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
30 /* Machine specific panic information string */
31 char *mach_panic_string;
34 static unsigned long tainted_mask;
35 static int pause_on_oops;
36 static int pause_on_oops_flag;
37 static DEFINE_SPINLOCK(pause_on_oops_lock);
39 #ifndef CONFIG_PANIC_TIMEOUT
40 #define CONFIG_PANIC_TIMEOUT 0
42 int panic_timeout = CONFIG_PANIC_TIMEOUT;
43 EXPORT_SYMBOL_GPL(panic_timeout);
45 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
47 EXPORT_SYMBOL(panic_notifier_list);
49 static long no_blink(int state)
54 /* Returns how long it waited in ms */
55 long (*panic_blink)(int state);
56 EXPORT_SYMBOL(panic_blink);
59 * panic - halt the system
60 * @fmt: The text string to print
62 * Display a message, then perform cleanups.
64 * This function never returns.
66 NORET_TYPE void panic(const char * fmt, ...)
68 static char buf[1024];
74 * It's possible to come here directly from a panic-assertion and
75 * not have preempt disabled. Some functions called from here want
76 * preempt to be disabled. No point enabling it later though...
83 vsnprintf(buf, sizeof(buf), fmt, args);
85 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
86 #ifdef CONFIG_DEBUG_BUGVERBOSE
91 * If we have crashed and we have a crash kernel loaded let it handle
93 * Do we want to call this before we try to display a message?
97 kmsg_dump(KMSG_DUMP_PANIC);
100 * Note smp_send_stop is the usual smp shutdown function, which
101 * unfortunately means it may not be hardened to work in a panic
106 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
111 panic_blink = no_blink;
113 if (panic_timeout > 0) {
115 * Delay timeout seconds before rebooting the machine.
116 * We can't use the "normal" timers since we just panicked.
118 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
120 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
121 touch_nmi_watchdog();
123 i += panic_blink(state ^= 1);
124 i_next = i + 3600 / PANIC_BLINK_SPD;
126 mdelay(PANIC_TIMER_STEP);
129 * This will not be a clean reboot, with everything
130 * shutting down. But if there is a chance of
131 * rebooting the system it will be rebooted.
137 extern int stop_a_enabled;
138 /* Make sure the user can actually press Stop-A (L1-A) */
140 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
143 #if defined(CONFIG_S390)
145 unsigned long caller;
147 caller = (unsigned long)__builtin_return_address(0);
148 disabled_wait(caller);
152 for (i = 0; ; i += PANIC_TIMER_STEP) {
153 touch_softlockup_watchdog();
155 i += panic_blink(state ^= 1);
156 i_next = i + 3600 / PANIC_BLINK_SPD;
158 mdelay(PANIC_TIMER_STEP);
162 EXPORT_SYMBOL(panic);
171 static const struct tnt tnts[] = {
172 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
173 { TAINT_FORCED_MODULE, 'F', ' ' },
174 { TAINT_UNSAFE_SMP, 'S', ' ' },
175 { TAINT_FORCED_RMMOD, 'R', ' ' },
176 { TAINT_MACHINE_CHECK, 'M', ' ' },
177 { TAINT_BAD_PAGE, 'B', ' ' },
178 { TAINT_USER, 'U', ' ' },
179 { TAINT_DIE, 'D', ' ' },
180 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
181 { TAINT_WARN, 'W', ' ' },
182 { TAINT_CRAP, 'C', ' ' },
183 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
187 * print_tainted - return a string to represent the kernel taint state.
189 * 'P' - Proprietary module has been loaded.
190 * 'F' - Module has been forcibly loaded.
191 * 'S' - SMP with CPUs not designed for SMP.
192 * 'R' - User forced a module unload.
193 * 'M' - System experienced a machine check exception.
194 * 'B' - System has hit bad_page.
195 * 'U' - Userspace-defined naughtiness.
196 * 'D' - Kernel has oopsed before
197 * 'A' - ACPI table overridden.
198 * 'W' - Taint on warning.
199 * 'C' - modules from drivers/staging are loaded.
200 * 'I' - Working around severe firmware bug.
202 * The string is overwritten by the next call to print_tainted().
204 const char *print_tainted(void)
206 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
212 s = buf + sprintf(buf, "Tainted: ");
213 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
214 const struct tnt *t = &tnts[i];
215 *s++ = test_bit(t->bit, &tainted_mask) ?
220 snprintf(buf, sizeof(buf), "Not tainted");
225 int test_taint(unsigned flag)
227 return test_bit(flag, &tainted_mask);
229 EXPORT_SYMBOL(test_taint);
231 unsigned long get_taint(void)
236 void add_taint(unsigned flag)
239 * Can't trust the integrity of the kernel anymore.
240 * We don't call directly debug_locks_off() because the issue
241 * is not necessarily serious enough to set oops_in_progress to 1
242 * Also we want to keep up lockdep for staging development and
248 case TAINT_FIRMWARE_WORKAROUND:
252 if (__debug_locks_off())
253 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
256 set_bit(flag, &tainted_mask);
258 EXPORT_SYMBOL(add_taint);
260 static void spin_msec(int msecs)
264 for (i = 0; i < msecs; i++) {
265 touch_nmi_watchdog();
271 * It just happens that oops_enter() and oops_exit() are identically
274 static void do_oops_enter_exit(void)
277 static int spin_counter;
282 spin_lock_irqsave(&pause_on_oops_lock, flags);
283 if (pause_on_oops_flag == 0) {
284 /* This CPU may now print the oops message */
285 pause_on_oops_flag = 1;
287 /* We need to stall this CPU */
289 /* This CPU gets to do the counting */
290 spin_counter = pause_on_oops;
292 spin_unlock(&pause_on_oops_lock);
293 spin_msec(MSEC_PER_SEC);
294 spin_lock(&pause_on_oops_lock);
295 } while (--spin_counter);
296 pause_on_oops_flag = 0;
298 /* This CPU waits for a different one */
299 while (spin_counter) {
300 spin_unlock(&pause_on_oops_lock);
302 spin_lock(&pause_on_oops_lock);
306 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
310 * Return true if the calling CPU is allowed to print oops-related info.
311 * This is a bit racy..
313 int oops_may_print(void)
315 return pause_on_oops_flag == 0;
319 * Called when the architecture enters its oops handler, before it prints
320 * anything. If this is the first CPU to oops, and it's oopsing the first
321 * time then let it proceed.
323 * This is all enabled by the pause_on_oops kernel boot option. We do all
324 * this to ensure that oopses don't scroll off the screen. It has the
325 * side-effect of preventing later-oopsing CPUs from mucking up the display,
328 * It turns out that the CPU which is allowed to print ends up pausing for
329 * the right duration, whereas all the other CPUs pause for twice as long:
330 * once in oops_enter(), once in oops_exit().
332 void oops_enter(void)
335 /* can't trust the integrity of the kernel anymore: */
337 do_oops_enter_exit();
341 * 64-bit random ID for oopses:
345 static int init_oops_id(void)
348 get_random_bytes(&oops_id, sizeof(oops_id));
354 late_initcall(init_oops_id);
356 void print_oops_end_marker(void)
360 if (mach_panic_string)
361 printk(KERN_WARNING "Board Information: %s\n",
364 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
365 (unsigned long long)oops_id);
369 * Called when the architecture exits its oops handler, after printing
374 do_oops_enter_exit();
375 print_oops_end_marker();
376 kmsg_dump(KMSG_DUMP_OOPS);
379 #ifdef WANT_WARN_ON_SLOWPATH
380 struct slowpath_args {
385 static void warn_slowpath_common(const char *file, int line, void *caller,
386 unsigned taint, struct slowpath_args *args)
390 printk(KERN_WARNING "------------[ cut here ]------------\n");
391 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
392 board = dmi_get_system_info(DMI_PRODUCT_NAME);
394 printk(KERN_WARNING "Hardware name: %s\n", board);
397 vprintk(args->fmt, args->args);
401 print_oops_end_marker();
405 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
407 struct slowpath_args args;
410 va_start(args.args, fmt);
411 warn_slowpath_common(file, line, __builtin_return_address(0),
415 EXPORT_SYMBOL(warn_slowpath_fmt);
417 void warn_slowpath_fmt_taint(const char *file, int line,
418 unsigned taint, const char *fmt, ...)
420 struct slowpath_args args;
423 va_start(args.args, fmt);
424 warn_slowpath_common(file, line, __builtin_return_address(0),
428 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
430 void warn_slowpath_null(const char *file, int line)
432 warn_slowpath_common(file, line, __builtin_return_address(0),
435 EXPORT_SYMBOL(warn_slowpath_null);
438 #ifdef CONFIG_CC_STACKPROTECTOR
441 * Called when gcc's -fstack-protector feature is used, and
442 * gcc detects corruption of the on-stack canary value
444 void __stack_chk_fail(void)
446 panic("stack-protector: Kernel stack is corrupted in: %p\n",
447 __builtin_return_address(0));
449 EXPORT_SYMBOL(__stack_chk_fail);
453 core_param(panic, panic_timeout, int, 0644);
454 core_param(pause_on_oops, pause_on_oops, int, 0644);
456 static int __init oops_setup(char *s)
460 if (!strcmp(s, "panic"))
464 early_param("oops", oops_setup);