1 // SPDX-License-Identifier: GPL-2.0-only 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 */ 12 #include <linux/debug_locks.h> 13 #include <linux/sched/debug.h> 14 #include <linux/interrupt.h> 15 #include <linux/kgdb.h> 16 #include <linux/kmsg_dump.h> 17 #include <linux/kallsyms.h> 18 #include <linux/notifier.h> 19 #include <linux/vt_kern.h> 20 #include <linux/module.h> 21 #include <linux/random.h> 22 #include <linux/ftrace.h> 23 #include <linux/reboot.h> 24 #include <linux/delay.h> 25 #include <linux/kexec.h> 26 #include <linux/panic_notifier.h> 27 #include <linux/sched.h> 28 #include <linux/string_helpers.h> 29 #include <linux/sysrq.h> 30 #include <linux/init.h> 31 #include <linux/nmi.h> 32 #include <linux/console.h> 33 #include <linux/bug.h> 34 #include <linux/ratelimit.h> 35 #include <linux/debugfs.h> 36 #include <linux/sysfs.h> 37 #include <trace/events/error_report.h> 38 #include <asm/sections.h> 39 40 #define PANIC_TIMER_STEP 100 41 #define PANIC_BLINK_SPD 18 42 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 */ 48 static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; 49 #else 50 #define sysctl_oops_all_cpu_backtrace 0 51 #endif /* CONFIG_SMP */ 52 53 int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; 54 static unsigned long tainted_mask = 55 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; 56 static int pause_on_oops; 57 static int pause_on_oops_flag; 58 static DEFINE_SPINLOCK(pause_on_oops_lock); 59 bool crash_kexec_post_notifiers; 60 int panic_on_warn __read_mostly; 61 unsigned long panic_on_taint; 62 bool panic_on_taint_nousertaint = false; 63 static unsigned int warn_limit __read_mostly; 64 65 int panic_timeout = CONFIG_PANIC_TIMEOUT; 66 EXPORT_SYMBOL_GPL(panic_timeout); 67 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 73 #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 74 #define PANIC_PRINT_ALL_CPU_BT 0x00000040 75 unsigned long panic_print; 76 77 ATOMIC_NOTIFIER_HEAD(panic_notifier_list); 78 79 EXPORT_SYMBOL(panic_notifier_list); 80 81 #ifdef CONFIG_SYSCTL 82 static struct ctl_table kern_panic_table[] = { 83 #ifdef CONFIG_SMP 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 }, 93 #endif 94 { 95 .procname = "warn_limit", 96 .data = &warn_limit, 97 .maxlen = sizeof(warn_limit), 98 .mode = 0644, 99 .proc_handler = proc_douintvec, 100 }, 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 111 112 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 130 131 static long no_blink(int state) 132 { 133 return 0; 134 } 135 136 /* Returns how long it waited in ms */ 137 long (*panic_blink)(int state); 138 EXPORT_SYMBOL(panic_blink); 139 140 /* 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 } 148 149 /* 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 } 157 158 /* 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 } 183 184 atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); 185 186 /* 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); 205 206 static void panic_print_sys_info(bool console_flush) 207 { 208 if (console_flush) { 209 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) 210 console_flush_on_panic(CONSOLE_REPLAY_ALL); 211 return; 212 } 213 214 if (panic_print & PANIC_PRINT_ALL_CPU_BT) 215 trigger_all_cpu_backtrace(); 216 217 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 } 232 233 void check_panic_on_warn(const char *origin) 234 { 235 unsigned int limit; 236 237 if (panic_on_warn) 238 panic("%s: panic_on_warn set ...\n", origin); 239 240 limit = READ_ONCE(warn_limit); 241 if (atomic_inc_return(&warn_count) >= limit && limit) 242 panic("%s: system warned too often (kernel.warn_limit is %d)", 243 origin, limit); 244 } 245 246 /** 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 */ 254 void panic(const char *fmt, ...) 255 { 256 static char buf[1024]; 257 va_list args; 258 long i, i_next = 0, len; 259 int state = 0; 260 int old_cpu, this_cpu; 261 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; 262 263 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 } 272 273 /* 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 277 * after setting panic_cpu) from invoking panic() again. 278 */ 279 local_irq_disable(); 280 preempt_disable_notrace(); 281 282 /* 283 * It's possible to come here directly from a panic-assertion and 284 * not have preempt disabled. Some functions called from here want 285 * preempt to be disabled. No point enabling it later though... 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(). 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. 296 */ 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) 301 panic_smp_self_stop(); 302 303 console_verbose(); 304 bust_spinlocks(1); 305 va_start(args, fmt); 306 len = vscnprintf(buf, sizeof(buf), fmt, args); 307 va_end(args); 308 309 if (len && buf[len - 1] == '\n') 310 buf[len - 1] = '\0'; 311 312 pr_emerg("Kernel panic - not syncing: %s\n", buf); 313 #ifdef CONFIG_DEBUG_BUGVERBOSE 314 /* 315 * Avoid nested stack-dumping if a panic occurs during oops processing 316 */ 317 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) 318 dump_stack(); 319 #endif 320 321 /* 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); 327 328 /* 329 * If we have crashed and we have a crash kernel loaded let it handle 330 * everything else. 331 * If we want to run this after calling panic_notifiers, pass 332 * the "crash_kexec_post_notifiers" option to the kernel. 333 * 334 * Bypass the panic_cpu check and call __crash_kexec directly. 335 */ 336 if (!_crash_kexec_post_notifiers) { 337 __crash_kexec(NULL); 338 339 /* 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 } 353 354 /* 355 * Run any panic handlers, including those that might need to 356 * add information to the kmsg dump output. 357 */ 358 atomic_notifier_call_chain(&panic_notifier_list, 0, buf); 359 360 panic_print_sys_info(false); 361 362 kmsg_dump(KMSG_DUMP_PANIC); 363 364 /* 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. 370 * 371 * Bypass the panic_cpu check and call __crash_kexec directly. 372 */ 373 if (_crash_kexec_post_notifiers) 374 __crash_kexec(NULL); 375 376 console_unblank(); 377 378 /* 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 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. 385 */ 386 debug_locks_off(); 387 console_flush_on_panic(CONSOLE_FLUSH_PENDING); 388 389 panic_print_sys_info(true); 390 391 if (!panic_blink) 392 panic_blink = no_blink; 393 394 if (panic_timeout > 0) { 395 /* 396 * Delay timeout seconds before rebooting the machine. 397 * We can't use the "normal" timers since we just panicked. 398 */ 399 pr_emerg("Rebooting in %d seconds..\n", panic_timeout); 400 401 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { 402 touch_nmi_watchdog(); 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); 408 } 409 } 410 if (panic_timeout != 0) { 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. 415 */ 416 if (panic_reboot_mode != REBOOT_UNDEFINED) 417 reboot_mode = panic_reboot_mode; 418 emergency_restart(); 419 } 420 #ifdef __sparc__ 421 { 422 extern int stop_a_enabled; 423 /* Make sure the user can actually press Stop-A (L1-A) */ 424 stop_a_enabled = 1; 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"); 427 } 428 #endif 429 #if defined(CONFIG_S390) 430 disabled_wait(); 431 #endif 432 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); 433 434 /* Do not scroll important messages printed above */ 435 suppress_printk = 1; 436 local_irq_enable(); 437 for (i = 0; ; i += PANIC_TIMER_STEP) { 438 touch_softlockup_watchdog(); 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); 444 } 445 } 446 447 EXPORT_SYMBOL(panic); 448 449 /* 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] = { 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 }, 471 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, 472 [ TAINT_TEST ] = { 'N', ' ', true }, 473 }; 474 475 /** 476 * print_tainted - return a string to represent the kernel taint state. 477 * 478 * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst 479 * 480 * The string is overwritten by the next call to print_tainted(), 481 * but is always NULL terminated. 482 */ 483 const char *print_tainted(void) 484 { 485 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; 486 487 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); 488 489 if (tainted_mask) { 490 char *s; 491 int i; 492 493 s = buf + sprintf(buf, "Tainted: "); 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) ? 497 t->c_true : t->c_false; 498 } 499 *s = 0; 500 } else 501 snprintf(buf, sizeof(buf), "Not tainted"); 502 503 return buf; 504 } 505 506 int test_taint(unsigned flag) 507 { 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; 515 } 516 517 /** 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) 526 { 527 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) 528 pr_warn("Disabling lock debugging due to kernel taint\n"); 529 530 set_bit(flag, &tainted_mask); 531 532 if (tainted_mask & panic_on_taint) { 533 panic_on_taint = 0; 534 panic("panic_on_taint set ..."); 535 } 536 } 537 EXPORT_SYMBOL(add_taint); 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 /* 589 * Return true if the calling CPU is allowed to print oops-related info. 590 * This is a bit racy.. 591 */ 592 bool oops_may_print(void) 593 { 594 return pause_on_oops_flag == 0; 595 } 596 597 /* 598 * Called when the architecture enters its oops handler, before it prints 599 * anything. If this is the first CPU to oops, and it's oopsing the first 600 * time then let it proceed. 601 * 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. 606 * 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(). 610 */ 611 void oops_enter(void) 612 { 613 tracing_off(); 614 /* can't trust the integrity of the kernel anymore: */ 615 debug_locks_off(); 616 do_oops_enter_exit(); 617 618 if (sysctl_oops_all_cpu_backtrace) 619 trigger_all_cpu_backtrace(); 620 } 621 622 static void print_oops_end_marker(void) 623 { 624 pr_warn("---[ end trace %016llx ]---\n", 0ULL); 625 } 626 627 /* 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(); 634 print_oops_end_marker(); 635 kmsg_dump(KMSG_DUMP_OOPS); 636 } 637 638 struct warn_args { 639 const char *fmt; 640 va_list args; 641 }; 642 643 void __warn(const char *file, int line, void *caller, unsigned taint, 644 struct pt_regs *regs, struct warn_args *args) 645 { 646 disable_trace_on_warning(); 647 648 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); 655 656 if (args) 657 vprintk(args->fmt, args->args); 658 659 print_modules(); 660 661 if (regs) 662 show_regs(regs); 663 664 check_panic_on_warn("kernel"); 665 666 if (!regs) 667 dump_stack(); 668 669 print_irqtrace_events(current); 670 671 print_oops_end_marker(); 672 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); 673 674 /* Just a warning, don't kill lockdep. */ 675 add_taint(taint, LOCKDEP_STILL_OK); 676 } 677 678 #ifndef __WARN_FLAGS 679 void warn_slowpath_fmt(const char *file, int line, unsigned taint, 680 const char *fmt, ...) 681 { 682 struct warn_args args; 683 684 pr_warn(CUT_HERE); 685 686 if (!fmt) { 687 __warn(file, line, __builtin_return_address(0), taint, 688 NULL, NULL); 689 return; 690 } 691 692 args.fmt = fmt; 693 va_start(args.args, fmt); 694 __warn(file, line, __builtin_return_address(0), taint, NULL, &args); 695 va_end(args.args); 696 } 697 EXPORT_SYMBOL(warn_slowpath_fmt); 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); 710 #endif 711 712 #ifdef CONFIG_BUG 713 714 /* Support resetting WARN*_ONCE state */ 715 716 static int clear_warn_once_set(void *data, u64 val) 717 { 718 generic_bug_clear_once(); 719 memset(__start_once, 0, __end_once - __start_once); 720 return 0; 721 } 722 723 DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, 724 "%lld\n"); 725 726 static __init int register_warn_debugfs(void) 727 { 728 /* Don't care about failure */ 729 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, 730 &clear_warn_once_fops); 731 return 0; 732 } 733 734 device_initcall(register_warn_debugfs); 735 #endif 736 737 #ifdef CONFIG_STACKPROTECTOR 738 739 /* 740 * Called when gcc's -fstack-protector feature is used, and 741 * gcc detects corruption of the on-stack canary value 742 */ 743 __visible noinstr void __stack_chk_fail(void) 744 { 745 instrumentation_begin(); 746 panic("stack-protector: Kernel stack is corrupted in: %pB", 747 __builtin_return_address(0)); 748 instrumentation_end(); 749 } 750 EXPORT_SYMBOL(__stack_chk_fail); 751 752 #endif 753 754 core_param(panic, panic_timeout, int, 0644); 755 core_param(panic_print, panic_print, ulong, 0644); 756 core_param(pause_on_oops, pause_on_oops, int, 0644); 757 core_param(panic_on_warn, panic_on_warn, int, 0644); 758 core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); 759 760 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); 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; 789 790 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n", 791 panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint)); 792 793 return 0; 794 } 795 early_param("panic_on_taint", panic_on_taint_setup); 796