]>
Commit | Line | Data |
---|---|---|
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> | |
f39650de | 26 | #include <linux/panic_notifier.h> |
c95dbf27 | 27 | #include <linux/sched.h> |
1da177e4 | 28 | #include <linux/sysrq.h> |
c95dbf27 | 29 | #include <linux/init.h> |
1da177e4 | 30 | #include <linux/nmi.h> |
08d78658 | 31 | #include <linux/console.h> |
2553b67a | 32 | #include <linux/bug.h> |
7a46ec0e | 33 | #include <linux/ratelimit.h> |
b1fca27d | 34 | #include <linux/debugfs.h> |
23b36fec | 35 | #include <trace/events/error_report.h> |
b1fca27d | 36 | #include <asm/sections.h> |
1da177e4 | 37 | |
c7ff0d9c TS |
38 | #define PANIC_TIMER_STEP 100 |
39 | #define PANIC_BLINK_SPD 18 | |
40 | ||
60c958d8 GP |
41 | #ifdef CONFIG_SMP |
42 | /* | |
43 | * Should we dump all CPUs backtraces in an oops event? | |
44 | * Defaults to 0, can be changed via sysctl. | |
45 | */ | |
46 | unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; | |
47 | #endif /* CONFIG_SMP */ | |
48 | ||
2a01bb38 | 49 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
bc4f2f54 | 50 | static unsigned long tainted_mask = |
595b893e | 51 | IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; |
dd287796 AM |
52 | static int pause_on_oops; |
53 | static int pause_on_oops_flag; | |
54 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
5375b708 | 55 | bool crash_kexec_post_notifiers; |
9e3961a0 | 56 | int panic_on_warn __read_mostly; |
db38d5c1 RA |
57 | unsigned long panic_on_taint; |
58 | bool panic_on_taint_nousertaint = false; | |
1da177e4 | 59 | |
5800dc3c | 60 | int panic_timeout = CONFIG_PANIC_TIMEOUT; |
81e88fdc | 61 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 62 | |
d999bd93 FT |
63 | #define PANIC_PRINT_TASK_INFO 0x00000001 |
64 | #define PANIC_PRINT_MEM_INFO 0x00000002 | |
65 | #define PANIC_PRINT_TIMER_INFO 0x00000004 | |
66 | #define PANIC_PRINT_LOCK_INFO 0x00000008 | |
67 | #define PANIC_PRINT_FTRACE_INFO 0x00000010 | |
de6da1e8 | 68 | #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 |
8d470a45 | 69 | #define PANIC_PRINT_ALL_CPU_BT 0x00000040 |
81c9d43f | 70 | unsigned long panic_print; |
d999bd93 | 71 | |
e041c683 | 72 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
73 | |
74 | EXPORT_SYMBOL(panic_notifier_list); | |
75 | ||
c7ff0d9c | 76 | static long no_blink(int state) |
8aeee85a | 77 | { |
c7ff0d9c | 78 | return 0; |
8aeee85a AB |
79 | } |
80 | ||
c7ff0d9c TS |
81 | /* Returns how long it waited in ms */ |
82 | long (*panic_blink)(int state); | |
83 | EXPORT_SYMBOL(panic_blink); | |
84 | ||
93e13a36 MH |
85 | /* |
86 | * Stop ourself in panic -- architecture code may override this | |
87 | */ | |
88 | void __weak panic_smp_self_stop(void) | |
89 | { | |
90 | while (1) | |
91 | cpu_relax(); | |
92 | } | |
93 | ||
58c5661f HK |
94 | /* |
95 | * Stop ourselves in NMI context if another CPU has already panicked. Arch code | |
96 | * may override this to prepare for crash dumping, e.g. save regs info. | |
97 | */ | |
98 | void __weak nmi_panic_self_stop(struct pt_regs *regs) | |
99 | { | |
100 | panic_smp_self_stop(); | |
101 | } | |
102 | ||
0ee59413 HK |
103 | /* |
104 | * Stop other CPUs in panic. Architecture dependent code may override this | |
105 | * with more suitable version. For example, if the architecture supports | |
106 | * crash dump, it should save registers of each stopped CPU and disable | |
107 | * per-CPU features such as virtualization extensions. | |
108 | */ | |
109 | void __weak crash_smp_send_stop(void) | |
110 | { | |
111 | static int cpus_stopped; | |
112 | ||
113 | /* | |
114 | * This function can be called twice in panic path, but obviously | |
115 | * we execute this only once. | |
116 | */ | |
117 | if (cpus_stopped) | |
118 | return; | |
119 | ||
120 | /* | |
121 | * Note smp_send_stop is the usual smp shutdown function, which | |
122 | * unfortunately means it may not be hardened to work in a panic | |
123 | * situation. | |
124 | */ | |
125 | smp_send_stop(); | |
126 | cpus_stopped = 1; | |
127 | } | |
128 | ||
1717f209 HK |
129 | atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); |
130 | ||
ebc41f20 HK |
131 | /* |
132 | * A variant of panic() called from NMI context. We return if we've already | |
133 | * panicked on this CPU. If another CPU already panicked, loop in | |
134 | * nmi_panic_self_stop() which can provide architecture dependent code such | |
135 | * as saving register state for crash dump. | |
136 | */ | |
137 | void nmi_panic(struct pt_regs *regs, const char *msg) | |
138 | { | |
139 | int old_cpu, cpu; | |
140 | ||
141 | cpu = raw_smp_processor_id(); | |
142 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); | |
143 | ||
144 | if (old_cpu == PANIC_CPU_INVALID) | |
145 | panic("%s", msg); | |
146 | else if (old_cpu != cpu) | |
147 | nmi_panic_self_stop(regs); | |
148 | } | |
149 | EXPORT_SYMBOL(nmi_panic); | |
150 | ||
f953f140 | 151 | static void panic_print_sys_info(bool console_flush) |
d999bd93 | 152 | { |
f953f140 GP |
153 | if (console_flush) { |
154 | if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) | |
155 | console_flush_on_panic(CONSOLE_REPLAY_ALL); | |
156 | return; | |
157 | } | |
de6da1e8 | 158 | |
8d470a45 GP |
159 | if (panic_print & PANIC_PRINT_ALL_CPU_BT) |
160 | trigger_all_cpu_backtrace(); | |
161 | ||
d999bd93 FT |
162 | if (panic_print & PANIC_PRINT_TASK_INFO) |
163 | show_state(); | |
164 | ||
165 | if (panic_print & PANIC_PRINT_MEM_INFO) | |
166 | show_mem(0, NULL); | |
167 | ||
168 | if (panic_print & PANIC_PRINT_TIMER_INFO) | |
169 | sysrq_timer_list_show(); | |
170 | ||
171 | if (panic_print & PANIC_PRINT_LOCK_INFO) | |
172 | debug_show_all_locks(); | |
173 | ||
174 | if (panic_print & PANIC_PRINT_FTRACE_INFO) | |
175 | ftrace_dump(DUMP_ALL); | |
176 | } | |
177 | ||
1da177e4 LT |
178 | /** |
179 | * panic - halt the system | |
180 | * @fmt: The text string to print | |
181 | * | |
182 | * Display a message, then perform cleanups. | |
183 | * | |
184 | * This function never returns. | |
185 | */ | |
9402c95f | 186 | void panic(const char *fmt, ...) |
1da177e4 | 187 | { |
1da177e4 LT |
188 | static char buf[1024]; |
189 | va_list args; | |
b49dec1c | 190 | long i, i_next = 0, len; |
c7ff0d9c | 191 | int state = 0; |
1717f209 | 192 | int old_cpu, this_cpu; |
b26e27dd | 193 | bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; |
1da177e4 | 194 | |
1a2383e8 TY |
195 | if (panic_on_warn) { |
196 | /* | |
197 | * This thread may hit another WARN() in the panic path. | |
198 | * Resetting this prevents additional WARN() from panicking the | |
199 | * system on this thread. Other threads are blocked by the | |
200 | * panic_mutex in panic(). | |
201 | */ | |
202 | panic_on_warn = 0; | |
203 | } | |
204 | ||
190320c3 VM |
205 | /* |
206 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
207 | * from deadlocking the first cpu that invokes the panic, since | |
208 | * there is nothing to prevent an interrupt handler (that runs | |
1717f209 | 209 | * after setting panic_cpu) from invoking panic() again. |
190320c3 VM |
210 | */ |
211 | local_irq_disable(); | |
20bb759a | 212 | preempt_disable_notrace(); |
190320c3 | 213 | |
dc009d92 | 214 | /* |
c95dbf27 IM |
215 | * It's possible to come here directly from a panic-assertion and |
216 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 217 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
218 | * |
219 | * Only one CPU is allowed to execute the panic code from here. For | |
220 | * multiple parallel invocations of panic, all other CPUs either | |
221 | * stop themself or will wait until they are stopped by the 1st CPU | |
222 | * with smp_send_stop(). | |
1717f209 HK |
223 | * |
224 | * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which | |
225 | * comes here, so go ahead. | |
226 | * `old_cpu == this_cpu' means we came from nmi_panic() which sets | |
227 | * panic_cpu to this CPU. In this case, this is also the 1st CPU. | |
dc009d92 | 228 | */ |
1717f209 HK |
229 | this_cpu = raw_smp_processor_id(); |
230 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
231 | ||
232 | if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) | |
93e13a36 | 233 | panic_smp_self_stop(); |
dc009d92 | 234 | |
5b530fc1 | 235 | console_verbose(); |
1da177e4 LT |
236 | bust_spinlocks(1); |
237 | va_start(args, fmt); | |
b49dec1c | 238 | len = vscnprintf(buf, sizeof(buf), fmt, args); |
1da177e4 | 239 | va_end(args); |
b49dec1c BP |
240 | |
241 | if (len && buf[len - 1] == '\n') | |
242 | buf[len - 1] = '\0'; | |
243 | ||
d7c0847f | 244 | pr_emerg("Kernel panic - not syncing: %s\n", buf); |
5cb27301 | 245 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
246 | /* |
247 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
248 | */ | |
026ee1f6 | 249 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 250 | dump_stack(); |
5cb27301 | 251 | #endif |
1da177e4 | 252 | |
7d92bda2 DA |
253 | /* |
254 | * If kgdb is enabled, give it a chance to run before we stop all | |
255 | * the other CPUs or else we won't be able to debug processes left | |
256 | * running on them. | |
257 | */ | |
258 | kgdb_panic(buf); | |
259 | ||
dc009d92 EB |
260 | /* |
261 | * If we have crashed and we have a crash kernel loaded let it handle | |
262 | * everything else. | |
f06e5153 MH |
263 | * If we want to run this after calling panic_notifiers, pass |
264 | * the "crash_kexec_post_notifiers" option to the kernel. | |
7bbee5ca HK |
265 | * |
266 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
dc009d92 | 267 | */ |
b26e27dd | 268 | if (!_crash_kexec_post_notifiers) { |
7bbee5ca | 269 | __crash_kexec(NULL); |
dc009d92 | 270 | |
0ee59413 HK |
271 | /* |
272 | * Note smp_send_stop is the usual smp shutdown function, which | |
273 | * unfortunately means it may not be hardened to work in a | |
274 | * panic situation. | |
275 | */ | |
276 | smp_send_stop(); | |
277 | } else { | |
278 | /* | |
279 | * If we want to do crash dump after notifier calls and | |
280 | * kmsg_dump, we will need architecture dependent extra | |
281 | * works in addition to stopping other CPUs. | |
282 | */ | |
283 | crash_smp_send_stop(); | |
284 | } | |
1da177e4 | 285 | |
6723734c KC |
286 | /* |
287 | * Run any panic handlers, including those that might need to | |
288 | * add information to the kmsg dump output. | |
289 | */ | |
e041c683 | 290 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 291 | |
f953f140 GP |
292 | panic_print_sys_info(false); |
293 | ||
6723734c KC |
294 | kmsg_dump(KMSG_DUMP_PANIC); |
295 | ||
f06e5153 MH |
296 | /* |
297 | * If you doubt kdump always works fine in any situation, | |
298 | * "crash_kexec_post_notifiers" offers you a chance to run | |
299 | * panic_notifiers and dumping kmsg before kdump. | |
300 | * Note: since some panic_notifiers can make crashed kernel | |
301 | * more unstable, it can increase risks of the kdump failure too. | |
7bbee5ca HK |
302 | * |
303 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
f06e5153 | 304 | */ |
b26e27dd | 305 | if (_crash_kexec_post_notifiers) |
7bbee5ca | 306 | __crash_kexec(NULL); |
f06e5153 | 307 | |
c7c3f05e SS |
308 | #ifdef CONFIG_VT |
309 | unblank_screen(); | |
310 | #endif | |
311 | console_unblank(); | |
d014e889 | 312 | |
08d78658 VK |
313 | /* |
314 | * We may have ended up stopping the CPU holding the lock (in | |
315 | * smp_send_stop()) while still having some valuable data in the console | |
316 | * buffer. Try to acquire the lock then release it regardless of the | |
7625b3a0 VK |
317 | * result. The release will also print the buffers out. Locks debug |
318 | * should be disabled to avoid reporting bad unlock balance when | |
319 | * panic() is not being callled from OOPS. | |
08d78658 | 320 | */ |
7625b3a0 | 321 | debug_locks_off(); |
de6da1e8 | 322 | console_flush_on_panic(CONSOLE_FLUSH_PENDING); |
08d78658 | 323 | |
f953f140 | 324 | panic_print_sys_info(true); |
d999bd93 | 325 | |
c7ff0d9c TS |
326 | if (!panic_blink) |
327 | panic_blink = no_blink; | |
328 | ||
dc009d92 | 329 | if (panic_timeout > 0) { |
1da177e4 | 330 | /* |
c95dbf27 IM |
331 | * Delay timeout seconds before rebooting the machine. |
332 | * We can't use the "normal" timers since we just panicked. | |
333 | */ | |
ff7a28a0 | 334 | pr_emerg("Rebooting in %d seconds..\n", panic_timeout); |
c95dbf27 | 335 | |
c7ff0d9c | 336 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 337 | touch_nmi_watchdog(); |
c7ff0d9c TS |
338 | if (i >= i_next) { |
339 | i += panic_blink(state ^= 1); | |
340 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
341 | } | |
342 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 343 | } |
4302fbc8 HD |
344 | } |
345 | if (panic_timeout != 0) { | |
c95dbf27 IM |
346 | /* |
347 | * This will not be a clean reboot, with everything | |
348 | * shutting down. But if there is a chance of | |
349 | * rebooting the system it will be rebooted. | |
1da177e4 | 350 | */ |
b287a25a AK |
351 | if (panic_reboot_mode != REBOOT_UNDEFINED) |
352 | reboot_mode = panic_reboot_mode; | |
2f048ea8 | 353 | emergency_restart(); |
1da177e4 LT |
354 | } |
355 | #ifdef __sparc__ | |
356 | { | |
357 | extern int stop_a_enabled; | |
a271c241 | 358 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 359 | stop_a_enabled = 1; |
7db60d05 VK |
360 | pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" |
361 | "twice on console to return to the boot prom\n"); | |
1da177e4 LT |
362 | } |
363 | #endif | |
347a8dc3 | 364 | #if defined(CONFIG_S390) |
98587c2d | 365 | disabled_wait(); |
1da177e4 | 366 | #endif |
5ad75105 | 367 | pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); |
c39ea0b9 FT |
368 | |
369 | /* Do not scroll important messages printed above */ | |
370 | suppress_printk = 1; | |
1da177e4 | 371 | local_irq_enable(); |
c7ff0d9c | 372 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 373 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
374 | if (i >= i_next) { |
375 | i += panic_blink(state ^= 1); | |
376 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
377 | } | |
378 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
379 | } |
380 | } | |
381 | ||
382 | EXPORT_SYMBOL(panic); | |
383 | ||
7fd8329b PM |
384 | /* |
385 | * TAINT_FORCED_RMMOD could be a per-module flag but the module | |
386 | * is being removed anyway. | |
387 | */ | |
388 | const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { | |
47d4b263 KC |
389 | [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, |
390 | [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, | |
391 | [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, | |
392 | [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, | |
393 | [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, | |
394 | [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, | |
395 | [ TAINT_USER ] = { 'U', ' ', false }, | |
396 | [ TAINT_DIE ] = { 'D', ' ', false }, | |
397 | [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, | |
398 | [ TAINT_WARN ] = { 'W', ' ', false }, | |
399 | [ TAINT_CRAP ] = { 'C', ' ', true }, | |
400 | [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, | |
401 | [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, | |
402 | [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, | |
403 | [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, | |
404 | [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, | |
405 | [ TAINT_AUX ] = { 'X', ' ', true }, | |
bc4f2f54 | 406 | [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, |
25ddbb18 AK |
407 | }; |
408 | ||
1da177e4 | 409 | /** |
9c4560e5 | 410 | * print_tainted - return a string to represent the kernel taint state. |
1da177e4 | 411 | * |
57043247 | 412 | * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst |
1da177e4 | 413 | * |
9c4560e5 KC |
414 | * The string is overwritten by the next call to print_tainted(), |
415 | * but is always NULL terminated. | |
1da177e4 | 416 | */ |
1da177e4 LT |
417 | const char *print_tainted(void) |
418 | { | |
7fd8329b | 419 | static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; |
25ddbb18 | 420 | |
47d4b263 KC |
421 | BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); |
422 | ||
25ddbb18 AK |
423 | if (tainted_mask) { |
424 | char *s; | |
425 | int i; | |
426 | ||
427 | s = buf + sprintf(buf, "Tainted: "); | |
7fd8329b PM |
428 | for (i = 0; i < TAINT_FLAGS_COUNT; i++) { |
429 | const struct taint_flag *t = &taint_flags[i]; | |
430 | *s++ = test_bit(i, &tainted_mask) ? | |
5eb7c0d0 | 431 | t->c_true : t->c_false; |
25ddbb18 AK |
432 | } |
433 | *s = 0; | |
434 | } else | |
1da177e4 | 435 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
436 | |
437 | return buf; | |
1da177e4 LT |
438 | } |
439 | ||
25ddbb18 | 440 | int test_taint(unsigned flag) |
1da177e4 | 441 | { |
25ddbb18 AK |
442 | return test_bit(flag, &tainted_mask); |
443 | } | |
444 | EXPORT_SYMBOL(test_taint); | |
445 | ||
446 | unsigned long get_taint(void) | |
447 | { | |
448 | return tainted_mask; | |
1da177e4 | 449 | } |
dd287796 | 450 | |
373d4d09 RR |
451 | /** |
452 | * add_taint: add a taint flag if not already set. | |
453 | * @flag: one of the TAINT_* constants. | |
454 | * @lockdep_ok: whether lock debugging is still OK. | |
455 | * | |
456 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
457 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
458 | */ | |
459 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 460 | { |
373d4d09 | 461 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
d7c0847f | 462 | pr_warn("Disabling lock debugging due to kernel taint\n"); |
9eeba613 | 463 | |
25ddbb18 | 464 | set_bit(flag, &tainted_mask); |
db38d5c1 RA |
465 | |
466 | if (tainted_mask & panic_on_taint) { | |
467 | panic_on_taint = 0; | |
468 | panic("panic_on_taint set ..."); | |
469 | } | |
dd287796 | 470 | } |
1da177e4 | 471 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
472 | |
473 | static void spin_msec(int msecs) | |
474 | { | |
475 | int i; | |
476 | ||
477 | for (i = 0; i < msecs; i++) { | |
478 | touch_nmi_watchdog(); | |
479 | mdelay(1); | |
480 | } | |
481 | } | |
482 | ||
483 | /* | |
484 | * It just happens that oops_enter() and oops_exit() are identically | |
485 | * implemented... | |
486 | */ | |
487 | static void do_oops_enter_exit(void) | |
488 | { | |
489 | unsigned long flags; | |
490 | static int spin_counter; | |
491 | ||
492 | if (!pause_on_oops) | |
493 | return; | |
494 | ||
495 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
496 | if (pause_on_oops_flag == 0) { | |
497 | /* This CPU may now print the oops message */ | |
498 | pause_on_oops_flag = 1; | |
499 | } else { | |
500 | /* We need to stall this CPU */ | |
501 | if (!spin_counter) { | |
502 | /* This CPU gets to do the counting */ | |
503 | spin_counter = pause_on_oops; | |
504 | do { | |
505 | spin_unlock(&pause_on_oops_lock); | |
506 | spin_msec(MSEC_PER_SEC); | |
507 | spin_lock(&pause_on_oops_lock); | |
508 | } while (--spin_counter); | |
509 | pause_on_oops_flag = 0; | |
510 | } else { | |
511 | /* This CPU waits for a different one */ | |
512 | while (spin_counter) { | |
513 | spin_unlock(&pause_on_oops_lock); | |
514 | spin_msec(1); | |
515 | spin_lock(&pause_on_oops_lock); | |
516 | } | |
517 | } | |
518 | } | |
519 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
520 | } | |
521 | ||
522 | /* | |
c95dbf27 IM |
523 | * Return true if the calling CPU is allowed to print oops-related info. |
524 | * This is a bit racy.. | |
dd287796 | 525 | */ |
79076e12 | 526 | bool oops_may_print(void) |
dd287796 AM |
527 | { |
528 | return pause_on_oops_flag == 0; | |
529 | } | |
530 | ||
531 | /* | |
532 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
533 | * anything. If this is the first CPU to oops, and it's oopsing the first |
534 | * time then let it proceed. | |
dd287796 | 535 | * |
c95dbf27 IM |
536 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
537 | * this to ensure that oopses don't scroll off the screen. It has the | |
538 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
539 | * too. | |
dd287796 | 540 | * |
c95dbf27 IM |
541 | * It turns out that the CPU which is allowed to print ends up pausing for |
542 | * the right duration, whereas all the other CPUs pause for twice as long: | |
543 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
544 | */ |
545 | void oops_enter(void) | |
546 | { | |
bdff7870 | 547 | tracing_off(); |
c95dbf27 IM |
548 | /* can't trust the integrity of the kernel anymore: */ |
549 | debug_locks_off(); | |
dd287796 | 550 | do_oops_enter_exit(); |
60c958d8 GP |
551 | |
552 | if (sysctl_oops_all_cpu_backtrace) | |
553 | trigger_all_cpu_backtrace(); | |
dd287796 AM |
554 | } |
555 | ||
63037f74 | 556 | static void print_oops_end_marker(void) |
71c33911 | 557 | { |
e83a4472 | 558 | pr_warn("---[ end trace %016llx ]---\n", 0ULL); |
71c33911 AV |
559 | } |
560 | ||
dd287796 AM |
561 | /* |
562 | * Called when the architecture exits its oops handler, after printing | |
563 | * everything. | |
564 | */ | |
565 | void oops_exit(void) | |
566 | { | |
567 | do_oops_enter_exit(); | |
71c33911 | 568 | print_oops_end_marker(); |
456b565c | 569 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 570 | } |
3162f751 | 571 | |
2553b67a | 572 | struct warn_args { |
0f6f49a8 | 573 | const char *fmt; |
a8f18b90 | 574 | va_list args; |
0f6f49a8 | 575 | }; |
bd89bb29 | 576 | |
2553b67a JP |
577 | void __warn(const char *file, int line, void *caller, unsigned taint, |
578 | struct pt_regs *regs, struct warn_args *args) | |
0f6f49a8 | 579 | { |
de7edd31 SRRH |
580 | disable_trace_on_warning(); |
581 | ||
2bb2b7b5 JO |
582 | printk_prefer_direct_enter(); |
583 | ||
2553b67a JP |
584 | if (file) |
585 | pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", | |
586 | raw_smp_processor_id(), current->pid, file, line, | |
587 | caller); | |
588 | else | |
589 | pr_warn("WARNING: CPU: %d PID: %d at %pS\n", | |
590 | raw_smp_processor_id(), current->pid, caller); | |
74853dba | 591 | |
0f6f49a8 LT |
592 | if (args) |
593 | vprintk(args->fmt, args->args); | |
a8f18b90 | 594 | |
3f388f28 AK |
595 | print_modules(); |
596 | ||
597 | if (regs) | |
598 | show_regs(regs); | |
599 | ||
1a2383e8 | 600 | if (panic_on_warn) |
9e3961a0 | 601 | panic("panic_on_warn set ...\n"); |
9e3961a0 | 602 | |
2f31ad64 CL |
603 | if (!regs) |
604 | dump_stack(); | |
2553b67a | 605 | |
4c281074 SRV |
606 | print_irqtrace_events(current); |
607 | ||
a8f18b90 | 608 | print_oops_end_marker(); |
23b36fec | 609 | trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); |
2553b67a | 610 | |
373d4d09 RR |
611 | /* Just a warning, don't kill lockdep. */ |
612 | add_taint(taint, LOCKDEP_STILL_OK); | |
2bb2b7b5 JO |
613 | |
614 | printk_prefer_direct_exit(); | |
a8f18b90 | 615 | } |
0f6f49a8 | 616 | |
2da1ead4 | 617 | #ifndef __WARN_FLAGS |
ee871133 KC |
618 | void warn_slowpath_fmt(const char *file, int line, unsigned taint, |
619 | const char *fmt, ...) | |
b2be0527 | 620 | { |
2553b67a | 621 | struct warn_args args; |
b2be0527 | 622 | |
d38aba49 KC |
623 | pr_warn(CUT_HERE); |
624 | ||
f2f84b05 | 625 | if (!fmt) { |
f2f84b05 KC |
626 | __warn(file, line, __builtin_return_address(0), taint, |
627 | NULL, NULL); | |
628 | return; | |
629 | } | |
630 | ||
b2be0527 BH |
631 | args.fmt = fmt; |
632 | va_start(args.args, fmt); | |
2553b67a | 633 | __warn(file, line, __builtin_return_address(0), taint, NULL, &args); |
b2be0527 BH |
634 | va_end(args.args); |
635 | } | |
ee871133 | 636 | EXPORT_SYMBOL(warn_slowpath_fmt); |
a7bed27a KC |
637 | #else |
638 | void __warn_printk(const char *fmt, ...) | |
639 | { | |
640 | va_list args; | |
641 | ||
642 | pr_warn(CUT_HERE); | |
643 | ||
644 | va_start(args, fmt); | |
645 | vprintk(fmt, args); | |
646 | va_end(args); | |
647 | } | |
648 | EXPORT_SYMBOL(__warn_printk); | |
79b4cc5e AV |
649 | #endif |
650 | ||
b1fca27d AK |
651 | #ifdef CONFIG_BUG |
652 | ||
653 | /* Support resetting WARN*_ONCE state */ | |
654 | ||
655 | static int clear_warn_once_set(void *data, u64 val) | |
656 | { | |
aaf5dcfb | 657 | generic_bug_clear_once(); |
b1fca27d AK |
658 | memset(__start_once, 0, __end_once - __start_once); |
659 | return 0; | |
660 | } | |
661 | ||
4169680e Y |
662 | DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, |
663 | "%lld\n"); | |
b1fca27d AK |
664 | |
665 | static __init int register_warn_debugfs(void) | |
666 | { | |
667 | /* Don't care about failure */ | |
4169680e Y |
668 | debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, |
669 | &clear_warn_once_fops); | |
b1fca27d AK |
670 | return 0; |
671 | } | |
672 | ||
673 | device_initcall(register_warn_debugfs); | |
674 | #endif | |
675 | ||
050e9baa | 676 | #ifdef CONFIG_STACKPROTECTOR |
54371a43 | 677 | |
3162f751 AV |
678 | /* |
679 | * Called when gcc's -fstack-protector feature is used, and | |
680 | * gcc detects corruption of the on-stack canary value | |
681 | */ | |
5916d5f9 | 682 | __visible noinstr void __stack_chk_fail(void) |
3162f751 | 683 | { |
5916d5f9 | 684 | instrumentation_begin(); |
95c4fb78 | 685 | panic("stack-protector: Kernel stack is corrupted in: %pB", |
517a92c4 | 686 | __builtin_return_address(0)); |
5916d5f9 | 687 | instrumentation_end(); |
3162f751 AV |
688 | } |
689 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 690 | |
3162f751 | 691 | #endif |
f44dd164 RR |
692 | |
693 | core_param(panic, panic_timeout, int, 0644); | |
d999bd93 | 694 | core_param(panic_print, panic_print, ulong, 0644); |
f44dd164 | 695 | core_param(pause_on_oops, pause_on_oops, int, 0644); |
9e3961a0 | 696 | core_param(panic_on_warn, panic_on_warn, int, 0644); |
b26e27dd | 697 | core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); |
f06e5153 | 698 | |
d404ab0a OH |
699 | static int __init oops_setup(char *s) |
700 | { | |
701 | if (!s) | |
702 | return -EINVAL; | |
703 | if (!strcmp(s, "panic")) | |
704 | panic_on_oops = 1; | |
705 | return 0; | |
706 | } | |
707 | early_param("oops", oops_setup); | |
db38d5c1 RA |
708 | |
709 | static int __init panic_on_taint_setup(char *s) | |
710 | { | |
711 | char *taint_str; | |
712 | ||
713 | if (!s) | |
714 | return -EINVAL; | |
715 | ||
716 | taint_str = strsep(&s, ","); | |
717 | if (kstrtoul(taint_str, 16, &panic_on_taint)) | |
718 | return -EINVAL; | |
719 | ||
720 | /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ | |
721 | panic_on_taint &= TAINT_FLAGS_MAX; | |
722 | ||
723 | if (!panic_on_taint) | |
724 | return -EINVAL; | |
725 | ||
726 | if (s && !strcmp(s, "nousertaint")) | |
727 | panic_on_taint_nousertaint = true; | |
728 | ||
729 | pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%sabled\n", | |
730 | panic_on_taint, panic_on_taint_nousertaint ? "en" : "dis"); | |
731 | ||
732 | return 0; | |
733 | } | |
734 | early_param("panic_on_taint", panic_on_taint_setup); |