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);
37 EXPORT_SYMBOL_GPL(panic_timeout);
39 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
41 EXPORT_SYMBOL(panic_notifier_list);
43 static long no_blink(int state)
48 /* Returns how long it waited in ms */
49 long (*panic_blink)(int state);
50 EXPORT_SYMBOL(panic_blink);
53 * Stop ourself in panic -- architecture code may override this
55 void __weak panic_smp_self_stop(void)
62 * panic - halt the system
63 * @fmt: The text string to print
65 * Display a message, then perform cleanups.
67 * This function never returns.
69 void panic(const char *fmt, ...)
71 static DEFINE_SPINLOCK(panic_lock);
72 static char buf[1024];
78 * It's possible to come here directly from a panic-assertion and
79 * not have preempt disabled. Some functions called from here want
80 * preempt to be disabled. No point enabling it later though...
82 * Only one CPU is allowed to execute the panic code from here. For
83 * multiple parallel invocations of panic, all other CPUs either
84 * stop themself or will wait until they are stopped by the 1st CPU
85 * with smp_send_stop().
87 if (!spin_trylock(&panic_lock))
88 panic_smp_self_stop();
93 vsnprintf(buf, sizeof(buf), fmt, args);
95 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
96 #ifdef CONFIG_DEBUG_BUGVERBOSE
101 * If we have crashed and we have a crash kernel loaded let it handle
103 * Do we want to call this before we try to display a message?
107 kmsg_dump(KMSG_DUMP_PANIC);
110 * Note smp_send_stop is the usual smp shutdown function, which
111 * unfortunately means it may not be hardened to work in a panic
116 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
121 panic_blink = no_blink;
123 if (panic_timeout > 0) {
125 * Delay timeout seconds before rebooting the machine.
126 * We can't use the "normal" timers since we just panicked.
128 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
130 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
131 touch_nmi_watchdog();
133 i += panic_blink(state ^= 1);
134 i_next = i + 3600 / PANIC_BLINK_SPD;
136 mdelay(PANIC_TIMER_STEP);
139 if (panic_timeout != 0) {
141 * This will not be a clean reboot, with everything
142 * shutting down. But if there is a chance of
143 * rebooting the system it will be rebooted.
149 extern int stop_a_enabled;
150 /* Make sure the user can actually press Stop-A (L1-A) */
152 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
155 #if defined(CONFIG_S390)
157 unsigned long caller;
159 caller = (unsigned long)__builtin_return_address(0);
160 disabled_wait(caller);
164 for (i = 0; ; i += PANIC_TIMER_STEP) {
165 touch_softlockup_watchdog();
167 i += panic_blink(state ^= 1);
168 i_next = i + 3600 / PANIC_BLINK_SPD;
170 mdelay(PANIC_TIMER_STEP);
174 EXPORT_SYMBOL(panic);
183 static const struct tnt tnts[] = {
184 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
185 { TAINT_FORCED_MODULE, 'F', ' ' },
186 { TAINT_UNSAFE_SMP, 'S', ' ' },
187 { TAINT_FORCED_RMMOD, 'R', ' ' },
188 { TAINT_MACHINE_CHECK, 'M', ' ' },
189 { TAINT_BAD_PAGE, 'B', ' ' },
190 { TAINT_USER, 'U', ' ' },
191 { TAINT_DIE, 'D', ' ' },
192 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
193 { TAINT_WARN, 'W', ' ' },
194 { TAINT_CRAP, 'C', ' ' },
195 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
196 { TAINT_OOT_MODULE, 'O', ' ' },
200 * print_tainted - return a string to represent the kernel taint state.
202 * 'P' - Proprietary module has been loaded.
203 * 'F' - Module has been forcibly loaded.
204 * 'S' - SMP with CPUs not designed for SMP.
205 * 'R' - User forced a module unload.
206 * 'M' - System experienced a machine check exception.
207 * 'B' - System has hit bad_page.
208 * 'U' - Userspace-defined naughtiness.
209 * 'D' - Kernel has oopsed before
210 * 'A' - ACPI table overridden.
211 * 'W' - Taint on warning.
212 * 'C' - modules from drivers/staging are loaded.
213 * 'I' - Working around severe firmware bug.
214 * 'O' - Out-of-tree module has been loaded.
216 * The string is overwritten by the next call to print_tainted().
218 const char *print_tainted(void)
220 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
226 s = buf + sprintf(buf, "Tainted: ");
227 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
228 const struct tnt *t = &tnts[i];
229 *s++ = test_bit(t->bit, &tainted_mask) ?
234 snprintf(buf, sizeof(buf), "Not tainted");
239 int test_taint(unsigned flag)
241 return test_bit(flag, &tainted_mask);
243 EXPORT_SYMBOL(test_taint);
245 unsigned long get_taint(void)
250 void add_taint(unsigned flag)
253 * Can't trust the integrity of the kernel anymore.
254 * We don't call directly debug_locks_off() because the issue
255 * is not necessarily serious enough to set oops_in_progress to 1
256 * Also we want to keep up lockdep for staging/out-of-tree
257 * development and post-warning case.
261 case TAINT_OOT_MODULE:
263 case TAINT_FIRMWARE_WORKAROUND:
267 if (__debug_locks_off())
268 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
271 set_bit(flag, &tainted_mask);
273 EXPORT_SYMBOL(add_taint);
275 static void spin_msec(int msecs)
279 for (i = 0; i < msecs; i++) {
280 touch_nmi_watchdog();
286 * It just happens that oops_enter() and oops_exit() are identically
289 static void do_oops_enter_exit(void)
292 static int spin_counter;
297 spin_lock_irqsave(&pause_on_oops_lock, flags);
298 if (pause_on_oops_flag == 0) {
299 /* This CPU may now print the oops message */
300 pause_on_oops_flag = 1;
302 /* We need to stall this CPU */
304 /* This CPU gets to do the counting */
305 spin_counter = pause_on_oops;
307 spin_unlock(&pause_on_oops_lock);
308 spin_msec(MSEC_PER_SEC);
309 spin_lock(&pause_on_oops_lock);
310 } while (--spin_counter);
311 pause_on_oops_flag = 0;
313 /* This CPU waits for a different one */
314 while (spin_counter) {
315 spin_unlock(&pause_on_oops_lock);
317 spin_lock(&pause_on_oops_lock);
321 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
325 * Return true if the calling CPU is allowed to print oops-related info.
326 * This is a bit racy..
328 int oops_may_print(void)
330 return pause_on_oops_flag == 0;
334 * Called when the architecture enters its oops handler, before it prints
335 * anything. If this is the first CPU to oops, and it's oopsing the first
336 * time then let it proceed.
338 * This is all enabled by the pause_on_oops kernel boot option. We do all
339 * this to ensure that oopses don't scroll off the screen. It has the
340 * side-effect of preventing later-oopsing CPUs from mucking up the display,
343 * It turns out that the CPU which is allowed to print ends up pausing for
344 * the right duration, whereas all the other CPUs pause for twice as long:
345 * once in oops_enter(), once in oops_exit().
347 void oops_enter(void)
350 /* can't trust the integrity of the kernel anymore: */
352 do_oops_enter_exit();
356 * 64-bit random ID for oopses:
360 static int init_oops_id(void)
363 get_random_bytes(&oops_id, sizeof(oops_id));
369 late_initcall(init_oops_id);
371 void print_oops_end_marker(void)
374 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
375 (unsigned long long)oops_id);
379 * Called when the architecture exits its oops handler, after printing
384 do_oops_enter_exit();
385 print_oops_end_marker();
386 kmsg_dump(KMSG_DUMP_OOPS);
389 #ifdef WANT_WARN_ON_SLOWPATH
390 struct slowpath_args {
395 static void warn_slowpath_common(const char *file, int line, void *caller,
396 unsigned taint, struct slowpath_args *args)
400 printk(KERN_WARNING "------------[ cut here ]------------\n");
401 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
402 board = dmi_get_system_info(DMI_PRODUCT_NAME);
404 printk(KERN_WARNING "Hardware name: %s\n", board);
407 vprintk(args->fmt, args->args);
411 print_oops_end_marker();
415 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
417 struct slowpath_args args;
420 va_start(args.args, fmt);
421 warn_slowpath_common(file, line, __builtin_return_address(0),
425 EXPORT_SYMBOL(warn_slowpath_fmt);
427 void warn_slowpath_fmt_taint(const char *file, int line,
428 unsigned taint, const char *fmt, ...)
430 struct slowpath_args args;
433 va_start(args.args, fmt);
434 warn_slowpath_common(file, line, __builtin_return_address(0),
438 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
440 void warn_slowpath_null(const char *file, int line)
442 warn_slowpath_common(file, line, __builtin_return_address(0),
445 EXPORT_SYMBOL(warn_slowpath_null);
448 #ifdef CONFIG_CC_STACKPROTECTOR
451 * Called when gcc's -fstack-protector feature is used, and
452 * gcc detects corruption of the on-stack canary value
454 void __stack_chk_fail(void)
456 panic("stack-protector: Kernel stack is corrupted in: %p\n",
457 __builtin_return_address(0));
459 EXPORT_SYMBOL(__stack_chk_fail);
463 core_param(panic, panic_timeout, int, 0644);
464 core_param(pause_on_oops, pause_on_oops, int, 0644);
466 static int __init oops_setup(char *s)
470 if (!strcmp(s, "panic"))
474 early_param("oops", oops_setup);