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/ftrace.h>
19 #include <linux/reboot.h>
20 #include <linux/delay.h>
21 #include <linux/kexec.h>
22 #include <linux/sched.h>
23 #include <linux/sysrq.h>
24 #include <linux/init.h>
25 #include <linux/nmi.h>
26 #include <linux/console.h>
27 #include <soc/qcom/minidump.h>
29 #define CREATE_TRACE_POINTS
30 #include <trace/events/exception.h>
32 #define PANIC_TIMER_STEP 100
33 #define PANIC_BLINK_SPD 18
35 int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
36 static unsigned long tainted_mask;
37 static int pause_on_oops;
38 static int pause_on_oops_flag;
39 static DEFINE_SPINLOCK(pause_on_oops_lock);
40 bool crash_kexec_post_notifiers;
41 int panic_on_warn __read_mostly;
43 int panic_timeout = CONFIG_PANIC_TIMEOUT;
44 EXPORT_SYMBOL_GPL(panic_timeout);
46 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
48 EXPORT_SYMBOL(panic_notifier_list);
50 static long no_blink(int state)
55 /* Returns how long it waited in ms */
56 long (*panic_blink)(int state);
57 EXPORT_SYMBOL(panic_blink);
60 * Stop ourself in panic -- architecture code may override this
62 void __weak panic_smp_self_stop(void)
69 * panic - halt the system
70 * @fmt: The text string to print
72 * Display a message, then perform cleanups.
74 * This function never returns.
76 void panic(const char *fmt, ...)
78 static DEFINE_SPINLOCK(panic_lock);
79 static char buf[1024];
84 trace_kernel_panic(0);
87 * Disable local interrupts. This will prevent panic_smp_self_stop
88 * from deadlocking the first cpu that invokes the panic, since
89 * there is nothing to prevent an interrupt handler (that runs
90 * after the panic_lock is acquired) from invoking panic again.
95 * It's possible to come here directly from a panic-assertion and
96 * not have preempt disabled. Some functions called from here want
97 * preempt to be disabled. No point enabling it later though...
99 * Only one CPU is allowed to execute the panic code from here. For
100 * multiple parallel invocations of panic, all other CPUs either
101 * stop themself or will wait until they are stopped by the 1st CPU
102 * with smp_send_stop().
104 if (!spin_trylock(&panic_lock))
105 panic_smp_self_stop();
110 vsnprintf(buf, sizeof(buf), fmt, args);
112 dump_stack_minidump(0);
113 pr_emerg("Kernel panic - not syncing: %s\n", buf);
114 #ifdef CONFIG_DEBUG_BUGVERBOSE
116 * Avoid nested stack-dumping if a panic occurs during oops processing
118 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
123 * If we have crashed and we have a crash kernel loaded let it handle
125 * If we want to run this after calling panic_notifiers, pass
126 * the "crash_kexec_post_notifiers" option to the kernel.
128 if (!crash_kexec_post_notifiers)
132 * Note smp_send_stop is the usual smp shutdown function, which
133 * unfortunately means it may not be hardened to work in a panic
139 * Run any panic handlers, including those that might need to
140 * add information to the kmsg dump output.
142 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
144 kmsg_dump(KMSG_DUMP_PANIC);
147 * If you doubt kdump always works fine in any situation,
148 * "crash_kexec_post_notifiers" offers you a chance to run
149 * panic_notifiers and dumping kmsg before kdump.
150 * Note: since some panic_notifiers can make crashed kernel
151 * more unstable, it can increase risks of the kdump failure too.
153 if (crash_kexec_post_notifiers)
159 * We may have ended up stopping the CPU holding the lock (in
160 * smp_send_stop()) while still having some valuable data in the console
161 * buffer. Try to acquire the lock then release it regardless of the
162 * result. The release will also print the buffers out. Locks debug
163 * should be disabled to avoid reporting bad unlock balance when
164 * panic() is not being callled from OOPS.
167 console_flush_on_panic();
170 panic_blink = no_blink;
172 if (panic_timeout > 0) {
174 * Delay timeout seconds before rebooting the machine.
175 * We can't use the "normal" timers since we just panicked.
177 pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
179 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
180 touch_nmi_watchdog();
182 i += panic_blink(state ^= 1);
183 i_next = i + 3600 / PANIC_BLINK_SPD;
185 mdelay(PANIC_TIMER_STEP);
189 trace_kernel_panic_late(0);
191 if (panic_timeout != 0) {
193 * This will not be a clean reboot, with everything
194 * shutting down. But if there is a chance of
195 * rebooting the system it will be rebooted.
201 extern int stop_a_enabled;
202 /* Make sure the user can actually press Stop-A (L1-A) */
204 pr_emerg("Press Stop-A (L1-A) to return to the boot prom\n");
207 #if defined(CONFIG_S390)
209 unsigned long caller;
211 caller = (unsigned long)__builtin_return_address(0);
212 disabled_wait(caller);
215 pr_emerg("---[ end Kernel panic - not syncing: %s\n", buf);
217 for (i = 0; ; i += PANIC_TIMER_STEP) {
218 touch_softlockup_watchdog();
220 i += panic_blink(state ^= 1);
221 i_next = i + 3600 / PANIC_BLINK_SPD;
223 mdelay(PANIC_TIMER_STEP);
227 EXPORT_SYMBOL(panic);
236 static const struct tnt tnts[] = {
237 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
238 { TAINT_FORCED_MODULE, 'F', ' ' },
239 { TAINT_CPU_OUT_OF_SPEC, 'S', ' ' },
240 { TAINT_FORCED_RMMOD, 'R', ' ' },
241 { TAINT_MACHINE_CHECK, 'M', ' ' },
242 { TAINT_BAD_PAGE, 'B', ' ' },
243 { TAINT_USER, 'U', ' ' },
244 { TAINT_DIE, 'D', ' ' },
245 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
246 { TAINT_WARN, 'W', ' ' },
247 { TAINT_CRAP, 'C', ' ' },
248 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
249 { TAINT_OOT_MODULE, 'O', ' ' },
250 { TAINT_UNSIGNED_MODULE, 'E', ' ' },
251 { TAINT_SOFTLOCKUP, 'L', ' ' },
252 { TAINT_LIVEPATCH, 'K', ' ' },
256 * print_tainted - return a string to represent the kernel taint state.
258 * 'P' - Proprietary module has been loaded.
259 * 'F' - Module has been forcibly loaded.
260 * 'S' - SMP with CPUs not designed for SMP.
261 * 'R' - User forced a module unload.
262 * 'M' - System experienced a machine check exception.
263 * 'B' - System has hit bad_page.
264 * 'U' - Userspace-defined naughtiness.
265 * 'D' - Kernel has oopsed before
266 * 'A' - ACPI table overridden.
267 * 'W' - Taint on warning.
268 * 'C' - modules from drivers/staging are loaded.
269 * 'I' - Working around severe firmware bug.
270 * 'O' - Out-of-tree module has been loaded.
271 * 'E' - Unsigned module has been loaded.
272 * 'L' - A soft lockup has previously occurred.
273 * 'K' - Kernel has been live patched.
275 * The string is overwritten by the next call to print_tainted().
277 const char *print_tainted(void)
279 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ")];
285 s = buf + sprintf(buf, "Tainted: ");
286 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
287 const struct tnt *t = &tnts[i];
288 *s++ = test_bit(t->bit, &tainted_mask) ?
293 snprintf(buf, sizeof(buf), "Not tainted");
298 int test_taint(unsigned flag)
300 return test_bit(flag, &tainted_mask);
302 EXPORT_SYMBOL(test_taint);
304 unsigned long get_taint(void)
310 * add_taint: add a taint flag if not already set.
311 * @flag: one of the TAINT_* constants.
312 * @lockdep_ok: whether lock debugging is still OK.
314 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
315 * some notewortht-but-not-corrupting cases, it can be set to true.
317 void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
319 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
320 pr_warn("Disabling lock debugging due to kernel taint\n");
322 set_bit(flag, &tainted_mask);
324 EXPORT_SYMBOL(add_taint);
326 static void spin_msec(int msecs)
330 for (i = 0; i < msecs; i++) {
331 touch_nmi_watchdog();
337 * It just happens that oops_enter() and oops_exit() are identically
340 static void do_oops_enter_exit(void)
343 static int spin_counter;
348 spin_lock_irqsave(&pause_on_oops_lock, flags);
349 if (pause_on_oops_flag == 0) {
350 /* This CPU may now print the oops message */
351 pause_on_oops_flag = 1;
353 /* We need to stall this CPU */
355 /* This CPU gets to do the counting */
356 spin_counter = pause_on_oops;
358 spin_unlock(&pause_on_oops_lock);
359 spin_msec(MSEC_PER_SEC);
360 spin_lock(&pause_on_oops_lock);
361 } while (--spin_counter);
362 pause_on_oops_flag = 0;
364 /* This CPU waits for a different one */
365 while (spin_counter) {
366 spin_unlock(&pause_on_oops_lock);
368 spin_lock(&pause_on_oops_lock);
372 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
376 * Return true if the calling CPU is allowed to print oops-related info.
377 * This is a bit racy..
379 int oops_may_print(void)
381 return pause_on_oops_flag == 0;
385 * Called when the architecture enters its oops handler, before it prints
386 * anything. If this is the first CPU to oops, and it's oopsing the first
387 * time then let it proceed.
389 * This is all enabled by the pause_on_oops kernel boot option. We do all
390 * this to ensure that oopses don't scroll off the screen. It has the
391 * side-effect of preventing later-oopsing CPUs from mucking up the display,
394 * It turns out that the CPU which is allowed to print ends up pausing for
395 * the right duration, whereas all the other CPUs pause for twice as long:
396 * once in oops_enter(), once in oops_exit().
398 void oops_enter(void)
401 /* can't trust the integrity of the kernel anymore: */
403 do_oops_enter_exit();
407 * 64-bit random ID for oopses:
411 static int init_oops_id(void)
414 get_random_bytes(&oops_id, sizeof(oops_id));
420 late_initcall(init_oops_id);
422 void print_oops_end_marker(void)
425 pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
429 * Called when the architecture exits its oops handler, after printing
434 do_oops_enter_exit();
435 print_oops_end_marker();
436 kmsg_dump(KMSG_DUMP_OOPS);
439 #ifdef WANT_WARN_ON_SLOWPATH
440 struct slowpath_args {
445 static void warn_slowpath_common(const char *file, int line, void *caller,
446 unsigned taint, struct slowpath_args *args)
448 disable_trace_on_warning();
450 pr_warn("------------[ cut here ]------------\n");
451 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS()\n",
452 raw_smp_processor_id(), current->pid, file, line, caller);
455 vprintk(args->fmt, args->args);
459 * This thread may hit another WARN() in the panic path.
460 * Resetting this prevents additional WARN() from panicking the
461 * system on this thread. Other threads are blocked by the
462 * panic_mutex in panic().
465 panic("panic_on_warn set ...\n");
470 print_oops_end_marker();
471 /* Just a warning, don't kill lockdep. */
472 add_taint(taint, LOCKDEP_STILL_OK);
475 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
477 struct slowpath_args args;
480 va_start(args.args, fmt);
481 warn_slowpath_common(file, line, __builtin_return_address(0),
485 EXPORT_SYMBOL(warn_slowpath_fmt);
487 void warn_slowpath_fmt_taint(const char *file, int line,
488 unsigned taint, const char *fmt, ...)
490 struct slowpath_args args;
493 va_start(args.args, fmt);
494 warn_slowpath_common(file, line, __builtin_return_address(0),
498 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
500 void warn_slowpath_null(const char *file, int line)
502 warn_slowpath_common(file, line, __builtin_return_address(0),
505 EXPORT_SYMBOL(warn_slowpath_null);
508 #ifdef CONFIG_CC_STACKPROTECTOR
511 * Called when gcc's -fstack-protector feature is used, and
512 * gcc detects corruption of the on-stack canary value
514 __visible void __stack_chk_fail(void)
516 panic("stack-protector: Kernel stack is corrupted in: %p\n",
517 __builtin_return_address(0));
519 EXPORT_SYMBOL(__stack_chk_fail);
523 core_param(panic, panic_timeout, int, 0644);
524 core_param(pause_on_oops, pause_on_oops, int, 0644);
525 core_param(panic_on_warn, panic_on_warn, int, 0644);
527 static int __init setup_crash_kexec_post_notifiers(char *s)
529 crash_kexec_post_notifiers = true;
532 early_param("crash_kexec_post_notifiers", setup_crash_kexec_post_notifiers);
534 static int __init oops_setup(char *s)
538 if (!strcmp(s, "panic"))
542 early_param("oops", oops_setup);