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>
26 #define PANIC_TIMER_STEP 100
27 #define PANIC_BLINK_SPD 18
29 /* Machine specific panic information string */
30 char *mach_panic_string;
32 int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
33 static unsigned long tainted_mask;
34 static int pause_on_oops;
35 static int pause_on_oops_flag;
36 static DEFINE_SPINLOCK(pause_on_oops_lock);
38 #ifndef CONFIG_PANIC_TIMEOUT
39 #define CONFIG_PANIC_TIMEOUT 0
41 int panic_timeout = CONFIG_PANIC_TIMEOUT;
42 EXPORT_SYMBOL_GPL(panic_timeout);
44 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
46 EXPORT_SYMBOL(panic_notifier_list);
48 static long no_blink(int state)
53 /* Returns how long it waited in ms */
54 long (*panic_blink)(int state);
55 EXPORT_SYMBOL(panic_blink);
58 * Stop ourself in panic -- architecture code may override this
60 void __weak panic_smp_self_stop(void)
66 #ifdef CONFIG_TEGRA_NVDUMPER
67 void nvdumper_crash_setup_regs(void);
68 static int is_oops_called;
69 #endif /* CONFIG_TEGRA_NVDUMPER */
72 * panic - halt the system
73 * @fmt: The text string to print
75 * Display a message, then perform cleanups.
77 * This function never returns.
79 void panic(const char *fmt, ...)
81 static DEFINE_SPINLOCK(panic_lock);
82 static char buf[1024];
87 #ifdef CONFIG_TEGRA_NVDUMPER
88 /* if panic is called directly */
90 nvdumper_crash_setup_regs();
94 * Disable local interrupts. This will prevent panic_smp_self_stop
95 * from deadlocking the first cpu that invokes the panic, since
96 * there is nothing to prevent an interrupt handler (that runs
97 * after the panic_lock is acquired) from invoking panic again.
102 * It's possible to come here directly from a panic-assertion and
103 * not have preempt disabled. Some functions called from here want
104 * preempt to be disabled. No point enabling it later though...
106 * Only one CPU is allowed to execute the panic code from here. For
107 * multiple parallel invocations of panic, all other CPUs either
108 * stop themself or will wait until they are stopped by the 1st CPU
109 * with smp_send_stop().
111 if (!spin_trylock(&panic_lock))
112 panic_smp_self_stop();
117 vsnprintf(buf, sizeof(buf), fmt, args);
119 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
120 #ifdef CONFIG_DEBUG_BUGVERBOSE
122 * Avoid nested stack-dumping if a panic occurs during oops processing
124 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
129 * If we have crashed and we have a crash kernel loaded let it handle
131 * Do we want to call this before we try to display a message?
136 * Note smp_send_stop is the usual smp shutdown function, which
137 * unfortunately means it may not be hardened to work in a panic
142 kmsg_dump(KMSG_DUMP_PANIC);
144 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
149 panic_blink = no_blink;
151 if (panic_timeout > 0) {
153 * Delay timeout seconds before rebooting the machine.
154 * We can't use the "normal" timers since we just panicked.
156 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
158 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
159 touch_nmi_watchdog();
161 i += panic_blink(state ^= 1);
162 i_next = i + 3600 / PANIC_BLINK_SPD;
164 mdelay(PANIC_TIMER_STEP);
167 if (panic_timeout != 0) {
169 * This will not be a clean reboot, with everything
170 * shutting down. But if there is a chance of
171 * rebooting the system it will be rebooted.
177 extern int stop_a_enabled;
178 /* Make sure the user can actually press Stop-A (L1-A) */
180 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
183 #if defined(CONFIG_S390)
185 unsigned long caller;
187 caller = (unsigned long)__builtin_return_address(0);
188 disabled_wait(caller);
192 for (i = 0; ; i += PANIC_TIMER_STEP) {
193 touch_softlockup_watchdog();
195 i += panic_blink(state ^= 1);
196 i_next = i + 3600 / PANIC_BLINK_SPD;
198 mdelay(PANIC_TIMER_STEP);
202 EXPORT_SYMBOL(panic);
211 static const struct tnt tnts[] = {
212 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
213 { TAINT_FORCED_MODULE, 'F', ' ' },
214 { TAINT_UNSAFE_SMP, 'S', ' ' },
215 { TAINT_FORCED_RMMOD, 'R', ' ' },
216 { TAINT_MACHINE_CHECK, 'M', ' ' },
217 { TAINT_BAD_PAGE, 'B', ' ' },
218 { TAINT_USER, 'U', ' ' },
219 { TAINT_DIE, 'D', ' ' },
220 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
221 { TAINT_WARN, 'W', ' ' },
222 { TAINT_CRAP, 'C', ' ' },
223 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
224 { TAINT_OOT_MODULE, 'O', ' ' },
228 * print_tainted - return a string to represent the kernel taint state.
230 * 'P' - Proprietary module has been loaded.
231 * 'F' - Module has been forcibly loaded.
232 * 'S' - SMP with CPUs not designed for SMP.
233 * 'R' - User forced a module unload.
234 * 'M' - System experienced a machine check exception.
235 * 'B' - System has hit bad_page.
236 * 'U' - Userspace-defined naughtiness.
237 * 'D' - Kernel has oopsed before
238 * 'A' - ACPI table overridden.
239 * 'W' - Taint on warning.
240 * 'C' - modules from drivers/staging are loaded.
241 * 'I' - Working around severe firmware bug.
242 * 'O' - Out-of-tree module has been loaded.
244 * The string is overwritten by the next call to print_tainted().
246 const char *print_tainted(void)
248 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
254 s = buf + sprintf(buf, "Tainted: ");
255 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
256 const struct tnt *t = &tnts[i];
257 *s++ = test_bit(t->bit, &tainted_mask) ?
262 snprintf(buf, sizeof(buf), "Not tainted");
267 int test_taint(unsigned flag)
269 return test_bit(flag, &tainted_mask);
271 EXPORT_SYMBOL(test_taint);
273 unsigned long get_taint(void)
279 * add_taint: add a taint flag if not already set.
280 * @flag: one of the TAINT_* constants.
281 * @lockdep_ok: whether lock debugging is still OK.
283 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
284 * some notewortht-but-not-corrupting cases, it can be set to true.
286 void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
288 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
290 "Disabling lock debugging due to kernel taint\n");
292 set_bit(flag, &tainted_mask);
294 EXPORT_SYMBOL(add_taint);
296 static void spin_msec(int msecs)
300 for (i = 0; i < msecs; i++) {
301 touch_nmi_watchdog();
307 * It just happens that oops_enter() and oops_exit() are identically
310 static void do_oops_enter_exit(void)
313 static int spin_counter;
318 spin_lock_irqsave(&pause_on_oops_lock, flags);
319 if (pause_on_oops_flag == 0) {
320 /* This CPU may now print the oops message */
321 pause_on_oops_flag = 1;
323 /* We need to stall this CPU */
325 /* This CPU gets to do the counting */
326 spin_counter = pause_on_oops;
328 spin_unlock(&pause_on_oops_lock);
329 spin_msec(MSEC_PER_SEC);
330 spin_lock(&pause_on_oops_lock);
331 } while (--spin_counter);
332 pause_on_oops_flag = 0;
334 /* This CPU waits for a different one */
335 while (spin_counter) {
336 spin_unlock(&pause_on_oops_lock);
338 spin_lock(&pause_on_oops_lock);
342 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
346 * Return true if the calling CPU is allowed to print oops-related info.
347 * This is a bit racy..
349 int oops_may_print(void)
351 return pause_on_oops_flag == 0;
355 * Called when the architecture enters its oops handler, before it prints
356 * anything. If this is the first CPU to oops, and it's oopsing the first
357 * time then let it proceed.
359 * This is all enabled by the pause_on_oops kernel boot option. We do all
360 * this to ensure that oopses don't scroll off the screen. It has the
361 * side-effect of preventing later-oopsing CPUs from mucking up the display,
364 * It turns out that the CPU which is allowed to print ends up pausing for
365 * the right duration, whereas all the other CPUs pause for twice as long:
366 * once in oops_enter(), once in oops_exit().
368 void oops_enter(void)
370 #ifdef CONFIG_TEGRA_NVDUMPER
375 /* can't trust the integrity of the kernel anymore: */
377 do_oops_enter_exit();
381 * 64-bit random ID for oopses:
385 static int init_oops_id(void)
388 get_random_bytes(&oops_id, sizeof(oops_id));
394 late_initcall(init_oops_id);
396 void print_oops_end_marker(void)
400 if (mach_panic_string)
401 printk(KERN_WARNING "Board Information: %s\n",
404 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
405 (unsigned long long)oops_id);
409 * Called when the architecture exits its oops handler, after printing
414 do_oops_enter_exit();
415 print_oops_end_marker();
416 kmsg_dump(KMSG_DUMP_OOPS);
419 #ifdef WANT_WARN_ON_SLOWPATH
420 struct slowpath_args {
425 static void warn_slowpath_common(const char *file, int line, void *caller,
426 unsigned taint, struct slowpath_args *args)
428 printk(KERN_WARNING "------------[ cut here ]------------\n");
429 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
432 vprintk(args->fmt, args->args);
436 print_oops_end_marker();
437 /* Just a warning, don't kill lockdep. */
438 add_taint(taint, LOCKDEP_STILL_OK);
441 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
443 struct slowpath_args args;
446 va_start(args.args, fmt);
447 warn_slowpath_common(file, line, __builtin_return_address(0),
451 EXPORT_SYMBOL(warn_slowpath_fmt);
453 void warn_slowpath_fmt_taint(const char *file, int line,
454 unsigned taint, const char *fmt, ...)
456 struct slowpath_args args;
459 va_start(args.args, fmt);
460 warn_slowpath_common(file, line, __builtin_return_address(0),
464 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
466 void warn_slowpath_null(const char *file, int line)
468 warn_slowpath_common(file, line, __builtin_return_address(0),
471 EXPORT_SYMBOL(warn_slowpath_null);
474 #ifdef CONFIG_CC_STACKPROTECTOR
477 * Called when gcc's -fstack-protector feature is used, and
478 * gcc detects corruption of the on-stack canary value
480 void __stack_chk_fail(void)
482 panic("stack-protector: Kernel stack is corrupted in: %p\n",
483 __builtin_return_address(0));
485 EXPORT_SYMBOL(__stack_chk_fail);
489 core_param(panic, panic_timeout, int, 0644);
490 core_param(pause_on_oops, pause_on_oops, int, 0644);
492 static int __init oops_setup(char *s)
496 if (!strcmp(s, "panic"))
500 early_param("oops", oops_setup);