops_enter_exit();
359 print_oops_end_marker();
360 kmsg_dump(KMSG_DUMP_OOPS);
363 #ifdef WANT_WARN_ON_SLOWPATH
364 struct slowpath_args {
369 static void warn_slowpath_common(const char *file, int line, void *caller,
370 unsigned taint, struct slowpath_args *args)
374 printk(KERN_WARNING "------------[ cut here ]------------\n");
375 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
376 board = dmi_get_system_info(DMI_PRODUCT_NAME);
378 printk(KERN_WARNING "Hardware name: %s\n", board);
381 vprintk(args->fmt, args->args);
385 print_oops_end_marker();
389 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
391 struct slowpath_args args;
394 va_start(args.args, fmt);
395 warn_slowpath_common(file, line, __builtin_return_address(0),
399 EXPORT_SYMBOL(warn_slowpath_fmt);
401 void warn_slowpath_fmt_taint(const char *file, int line,
402 unsigned taint, const char *fmt, ...)
404 struct slowpath_args args;
407 va_start(args.args, fmt);
408 warn_slowpath_common(file, line, __builtin_return_address(0),
412 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
414 void warn_slowpath_null(const char *file, int line)
416 warn_slowpath_common(file, line, __builtin_return_address(0),
419 EXPORT_SYMBOL(warn_slowpath_null);
422 #ifdef CONFIG_CC_STACKPROTECTOR
425 * Called when gcc's -fstack-protector feature is used, and
426 * gcc detects corruption of the on-stack canary value
428 void __stack_chk_fail(void)
430 panic("stack-protector: Kernel stack is corrupted in: %p\n",
431 __builtin_return_address(0));
433 EXPORT_SYMBOL(__stack_chk_fail);
437 core_param(panic, panic_timeout, int, 0644);
438 core_param(pause_on_oops, pause_on_oops, int, 0644);