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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/panic.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | /* | |
9 | * This function is used through-out the kernel (including mm and fs) | |
10 | * to indicate a major problem. | |
11 | */ | |
c95dbf27 | 12 | #include <linux/debug_locks.h> |
b17b0153 | 13 | #include <linux/sched/debug.h> |
c95dbf27 | 14 | #include <linux/interrupt.h> |
456b565c | 15 | #include <linux/kmsg_dump.h> |
c95dbf27 IM |
16 | #include <linux/kallsyms.h> |
17 | #include <linux/notifier.h> | |
c7c3f05e | 18 | #include <linux/vt_kern.h> |
1da177e4 | 19 | #include <linux/module.h> |
c95dbf27 | 20 | #include <linux/random.h> |
de7edd31 | 21 | #include <linux/ftrace.h> |
1da177e4 | 22 | #include <linux/reboot.h> |
c95dbf27 IM |
23 | #include <linux/delay.h> |
24 | #include <linux/kexec.h> | |
25 | #include <linux/sched.h> | |
1da177e4 | 26 | #include <linux/sysrq.h> |
c95dbf27 | 27 | #include <linux/init.h> |
1da177e4 | 28 | #include <linux/nmi.h> |
08d78658 | 29 | #include <linux/console.h> |
2553b67a | 30 | #include <linux/bug.h> |
7a46ec0e | 31 | #include <linux/ratelimit.h> |
b1fca27d AK |
32 | #include <linux/debugfs.h> |
33 | #include <asm/sections.h> | |
1da177e4 | 34 | |
c7ff0d9c TS |
35 | #define PANIC_TIMER_STEP 100 |
36 | #define PANIC_BLINK_SPD 18 | |
37 | ||
2a01bb38 | 38 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
bc4f2f54 KC |
39 | static unsigned long tainted_mask = |
40 | IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; | |
dd287796 AM |
41 | static int pause_on_oops; |
42 | static int pause_on_oops_flag; | |
43 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
5375b708 | 44 | bool crash_kexec_post_notifiers; |
9e3961a0 | 45 | int panic_on_warn __read_mostly; |
1da177e4 | 46 | |
5800dc3c | 47 | int panic_timeout = CONFIG_PANIC_TIMEOUT; |
81e88fdc | 48 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 49 | |
d999bd93 FT |
50 | #define PANIC_PRINT_TASK_INFO 0x00000001 |
51 | #define PANIC_PRINT_MEM_INFO 0x00000002 | |
52 | #define PANIC_PRINT_TIMER_INFO 0x00000004 | |
53 | #define PANIC_PRINT_LOCK_INFO 0x00000008 | |
54 | #define PANIC_PRINT_FTRACE_INFO 0x00000010 | |
de6da1e8 | 55 | #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 |
81c9d43f | 56 | unsigned long panic_print; |
d999bd93 | 57 | |
e041c683 | 58 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
59 | |
60 | EXPORT_SYMBOL(panic_notifier_list); | |
61 | ||
c7ff0d9c | 62 | static long no_blink(int state) |
8aeee85a | 63 | { |
c7ff0d9c | 64 | return 0; |
8aeee85a AB |
65 | } |
66 | ||
c7ff0d9c TS |
67 | /* Returns how long it waited in ms */ |
68 | long (*panic_blink)(int state); | |
69 | EXPORT_SYMBOL(panic_blink); | |
70 | ||
93e13a36 MH |
71 | /* |
72 | * Stop ourself in panic -- architecture code may override this | |
73 | */ | |
74 | void __weak panic_smp_self_stop(void) | |
75 | { | |
76 | while (1) | |
77 | cpu_relax(); | |
78 | } | |
79 | ||
58c5661f HK |
80 | /* |
81 | * Stop ourselves in NMI context if another CPU has already panicked. Arch code | |
82 | * may override this to prepare for crash dumping, e.g. save regs info. | |
83 | */ | |
84 | void __weak nmi_panic_self_stop(struct pt_regs *regs) | |
85 | { | |
86 | panic_smp_self_stop(); | |
87 | } | |
88 | ||
0ee59413 HK |
89 | /* |
90 | * Stop other CPUs in panic. Architecture dependent code may override this | |
91 | * with more suitable version. For example, if the architecture supports | |
92 | * crash dump, it should save registers of each stopped CPU and disable | |
93 | * per-CPU features such as virtualization extensions. | |
94 | */ | |
95 | void __weak crash_smp_send_stop(void) | |
96 | { | |
97 | static int cpus_stopped; | |
98 | ||
99 | /* | |
100 | * This function can be called twice in panic path, but obviously | |
101 | * we execute this only once. | |
102 | */ | |
103 | if (cpus_stopped) | |
104 | return; | |
105 | ||
106 | /* | |
107 | * Note smp_send_stop is the usual smp shutdown function, which | |
108 | * unfortunately means it may not be hardened to work in a panic | |
109 | * situation. | |
110 | */ | |
111 | smp_send_stop(); | |
112 | cpus_stopped = 1; | |
113 | } | |
114 | ||
1717f209 HK |
115 | atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); |
116 | ||
ebc41f20 HK |
117 | /* |
118 | * A variant of panic() called from NMI context. We return if we've already | |
119 | * panicked on this CPU. If another CPU already panicked, loop in | |
120 | * nmi_panic_self_stop() which can provide architecture dependent code such | |
121 | * as saving register state for crash dump. | |
122 | */ | |
123 | void nmi_panic(struct pt_regs *regs, const char *msg) | |
124 | { | |
125 | int old_cpu, cpu; | |
126 | ||
127 | cpu = raw_smp_processor_id(); | |
128 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); | |
129 | ||
130 | if (old_cpu == PANIC_CPU_INVALID) | |
131 | panic("%s", msg); | |
132 | else if (old_cpu != cpu) | |
133 | nmi_panic_self_stop(regs); | |
134 | } | |
135 | EXPORT_SYMBOL(nmi_panic); | |
136 | ||
d999bd93 FT |
137 | static void panic_print_sys_info(void) |
138 | { | |
de6da1e8 FT |
139 | if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) |
140 | console_flush_on_panic(CONSOLE_REPLAY_ALL); | |
141 | ||
d999bd93 FT |
142 | if (panic_print & PANIC_PRINT_TASK_INFO) |
143 | show_state(); | |
144 | ||
145 | if (panic_print & PANIC_PRINT_MEM_INFO) | |
146 | show_mem(0, NULL); | |
147 | ||
148 | if (panic_print & PANIC_PRINT_TIMER_INFO) | |
149 | sysrq_timer_list_show(); | |
150 | ||
151 | if (panic_print & PANIC_PRINT_LOCK_INFO) | |
152 | debug_show_all_locks(); | |
153 | ||
154 | if (panic_print & PANIC_PRINT_FTRACE_INFO) | |
155 | ftrace_dump(DUMP_ALL); | |
156 | } | |
157 | ||
1da177e4 LT |
158 | /** |
159 | * panic - halt the system | |
160 | * @fmt: The text string to print | |
161 | * | |
162 | * Display a message, then perform cleanups. | |
163 | * | |
164 | * This function never returns. | |
165 | */ | |
9402c95f | 166 | void panic(const char *fmt, ...) |
1da177e4 | 167 | { |
1da177e4 LT |
168 | static char buf[1024]; |
169 | va_list args; | |
b49dec1c | 170 | long i, i_next = 0, len; |
c7ff0d9c | 171 | int state = 0; |
1717f209 | 172 | int old_cpu, this_cpu; |
b26e27dd | 173 | bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; |
1da177e4 | 174 | |
190320c3 VM |
175 | /* |
176 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
177 | * from deadlocking the first cpu that invokes the panic, since | |
178 | * there is nothing to prevent an interrupt handler (that runs | |
1717f209 | 179 | * after setting panic_cpu) from invoking panic() again. |
190320c3 VM |
180 | */ |
181 | local_irq_disable(); | |
182 | ||
dc009d92 | 183 | /* |
c95dbf27 IM |
184 | * It's possible to come here directly from a panic-assertion and |
185 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 186 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
187 | * |
188 | * Only one CPU is allowed to execute the panic code from here. For | |
189 | * multiple parallel invocations of panic, all other CPUs either | |
190 | * stop themself or will wait until they are stopped by the 1st CPU | |
191 | * with smp_send_stop(). | |
1717f209 HK |
192 | * |
193 | * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which | |
194 | * comes here, so go ahead. | |
195 | * `old_cpu == this_cpu' means we came from nmi_panic() which sets | |
196 | * panic_cpu to this CPU. In this case, this is also the 1st CPU. | |
dc009d92 | 197 | */ |
1717f209 HK |
198 | this_cpu = raw_smp_processor_id(); |
199 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
200 | ||
201 | if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) | |
93e13a36 | 202 | panic_smp_self_stop(); |
dc009d92 | 203 | |
5b530fc1 | 204 | console_verbose(); |
1da177e4 LT |
205 | bust_spinlocks(1); |
206 | va_start(args, fmt); | |
b49dec1c | 207 | len = vscnprintf(buf, sizeof(buf), fmt, args); |
1da177e4 | 208 | va_end(args); |
b49dec1c BP |
209 | |
210 | if (len && buf[len - 1] == '\n') | |
211 | buf[len - 1] = '\0'; | |
212 | ||
d7c0847f | 213 | pr_emerg("Kernel panic - not syncing: %s\n", buf); |
5cb27301 | 214 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
215 | /* |
216 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
217 | */ | |
026ee1f6 | 218 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 219 | dump_stack(); |
5cb27301 | 220 | #endif |
1da177e4 | 221 | |
dc009d92 EB |
222 | /* |
223 | * If we have crashed and we have a crash kernel loaded let it handle | |
224 | * everything else. | |
f06e5153 MH |
225 | * If we want to run this after calling panic_notifiers, pass |
226 | * the "crash_kexec_post_notifiers" option to the kernel. | |
7bbee5ca HK |
227 | * |
228 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
dc009d92 | 229 | */ |
b26e27dd | 230 | if (!_crash_kexec_post_notifiers) { |
f92bac3b | 231 | printk_safe_flush_on_panic(); |
7bbee5ca | 232 | __crash_kexec(NULL); |
dc009d92 | 233 | |
0ee59413 HK |
234 | /* |
235 | * Note smp_send_stop is the usual smp shutdown function, which | |
236 | * unfortunately means it may not be hardened to work in a | |
237 | * panic situation. | |
238 | */ | |
239 | smp_send_stop(); | |
240 | } else { | |
241 | /* | |
242 | * If we want to do crash dump after notifier calls and | |
243 | * kmsg_dump, we will need architecture dependent extra | |
244 | * works in addition to stopping other CPUs. | |
245 | */ | |
246 | crash_smp_send_stop(); | |
247 | } | |
1da177e4 | 248 | |
6723734c KC |
249 | /* |
250 | * Run any panic handlers, including those that might need to | |
251 | * add information to the kmsg dump output. | |
252 | */ | |
e041c683 | 253 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 254 | |
cf9b1106 | 255 | /* Call flush even twice. It tries harder with a single online CPU */ |
f92bac3b | 256 | printk_safe_flush_on_panic(); |
6723734c KC |
257 | kmsg_dump(KMSG_DUMP_PANIC); |
258 | ||
f06e5153 MH |
259 | /* |
260 | * If you doubt kdump always works fine in any situation, | |
261 | * "crash_kexec_post_notifiers" offers you a chance to run | |
262 | * panic_notifiers and dumping kmsg before kdump. | |
263 | * Note: since some panic_notifiers can make crashed kernel | |
264 | * more unstable, it can increase risks of the kdump failure too. | |
7bbee5ca HK |
265 | * |
266 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
f06e5153 | 267 | */ |
b26e27dd | 268 | if (_crash_kexec_post_notifiers) |
7bbee5ca | 269 | __crash_kexec(NULL); |
f06e5153 | 270 | |
c7c3f05e SS |
271 | #ifdef CONFIG_VT |
272 | unblank_screen(); | |
273 | #endif | |
274 | console_unblank(); | |
d014e889 | 275 | |
08d78658 VK |
276 | /* |
277 | * We may have ended up stopping the CPU holding the lock (in | |
278 | * smp_send_stop()) while still having some valuable data in the console | |
279 | * buffer. Try to acquire the lock then release it regardless of the | |
7625b3a0 VK |
280 | * result. The release will also print the buffers out. Locks debug |
281 | * should be disabled to avoid reporting bad unlock balance when | |
282 | * panic() is not being callled from OOPS. | |
08d78658 | 283 | */ |
7625b3a0 | 284 | debug_locks_off(); |
de6da1e8 | 285 | console_flush_on_panic(CONSOLE_FLUSH_PENDING); |
08d78658 | 286 | |
d999bd93 FT |
287 | panic_print_sys_info(); |
288 | ||
c7ff0d9c TS |
289 | if (!panic_blink) |
290 | panic_blink = no_blink; | |
291 | ||
dc009d92 | 292 | if (panic_timeout > 0) { |
1da177e4 | 293 | /* |
c95dbf27 IM |
294 | * Delay timeout seconds before rebooting the machine. |
295 | * We can't use the "normal" timers since we just panicked. | |
296 | */ | |
ff7a28a0 | 297 | pr_emerg("Rebooting in %d seconds..\n", panic_timeout); |
c95dbf27 | 298 | |
c7ff0d9c | 299 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 300 | touch_nmi_watchdog(); |
c7ff0d9c TS |
301 | if (i >= i_next) { |
302 | i += panic_blink(state ^= 1); | |
303 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
304 | } | |
305 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 306 | } |
4302fbc8 HD |
307 | } |
308 | if (panic_timeout != 0) { | |
c95dbf27 IM |
309 | /* |
310 | * This will not be a clean reboot, with everything | |
311 | * shutting down. But if there is a chance of | |
312 | * rebooting the system it will be rebooted. | |
1da177e4 | 313 | */ |
b287a25a AK |
314 | if (panic_reboot_mode != REBOOT_UNDEFINED) |
315 | reboot_mode = panic_reboot_mode; | |
2f048ea8 | 316 | emergency_restart(); |
1da177e4 LT |
317 | } |
318 | #ifdef __sparc__ | |
319 | { | |
320 | extern int stop_a_enabled; | |
a271c241 | 321 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 322 | stop_a_enabled = 1; |
7db60d05 VK |
323 | pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" |
324 | "twice on console to return to the boot prom\n"); | |
1da177e4 LT |
325 | } |
326 | #endif | |
347a8dc3 | 327 | #if defined(CONFIG_S390) |
98587c2d | 328 | disabled_wait(); |
1da177e4 | 329 | #endif |
5ad75105 | 330 | pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); |
c39ea0b9 FT |
331 | |
332 | /* Do not scroll important messages printed above */ | |
333 | suppress_printk = 1; | |
1da177e4 | 334 | local_irq_enable(); |
c7ff0d9c | 335 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 336 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
337 | if (i >= i_next) { |
338 | i += panic_blink(state ^= 1); | |
339 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
340 | } | |
341 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
342 | } |
343 | } | |
344 | ||
345 | EXPORT_SYMBOL(panic); | |
346 | ||
7fd8329b PM |
347 | /* |
348 | * TAINT_FORCED_RMMOD could be a per-module flag but the module | |
349 | * is being removed anyway. | |
350 | */ | |
351 | const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { | |
47d4b263 KC |
352 | [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, |
353 | [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, | |
354 | [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, | |
355 | [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, | |
356 | [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, | |
357 | [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, | |
358 | [ TAINT_USER ] = { 'U', ' ', false }, | |
359 | [ TAINT_DIE ] = { 'D', ' ', false }, | |
360 | [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, | |
361 | [ TAINT_WARN ] = { 'W', ' ', false }, | |
362 | [ TAINT_CRAP ] = { 'C', ' ', true }, | |
363 | [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, | |
364 | [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, | |
365 | [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, | |
366 | [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, | |
367 | [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, | |
368 | [ TAINT_AUX ] = { 'X', ' ', true }, | |
bc4f2f54 | 369 | [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, |
25ddbb18 AK |
370 | }; |
371 | ||
1da177e4 | 372 | /** |
9c4560e5 | 373 | * print_tainted - return a string to represent the kernel taint state. |
1da177e4 | 374 | * |
9c4560e5 | 375 | * For individual taint flag meanings, see Documentation/sysctl/kernel.txt |
1da177e4 | 376 | * |
9c4560e5 KC |
377 | * The string is overwritten by the next call to print_tainted(), |
378 | * but is always NULL terminated. | |
1da177e4 | 379 | */ |
1da177e4 LT |
380 | const char *print_tainted(void) |
381 | { | |
7fd8329b | 382 | static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; |
25ddbb18 | 383 | |
47d4b263 KC |
384 | BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); |
385 | ||
25ddbb18 AK |
386 | if (tainted_mask) { |
387 | char *s; | |
388 | int i; | |
389 | ||
390 | s = buf + sprintf(buf, "Tainted: "); | |
7fd8329b PM |
391 | for (i = 0; i < TAINT_FLAGS_COUNT; i++) { |
392 | const struct taint_flag *t = &taint_flags[i]; | |
393 | *s++ = test_bit(i, &tainted_mask) ? | |
5eb7c0d0 | 394 | t->c_true : t->c_false; |
25ddbb18 AK |
395 | } |
396 | *s = 0; | |
397 | } else | |
1da177e4 | 398 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
399 | |
400 | return buf; | |
1da177e4 LT |
401 | } |
402 | ||
25ddbb18 | 403 | int test_taint(unsigned flag) |
1da177e4 | 404 | { |
25ddbb18 AK |
405 | return test_bit(flag, &tainted_mask); |
406 | } | |
407 | EXPORT_SYMBOL(test_taint); | |
408 | ||
409 | unsigned long get_taint(void) | |
410 | { | |
411 | return tainted_mask; | |
1da177e4 | 412 | } |
dd287796 | 413 | |
373d4d09 RR |
414 | /** |
415 | * add_taint: add a taint flag if not already set. | |
416 | * @flag: one of the TAINT_* constants. | |
417 | * @lockdep_ok: whether lock debugging is still OK. | |
418 | * | |
419 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
420 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
421 | */ | |
422 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 423 | { |
373d4d09 | 424 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
d7c0847f | 425 | pr_warn("Disabling lock debugging due to kernel taint\n"); |
9eeba613 | 426 | |
25ddbb18 | 427 | set_bit(flag, &tainted_mask); |
dd287796 | 428 | } |
1da177e4 | 429 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
430 | |
431 | static void spin_msec(int msecs) | |
432 | { | |
433 | int i; | |
434 | ||
435 | for (i = 0; i < msecs; i++) { | |
436 | touch_nmi_watchdog(); | |
437 | mdelay(1); | |
438 | } | |
439 | } | |
440 | ||
441 | /* | |
442 | * It just happens that oops_enter() and oops_exit() are identically | |
443 | * implemented... | |
444 | */ | |
445 | static void do_oops_enter_exit(void) | |
446 | { | |
447 | unsigned long flags; | |
448 | static int spin_counter; | |
449 | ||
450 | if (!pause_on_oops) | |
451 | return; | |
452 | ||
453 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
454 | if (pause_on_oops_flag == 0) { | |
455 | /* This CPU may now print the oops message */ | |
456 | pause_on_oops_flag = 1; | |
457 | } else { | |
458 | /* We need to stall this CPU */ | |
459 | if (!spin_counter) { | |
460 | /* This CPU gets to do the counting */ | |
461 | spin_counter = pause_on_oops; | |
462 | do { | |
463 | spin_unlock(&pause_on_oops_lock); | |
464 | spin_msec(MSEC_PER_SEC); | |
465 | spin_lock(&pause_on_oops_lock); | |
466 | } while (--spin_counter); | |
467 | pause_on_oops_flag = 0; | |
468 | } else { | |
469 | /* This CPU waits for a different one */ | |
470 | while (spin_counter) { | |
471 | spin_unlock(&pause_on_oops_lock); | |
472 | spin_msec(1); | |
473 | spin_lock(&pause_on_oops_lock); | |
474 | } | |
475 | } | |
476 | } | |
477 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
478 | } | |
479 | ||
480 | /* | |
c95dbf27 IM |
481 | * Return true if the calling CPU is allowed to print oops-related info. |
482 | * This is a bit racy.. | |
dd287796 AM |
483 | */ |
484 | int oops_may_print(void) | |
485 | { | |
486 | return pause_on_oops_flag == 0; | |
487 | } | |
488 | ||
489 | /* | |
490 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
491 | * anything. If this is the first CPU to oops, and it's oopsing the first |
492 | * time then let it proceed. | |
dd287796 | 493 | * |
c95dbf27 IM |
494 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
495 | * this to ensure that oopses don't scroll off the screen. It has the | |
496 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
497 | * too. | |
dd287796 | 498 | * |
c95dbf27 IM |
499 | * It turns out that the CPU which is allowed to print ends up pausing for |
500 | * the right duration, whereas all the other CPUs pause for twice as long: | |
501 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
502 | */ |
503 | void oops_enter(void) | |
504 | { | |
bdff7870 | 505 | tracing_off(); |
c95dbf27 IM |
506 | /* can't trust the integrity of the kernel anymore: */ |
507 | debug_locks_off(); | |
dd287796 AM |
508 | do_oops_enter_exit(); |
509 | } | |
510 | ||
2c3b20e9 AV |
511 | /* |
512 | * 64-bit random ID for oopses: | |
513 | */ | |
514 | static u64 oops_id; | |
515 | ||
516 | static int init_oops_id(void) | |
517 | { | |
518 | if (!oops_id) | |
519 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
520 | else |
521 | oops_id++; | |
2c3b20e9 AV |
522 | |
523 | return 0; | |
524 | } | |
525 | late_initcall(init_oops_id); | |
526 | ||
863a6049 | 527 | void print_oops_end_marker(void) |
71c33911 AV |
528 | { |
529 | init_oops_id(); | |
d7c0847f | 530 | pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id); |
71c33911 AV |
531 | } |
532 | ||
dd287796 AM |
533 | /* |
534 | * Called when the architecture exits its oops handler, after printing | |
535 | * everything. | |
536 | */ | |
537 | void oops_exit(void) | |
538 | { | |
539 | do_oops_enter_exit(); | |
71c33911 | 540 | print_oops_end_marker(); |
456b565c | 541 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 542 | } |
3162f751 | 543 | |
2553b67a | 544 | struct warn_args { |
0f6f49a8 | 545 | const char *fmt; |
a8f18b90 | 546 | va_list args; |
0f6f49a8 | 547 | }; |
bd89bb29 | 548 | |
2553b67a JP |
549 | void __warn(const char *file, int line, void *caller, unsigned taint, |
550 | struct pt_regs *regs, struct warn_args *args) | |
0f6f49a8 | 551 | { |
de7edd31 SRRH |
552 | disable_trace_on_warning(); |
553 | ||
a7bed27a KC |
554 | if (args) |
555 | pr_warn(CUT_HERE); | |
2553b67a JP |
556 | |
557 | if (file) | |
558 | pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", | |
559 | raw_smp_processor_id(), current->pid, file, line, | |
560 | caller); | |
561 | else | |
562 | pr_warn("WARNING: CPU: %d PID: %d at %pS\n", | |
563 | raw_smp_processor_id(), current->pid, caller); | |
74853dba | 564 | |
0f6f49a8 LT |
565 | if (args) |
566 | vprintk(args->fmt, args->args); | |
a8f18b90 | 567 | |
9e3961a0 PB |
568 | if (panic_on_warn) { |
569 | /* | |
570 | * This thread may hit another WARN() in the panic path. | |
571 | * Resetting this prevents additional WARN() from panicking the | |
572 | * system on this thread. Other threads are blocked by the | |
573 | * panic_mutex in panic(). | |
574 | */ | |
575 | panic_on_warn = 0; | |
576 | panic("panic_on_warn set ...\n"); | |
577 | } | |
578 | ||
a8f18b90 | 579 | print_modules(); |
2553b67a JP |
580 | |
581 | if (regs) | |
582 | show_regs(regs); | |
583 | else | |
584 | dump_stack(); | |
585 | ||
4c281074 SRV |
586 | print_irqtrace_events(current); |
587 | ||
a8f18b90 | 588 | print_oops_end_marker(); |
2553b67a | 589 | |
373d4d09 RR |
590 | /* Just a warning, don't kill lockdep. */ |
591 | add_taint(taint, LOCKDEP_STILL_OK); | |
a8f18b90 | 592 | } |
0f6f49a8 | 593 | |
2553b67a | 594 | #ifdef WANT_WARN_ON_SLOWPATH |
0f6f49a8 LT |
595 | void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) |
596 | { | |
2553b67a | 597 | struct warn_args args; |
0f6f49a8 LT |
598 | |
599 | args.fmt = fmt; | |
600 | va_start(args.args, fmt); | |
2553b67a JP |
601 | __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, |
602 | &args); | |
0f6f49a8 LT |
603 | va_end(args.args); |
604 | } | |
57adc4d2 AK |
605 | EXPORT_SYMBOL(warn_slowpath_fmt); |
606 | ||
b2be0527 BH |
607 | void warn_slowpath_fmt_taint(const char *file, int line, |
608 | unsigned taint, const char *fmt, ...) | |
609 | { | |
2553b67a | 610 | struct warn_args args; |
b2be0527 BH |
611 | |
612 | args.fmt = fmt; | |
613 | va_start(args.args, fmt); | |
2553b67a | 614 | __warn(file, line, __builtin_return_address(0), taint, NULL, &args); |
b2be0527 BH |
615 | va_end(args.args); |
616 | } | |
617 | EXPORT_SYMBOL(warn_slowpath_fmt_taint); | |
618 | ||
57adc4d2 AK |
619 | void warn_slowpath_null(const char *file, int line) |
620 | { | |
a7bed27a | 621 | pr_warn(CUT_HERE); |
2553b67a | 622 | __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, NULL); |
57adc4d2 AK |
623 | } |
624 | EXPORT_SYMBOL(warn_slowpath_null); | |
a7bed27a KC |
625 | #else |
626 | void __warn_printk(const char *fmt, ...) | |
627 | { | |
628 | va_list args; | |
629 | ||
630 | pr_warn(CUT_HERE); | |
631 | ||
632 | va_start(args, fmt); | |
633 | vprintk(fmt, args); | |
634 | va_end(args); | |
635 | } | |
636 | EXPORT_SYMBOL(__warn_printk); | |
79b4cc5e AV |
637 | #endif |
638 | ||
b1fca27d AK |
639 | #ifdef CONFIG_BUG |
640 | ||
641 | /* Support resetting WARN*_ONCE state */ | |
642 | ||
643 | static int clear_warn_once_set(void *data, u64 val) | |
644 | { | |
aaf5dcfb | 645 | generic_bug_clear_once(); |
b1fca27d AK |
646 | memset(__start_once, 0, __end_once - __start_once); |
647 | return 0; | |
648 | } | |
649 | ||
4169680e Y |
650 | DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, |
651 | "%lld\n"); | |
b1fca27d AK |
652 | |
653 | static __init int register_warn_debugfs(void) | |
654 | { | |
655 | /* Don't care about failure */ | |
4169680e Y |
656 | debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, |
657 | &clear_warn_once_fops); | |
b1fca27d AK |
658 | return 0; |
659 | } | |
660 | ||
661 | device_initcall(register_warn_debugfs); | |
662 | #endif | |
663 | ||
050e9baa | 664 | #ifdef CONFIG_STACKPROTECTOR |
54371a43 | 665 | |
3162f751 AV |
666 | /* |
667 | * Called when gcc's -fstack-protector feature is used, and | |
668 | * gcc detects corruption of the on-stack canary value | |
669 | */ | |
a7330c99 | 670 | __visible void __stack_chk_fail(void) |
3162f751 | 671 | { |
95c4fb78 | 672 | panic("stack-protector: Kernel stack is corrupted in: %pB", |
517a92c4 | 673 | __builtin_return_address(0)); |
3162f751 AV |
674 | } |
675 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 676 | |
3162f751 | 677 | #endif |
f44dd164 | 678 | |
7a46ec0e KC |
679 | #ifdef CONFIG_ARCH_HAS_REFCOUNT |
680 | void refcount_error_report(struct pt_regs *regs, const char *err) | |
681 | { | |
682 | WARN_RATELIMIT(1, "refcount_t %s at %pB in %s[%d], uid/euid: %u/%u\n", | |
683 | err, (void *)instruction_pointer(regs), | |
684 | current->comm, task_pid_nr(current), | |
685 | from_kuid_munged(&init_user_ns, current_uid()), | |
686 | from_kuid_munged(&init_user_ns, current_euid())); | |
687 | } | |
688 | #endif | |
689 | ||
f44dd164 | 690 | core_param(panic, panic_timeout, int, 0644); |
d999bd93 | 691 | core_param(panic_print, panic_print, ulong, 0644); |
f44dd164 | 692 | core_param(pause_on_oops, pause_on_oops, int, 0644); |
9e3961a0 | 693 | core_param(panic_on_warn, panic_on_warn, int, 0644); |
b26e27dd | 694 | core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); |
f06e5153 | 695 | |
d404ab0a OH |
696 | static int __init oops_setup(char *s) |
697 | { | |
698 | if (!s) | |
699 | return -EINVAL; | |
700 | if (!strcmp(s, "panic")) | |
701 | panic_on_oops = 1; | |
702 | return 0; | |
703 | } | |
704 | early_param("oops", oops_setup); |