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 * panic - halt the system
54 * @fmt: The text string to print
56 * Display a message, then perform cleanups.
58 * This function never returns.
60 NORET_TYPE void panic(const char * fmt, ...)
62 static char buf[1024];
68 * It's possible to come here directly from a panic-assertion and
69 * not have preempt disabled. Some functions called from here want
70 * preempt to be disabled. No point enabling it later though...
77 vsnprintf(buf, sizeof(buf), fmt, args);
79 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
80 #ifdef CONFIG_DEBUG_BUGVERBOSE
85 * If we have crashed and we have a crash kernel loaded let it handle
87 * Do we want to call this before we try to display a message?
91 kmsg_dump(KMSG_DUMP_PANIC);
94 * Note smp_send_stop is the usual smp shutdown function, which
95 * unfortunately means it may not be hardened to work in a panic
100 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
105 panic_blink = no_blink;
107 if (panic_timeout > 0) {
109 * Delay timeout seconds before rebooting the machine.
110 * We can't use the "normal" timers since we just panicked.
112 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
114 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
115 touch_nmi_watchdog();
117 i += panic_blink(state ^= 1);
118 i_next = i + 3600 / PANIC_BLINK_SPD;
120 mdelay(PANIC_TIMER_STEP);
123 if (panic_timeout != 0) {
125 * This will not be a clean reboot, with everything
126 * shutting down. But if there is a chance of
127 * rebooting the system it will be rebooted.
133 extern int stop_a_enabled;
134 /* Make sure the user can actually press Stop-A (L1-A) */
136 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
139 #if defined(CONFIG_S390)
141 unsigned long caller;
143 caller = (unsigned long)__builtin_return_address(0);
144 disabled_wait(caller);
148 for (i = 0; ; i += PANIC_TIMER_STEP) {
149 touch_softlockup_watchdog();
151 i += panic_blink(state ^= 1);
152 i_next = i + 3600 / PANIC_BLINK_SPD;
154 mdelay(PANIC_TIMER_STEP);
158 EXPORT_SYMBOL(panic);
167 static const struct tnt tnts[] = {
168 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
169 { TAINT_FORCED_MODULE, 'F', ' ' },
170 { TAINT_UNSAFE_SMP, 'S', ' ' },
171 { TAINT_FORCED_RMMOD, 'R', ' ' },
172 { TAINT_MACHINE_CHECK, 'M', ' ' },
173 { TAINT_BAD_PAGE, 'B', ' ' },
174 { TAINT_USER, 'U', ' ' },
175 { TAINT_DIE, 'D', ' ' },
176 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
177 { TAINT_WARN, 'W', ' ' },
178 { TAINT_CRAP, 'C', ' ' },
179 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
180 { TAINT_OOT_MODULE, 'O', ' ' },
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.
198 * 'O' - Out-of-tree module has been loaded.
200 * The string is overwritten by the next call to print_tainted().
202 const char *print_tainted(void)
204 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
210 s = buf + sprintf(buf, "Tainted: ");
211 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
212 const struct tnt *t = &tnts[i];
213 *s++ = test_bit(t->bit, &tainted_mask) ?
218 snprintf(buf, sizeof(buf), "Not tainted");
223 int test_taint(unsigned flag)
225 return test_bit(flag, &tainted_mask);
227 EXPORT_SYMBOL(test_taint);
229 unsigned long get_taint(void)
234 void add_taint(unsigned flag)
237 * Can't trust the integrity of the kernel anymore.
238 * We don't call directly debug_locks_off() because the issue
239 * is not necessarily serious enough to set oops_in_progress to 1
240 * Also we want to keep up lockdep for staging/out-of-tree
241 * development and post-warning case.
245 case TAINT_OOT_MODULE:
247 case TAINT_FIRMWARE_WORKAROUND:
251 if (__debug_locks_off())
252 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
255 set_bit(flag, &tainted_mask);
257 EXPORT_SYMBOL(add_taint);
259 static void spin_msec(int msecs)
263 for (i = 0; i < msecs; i++) {
264 touch_nmi_watchdog();
270 * It just happens that oops_enter() and oops_exit() are identically
273 static void do_oops_enter_exit(void)
276 static int spin_counter;
281 spin_lock_irqsave(&pause_on_oops_lock, flags);
282 if (pause_on_oops_flag == 0) {
283 /* This CPU may now print the oops message */
284 pause_on_oops_flag = 1;
286 /* We need to stall this CPU */
288 /* This CPU gets to do the counting */
289 spin_counter = pause_on_oops;
291 spin_unlock(&pause_on_oops_lock);
292 spin_msec(MSEC_PER_SEC);
293 spin_lock(&pause_on_oops_lock);
294 } while (--spin_counter);
295 pause_on_oops_flag = 0;
297 /* This CPU waits for a different one */
298 while (spin_counter) {
299 spin_unlock(&pause_on_oops_lock);
301 spin_lock(&pause_on_oops_lock);
305 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
309 * Return true if the calling CPU is allowed to print oops-related info.
310 * This is a bit racy..
312 int oops_may_print(void)
314 return pause_on_oops_flag == 0;
318 * Called when the architecture enters its oops handler, before it prints
319 * anything. If this is the first CPU to oops, and it's oopsing the first
320 * time then let it proceed.
322 * This is all enabled by the pause_on_oops kernel boot option. We do all
323 * this to ensure that oopses don't scroll off the screen. It has the
324 * side-effect of preventing later-oopsing CPUs from mucking up the display,
327 * It turns out that the CPU which is allowed to print ends up pausing for
328 * the right duration, whereas all the other CPUs pause for twice as long:
329 * once in oops_enter(), once in oops_exit().
331 void oops_enter(void)
334 /* can't trust the integrity of the kernel anymore: */
336 do_oops_enter_exit();
340 * 64-bit random ID for oopses:
344 static int init_oops_id(void)
347 get_random_bytes(&oops_id, sizeof(oops_id));
353 late_initcall(init_oops_id);
355 void print_oops_end_marker(void)
358 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
359 (unsigned long long)oops_id);
363 * Called when the architecture exits its oops handler, after printing
368 do_oops_enter_exit();
369 print_oops_end_marker();
370 kmsg_dump(KMSG_DUMP_OOPS);
373 #ifdef WANT_WARN_ON_SLOWPATH
374 struct slowpath_args {
379 static void warn_slowpath_common(const char *file, int line, void *caller,
380 unsigned taint, struct slowpath_args *args)
384 printk(KERN_WARNING "------------[ cut here ]------------\n");
385 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
386 board = dmi_get_system_info(DMI_PRODUCT_NAME);
388 printk(KERN_WARNING "Hardware name: %s\n", board);
391 vprintk(args->fmt, args->args);
395 print_oops_end_marker();
399 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
401 struct slowpath_args args;
404 va_start(args.args, fmt);
405 warn_slowpath_common(file, line, __builtin_return_address(0),
409 EXPORT_SYMBOL(warn_slowpath_fmt);
411 void warn_slowpath_fmt_taint(const char *file, int line,
412 unsigned taint, const char *fmt, ...)
414 struct slowpath_args args;
417 va_start(args.args, fmt);
418 warn_slowpath_common(file, line, __builtin_return_address(0),
422 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
424 void warn_slowpath_null(const char *file, int line)
426 warn_slowpath_common(file, line, __builtin_return_address(0),
429 EXPORT_SYMBOL(warn_slowpath_null);
432 #ifdef CONFIG_CC_STACKPROTECTOR
435 * Called when gcc's -fstack-protector feature is used, and
436 * gcc detects corruption of the on-stack canary value
438 void __stack_chk_fail(void)
440 panic("stack-protector: Kernel stack is corrupted in: %p\n",
441 __builtin_return_address(0));
443 EXPORT_SYMBOL(__stack_chk_fail);
447 core_param(panic, panic_timeout, int, 0644);
448 core_param(pause_on_oops, pause_on_oops, int, 0644);
450 static int __init oops_setup(char *s)
454 if (!strcmp(s, "panic"))
458 early_param("oops", oops_setup);