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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> | |
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 | */ | |
9df91869 | 46 | static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; |
47 | #else | |
48 | #define sysctl_oops_all_cpu_backtrace 0 | |
60c958d8 GP |
49 | #endif /* CONFIG_SMP */ |
50 | ||
2a01bb38 | 51 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
bc4f2f54 | 52 | static unsigned long tainted_mask = |
595b893e | 53 | IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; |
dd287796 AM |
54 | static int pause_on_oops; |
55 | static int pause_on_oops_flag; | |
56 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
5375b708 | 57 | bool crash_kexec_post_notifiers; |
9e3961a0 | 58 | int panic_on_warn __read_mostly; |
db38d5c1 RA |
59 | unsigned long panic_on_taint; |
60 | bool panic_on_taint_nousertaint = false; | |
1da177e4 | 61 | |
5800dc3c | 62 | int panic_timeout = CONFIG_PANIC_TIMEOUT; |
81e88fdc | 63 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 64 | |
d999bd93 FT |
65 | #define PANIC_PRINT_TASK_INFO 0x00000001 |
66 | #define PANIC_PRINT_MEM_INFO 0x00000002 | |
67 | #define PANIC_PRINT_TIMER_INFO 0x00000004 | |
68 | #define PANIC_PRINT_LOCK_INFO 0x00000008 | |
69 | #define PANIC_PRINT_FTRACE_INFO 0x00000010 | |
de6da1e8 | 70 | #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 |
8d470a45 | 71 | #define PANIC_PRINT_ALL_CPU_BT 0x00000040 |
81c9d43f | 72 | unsigned long panic_print; |
d999bd93 | 73 | |
e041c683 | 74 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
75 | |
76 | EXPORT_SYMBOL(panic_notifier_list); | |
77 | ||
9df91869 | 78 | #if defined(CONFIG_SMP) && defined(CONFIG_SYSCTL) |
79 | static struct ctl_table kern_panic_table[] = { | |
80 | { | |
81 | .procname = "oops_all_cpu_backtrace", | |
82 | .data = &sysctl_oops_all_cpu_backtrace, | |
83 | .maxlen = sizeof(int), | |
84 | .mode = 0644, | |
85 | .proc_handler = proc_dointvec_minmax, | |
86 | .extra1 = SYSCTL_ZERO, | |
87 | .extra2 = SYSCTL_ONE, | |
88 | }, | |
89 | { } | |
90 | }; | |
91 | ||
92 | static __init int kernel_panic_sysctls_init(void) | |
93 | { | |
94 | register_sysctl_init("kernel", kern_panic_table); | |
95 | return 0; | |
96 | } | |
97 | late_initcall(kernel_panic_sysctls_init); | |
98 | #endif | |
99 | ||
c7ff0d9c | 100 | static long no_blink(int state) |
8aeee85a | 101 | { |
c7ff0d9c | 102 | return 0; |
8aeee85a AB |
103 | } |
104 | ||
c7ff0d9c TS |
105 | /* Returns how long it waited in ms */ |
106 | long (*panic_blink)(int state); | |
107 | EXPORT_SYMBOL(panic_blink); | |
108 | ||
93e13a36 MH |
109 | /* |
110 | * Stop ourself in panic -- architecture code may override this | |
111 | */ | |
112 | void __weak panic_smp_self_stop(void) | |
113 | { | |
114 | while (1) | |
115 | cpu_relax(); | |
116 | } | |
117 | ||
58c5661f HK |
118 | /* |
119 | * Stop ourselves in NMI context if another CPU has already panicked. Arch code | |
120 | * may override this to prepare for crash dumping, e.g. save regs info. | |
121 | */ | |
122 | void __weak nmi_panic_self_stop(struct pt_regs *regs) | |
123 | { | |
124 | panic_smp_self_stop(); | |
125 | } | |
126 | ||
0ee59413 HK |
127 | /* |
128 | * Stop other CPUs in panic. Architecture dependent code may override this | |
129 | * with more suitable version. For example, if the architecture supports | |
130 | * crash dump, it should save registers of each stopped CPU and disable | |
131 | * per-CPU features such as virtualization extensions. | |
132 | */ | |
133 | void __weak crash_smp_send_stop(void) | |
134 | { | |
135 | static int cpus_stopped; | |
136 | ||
137 | /* | |
138 | * This function can be called twice in panic path, but obviously | |
139 | * we execute this only once. | |
140 | */ | |
141 | if (cpus_stopped) | |
142 | return; | |
143 | ||
144 | /* | |
145 | * Note smp_send_stop is the usual smp shutdown function, which | |
146 | * unfortunately means it may not be hardened to work in a panic | |
147 | * situation. | |
148 | */ | |
149 | smp_send_stop(); | |
150 | cpus_stopped = 1; | |
151 | } | |
152 | ||
1717f209 HK |
153 | atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); |
154 | ||
ebc41f20 HK |
155 | /* |
156 | * A variant of panic() called from NMI context. We return if we've already | |
157 | * panicked on this CPU. If another CPU already panicked, loop in | |
158 | * nmi_panic_self_stop() which can provide architecture dependent code such | |
159 | * as saving register state for crash dump. | |
160 | */ | |
161 | void nmi_panic(struct pt_regs *regs, const char *msg) | |
162 | { | |
163 | int old_cpu, cpu; | |
164 | ||
165 | cpu = raw_smp_processor_id(); | |
166 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); | |
167 | ||
168 | if (old_cpu == PANIC_CPU_INVALID) | |
169 | panic("%s", msg); | |
170 | else if (old_cpu != cpu) | |
171 | nmi_panic_self_stop(regs); | |
172 | } | |
173 | EXPORT_SYMBOL(nmi_panic); | |
174 | ||
f953f140 | 175 | static void panic_print_sys_info(bool console_flush) |
d999bd93 | 176 | { |
f953f140 GP |
177 | if (console_flush) { |
178 | if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) | |
179 | console_flush_on_panic(CONSOLE_REPLAY_ALL); | |
180 | return; | |
181 | } | |
de6da1e8 | 182 | |
8d470a45 GP |
183 | if (panic_print & PANIC_PRINT_ALL_CPU_BT) |
184 | trigger_all_cpu_backtrace(); | |
185 | ||
d999bd93 FT |
186 | if (panic_print & PANIC_PRINT_TASK_INFO) |
187 | show_state(); | |
188 | ||
189 | if (panic_print & PANIC_PRINT_MEM_INFO) | |
190 | show_mem(0, NULL); | |
191 | ||
192 | if (panic_print & PANIC_PRINT_TIMER_INFO) | |
193 | sysrq_timer_list_show(); | |
194 | ||
195 | if (panic_print & PANIC_PRINT_LOCK_INFO) | |
196 | debug_show_all_locks(); | |
197 | ||
198 | if (panic_print & PANIC_PRINT_FTRACE_INFO) | |
199 | ftrace_dump(DUMP_ALL); | |
200 | } | |
201 | ||
1da177e4 LT |
202 | /** |
203 | * panic - halt the system | |
204 | * @fmt: The text string to print | |
205 | * | |
206 | * Display a message, then perform cleanups. | |
207 | * | |
208 | * This function never returns. | |
209 | */ | |
9402c95f | 210 | void panic(const char *fmt, ...) |
1da177e4 | 211 | { |
1da177e4 LT |
212 | static char buf[1024]; |
213 | va_list args; | |
b49dec1c | 214 | long i, i_next = 0, len; |
c7ff0d9c | 215 | int state = 0; |
1717f209 | 216 | int old_cpu, this_cpu; |
b26e27dd | 217 | bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; |
1da177e4 | 218 | |
1a2383e8 TY |
219 | if (panic_on_warn) { |
220 | /* | |
221 | * This thread may hit another WARN() in the panic path. | |
222 | * Resetting this prevents additional WARN() from panicking the | |
223 | * system on this thread. Other threads are blocked by the | |
224 | * panic_mutex in panic(). | |
225 | */ | |
226 | panic_on_warn = 0; | |
227 | } | |
228 | ||
190320c3 VM |
229 | /* |
230 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
231 | * from deadlocking the first cpu that invokes the panic, since | |
232 | * there is nothing to prevent an interrupt handler (that runs | |
1717f209 | 233 | * after setting panic_cpu) from invoking panic() again. |
190320c3 VM |
234 | */ |
235 | local_irq_disable(); | |
20bb759a | 236 | preempt_disable_notrace(); |
190320c3 | 237 | |
dc009d92 | 238 | /* |
c95dbf27 IM |
239 | * It's possible to come here directly from a panic-assertion and |
240 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 241 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
242 | * |
243 | * Only one CPU is allowed to execute the panic code from here. For | |
244 | * multiple parallel invocations of panic, all other CPUs either | |
245 | * stop themself or will wait until they are stopped by the 1st CPU | |
246 | * with smp_send_stop(). | |
1717f209 HK |
247 | * |
248 | * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which | |
249 | * comes here, so go ahead. | |
250 | * `old_cpu == this_cpu' means we came from nmi_panic() which sets | |
251 | * panic_cpu to this CPU. In this case, this is also the 1st CPU. | |
dc009d92 | 252 | */ |
1717f209 HK |
253 | this_cpu = raw_smp_processor_id(); |
254 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
255 | ||
256 | if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) | |
93e13a36 | 257 | panic_smp_self_stop(); |
dc009d92 | 258 | |
5b530fc1 | 259 | console_verbose(); |
1da177e4 LT |
260 | bust_spinlocks(1); |
261 | va_start(args, fmt); | |
b49dec1c | 262 | len = vscnprintf(buf, sizeof(buf), fmt, args); |
1da177e4 | 263 | va_end(args); |
b49dec1c BP |
264 | |
265 | if (len && buf[len - 1] == '\n') | |
266 | buf[len - 1] = '\0'; | |
267 | ||
d7c0847f | 268 | pr_emerg("Kernel panic - not syncing: %s\n", buf); |
5cb27301 | 269 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
270 | /* |
271 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
272 | */ | |
026ee1f6 | 273 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 274 | dump_stack(); |
5cb27301 | 275 | #endif |
1da177e4 | 276 | |
7d92bda2 DA |
277 | /* |
278 | * If kgdb is enabled, give it a chance to run before we stop all | |
279 | * the other CPUs or else we won't be able to debug processes left | |
280 | * running on them. | |
281 | */ | |
282 | kgdb_panic(buf); | |
283 | ||
dc009d92 EB |
284 | /* |
285 | * If we have crashed and we have a crash kernel loaded let it handle | |
286 | * everything else. | |
f06e5153 MH |
287 | * If we want to run this after calling panic_notifiers, pass |
288 | * the "crash_kexec_post_notifiers" option to the kernel. | |
7bbee5ca HK |
289 | * |
290 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
dc009d92 | 291 | */ |
b26e27dd | 292 | if (!_crash_kexec_post_notifiers) { |
7bbee5ca | 293 | __crash_kexec(NULL); |
dc009d92 | 294 | |
0ee59413 HK |
295 | /* |
296 | * Note smp_send_stop is the usual smp shutdown function, which | |
297 | * unfortunately means it may not be hardened to work in a | |
298 | * panic situation. | |
299 | */ | |
300 | smp_send_stop(); | |
301 | } else { | |
302 | /* | |
303 | * If we want to do crash dump after notifier calls and | |
304 | * kmsg_dump, we will need architecture dependent extra | |
305 | * works in addition to stopping other CPUs. | |
306 | */ | |
307 | crash_smp_send_stop(); | |
308 | } | |
1da177e4 | 309 | |
6723734c KC |
310 | /* |
311 | * Run any panic handlers, including those that might need to | |
312 | * add information to the kmsg dump output. | |
313 | */ | |
e041c683 | 314 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 315 | |
f953f140 GP |
316 | panic_print_sys_info(false); |
317 | ||
6723734c KC |
318 | kmsg_dump(KMSG_DUMP_PANIC); |
319 | ||
f06e5153 MH |
320 | /* |
321 | * If you doubt kdump always works fine in any situation, | |
322 | * "crash_kexec_post_notifiers" offers you a chance to run | |
323 | * panic_notifiers and dumping kmsg before kdump. | |
324 | * Note: since some panic_notifiers can make crashed kernel | |
325 | * more unstable, it can increase risks of the kdump failure too. | |
7bbee5ca HK |
326 | * |
327 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
f06e5153 | 328 | */ |
b26e27dd | 329 | if (_crash_kexec_post_notifiers) |
7bbee5ca | 330 | __crash_kexec(NULL); |
f06e5153 | 331 | |
c7c3f05e | 332 | console_unblank(); |
d014e889 | 333 | |
08d78658 VK |
334 | /* |
335 | * We may have ended up stopping the CPU holding the lock (in | |
336 | * smp_send_stop()) while still having some valuable data in the console | |
337 | * buffer. Try to acquire the lock then release it regardless of the | |
7625b3a0 VK |
338 | * result. The release will also print the buffers out. Locks debug |
339 | * should be disabled to avoid reporting bad unlock balance when | |
340 | * panic() is not being callled from OOPS. | |
08d78658 | 341 | */ |
7625b3a0 | 342 | debug_locks_off(); |
de6da1e8 | 343 | console_flush_on_panic(CONSOLE_FLUSH_PENDING); |
08d78658 | 344 | |
f953f140 | 345 | panic_print_sys_info(true); |
d999bd93 | 346 | |
c7ff0d9c TS |
347 | if (!panic_blink) |
348 | panic_blink = no_blink; | |
349 | ||
dc009d92 | 350 | if (panic_timeout > 0) { |
1da177e4 | 351 | /* |
c95dbf27 IM |
352 | * Delay timeout seconds before rebooting the machine. |
353 | * We can't use the "normal" timers since we just panicked. | |
354 | */ | |
ff7a28a0 | 355 | pr_emerg("Rebooting in %d seconds..\n", panic_timeout); |
c95dbf27 | 356 | |
c7ff0d9c | 357 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 358 | touch_nmi_watchdog(); |
c7ff0d9c TS |
359 | if (i >= i_next) { |
360 | i += panic_blink(state ^= 1); | |
361 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
362 | } | |
363 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 364 | } |
4302fbc8 HD |
365 | } |
366 | if (panic_timeout != 0) { | |
c95dbf27 IM |
367 | /* |
368 | * This will not be a clean reboot, with everything | |
369 | * shutting down. But if there is a chance of | |
370 | * rebooting the system it will be rebooted. | |
1da177e4 | 371 | */ |
b287a25a AK |
372 | if (panic_reboot_mode != REBOOT_UNDEFINED) |
373 | reboot_mode = panic_reboot_mode; | |
2f048ea8 | 374 | emergency_restart(); |
1da177e4 LT |
375 | } |
376 | #ifdef __sparc__ | |
377 | { | |
378 | extern int stop_a_enabled; | |
a271c241 | 379 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 380 | stop_a_enabled = 1; |
7db60d05 VK |
381 | pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" |
382 | "twice on console to return to the boot prom\n"); | |
1da177e4 LT |
383 | } |
384 | #endif | |
347a8dc3 | 385 | #if defined(CONFIG_S390) |
98587c2d | 386 | disabled_wait(); |
1da177e4 | 387 | #endif |
5ad75105 | 388 | pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); |
c39ea0b9 FT |
389 | |
390 | /* Do not scroll important messages printed above */ | |
391 | suppress_printk = 1; | |
1da177e4 | 392 | local_irq_enable(); |
c7ff0d9c | 393 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 394 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
395 | if (i >= i_next) { |
396 | i += panic_blink(state ^= 1); | |
397 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
398 | } | |
399 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
400 | } |
401 | } | |
402 | ||
403 | EXPORT_SYMBOL(panic); | |
404 | ||
7fd8329b PM |
405 | /* |
406 | * TAINT_FORCED_RMMOD could be a per-module flag but the module | |
407 | * is being removed anyway. | |
408 | */ | |
409 | const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { | |
47d4b263 KC |
410 | [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, |
411 | [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, | |
412 | [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, | |
413 | [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, | |
414 | [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, | |
415 | [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, | |
416 | [ TAINT_USER ] = { 'U', ' ', false }, | |
417 | [ TAINT_DIE ] = { 'D', ' ', false }, | |
418 | [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, | |
419 | [ TAINT_WARN ] = { 'W', ' ', false }, | |
420 | [ TAINT_CRAP ] = { 'C', ' ', true }, | |
421 | [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, | |
422 | [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, | |
423 | [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, | |
424 | [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, | |
425 | [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, | |
426 | [ TAINT_AUX ] = { 'X', ' ', true }, | |
bc4f2f54 | 427 | [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, |
2852ca7f | 428 | [ TAINT_TEST ] = { 'N', ' ', true }, |
25ddbb18 AK |
429 | }; |
430 | ||
1da177e4 | 431 | /** |
9c4560e5 | 432 | * print_tainted - return a string to represent the kernel taint state. |
1da177e4 | 433 | * |
57043247 | 434 | * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst |
1da177e4 | 435 | * |
9c4560e5 KC |
436 | * The string is overwritten by the next call to print_tainted(), |
437 | * but is always NULL terminated. | |
1da177e4 | 438 | */ |
1da177e4 LT |
439 | const char *print_tainted(void) |
440 | { | |
7fd8329b | 441 | static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; |
25ddbb18 | 442 | |
47d4b263 KC |
443 | BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); |
444 | ||
25ddbb18 AK |
445 | if (tainted_mask) { |
446 | char *s; | |
447 | int i; | |
448 | ||
449 | s = buf + sprintf(buf, "Tainted: "); | |
7fd8329b PM |
450 | for (i = 0; i < TAINT_FLAGS_COUNT; i++) { |
451 | const struct taint_flag *t = &taint_flags[i]; | |
452 | *s++ = test_bit(i, &tainted_mask) ? | |
5eb7c0d0 | 453 | t->c_true : t->c_false; |
25ddbb18 AK |
454 | } |
455 | *s = 0; | |
456 | } else | |
1da177e4 | 457 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
458 | |
459 | return buf; | |
1da177e4 LT |
460 | } |
461 | ||
25ddbb18 | 462 | int test_taint(unsigned flag) |
1da177e4 | 463 | { |
25ddbb18 AK |
464 | return test_bit(flag, &tainted_mask); |
465 | } | |
466 | EXPORT_SYMBOL(test_taint); | |
467 | ||
468 | unsigned long get_taint(void) | |
469 | { | |
470 | return tainted_mask; | |
1da177e4 | 471 | } |
dd287796 | 472 | |
373d4d09 RR |
473 | /** |
474 | * add_taint: add a taint flag if not already set. | |
475 | * @flag: one of the TAINT_* constants. | |
476 | * @lockdep_ok: whether lock debugging is still OK. | |
477 | * | |
478 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
479 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
480 | */ | |
481 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 482 | { |
373d4d09 | 483 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
d7c0847f | 484 | pr_warn("Disabling lock debugging due to kernel taint\n"); |
9eeba613 | 485 | |
25ddbb18 | 486 | set_bit(flag, &tainted_mask); |
db38d5c1 RA |
487 | |
488 | if (tainted_mask & panic_on_taint) { | |
489 | panic_on_taint = 0; | |
490 | panic("panic_on_taint set ..."); | |
491 | } | |
dd287796 | 492 | } |
1da177e4 | 493 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
494 | |
495 | static void spin_msec(int msecs) | |
496 | { | |
497 | int i; | |
498 | ||
499 | for (i = 0; i < msecs; i++) { | |
500 | touch_nmi_watchdog(); | |
501 | mdelay(1); | |
502 | } | |
503 | } | |
504 | ||
505 | /* | |
506 | * It just happens that oops_enter() and oops_exit() are identically | |
507 | * implemented... | |
508 | */ | |
509 | static void do_oops_enter_exit(void) | |
510 | { | |
511 | unsigned long flags; | |
512 | static int spin_counter; | |
513 | ||
514 | if (!pause_on_oops) | |
515 | return; | |
516 | ||
517 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
518 | if (pause_on_oops_flag == 0) { | |
519 | /* This CPU may now print the oops message */ | |
520 | pause_on_oops_flag = 1; | |
521 | } else { | |
522 | /* We need to stall this CPU */ | |
523 | if (!spin_counter) { | |
524 | /* This CPU gets to do the counting */ | |
525 | spin_counter = pause_on_oops; | |
526 | do { | |
527 | spin_unlock(&pause_on_oops_lock); | |
528 | spin_msec(MSEC_PER_SEC); | |
529 | spin_lock(&pause_on_oops_lock); | |
530 | } while (--spin_counter); | |
531 | pause_on_oops_flag = 0; | |
532 | } else { | |
533 | /* This CPU waits for a different one */ | |
534 | while (spin_counter) { | |
535 | spin_unlock(&pause_on_oops_lock); | |
536 | spin_msec(1); | |
537 | spin_lock(&pause_on_oops_lock); | |
538 | } | |
539 | } | |
540 | } | |
541 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
542 | } | |
543 | ||
544 | /* | |
c95dbf27 IM |
545 | * Return true if the calling CPU is allowed to print oops-related info. |
546 | * This is a bit racy.. | |
dd287796 | 547 | */ |
79076e12 | 548 | bool oops_may_print(void) |
dd287796 AM |
549 | { |
550 | return pause_on_oops_flag == 0; | |
551 | } | |
552 | ||
553 | /* | |
554 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
555 | * anything. If this is the first CPU to oops, and it's oopsing the first |
556 | * time then let it proceed. | |
dd287796 | 557 | * |
c95dbf27 IM |
558 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
559 | * this to ensure that oopses don't scroll off the screen. It has the | |
560 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
561 | * too. | |
dd287796 | 562 | * |
c95dbf27 IM |
563 | * It turns out that the CPU which is allowed to print ends up pausing for |
564 | * the right duration, whereas all the other CPUs pause for twice as long: | |
565 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
566 | */ |
567 | void oops_enter(void) | |
568 | { | |
bdff7870 | 569 | tracing_off(); |
c95dbf27 IM |
570 | /* can't trust the integrity of the kernel anymore: */ |
571 | debug_locks_off(); | |
dd287796 | 572 | do_oops_enter_exit(); |
60c958d8 GP |
573 | |
574 | if (sysctl_oops_all_cpu_backtrace) | |
575 | trigger_all_cpu_backtrace(); | |
dd287796 AM |
576 | } |
577 | ||
63037f74 | 578 | static void print_oops_end_marker(void) |
71c33911 | 579 | { |
e83a4472 | 580 | pr_warn("---[ end trace %016llx ]---\n", 0ULL); |
71c33911 AV |
581 | } |
582 | ||
dd287796 AM |
583 | /* |
584 | * Called when the architecture exits its oops handler, after printing | |
585 | * everything. | |
586 | */ | |
587 | void oops_exit(void) | |
588 | { | |
589 | do_oops_enter_exit(); | |
71c33911 | 590 | print_oops_end_marker(); |
456b565c | 591 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 592 | } |
3162f751 | 593 | |
2553b67a | 594 | struct warn_args { |
0f6f49a8 | 595 | const char *fmt; |
a8f18b90 | 596 | va_list args; |
0f6f49a8 | 597 | }; |
bd89bb29 | 598 | |
2553b67a JP |
599 | void __warn(const char *file, int line, void *caller, unsigned taint, |
600 | struct pt_regs *regs, struct warn_args *args) | |
0f6f49a8 | 601 | { |
de7edd31 SRRH |
602 | disable_trace_on_warning(); |
603 | ||
2553b67a JP |
604 | if (file) |
605 | pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", | |
606 | raw_smp_processor_id(), current->pid, file, line, | |
607 | caller); | |
608 | else | |
609 | pr_warn("WARNING: CPU: %d PID: %d at %pS\n", | |
610 | raw_smp_processor_id(), current->pid, caller); | |
74853dba | 611 | |
0f6f49a8 LT |
612 | if (args) |
613 | vprintk(args->fmt, args->args); | |
a8f18b90 | 614 | |
3f388f28 AK |
615 | print_modules(); |
616 | ||
617 | if (regs) | |
618 | show_regs(regs); | |
619 | ||
1a2383e8 | 620 | if (panic_on_warn) |
9e3961a0 | 621 | panic("panic_on_warn set ...\n"); |
9e3961a0 | 622 | |
2f31ad64 CL |
623 | if (!regs) |
624 | dump_stack(); | |
2553b67a | 625 | |
4c281074 SRV |
626 | print_irqtrace_events(current); |
627 | ||
a8f18b90 | 628 | print_oops_end_marker(); |
23b36fec | 629 | trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); |
2553b67a | 630 | |
373d4d09 RR |
631 | /* Just a warning, don't kill lockdep. */ |
632 | add_taint(taint, LOCKDEP_STILL_OK); | |
a8f18b90 | 633 | } |
0f6f49a8 | 634 | |
2da1ead4 | 635 | #ifndef __WARN_FLAGS |
ee871133 KC |
636 | void warn_slowpath_fmt(const char *file, int line, unsigned taint, |
637 | const char *fmt, ...) | |
b2be0527 | 638 | { |
2553b67a | 639 | struct warn_args args; |
b2be0527 | 640 | |
d38aba49 KC |
641 | pr_warn(CUT_HERE); |
642 | ||
f2f84b05 | 643 | if (!fmt) { |
f2f84b05 KC |
644 | __warn(file, line, __builtin_return_address(0), taint, |
645 | NULL, NULL); | |
646 | return; | |
647 | } | |
648 | ||
b2be0527 BH |
649 | args.fmt = fmt; |
650 | va_start(args.args, fmt); | |
2553b67a | 651 | __warn(file, line, __builtin_return_address(0), taint, NULL, &args); |
b2be0527 BH |
652 | va_end(args.args); |
653 | } | |
ee871133 | 654 | EXPORT_SYMBOL(warn_slowpath_fmt); |
a7bed27a KC |
655 | #else |
656 | void __warn_printk(const char *fmt, ...) | |
657 | { | |
658 | va_list args; | |
659 | ||
660 | pr_warn(CUT_HERE); | |
661 | ||
662 | va_start(args, fmt); | |
663 | vprintk(fmt, args); | |
664 | va_end(args); | |
665 | } | |
666 | EXPORT_SYMBOL(__warn_printk); | |
79b4cc5e AV |
667 | #endif |
668 | ||
b1fca27d AK |
669 | #ifdef CONFIG_BUG |
670 | ||
671 | /* Support resetting WARN*_ONCE state */ | |
672 | ||
673 | static int clear_warn_once_set(void *data, u64 val) | |
674 | { | |
aaf5dcfb | 675 | generic_bug_clear_once(); |
b1fca27d AK |
676 | memset(__start_once, 0, __end_once - __start_once); |
677 | return 0; | |
678 | } | |
679 | ||
4169680e Y |
680 | DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, |
681 | "%lld\n"); | |
b1fca27d AK |
682 | |
683 | static __init int register_warn_debugfs(void) | |
684 | { | |
685 | /* Don't care about failure */ | |
4169680e Y |
686 | debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, |
687 | &clear_warn_once_fops); | |
b1fca27d AK |
688 | return 0; |
689 | } | |
690 | ||
691 | device_initcall(register_warn_debugfs); | |
692 | #endif | |
693 | ||
050e9baa | 694 | #ifdef CONFIG_STACKPROTECTOR |
54371a43 | 695 | |
3162f751 AV |
696 | /* |
697 | * Called when gcc's -fstack-protector feature is used, and | |
698 | * gcc detects corruption of the on-stack canary value | |
699 | */ | |
5916d5f9 | 700 | __visible noinstr void __stack_chk_fail(void) |
3162f751 | 701 | { |
5916d5f9 | 702 | instrumentation_begin(); |
95c4fb78 | 703 | panic("stack-protector: Kernel stack is corrupted in: %pB", |
517a92c4 | 704 | __builtin_return_address(0)); |
5916d5f9 | 705 | instrumentation_end(); |
3162f751 AV |
706 | } |
707 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 708 | |
3162f751 | 709 | #endif |
f44dd164 RR |
710 | |
711 | core_param(panic, panic_timeout, int, 0644); | |
d999bd93 | 712 | core_param(panic_print, panic_print, ulong, 0644); |
f44dd164 | 713 | core_param(pause_on_oops, pause_on_oops, int, 0644); |
9e3961a0 | 714 | core_param(panic_on_warn, panic_on_warn, int, 0644); |
b26e27dd | 715 | core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); |
f06e5153 | 716 | |
d404ab0a OH |
717 | static int __init oops_setup(char *s) |
718 | { | |
719 | if (!s) | |
720 | return -EINVAL; | |
721 | if (!strcmp(s, "panic")) | |
722 | panic_on_oops = 1; | |
723 | return 0; | |
724 | } | |
725 | early_param("oops", oops_setup); | |
db38d5c1 RA |
726 | |
727 | static int __init panic_on_taint_setup(char *s) | |
728 | { | |
729 | char *taint_str; | |
730 | ||
731 | if (!s) | |
732 | return -EINVAL; | |
733 | ||
734 | taint_str = strsep(&s, ","); | |
735 | if (kstrtoul(taint_str, 16, &panic_on_taint)) | |
736 | return -EINVAL; | |
737 | ||
738 | /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ | |
739 | panic_on_taint &= TAINT_FLAGS_MAX; | |
740 | ||
741 | if (!panic_on_taint) | |
742 | return -EINVAL; | |
743 | ||
744 | if (s && !strcmp(s, "nousertaint")) | |
745 | panic_on_taint_nousertaint = true; | |
746 | ||
747 | pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%sabled\n", | |
748 | panic_on_taint, panic_on_taint_nousertaint ? "en" : "dis"); | |
749 | ||
750 | return 0; | |
751 | } | |
752 | early_param("panic_on_taint", panic_on_taint_setup); |