Commit | Line | Data |
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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> |
7d92bda2 | 15 | #include <linux/kgdb.h> |
456b565c | 16 | #include <linux/kmsg_dump.h> |
c95dbf27 IM |
17 | #include <linux/kallsyms.h> |
18 | #include <linux/notifier.h> | |
c7c3f05e | 19 | #include <linux/vt_kern.h> |
1da177e4 | 20 | #include <linux/module.h> |
c95dbf27 | 21 | #include <linux/random.h> |
de7edd31 | 22 | #include <linux/ftrace.h> |
1da177e4 | 23 | #include <linux/reboot.h> |
c95dbf27 IM |
24 | #include <linux/delay.h> |
25 | #include <linux/kexec.h> | |
26 | #include <linux/sched.h> | |
1da177e4 | 27 | #include <linux/sysrq.h> |
c95dbf27 | 28 | #include <linux/init.h> |
1da177e4 | 29 | #include <linux/nmi.h> |
08d78658 | 30 | #include <linux/console.h> |
2553b67a | 31 | #include <linux/bug.h> |
7a46ec0e | 32 | #include <linux/ratelimit.h> |
b1fca27d AK |
33 | #include <linux/debugfs.h> |
34 | #include <asm/sections.h> | |
1da177e4 | 35 | |
c7ff0d9c TS |
36 | #define PANIC_TIMER_STEP 100 |
37 | #define PANIC_BLINK_SPD 18 | |
38 | ||
2a01bb38 | 39 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
bc4f2f54 KC |
40 | static unsigned long tainted_mask = |
41 | IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; | |
dd287796 AM |
42 | static int pause_on_oops; |
43 | static int pause_on_oops_flag; | |
44 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
5375b708 | 45 | bool crash_kexec_post_notifiers; |
9e3961a0 | 46 | int panic_on_warn __read_mostly; |
1da177e4 | 47 | |
5800dc3c | 48 | int panic_timeout = CONFIG_PANIC_TIMEOUT; |
81e88fdc | 49 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 50 | |
d999bd93 FT |
51 | #define PANIC_PRINT_TASK_INFO 0x00000001 |
52 | #define PANIC_PRINT_MEM_INFO 0x00000002 | |
53 | #define PANIC_PRINT_TIMER_INFO 0x00000004 | |
54 | #define PANIC_PRINT_LOCK_INFO 0x00000008 | |
55 | #define PANIC_PRINT_FTRACE_INFO 0x00000010 | |
de6da1e8 | 56 | #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 |
81c9d43f | 57 | unsigned long panic_print; |
d999bd93 | 58 | |
e041c683 | 59 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
60 | |
61 | EXPORT_SYMBOL(panic_notifier_list); | |
62 | ||
c7ff0d9c | 63 | static long no_blink(int state) |
8aeee85a | 64 | { |
c7ff0d9c | 65 | return 0; |
8aeee85a AB |
66 | } |
67 | ||
c7ff0d9c TS |
68 | /* Returns how long it waited in ms */ |
69 | long (*panic_blink)(int state); | |
70 | EXPORT_SYMBOL(panic_blink); | |
71 | ||
93e13a36 MH |
72 | /* |
73 | * Stop ourself in panic -- architecture code may override this | |
74 | */ | |
75 | void __weak panic_smp_self_stop(void) | |
76 | { | |
77 | while (1) | |
78 | cpu_relax(); | |
79 | } | |
80 | ||
58c5661f HK |
81 | /* |
82 | * Stop ourselves in NMI context if another CPU has already panicked. Arch code | |
83 | * may override this to prepare for crash dumping, e.g. save regs info. | |
84 | */ | |
85 | void __weak nmi_panic_self_stop(struct pt_regs *regs) | |
86 | { | |
87 | panic_smp_self_stop(); | |
88 | } | |
89 | ||
0ee59413 HK |
90 | /* |
91 | * Stop other CPUs in panic. Architecture dependent code may override this | |
92 | * with more suitable version. For example, if the architecture supports | |
93 | * crash dump, it should save registers of each stopped CPU and disable | |
94 | * per-CPU features such as virtualization extensions. | |
95 | */ | |
96 | void __weak crash_smp_send_stop(void) | |
97 | { | |
98 | static int cpus_stopped; | |
99 | ||
100 | /* | |
101 | * This function can be called twice in panic path, but obviously | |
102 | * we execute this only once. | |
103 | */ | |
104 | if (cpus_stopped) | |
105 | return; | |
106 | ||
107 | /* | |
108 | * Note smp_send_stop is the usual smp shutdown function, which | |
109 | * unfortunately means it may not be hardened to work in a panic | |
110 | * situation. | |
111 | */ | |
112 | smp_send_stop(); | |
113 | cpus_stopped = 1; | |
114 | } | |
115 | ||
1717f209 HK |
116 | atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); |
117 | ||
ebc41f20 HK |
118 | /* |
119 | * A variant of panic() called from NMI context. We return if we've already | |
120 | * panicked on this CPU. If another CPU already panicked, loop in | |
121 | * nmi_panic_self_stop() which can provide architecture dependent code such | |
122 | * as saving register state for crash dump. | |
123 | */ | |
124 | void nmi_panic(struct pt_regs *regs, const char *msg) | |
125 | { | |
126 | int old_cpu, cpu; | |
127 | ||
128 | cpu = raw_smp_processor_id(); | |
129 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); | |
130 | ||
131 | if (old_cpu == PANIC_CPU_INVALID) | |
132 | panic("%s", msg); | |
133 | else if (old_cpu != cpu) | |
134 | nmi_panic_self_stop(regs); | |
135 | } | |
136 | EXPORT_SYMBOL(nmi_panic); | |
137 | ||
d999bd93 FT |
138 | static void panic_print_sys_info(void) |
139 | { | |
de6da1e8 FT |
140 | if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) |
141 | console_flush_on_panic(CONSOLE_REPLAY_ALL); | |
142 | ||
d999bd93 FT |
143 | if (panic_print & PANIC_PRINT_TASK_INFO) |
144 | show_state(); | |
145 | ||
146 | if (panic_print & PANIC_PRINT_MEM_INFO) | |
147 | show_mem(0, NULL); | |
148 | ||
149 | if (panic_print & PANIC_PRINT_TIMER_INFO) | |
150 | sysrq_timer_list_show(); | |
151 | ||
152 | if (panic_print & PANIC_PRINT_LOCK_INFO) | |
153 | debug_show_all_locks(); | |
154 | ||
155 | if (panic_print & PANIC_PRINT_FTRACE_INFO) | |
156 | ftrace_dump(DUMP_ALL); | |
157 | } | |
158 | ||
1da177e4 LT |
159 | /** |
160 | * panic - halt the system | |
161 | * @fmt: The text string to print | |
162 | * | |
163 | * Display a message, then perform cleanups. | |
164 | * | |
165 | * This function never returns. | |
166 | */ | |
9402c95f | 167 | void panic(const char *fmt, ...) |
1da177e4 | 168 | { |
1da177e4 LT |
169 | static char buf[1024]; |
170 | va_list args; | |
b49dec1c | 171 | long i, i_next = 0, len; |
c7ff0d9c | 172 | int state = 0; |
1717f209 | 173 | int old_cpu, this_cpu; |
b26e27dd | 174 | bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; |
1da177e4 | 175 | |
190320c3 VM |
176 | /* |
177 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
178 | * from deadlocking the first cpu that invokes the panic, since | |
179 | * there is nothing to prevent an interrupt handler (that runs | |
1717f209 | 180 | * after setting panic_cpu) from invoking panic() again. |
190320c3 VM |
181 | */ |
182 | local_irq_disable(); | |
183 | ||
dc009d92 | 184 | /* |
c95dbf27 IM |
185 | * It's possible to come here directly from a panic-assertion and |
186 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 187 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
188 | * |
189 | * Only one CPU is allowed to execute the panic code from here. For | |
190 | * multiple parallel invocations of panic, all other CPUs either | |
191 | * stop themself or will wait until they are stopped by the 1st CPU | |
192 | * with smp_send_stop(). | |
1717f209 HK |
193 | * |
194 | * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which | |
195 | * comes here, so go ahead. | |
196 | * `old_cpu == this_cpu' means we came from nmi_panic() which sets | |
197 | * panic_cpu to this CPU. In this case, this is also the 1st CPU. | |
dc009d92 | 198 | */ |
1717f209 HK |
199 | this_cpu = raw_smp_processor_id(); |
200 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
201 | ||
202 | if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) | |
93e13a36 | 203 | panic_smp_self_stop(); |
dc009d92 | 204 | |
5b530fc1 | 205 | console_verbose(); |
1da177e4 LT |
206 | bust_spinlocks(1); |
207 | va_start(args, fmt); | |
b49dec1c | 208 | len = vscnprintf(buf, sizeof(buf), fmt, args); |
1da177e4 | 209 | va_end(args); |
b49dec1c BP |
210 | |
211 | if (len && buf[len - 1] == '\n') | |
212 | buf[len - 1] = '\0'; | |
213 | ||
d7c0847f | 214 | pr_emerg("Kernel panic - not syncing: %s\n", buf); |
5cb27301 | 215 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
216 | /* |
217 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
218 | */ | |
026ee1f6 | 219 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 220 | dump_stack(); |
5cb27301 | 221 | #endif |
1da177e4 | 222 | |
7d92bda2 DA |
223 | /* |
224 | * If kgdb is enabled, give it a chance to run before we stop all | |
225 | * the other CPUs or else we won't be able to debug processes left | |
226 | * running on them. | |
227 | */ | |
228 | kgdb_panic(buf); | |
229 | ||
dc009d92 EB |
230 | /* |
231 | * If we have crashed and we have a crash kernel loaded let it handle | |
232 | * everything else. | |
f06e5153 MH |
233 | * If we want to run this after calling panic_notifiers, pass |
234 | * the "crash_kexec_post_notifiers" option to the kernel. | |
7bbee5ca HK |
235 | * |
236 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
dc009d92 | 237 | */ |
b26e27dd | 238 | if (!_crash_kexec_post_notifiers) { |
f92bac3b | 239 | printk_safe_flush_on_panic(); |
7bbee5ca | 240 | __crash_kexec(NULL); |
dc009d92 | 241 | |
0ee59413 HK |
242 | /* |
243 | * Note smp_send_stop is the usual smp shutdown function, which | |
244 | * unfortunately means it may not be hardened to work in a | |
245 | * panic situation. | |
246 | */ | |
247 | smp_send_stop(); | |
248 | } else { | |
249 | /* | |
250 | * If we want to do crash dump after notifier calls and | |
251 | * kmsg_dump, we will need architecture dependent extra | |
252 | * works in addition to stopping other CPUs. | |
253 | */ | |
254 | crash_smp_send_stop(); | |
255 | } | |
1da177e4 | 256 | |
6723734c KC |
257 | /* |
258 | * Run any panic handlers, including those that might need to | |
259 | * add information to the kmsg dump output. | |
260 | */ | |
e041c683 | 261 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 262 | |
cf9b1106 | 263 | /* Call flush even twice. It tries harder with a single online CPU */ |
f92bac3b | 264 | printk_safe_flush_on_panic(); |
6723734c KC |
265 | kmsg_dump(KMSG_DUMP_PANIC); |
266 | ||
f06e5153 MH |
267 | /* |
268 | * If you doubt kdump always works fine in any situation, | |
269 | * "crash_kexec_post_notifiers" offers you a chance to run | |
270 | * panic_notifiers and dumping kmsg before kdump. | |
271 | * Note: since some panic_notifiers can make crashed kernel | |
272 | * more unstable, it can increase risks of the kdump failure too. | |
7bbee5ca HK |
273 | * |
274 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
f06e5153 | 275 | */ |
b26e27dd | 276 | if (_crash_kexec_post_notifiers) |
7bbee5ca | 277 | __crash_kexec(NULL); |
f06e5153 | 278 | |
c7c3f05e SS |
279 | #ifdef CONFIG_VT |
280 | unblank_screen(); | |
281 | #endif | |
282 | console_unblank(); | |
d014e889 | 283 | |
08d78658 VK |
284 | /* |
285 | * We may have ended up stopping the CPU holding the lock (in | |
286 | * smp_send_stop()) while still having some valuable data in the console | |
287 | * buffer. Try to acquire the lock then release it regardless of the | |
7625b3a0 VK |
288 | * result. The release will also print the buffers out. Locks debug |
289 | * should be disabled to avoid reporting bad unlock balance when | |
290 | * panic() is not being callled from OOPS. | |
08d78658 | 291 | */ |
7625b3a0 | 292 | debug_locks_off(); |
de6da1e8 | 293 | console_flush_on_panic(CONSOLE_FLUSH_PENDING); |
08d78658 | 294 | |
d999bd93 FT |
295 | panic_print_sys_info(); |
296 | ||
c7ff0d9c TS |
297 | if (!panic_blink) |
298 | panic_blink = no_blink; | |
299 | ||
dc009d92 | 300 | if (panic_timeout > 0) { |
1da177e4 | 301 | /* |
c95dbf27 IM |
302 | * Delay timeout seconds before rebooting the machine. |
303 | * We can't use the "normal" timers since we just panicked. | |
304 | */ | |
ff7a28a0 | 305 | pr_emerg("Rebooting in %d seconds..\n", panic_timeout); |
c95dbf27 | 306 | |
c7ff0d9c | 307 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 308 | touch_nmi_watchdog(); |
c7ff0d9c TS |
309 | if (i >= i_next) { |
310 | i += panic_blink(state ^= 1); | |
311 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
312 | } | |
313 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 314 | } |
4302fbc8 HD |
315 | } |
316 | if (panic_timeout != 0) { | |
c95dbf27 IM |
317 | /* |
318 | * This will not be a clean reboot, with everything | |
319 | * shutting down. But if there is a chance of | |
320 | * rebooting the system it will be rebooted. | |
1da177e4 | 321 | */ |
b287a25a AK |
322 | if (panic_reboot_mode != REBOOT_UNDEFINED) |
323 | reboot_mode = panic_reboot_mode; | |
2f048ea8 | 324 | emergency_restart(); |
1da177e4 LT |
325 | } |
326 | #ifdef __sparc__ | |
327 | { | |
328 | extern int stop_a_enabled; | |
a271c241 | 329 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 330 | stop_a_enabled = 1; |
7db60d05 VK |
331 | pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" |
332 | "twice on console to return to the boot prom\n"); | |
1da177e4 LT |
333 | } |
334 | #endif | |
347a8dc3 | 335 | #if defined(CONFIG_S390) |
98587c2d | 336 | disabled_wait(); |
1da177e4 | 337 | #endif |
5ad75105 | 338 | pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); |
c39ea0b9 FT |
339 | |
340 | /* Do not scroll important messages printed above */ | |
341 | suppress_printk = 1; | |
1da177e4 | 342 | local_irq_enable(); |
c7ff0d9c | 343 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 344 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
345 | if (i >= i_next) { |
346 | i += panic_blink(state ^= 1); | |
347 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
348 | } | |
349 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
350 | } |
351 | } | |
352 | ||
353 | EXPORT_SYMBOL(panic); | |
354 | ||
7fd8329b PM |
355 | /* |
356 | * TAINT_FORCED_RMMOD could be a per-module flag but the module | |
357 | * is being removed anyway. | |
358 | */ | |
359 | const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { | |
47d4b263 KC |
360 | [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, |
361 | [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, | |
362 | [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, | |
363 | [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, | |
364 | [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, | |
365 | [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, | |
366 | [ TAINT_USER ] = { 'U', ' ', false }, | |
367 | [ TAINT_DIE ] = { 'D', ' ', false }, | |
368 | [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, | |
369 | [ TAINT_WARN ] = { 'W', ' ', false }, | |
370 | [ TAINT_CRAP ] = { 'C', ' ', true }, | |
371 | [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, | |
372 | [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, | |
373 | [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, | |
374 | [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, | |
375 | [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, | |
376 | [ TAINT_AUX ] = { 'X', ' ', true }, | |
bc4f2f54 | 377 | [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, |
25ddbb18 AK |
378 | }; |
379 | ||
1da177e4 | 380 | /** |
9c4560e5 | 381 | * print_tainted - return a string to represent the kernel taint state. |
1da177e4 | 382 | * |
57043247 | 383 | * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst |
1da177e4 | 384 | * |
9c4560e5 KC |
385 | * The string is overwritten by the next call to print_tainted(), |
386 | * but is always NULL terminated. | |
1da177e4 | 387 | */ |
1da177e4 LT |
388 | const char *print_tainted(void) |
389 | { | |
7fd8329b | 390 | static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; |
25ddbb18 | 391 | |
47d4b263 KC |
392 | BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); |
393 | ||
25ddbb18 AK |
394 | if (tainted_mask) { |
395 | char *s; | |
396 | int i; | |
397 | ||
398 | s = buf + sprintf(buf, "Tainted: "); | |
7fd8329b PM |
399 | for (i = 0; i < TAINT_FLAGS_COUNT; i++) { |
400 | const struct taint_flag *t = &taint_flags[i]; | |
401 | *s++ = test_bit(i, &tainted_mask) ? | |
5eb7c0d0 | 402 | t->c_true : t->c_false; |
25ddbb18 AK |
403 | } |
404 | *s = 0; | |
405 | } else | |
1da177e4 | 406 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
407 | |
408 | return buf; | |
1da177e4 LT |
409 | } |
410 | ||
25ddbb18 | 411 | int test_taint(unsigned flag) |
1da177e4 | 412 | { |
25ddbb18 AK |
413 | return test_bit(flag, &tainted_mask); |
414 | } | |
415 | EXPORT_SYMBOL(test_taint); | |
416 | ||
417 | unsigned long get_taint(void) | |
418 | { | |
419 | return tainted_mask; | |
1da177e4 | 420 | } |
dd287796 | 421 | |
373d4d09 RR |
422 | /** |
423 | * add_taint: add a taint flag if not already set. | |
424 | * @flag: one of the TAINT_* constants. | |
425 | * @lockdep_ok: whether lock debugging is still OK. | |
426 | * | |
427 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
428 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
429 | */ | |
430 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 431 | { |
373d4d09 | 432 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
d7c0847f | 433 | pr_warn("Disabling lock debugging due to kernel taint\n"); |
9eeba613 | 434 | |
25ddbb18 | 435 | set_bit(flag, &tainted_mask); |
dd287796 | 436 | } |
1da177e4 | 437 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
438 | |
439 | static void spin_msec(int msecs) | |
440 | { | |
441 | int i; | |
442 | ||
443 | for (i = 0; i < msecs; i++) { | |
444 | touch_nmi_watchdog(); | |
445 | mdelay(1); | |
446 | } | |
447 | } | |
448 | ||
449 | /* | |
450 | * It just happens that oops_enter() and oops_exit() are identically | |
451 | * implemented... | |
452 | */ | |
453 | static void do_oops_enter_exit(void) | |
454 | { | |
455 | unsigned long flags; | |
456 | static int spin_counter; | |
457 | ||
458 | if (!pause_on_oops) | |
459 | return; | |
460 | ||
461 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
462 | if (pause_on_oops_flag == 0) { | |
463 | /* This CPU may now print the oops message */ | |
464 | pause_on_oops_flag = 1; | |
465 | } else { | |
466 | /* We need to stall this CPU */ | |
467 | if (!spin_counter) { | |
468 | /* This CPU gets to do the counting */ | |
469 | spin_counter = pause_on_oops; | |
470 | do { | |
471 | spin_unlock(&pause_on_oops_lock); | |
472 | spin_msec(MSEC_PER_SEC); | |
473 | spin_lock(&pause_on_oops_lock); | |
474 | } while (--spin_counter); | |
475 | pause_on_oops_flag = 0; | |
476 | } else { | |
477 | /* This CPU waits for a different one */ | |
478 | while (spin_counter) { | |
479 | spin_unlock(&pause_on_oops_lock); | |
480 | spin_msec(1); | |
481 | spin_lock(&pause_on_oops_lock); | |
482 | } | |
483 | } | |
484 | } | |
485 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
486 | } | |
487 | ||
488 | /* | |
c95dbf27 IM |
489 | * Return true if the calling CPU is allowed to print oops-related info. |
490 | * This is a bit racy.. | |
dd287796 AM |
491 | */ |
492 | int oops_may_print(void) | |
493 | { | |
494 | return pause_on_oops_flag == 0; | |
495 | } | |
496 | ||
497 | /* | |
498 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
499 | * anything. If this is the first CPU to oops, and it's oopsing the first |
500 | * time then let it proceed. | |
dd287796 | 501 | * |
c95dbf27 IM |
502 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
503 | * this to ensure that oopses don't scroll off the screen. It has the | |
504 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
505 | * too. | |
dd287796 | 506 | * |
c95dbf27 IM |
507 | * It turns out that the CPU which is allowed to print ends up pausing for |
508 | * the right duration, whereas all the other CPUs pause for twice as long: | |
509 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
510 | */ |
511 | void oops_enter(void) | |
512 | { | |
bdff7870 | 513 | tracing_off(); |
c95dbf27 IM |
514 | /* can't trust the integrity of the kernel anymore: */ |
515 | debug_locks_off(); | |
dd287796 AM |
516 | do_oops_enter_exit(); |
517 | } | |
518 | ||
2c3b20e9 AV |
519 | /* |
520 | * 64-bit random ID for oopses: | |
521 | */ | |
522 | static u64 oops_id; | |
523 | ||
524 | static int init_oops_id(void) | |
525 | { | |
526 | if (!oops_id) | |
527 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
528 | else |
529 | oops_id++; | |
2c3b20e9 AV |
530 | |
531 | return 0; | |
532 | } | |
533 | late_initcall(init_oops_id); | |
534 | ||
863a6049 | 535 | void print_oops_end_marker(void) |
71c33911 AV |
536 | { |
537 | init_oops_id(); | |
d7c0847f | 538 | pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id); |
71c33911 AV |
539 | } |
540 | ||
dd287796 AM |
541 | /* |
542 | * Called when the architecture exits its oops handler, after printing | |
543 | * everything. | |
544 | */ | |
545 | void oops_exit(void) | |
546 | { | |
547 | do_oops_enter_exit(); | |
71c33911 | 548 | print_oops_end_marker(); |
456b565c | 549 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 550 | } |
3162f751 | 551 | |
2553b67a | 552 | struct warn_args { |
0f6f49a8 | 553 | const char *fmt; |
a8f18b90 | 554 | va_list args; |
0f6f49a8 | 555 | }; |
bd89bb29 | 556 | |
2553b67a JP |
557 | void __warn(const char *file, int line, void *caller, unsigned taint, |
558 | struct pt_regs *regs, struct warn_args *args) | |
0f6f49a8 | 559 | { |
de7edd31 SRRH |
560 | disable_trace_on_warning(); |
561 | ||
2553b67a JP |
562 | if (file) |
563 | pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", | |
564 | raw_smp_processor_id(), current->pid, file, line, | |
565 | caller); | |
566 | else | |
567 | pr_warn("WARNING: CPU: %d PID: %d at %pS\n", | |
568 | raw_smp_processor_id(), current->pid, caller); | |
74853dba | 569 | |
0f6f49a8 LT |
570 | if (args) |
571 | vprintk(args->fmt, args->args); | |
a8f18b90 | 572 | |
9e3961a0 PB |
573 | if (panic_on_warn) { |
574 | /* | |
575 | * This thread may hit another WARN() in the panic path. | |
576 | * Resetting this prevents additional WARN() from panicking the | |
577 | * system on this thread. Other threads are blocked by the | |
578 | * panic_mutex in panic(). | |
579 | */ | |
580 | panic_on_warn = 0; | |
581 | panic("panic_on_warn set ...\n"); | |
582 | } | |
583 | ||
a8f18b90 | 584 | print_modules(); |
2553b67a JP |
585 | |
586 | if (regs) | |
587 | show_regs(regs); | |
588 | else | |
589 | dump_stack(); | |
590 | ||
4c281074 SRV |
591 | print_irqtrace_events(current); |
592 | ||
a8f18b90 | 593 | print_oops_end_marker(); |
2553b67a | 594 | |
373d4d09 RR |
595 | /* Just a warning, don't kill lockdep. */ |
596 | add_taint(taint, LOCKDEP_STILL_OK); | |
a8f18b90 | 597 | } |
0f6f49a8 | 598 | |
2da1ead4 | 599 | #ifndef __WARN_FLAGS |
ee871133 KC |
600 | void warn_slowpath_fmt(const char *file, int line, unsigned taint, |
601 | const char *fmt, ...) | |
b2be0527 | 602 | { |
2553b67a | 603 | struct warn_args args; |
b2be0527 | 604 | |
d38aba49 KC |
605 | pr_warn(CUT_HERE); |
606 | ||
f2f84b05 | 607 | if (!fmt) { |
f2f84b05 KC |
608 | __warn(file, line, __builtin_return_address(0), taint, |
609 | NULL, NULL); | |
610 | return; | |
611 | } | |
612 | ||
b2be0527 BH |
613 | args.fmt = fmt; |
614 | va_start(args.args, fmt); | |
2553b67a | 615 | __warn(file, line, __builtin_return_address(0), taint, NULL, &args); |
b2be0527 BH |
616 | va_end(args.args); |
617 | } | |
ee871133 | 618 | EXPORT_SYMBOL(warn_slowpath_fmt); |
a7bed27a KC |
619 | #else |
620 | void __warn_printk(const char *fmt, ...) | |
621 | { | |
622 | va_list args; | |
623 | ||
624 | pr_warn(CUT_HERE); | |
625 | ||
626 | va_start(args, fmt); | |
627 | vprintk(fmt, args); | |
628 | va_end(args); | |
629 | } | |
630 | EXPORT_SYMBOL(__warn_printk); | |
79b4cc5e AV |
631 | #endif |
632 | ||
b1fca27d AK |
633 | #ifdef CONFIG_BUG |
634 | ||
635 | /* Support resetting WARN*_ONCE state */ | |
636 | ||
637 | static int clear_warn_once_set(void *data, u64 val) | |
638 | { | |
aaf5dcfb | 639 | generic_bug_clear_once(); |
b1fca27d AK |
640 | memset(__start_once, 0, __end_once - __start_once); |
641 | return 0; | |
642 | } | |
643 | ||
4169680e Y |
644 | DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, |
645 | "%lld\n"); | |
b1fca27d AK |
646 | |
647 | static __init int register_warn_debugfs(void) | |
648 | { | |
649 | /* Don't care about failure */ | |
4169680e Y |
650 | debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, |
651 | &clear_warn_once_fops); | |
b1fca27d AK |
652 | return 0; |
653 | } | |
654 | ||
655 | device_initcall(register_warn_debugfs); | |
656 | #endif | |
657 | ||
050e9baa | 658 | #ifdef CONFIG_STACKPROTECTOR |
54371a43 | 659 | |
3162f751 AV |
660 | /* |
661 | * Called when gcc's -fstack-protector feature is used, and | |
662 | * gcc detects corruption of the on-stack canary value | |
663 | */ | |
a7330c99 | 664 | __visible void __stack_chk_fail(void) |
3162f751 | 665 | { |
95c4fb78 | 666 | panic("stack-protector: Kernel stack is corrupted in: %pB", |
517a92c4 | 667 | __builtin_return_address(0)); |
3162f751 AV |
668 | } |
669 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 670 | |
3162f751 | 671 | #endif |
f44dd164 | 672 | |
7a46ec0e KC |
673 | #ifdef CONFIG_ARCH_HAS_REFCOUNT |
674 | void refcount_error_report(struct pt_regs *regs, const char *err) | |
675 | { | |
676 | WARN_RATELIMIT(1, "refcount_t %s at %pB in %s[%d], uid/euid: %u/%u\n", | |
677 | err, (void *)instruction_pointer(regs), | |
678 | current->comm, task_pid_nr(current), | |
679 | from_kuid_munged(&init_user_ns, current_uid()), | |
680 | from_kuid_munged(&init_user_ns, current_euid())); | |
681 | } | |
682 | #endif | |
683 | ||
f44dd164 | 684 | core_param(panic, panic_timeout, int, 0644); |
d999bd93 | 685 | core_param(panic_print, panic_print, ulong, 0644); |
f44dd164 | 686 | core_param(pause_on_oops, pause_on_oops, int, 0644); |
9e3961a0 | 687 | core_param(panic_on_warn, panic_on_warn, int, 0644); |
b26e27dd | 688 | core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); |
f06e5153 | 689 | |
d404ab0a OH |
690 | static int __init oops_setup(char *s) |
691 | { | |
692 | if (!s) | |
693 | return -EINVAL; | |
694 | if (!strcmp(s, "panic")) | |
695 | panic_on_oops = 1; | |
696 | return 0; | |
697 | } | |
698 | early_param("oops", oops_setup); |