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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> |
5d5dd3e4 | 28 | #include <linux/string_helpers.h> |
1da177e4 | 29 | #include <linux/sysrq.h> |
c95dbf27 | 30 | #include <linux/init.h> |
1da177e4 | 31 | #include <linux/nmi.h> |
08d78658 | 32 | #include <linux/console.h> |
2553b67a | 33 | #include <linux/bug.h> |
7a46ec0e | 34 | #include <linux/ratelimit.h> |
b1fca27d | 35 | #include <linux/debugfs.h> |
8b05aa26 | 36 | #include <linux/sysfs.h> |
23b36fec | 37 | #include <trace/events/error_report.h> |
b1fca27d | 38 | #include <asm/sections.h> |
1da177e4 | 39 | |
c7ff0d9c TS |
40 | #define PANIC_TIMER_STEP 100 |
41 | #define PANIC_BLINK_SPD 18 | |
42 | ||
60c958d8 GP |
43 | #ifdef CONFIG_SMP |
44 | /* | |
45 | * Should we dump all CPUs backtraces in an oops event? | |
46 | * Defaults to 0, can be changed via sysctl. | |
47 | */ | |
9df91869 | 48 | static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; |
49 | #else | |
50 | #define sysctl_oops_all_cpu_backtrace 0 | |
60c958d8 GP |
51 | #endif /* CONFIG_SMP */ |
52 | ||
2a01bb38 | 53 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
bc4f2f54 | 54 | static unsigned long tainted_mask = |
595b893e | 55 | IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; |
dd287796 AM |
56 | static int pause_on_oops; |
57 | static int pause_on_oops_flag; | |
58 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
5375b708 | 59 | bool crash_kexec_post_notifiers; |
9e3961a0 | 60 | int panic_on_warn __read_mostly; |
db38d5c1 RA |
61 | unsigned long panic_on_taint; |
62 | bool panic_on_taint_nousertaint = false; | |
9fc9e278 | 63 | static unsigned int warn_limit __read_mostly; |
1da177e4 | 64 | |
5800dc3c | 65 | int panic_timeout = CONFIG_PANIC_TIMEOUT; |
81e88fdc | 66 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 67 | |
d999bd93 FT |
68 | #define PANIC_PRINT_TASK_INFO 0x00000001 |
69 | #define PANIC_PRINT_MEM_INFO 0x00000002 | |
70 | #define PANIC_PRINT_TIMER_INFO 0x00000004 | |
71 | #define PANIC_PRINT_LOCK_INFO 0x00000008 | |
72 | #define PANIC_PRINT_FTRACE_INFO 0x00000010 | |
de6da1e8 | 73 | #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 |
8d470a45 | 74 | #define PANIC_PRINT_ALL_CPU_BT 0x00000040 |
81c9d43f | 75 | unsigned long panic_print; |
d999bd93 | 76 | |
e041c683 | 77 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
78 | |
79 | EXPORT_SYMBOL(panic_notifier_list); | |
80 | ||
9360d035 | 81 | #ifdef CONFIG_SYSCTL |
9df91869 | 82 | static struct ctl_table kern_panic_table[] = { |
9360d035 | 83 | #ifdef CONFIG_SMP |
9df91869 | 84 | { |
85 | .procname = "oops_all_cpu_backtrace", | |
86 | .data = &sysctl_oops_all_cpu_backtrace, | |
87 | .maxlen = sizeof(int), | |
88 | .mode = 0644, | |
89 | .proc_handler = proc_dointvec_minmax, | |
90 | .extra1 = SYSCTL_ZERO, | |
91 | .extra2 = SYSCTL_ONE, | |
92 | }, | |
9360d035 | 93 | #endif |
9fc9e278 KC |
94 | { |
95 | .procname = "warn_limit", | |
96 | .data = &warn_limit, | |
97 | .maxlen = sizeof(warn_limit), | |
98 | .mode = 0644, | |
99 | .proc_handler = proc_douintvec, | |
100 | }, | |
9df91869 | 101 | { } |
102 | }; | |
103 | ||
104 | static __init int kernel_panic_sysctls_init(void) | |
105 | { | |
106 | register_sysctl_init("kernel", kern_panic_table); | |
107 | return 0; | |
108 | } | |
109 | late_initcall(kernel_panic_sysctls_init); | |
110 | #endif | |
111 | ||
8b05aa26 KC |
112 | static atomic_t warn_count = ATOMIC_INIT(0); |
113 | ||
114 | #ifdef CONFIG_SYSFS | |
115 | static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr, | |
116 | char *page) | |
117 | { | |
118 | return sysfs_emit(page, "%d\n", atomic_read(&warn_count)); | |
119 | } | |
120 | ||
121 | static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count); | |
122 | ||
123 | static __init int kernel_panic_sysfs_init(void) | |
124 | { | |
125 | sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL); | |
126 | return 0; | |
127 | } | |
128 | late_initcall(kernel_panic_sysfs_init); | |
129 | #endif | |
130 | ||
c7ff0d9c | 131 | static long no_blink(int state) |
8aeee85a | 132 | { |
c7ff0d9c | 133 | return 0; |
8aeee85a AB |
134 | } |
135 | ||
c7ff0d9c TS |
136 | /* Returns how long it waited in ms */ |
137 | long (*panic_blink)(int state); | |
138 | EXPORT_SYMBOL(panic_blink); | |
139 | ||
93e13a36 MH |
140 | /* |
141 | * Stop ourself in panic -- architecture code may override this | |
142 | */ | |
143 | void __weak panic_smp_self_stop(void) | |
144 | { | |
145 | while (1) | |
146 | cpu_relax(); | |
147 | } | |
148 | ||
58c5661f HK |
149 | /* |
150 | * Stop ourselves in NMI context if another CPU has already panicked. Arch code | |
151 | * may override this to prepare for crash dumping, e.g. save regs info. | |
152 | */ | |
153 | void __weak nmi_panic_self_stop(struct pt_regs *regs) | |
154 | { | |
155 | panic_smp_self_stop(); | |
156 | } | |
157 | ||
0ee59413 HK |
158 | /* |
159 | * Stop other CPUs in panic. Architecture dependent code may override this | |
160 | * with more suitable version. For example, if the architecture supports | |
161 | * crash dump, it should save registers of each stopped CPU and disable | |
162 | * per-CPU features such as virtualization extensions. | |
163 | */ | |
164 | void __weak crash_smp_send_stop(void) | |
165 | { | |
166 | static int cpus_stopped; | |
167 | ||
168 | /* | |
169 | * This function can be called twice in panic path, but obviously | |
170 | * we execute this only once. | |
171 | */ | |
172 | if (cpus_stopped) | |
173 | return; | |
174 | ||
175 | /* | |
176 | * Note smp_send_stop is the usual smp shutdown function, which | |
177 | * unfortunately means it may not be hardened to work in a panic | |
178 | * situation. | |
179 | */ | |
180 | smp_send_stop(); | |
181 | cpus_stopped = 1; | |
182 | } | |
183 | ||
1717f209 HK |
184 | atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); |
185 | ||
ebc41f20 HK |
186 | /* |
187 | * A variant of panic() called from NMI context. We return if we've already | |
188 | * panicked on this CPU. If another CPU already panicked, loop in | |
189 | * nmi_panic_self_stop() which can provide architecture dependent code such | |
190 | * as saving register state for crash dump. | |
191 | */ | |
192 | void nmi_panic(struct pt_regs *regs, const char *msg) | |
193 | { | |
194 | int old_cpu, cpu; | |
195 | ||
196 | cpu = raw_smp_processor_id(); | |
197 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); | |
198 | ||
199 | if (old_cpu == PANIC_CPU_INVALID) | |
200 | panic("%s", msg); | |
201 | else if (old_cpu != cpu) | |
202 | nmi_panic_self_stop(regs); | |
203 | } | |
204 | EXPORT_SYMBOL(nmi_panic); | |
205 | ||
f953f140 | 206 | static void panic_print_sys_info(bool console_flush) |
d999bd93 | 207 | { |
f953f140 GP |
208 | if (console_flush) { |
209 | if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) | |
210 | console_flush_on_panic(CONSOLE_REPLAY_ALL); | |
211 | return; | |
212 | } | |
de6da1e8 | 213 | |
8d470a45 GP |
214 | if (panic_print & PANIC_PRINT_ALL_CPU_BT) |
215 | trigger_all_cpu_backtrace(); | |
216 | ||
d999bd93 FT |
217 | if (panic_print & PANIC_PRINT_TASK_INFO) |
218 | show_state(); | |
219 | ||
220 | if (panic_print & PANIC_PRINT_MEM_INFO) | |
221 | show_mem(0, NULL); | |
222 | ||
223 | if (panic_print & PANIC_PRINT_TIMER_INFO) | |
224 | sysrq_timer_list_show(); | |
225 | ||
226 | if (panic_print & PANIC_PRINT_LOCK_INFO) | |
227 | debug_show_all_locks(); | |
228 | ||
229 | if (panic_print & PANIC_PRINT_FTRACE_INFO) | |
230 | ftrace_dump(DUMP_ALL); | |
231 | } | |
232 | ||
79cc1ba7 KC |
233 | void check_panic_on_warn(const char *origin) |
234 | { | |
7535b832 KC |
235 | unsigned int limit; |
236 | ||
79cc1ba7 KC |
237 | if (panic_on_warn) |
238 | panic("%s: panic_on_warn set ...\n", origin); | |
9fc9e278 | 239 | |
7535b832 KC |
240 | limit = READ_ONCE(warn_limit); |
241 | if (atomic_inc_return(&warn_count) >= limit && limit) | |
9fc9e278 | 242 | panic("%s: system warned too often (kernel.warn_limit is %d)", |
7535b832 | 243 | origin, limit); |
79cc1ba7 KC |
244 | } |
245 | ||
1da177e4 LT |
246 | /** |
247 | * panic - halt the system | |
248 | * @fmt: The text string to print | |
249 | * | |
250 | * Display a message, then perform cleanups. | |
251 | * | |
252 | * This function never returns. | |
253 | */ | |
9402c95f | 254 | void panic(const char *fmt, ...) |
1da177e4 | 255 | { |
1da177e4 LT |
256 | static char buf[1024]; |
257 | va_list args; | |
b49dec1c | 258 | long i, i_next = 0, len; |
c7ff0d9c | 259 | int state = 0; |
1717f209 | 260 | int old_cpu, this_cpu; |
b26e27dd | 261 | bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; |
1da177e4 | 262 | |
1a2383e8 TY |
263 | if (panic_on_warn) { |
264 | /* | |
265 | * This thread may hit another WARN() in the panic path. | |
266 | * Resetting this prevents additional WARN() from panicking the | |
267 | * system on this thread. Other threads are blocked by the | |
268 | * panic_mutex in panic(). | |
269 | */ | |
270 | panic_on_warn = 0; | |
271 | } | |
272 | ||
190320c3 VM |
273 | /* |
274 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
275 | * from deadlocking the first cpu that invokes the panic, since | |
276 | * there is nothing to prevent an interrupt handler (that runs | |
1717f209 | 277 | * after setting panic_cpu) from invoking panic() again. |
190320c3 VM |
278 | */ |
279 | local_irq_disable(); | |
20bb759a | 280 | preempt_disable_notrace(); |
190320c3 | 281 | |
dc009d92 | 282 | /* |
c95dbf27 IM |
283 | * It's possible to come here directly from a panic-assertion and |
284 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 285 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
286 | * |
287 | * Only one CPU is allowed to execute the panic code from here. For | |
288 | * multiple parallel invocations of panic, all other CPUs either | |
289 | * stop themself or will wait until they are stopped by the 1st CPU | |
290 | * with smp_send_stop(). | |
1717f209 HK |
291 | * |
292 | * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which | |
293 | * comes here, so go ahead. | |
294 | * `old_cpu == this_cpu' means we came from nmi_panic() which sets | |
295 | * panic_cpu to this CPU. In this case, this is also the 1st CPU. | |
dc009d92 | 296 | */ |
1717f209 HK |
297 | this_cpu = raw_smp_processor_id(); |
298 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
299 | ||
300 | if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) | |
93e13a36 | 301 | panic_smp_self_stop(); |
dc009d92 | 302 | |
5b530fc1 | 303 | console_verbose(); |
1da177e4 LT |
304 | bust_spinlocks(1); |
305 | va_start(args, fmt); | |
b49dec1c | 306 | len = vscnprintf(buf, sizeof(buf), fmt, args); |
1da177e4 | 307 | va_end(args); |
b49dec1c BP |
308 | |
309 | if (len && buf[len - 1] == '\n') | |
310 | buf[len - 1] = '\0'; | |
311 | ||
d7c0847f | 312 | pr_emerg("Kernel panic - not syncing: %s\n", buf); |
5cb27301 | 313 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
314 | /* |
315 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
316 | */ | |
026ee1f6 | 317 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 318 | dump_stack(); |
5cb27301 | 319 | #endif |
1da177e4 | 320 | |
7d92bda2 DA |
321 | /* |
322 | * If kgdb is enabled, give it a chance to run before we stop all | |
323 | * the other CPUs or else we won't be able to debug processes left | |
324 | * running on them. | |
325 | */ | |
326 | kgdb_panic(buf); | |
327 | ||
dc009d92 EB |
328 | /* |
329 | * If we have crashed and we have a crash kernel loaded let it handle | |
330 | * everything else. | |
f06e5153 MH |
331 | * If we want to run this after calling panic_notifiers, pass |
332 | * the "crash_kexec_post_notifiers" option to the kernel. | |
7bbee5ca HK |
333 | * |
334 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
dc009d92 | 335 | */ |
b26e27dd | 336 | if (!_crash_kexec_post_notifiers) { |
7bbee5ca | 337 | __crash_kexec(NULL); |
dc009d92 | 338 | |
0ee59413 HK |
339 | /* |
340 | * Note smp_send_stop is the usual smp shutdown function, which | |
341 | * unfortunately means it may not be hardened to work in a | |
342 | * panic situation. | |
343 | */ | |
344 | smp_send_stop(); | |
345 | } else { | |
346 | /* | |
347 | * If we want to do crash dump after notifier calls and | |
348 | * kmsg_dump, we will need architecture dependent extra | |
349 | * works in addition to stopping other CPUs. | |
350 | */ | |
351 | crash_smp_send_stop(); | |
352 | } | |
1da177e4 | 353 | |
6723734c KC |
354 | /* |
355 | * Run any panic handlers, including those that might need to | |
356 | * add information to the kmsg dump output. | |
357 | */ | |
e041c683 | 358 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 359 | |
f953f140 GP |
360 | panic_print_sys_info(false); |
361 | ||
6723734c KC |
362 | kmsg_dump(KMSG_DUMP_PANIC); |
363 | ||
f06e5153 MH |
364 | /* |
365 | * If you doubt kdump always works fine in any situation, | |
366 | * "crash_kexec_post_notifiers" offers you a chance to run | |
367 | * panic_notifiers and dumping kmsg before kdump. | |
368 | * Note: since some panic_notifiers can make crashed kernel | |
369 | * more unstable, it can increase risks of the kdump failure too. | |
7bbee5ca HK |
370 | * |
371 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
f06e5153 | 372 | */ |
b26e27dd | 373 | if (_crash_kexec_post_notifiers) |
7bbee5ca | 374 | __crash_kexec(NULL); |
f06e5153 | 375 | |
c7c3f05e | 376 | console_unblank(); |
d014e889 | 377 | |
08d78658 VK |
378 | /* |
379 | * We may have ended up stopping the CPU holding the lock (in | |
380 | * smp_send_stop()) while still having some valuable data in the console | |
381 | * buffer. Try to acquire the lock then release it regardless of the | |
7625b3a0 VK |
382 | * result. The release will also print the buffers out. Locks debug |
383 | * should be disabled to avoid reporting bad unlock balance when | |
384 | * panic() is not being callled from OOPS. | |
08d78658 | 385 | */ |
7625b3a0 | 386 | debug_locks_off(); |
de6da1e8 | 387 | console_flush_on_panic(CONSOLE_FLUSH_PENDING); |
08d78658 | 388 | |
f953f140 | 389 | panic_print_sys_info(true); |
d999bd93 | 390 | |
c7ff0d9c TS |
391 | if (!panic_blink) |
392 | panic_blink = no_blink; | |
393 | ||
dc009d92 | 394 | if (panic_timeout > 0) { |
1da177e4 | 395 | /* |
c95dbf27 IM |
396 | * Delay timeout seconds before rebooting the machine. |
397 | * We can't use the "normal" timers since we just panicked. | |
398 | */ | |
ff7a28a0 | 399 | pr_emerg("Rebooting in %d seconds..\n", panic_timeout); |
c95dbf27 | 400 | |
c7ff0d9c | 401 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 402 | touch_nmi_watchdog(); |
c7ff0d9c TS |
403 | if (i >= i_next) { |
404 | i += panic_blink(state ^= 1); | |
405 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
406 | } | |
407 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 408 | } |
4302fbc8 HD |
409 | } |
410 | if (panic_timeout != 0) { | |
c95dbf27 IM |
411 | /* |
412 | * This will not be a clean reboot, with everything | |
413 | * shutting down. But if there is a chance of | |
414 | * rebooting the system it will be rebooted. | |
1da177e4 | 415 | */ |
b287a25a AK |
416 | if (panic_reboot_mode != REBOOT_UNDEFINED) |
417 | reboot_mode = panic_reboot_mode; | |
2f048ea8 | 418 | emergency_restart(); |
1da177e4 LT |
419 | } |
420 | #ifdef __sparc__ | |
421 | { | |
422 | extern int stop_a_enabled; | |
a271c241 | 423 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 424 | stop_a_enabled = 1; |
7db60d05 VK |
425 | pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" |
426 | "twice on console to return to the boot prom\n"); | |
1da177e4 LT |
427 | } |
428 | #endif | |
347a8dc3 | 429 | #if defined(CONFIG_S390) |
98587c2d | 430 | disabled_wait(); |
1da177e4 | 431 | #endif |
5ad75105 | 432 | pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); |
c39ea0b9 FT |
433 | |
434 | /* Do not scroll important messages printed above */ | |
435 | suppress_printk = 1; | |
1da177e4 | 436 | local_irq_enable(); |
c7ff0d9c | 437 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 438 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
439 | if (i >= i_next) { |
440 | i += panic_blink(state ^= 1); | |
441 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
442 | } | |
443 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
444 | } |
445 | } | |
446 | ||
447 | EXPORT_SYMBOL(panic); | |
448 | ||
7fd8329b PM |
449 | /* |
450 | * TAINT_FORCED_RMMOD could be a per-module flag but the module | |
451 | * is being removed anyway. | |
452 | */ | |
453 | const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { | |
47d4b263 KC |
454 | [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, |
455 | [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, | |
456 | [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, | |
457 | [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, | |
458 | [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, | |
459 | [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, | |
460 | [ TAINT_USER ] = { 'U', ' ', false }, | |
461 | [ TAINT_DIE ] = { 'D', ' ', false }, | |
462 | [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, | |
463 | [ TAINT_WARN ] = { 'W', ' ', false }, | |
464 | [ TAINT_CRAP ] = { 'C', ' ', true }, | |
465 | [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, | |
466 | [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, | |
467 | [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, | |
468 | [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, | |
469 | [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, | |
470 | [ TAINT_AUX ] = { 'X', ' ', true }, | |
bc4f2f54 | 471 | [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, |
2852ca7f | 472 | [ TAINT_TEST ] = { 'N', ' ', true }, |
25ddbb18 AK |
473 | }; |
474 | ||
1da177e4 | 475 | /** |
9c4560e5 | 476 | * print_tainted - return a string to represent the kernel taint state. |
1da177e4 | 477 | * |
57043247 | 478 | * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst |
1da177e4 | 479 | * |
9c4560e5 KC |
480 | * The string is overwritten by the next call to print_tainted(), |
481 | * but is always NULL terminated. | |
1da177e4 | 482 | */ |
1da177e4 LT |
483 | const char *print_tainted(void) |
484 | { | |
7fd8329b | 485 | static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; |
25ddbb18 | 486 | |
47d4b263 KC |
487 | BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); |
488 | ||
25ddbb18 AK |
489 | if (tainted_mask) { |
490 | char *s; | |
491 | int i; | |
492 | ||
493 | s = buf + sprintf(buf, "Tainted: "); | |
7fd8329b PM |
494 | for (i = 0; i < TAINT_FLAGS_COUNT; i++) { |
495 | const struct taint_flag *t = &taint_flags[i]; | |
496 | *s++ = test_bit(i, &tainted_mask) ? | |
5eb7c0d0 | 497 | t->c_true : t->c_false; |
25ddbb18 AK |
498 | } |
499 | *s = 0; | |
500 | } else | |
1da177e4 | 501 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
502 | |
503 | return buf; | |
1da177e4 LT |
504 | } |
505 | ||
25ddbb18 | 506 | int test_taint(unsigned flag) |
1da177e4 | 507 | { |
25ddbb18 AK |
508 | return test_bit(flag, &tainted_mask); |
509 | } | |
510 | EXPORT_SYMBOL(test_taint); | |
511 | ||
512 | unsigned long get_taint(void) | |
513 | { | |
514 | return tainted_mask; | |
1da177e4 | 515 | } |
dd287796 | 516 | |
373d4d09 RR |
517 | /** |
518 | * add_taint: add a taint flag if not already set. | |
519 | * @flag: one of the TAINT_* constants. | |
520 | * @lockdep_ok: whether lock debugging is still OK. | |
521 | * | |
522 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
523 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
524 | */ | |
525 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 526 | { |
373d4d09 | 527 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
d7c0847f | 528 | pr_warn("Disabling lock debugging due to kernel taint\n"); |
9eeba613 | 529 | |
25ddbb18 | 530 | set_bit(flag, &tainted_mask); |
db38d5c1 RA |
531 | |
532 | if (tainted_mask & panic_on_taint) { | |
533 | panic_on_taint = 0; | |
534 | panic("panic_on_taint set ..."); | |
535 | } | |
dd287796 | 536 | } |
1da177e4 | 537 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
538 | |
539 | static void spin_msec(int msecs) | |
540 | { | |
541 | int i; | |
542 | ||
543 | for (i = 0; i < msecs; i++) { | |
544 | touch_nmi_watchdog(); | |
545 | mdelay(1); | |
546 | } | |
547 | } | |
548 | ||
549 | /* | |
550 | * It just happens that oops_enter() and oops_exit() are identically | |
551 | * implemented... | |
552 | */ | |
553 | static void do_oops_enter_exit(void) | |
554 | { | |
555 | unsigned long flags; | |
556 | static int spin_counter; | |
557 | ||
558 | if (!pause_on_oops) | |
559 | return; | |
560 | ||
561 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
562 | if (pause_on_oops_flag == 0) { | |
563 | /* This CPU may now print the oops message */ | |
564 | pause_on_oops_flag = 1; | |
565 | } else { | |
566 | /* We need to stall this CPU */ | |
567 | if (!spin_counter) { | |
568 | /* This CPU gets to do the counting */ | |
569 | spin_counter = pause_on_oops; | |
570 | do { | |
571 | spin_unlock(&pause_on_oops_lock); | |
572 | spin_msec(MSEC_PER_SEC); | |
573 | spin_lock(&pause_on_oops_lock); | |
574 | } while (--spin_counter); | |
575 | pause_on_oops_flag = 0; | |
576 | } else { | |
577 | /* This CPU waits for a different one */ | |
578 | while (spin_counter) { | |
579 | spin_unlock(&pause_on_oops_lock); | |
580 | spin_msec(1); | |
581 | spin_lock(&pause_on_oops_lock); | |
582 | } | |
583 | } | |
584 | } | |
585 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
586 | } | |
587 | ||
588 | /* | |
c95dbf27 IM |
589 | * Return true if the calling CPU is allowed to print oops-related info. |
590 | * This is a bit racy.. | |
dd287796 | 591 | */ |
79076e12 | 592 | bool oops_may_print(void) |
dd287796 AM |
593 | { |
594 | return pause_on_oops_flag == 0; | |
595 | } | |
596 | ||
597 | /* | |
598 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
599 | * anything. If this is the first CPU to oops, and it's oopsing the first |
600 | * time then let it proceed. | |
dd287796 | 601 | * |
c95dbf27 IM |
602 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
603 | * this to ensure that oopses don't scroll off the screen. It has the | |
604 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
605 | * too. | |
dd287796 | 606 | * |
c95dbf27 IM |
607 | * It turns out that the CPU which is allowed to print ends up pausing for |
608 | * the right duration, whereas all the other CPUs pause for twice as long: | |
609 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
610 | */ |
611 | void oops_enter(void) | |
612 | { | |
bdff7870 | 613 | tracing_off(); |
c95dbf27 IM |
614 | /* can't trust the integrity of the kernel anymore: */ |
615 | debug_locks_off(); | |
dd287796 | 616 | do_oops_enter_exit(); |
60c958d8 GP |
617 | |
618 | if (sysctl_oops_all_cpu_backtrace) | |
619 | trigger_all_cpu_backtrace(); | |
dd287796 AM |
620 | } |
621 | ||
63037f74 | 622 | static void print_oops_end_marker(void) |
71c33911 | 623 | { |
e83a4472 | 624 | pr_warn("---[ end trace %016llx ]---\n", 0ULL); |
71c33911 AV |
625 | } |
626 | ||
dd287796 AM |
627 | /* |
628 | * Called when the architecture exits its oops handler, after printing | |
629 | * everything. | |
630 | */ | |
631 | void oops_exit(void) | |
632 | { | |
633 | do_oops_enter_exit(); | |
71c33911 | 634 | print_oops_end_marker(); |
456b565c | 635 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 636 | } |
3162f751 | 637 | |
2553b67a | 638 | struct warn_args { |
0f6f49a8 | 639 | const char *fmt; |
a8f18b90 | 640 | va_list args; |
0f6f49a8 | 641 | }; |
bd89bb29 | 642 | |
2553b67a JP |
643 | void __warn(const char *file, int line, void *caller, unsigned taint, |
644 | struct pt_regs *regs, struct warn_args *args) | |
0f6f49a8 | 645 | { |
de7edd31 SRRH |
646 | disable_trace_on_warning(); |
647 | ||
2553b67a JP |
648 | if (file) |
649 | pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", | |
650 | raw_smp_processor_id(), current->pid, file, line, | |
651 | caller); | |
652 | else | |
653 | pr_warn("WARNING: CPU: %d PID: %d at %pS\n", | |
654 | raw_smp_processor_id(), current->pid, caller); | |
74853dba | 655 | |
0f6f49a8 LT |
656 | if (args) |
657 | vprintk(args->fmt, args->args); | |
a8f18b90 | 658 | |
3f388f28 AK |
659 | print_modules(); |
660 | ||
661 | if (regs) | |
662 | show_regs(regs); | |
663 | ||
79cc1ba7 | 664 | check_panic_on_warn("kernel"); |
9e3961a0 | 665 | |
2f31ad64 CL |
666 | if (!regs) |
667 | dump_stack(); | |
2553b67a | 668 | |
4c281074 SRV |
669 | print_irqtrace_events(current); |
670 | ||
a8f18b90 | 671 | print_oops_end_marker(); |
23b36fec | 672 | trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); |
2553b67a | 673 | |
373d4d09 RR |
674 | /* Just a warning, don't kill lockdep. */ |
675 | add_taint(taint, LOCKDEP_STILL_OK); | |
a8f18b90 | 676 | } |
0f6f49a8 | 677 | |
2da1ead4 | 678 | #ifndef __WARN_FLAGS |
ee871133 KC |
679 | void warn_slowpath_fmt(const char *file, int line, unsigned taint, |
680 | const char *fmt, ...) | |
b2be0527 | 681 | { |
2553b67a | 682 | struct warn_args args; |
b2be0527 | 683 | |
d38aba49 KC |
684 | pr_warn(CUT_HERE); |
685 | ||
f2f84b05 | 686 | if (!fmt) { |
f2f84b05 KC |
687 | __warn(file, line, __builtin_return_address(0), taint, |
688 | NULL, NULL); | |
689 | return; | |
690 | } | |
691 | ||
b2be0527 BH |
692 | args.fmt = fmt; |
693 | va_start(args.args, fmt); | |
2553b67a | 694 | __warn(file, line, __builtin_return_address(0), taint, NULL, &args); |
b2be0527 BH |
695 | va_end(args.args); |
696 | } | |
ee871133 | 697 | EXPORT_SYMBOL(warn_slowpath_fmt); |
a7bed27a KC |
698 | #else |
699 | void __warn_printk(const char *fmt, ...) | |
700 | { | |
701 | va_list args; | |
702 | ||
703 | pr_warn(CUT_HERE); | |
704 | ||
705 | va_start(args, fmt); | |
706 | vprintk(fmt, args); | |
707 | va_end(args); | |
708 | } | |
709 | EXPORT_SYMBOL(__warn_printk); | |
79b4cc5e AV |
710 | #endif |
711 | ||
b1fca27d AK |
712 | #ifdef CONFIG_BUG |
713 | ||
714 | /* Support resetting WARN*_ONCE state */ | |
715 | ||
716 | static int clear_warn_once_set(void *data, u64 val) | |
717 | { | |
aaf5dcfb | 718 | generic_bug_clear_once(); |
b1fca27d AK |
719 | memset(__start_once, 0, __end_once - __start_once); |
720 | return 0; | |
721 | } | |
722 | ||
4169680e Y |
723 | DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, |
724 | "%lld\n"); | |
b1fca27d AK |
725 | |
726 | static __init int register_warn_debugfs(void) | |
727 | { | |
728 | /* Don't care about failure */ | |
4169680e Y |
729 | debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, |
730 | &clear_warn_once_fops); | |
b1fca27d AK |
731 | return 0; |
732 | } | |
733 | ||
734 | device_initcall(register_warn_debugfs); | |
735 | #endif | |
736 | ||
050e9baa | 737 | #ifdef CONFIG_STACKPROTECTOR |
54371a43 | 738 | |
3162f751 AV |
739 | /* |
740 | * Called when gcc's -fstack-protector feature is used, and | |
741 | * gcc detects corruption of the on-stack canary value | |
742 | */ | |
5916d5f9 | 743 | __visible noinstr void __stack_chk_fail(void) |
3162f751 | 744 | { |
5916d5f9 | 745 | instrumentation_begin(); |
95c4fb78 | 746 | panic("stack-protector: Kernel stack is corrupted in: %pB", |
517a92c4 | 747 | __builtin_return_address(0)); |
5916d5f9 | 748 | instrumentation_end(); |
3162f751 AV |
749 | } |
750 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 751 | |
3162f751 | 752 | #endif |
f44dd164 RR |
753 | |
754 | core_param(panic, panic_timeout, int, 0644); | |
d999bd93 | 755 | core_param(panic_print, panic_print, ulong, 0644); |
f44dd164 | 756 | core_param(pause_on_oops, pause_on_oops, int, 0644); |
9e3961a0 | 757 | core_param(panic_on_warn, panic_on_warn, int, 0644); |
b26e27dd | 758 | core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); |
f06e5153 | 759 | |
d404ab0a OH |
760 | static int __init oops_setup(char *s) |
761 | { | |
762 | if (!s) | |
763 | return -EINVAL; | |
764 | if (!strcmp(s, "panic")) | |
765 | panic_on_oops = 1; | |
766 | return 0; | |
767 | } | |
768 | early_param("oops", oops_setup); | |
db38d5c1 RA |
769 | |
770 | static int __init panic_on_taint_setup(char *s) | |
771 | { | |
772 | char *taint_str; | |
773 | ||
774 | if (!s) | |
775 | return -EINVAL; | |
776 | ||
777 | taint_str = strsep(&s, ","); | |
778 | if (kstrtoul(taint_str, 16, &panic_on_taint)) | |
779 | return -EINVAL; | |
780 | ||
781 | /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ | |
782 | panic_on_taint &= TAINT_FLAGS_MAX; | |
783 | ||
784 | if (!panic_on_taint) | |
785 | return -EINVAL; | |
786 | ||
787 | if (s && !strcmp(s, "nousertaint")) | |
788 | panic_on_taint_nousertaint = true; | |
789 | ||
5d5dd3e4 AS |
790 | pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n", |
791 | panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint)); | |
db38d5c1 RA |
792 | |
793 | return 0; | |
794 | } | |
795 | early_param("panic_on_taint", panic_on_taint_setup); |