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 <linux/context_tracking.h> 38 #include <linux/seq_buf.h> 39 #include <trace/events/error_report.h> 40 #include <asm/sections.h> 41 42 #define PANIC_TIMER_STEP 100 43 #define PANIC_BLINK_SPD 18 44 45 #ifdef CONFIG_SMP 46 /* 47 * Should we dump all CPUs backtraces in an oops event? 48 * Defaults to 0, can be changed via sysctl. 49 */ 50 static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; 51 #else 52 #define sysctl_oops_all_cpu_backtrace 0 53 #endif /* CONFIG_SMP */ 54 55 int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; 56 static unsigned long tainted_mask = 57 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; 58 static int pause_on_oops; 59 static int pause_on_oops_flag; 60 static DEFINE_SPINLOCK(pause_on_oops_lock); 61 bool crash_kexec_post_notifiers; 62 int panic_on_warn __read_mostly; 63 unsigned long panic_on_taint; 64 bool panic_on_taint_nousertaint = false; 65 static unsigned int warn_limit __read_mostly; 66 67 bool panic_triggering_all_cpu_backtrace; 68 69 int panic_timeout = CONFIG_PANIC_TIMEOUT; 70 EXPORT_SYMBOL_GPL(panic_timeout); 71 72 #define PANIC_PRINT_TASK_INFO 0x00000001 73 #define PANIC_PRINT_MEM_INFO 0x00000002 74 #define PANIC_PRINT_TIMER_INFO 0x00000004 75 #define PANIC_PRINT_LOCK_INFO 0x00000008 76 #define PANIC_PRINT_FTRACE_INFO 0x00000010 77 #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 78 #define PANIC_PRINT_ALL_CPU_BT 0x00000040 79 #define PANIC_PRINT_BLOCKED_TASKS 0x00000080 80 unsigned long panic_print; 81 82 ATOMIC_NOTIFIER_HEAD(panic_notifier_list); 83 84 EXPORT_SYMBOL(panic_notifier_list); 85 86 #ifdef CONFIG_SYSCTL 87 static struct ctl_table kern_panic_table[] = { 88 #ifdef CONFIG_SMP 89 { 90 .procname = "oops_all_cpu_backtrace", 91 .data = &sysctl_oops_all_cpu_backtrace, 92 .maxlen = sizeof(int), 93 .mode = 0644, 94 .proc_handler = proc_dointvec_minmax, 95 .extra1 = SYSCTL_ZERO, 96 .extra2 = SYSCTL_ONE, 97 }, 98 #endif 99 { 100 .procname = "warn_limit", 101 .data = &warn_limit, 102 .maxlen = sizeof(warn_limit), 103 .mode = 0644, 104 .proc_handler = proc_douintvec, 105 }, 106 }; 107 108 static __init int kernel_panic_sysctls_init(void) 109 { 110 register_sysctl_init("kernel", kern_panic_table); 111 return 0; 112 } 113 late_initcall(kernel_panic_sysctls_init); 114 #endif 115 116 static atomic_t warn_count = ATOMIC_INIT(0); 117 118 #ifdef CONFIG_SYSFS 119 static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr, 120 char *page) 121 { 122 return sysfs_emit(page, "%d\n", atomic_read(&warn_count)); 123 } 124 125 static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count); 126 127 static __init int kernel_panic_sysfs_init(void) 128 { 129 sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL); 130 return 0; 131 } 132 late_initcall(kernel_panic_sysfs_init); 133 #endif 134 135 static long no_blink(int state) 136 { 137 return 0; 138 } 139 140 /* Returns how long it waited in ms */ 141 long (*panic_blink)(int state); 142 EXPORT_SYMBOL(panic_blink); 143 144 /* 145 * Stop ourself in panic -- architecture code may override this 146 */ 147 void __weak __noreturn panic_smp_self_stop(void) 148 { 149 while (1) 150 cpu_relax(); 151 } 152 153 /* 154 * Stop ourselves in NMI context if another CPU has already panicked. Arch code 155 * may override this to prepare for crash dumping, e.g. save regs info. 156 */ 157 void __weak __noreturn nmi_panic_self_stop(struct pt_regs *regs) 158 { 159 panic_smp_self_stop(); 160 } 161 162 /* 163 * Stop other CPUs in panic. Architecture dependent code may override this 164 * with more suitable version. For example, if the architecture supports 165 * crash dump, it should save registers of each stopped CPU and disable 166 * per-CPU features such as virtualization extensions. 167 */ 168 void __weak crash_smp_send_stop(void) 169 { 170 static int cpus_stopped; 171 172 /* 173 * This function can be called twice in panic path, but obviously 174 * we execute this only once. 175 */ 176 if (cpus_stopped) 177 return; 178 179 /* 180 * Note smp_send_stop is the usual smp shutdown function, which 181 * unfortunately means it may not be hardened to work in a panic 182 * situation. 183 */ 184 smp_send_stop(); 185 cpus_stopped = 1; 186 } 187 188 atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); 189 190 /* 191 * A variant of panic() called from NMI context. We return if we've already 192 * panicked on this CPU. If another CPU already panicked, loop in 193 * nmi_panic_self_stop() which can provide architecture dependent code such 194 * as saving register state for crash dump. 195 */ 196 void nmi_panic(struct pt_regs *regs, const char *msg) 197 { 198 int old_cpu, this_cpu; 199 200 old_cpu = PANIC_CPU_INVALID; 201 this_cpu = raw_smp_processor_id(); 202 203 /* atomic_try_cmpxchg updates old_cpu on failure */ 204 if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) 205 panic("%s", msg); 206 else if (old_cpu != this_cpu) 207 nmi_panic_self_stop(regs); 208 } 209 EXPORT_SYMBOL(nmi_panic); 210 211 static void panic_print_sys_info(bool console_flush) 212 { 213 if (console_flush) { 214 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) 215 console_flush_on_panic(CONSOLE_REPLAY_ALL); 216 return; 217 } 218 219 if (panic_print & PANIC_PRINT_TASK_INFO) 220 show_state(); 221 222 if (panic_print & PANIC_PRINT_MEM_INFO) 223 show_mem(); 224 225 if (panic_print & PANIC_PRINT_TIMER_INFO) 226 sysrq_timer_list_show(); 227 228 if (panic_print & PANIC_PRINT_LOCK_INFO) 229 debug_show_all_locks(); 230 231 if (panic_print & PANIC_PRINT_FTRACE_INFO) 232 ftrace_dump(DUMP_ALL); 233 234 if (panic_print & PANIC_PRINT_BLOCKED_TASKS) 235 show_state_filter(TASK_UNINTERRUPTIBLE); 236 } 237 238 void check_panic_on_warn(const char *origin) 239 { 240 unsigned int limit; 241 242 if (panic_on_warn) 243 panic("%s: panic_on_warn set ...\n", origin); 244 245 limit = READ_ONCE(warn_limit); 246 if (atomic_inc_return(&warn_count) >= limit && limit) 247 panic("%s: system warned too often (kernel.warn_limit is %d)", 248 origin, limit); 249 } 250 251 /* 252 * Helper that triggers the NMI backtrace (if set in panic_print) 253 * and then performs the secondary CPUs shutdown - we cannot have 254 * the NMI backtrace after the CPUs are off! 255 */ 256 static void panic_other_cpus_shutdown(bool crash_kexec) 257 { 258 if (panic_print & PANIC_PRINT_ALL_CPU_BT) { 259 /* Temporary allow non-panic CPUs to write their backtraces. */ 260 panic_triggering_all_cpu_backtrace = true; 261 trigger_all_cpu_backtrace(); 262 panic_triggering_all_cpu_backtrace = false; 263 } 264 265 /* 266 * Note that smp_send_stop() is the usual SMP shutdown function, 267 * which unfortunately may not be hardened to work in a panic 268 * situation. If we want to do crash dump after notifier calls 269 * and kmsg_dump, we will need architecture dependent extra 270 * bits in addition to stopping other CPUs, hence we rely on 271 * crash_smp_send_stop() for that. 272 */ 273 if (!crash_kexec) 274 smp_send_stop(); 275 else 276 crash_smp_send_stop(); 277 } 278 279 /** 280 * panic - halt the system 281 * @fmt: The text string to print 282 * 283 * Display a message, then perform cleanups. 284 * 285 * This function never returns. 286 */ 287 void panic(const char *fmt, ...) 288 { 289 static char buf[1024]; 290 va_list args; 291 long i, i_next = 0, len; 292 int state = 0; 293 int old_cpu, this_cpu; 294 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; 295 296 if (panic_on_warn) { 297 /* 298 * This thread may hit another WARN() in the panic path. 299 * Resetting this prevents additional WARN() from panicking the 300 * system on this thread. Other threads are blocked by the 301 * panic_mutex in panic(). 302 */ 303 panic_on_warn = 0; 304 } 305 306 /* 307 * Disable local interrupts. This will prevent panic_smp_self_stop 308 * from deadlocking the first cpu that invokes the panic, since 309 * there is nothing to prevent an interrupt handler (that runs 310 * after setting panic_cpu) from invoking panic() again. 311 */ 312 local_irq_disable(); 313 preempt_disable_notrace(); 314 315 /* 316 * It's possible to come here directly from a panic-assertion and 317 * not have preempt disabled. Some functions called from here want 318 * preempt to be disabled. No point enabling it later though... 319 * 320 * Only one CPU is allowed to execute the panic code from here. For 321 * multiple parallel invocations of panic, all other CPUs either 322 * stop themself or will wait until they are stopped by the 1st CPU 323 * with smp_send_stop(). 324 * 325 * cmpxchg success means this is the 1st CPU which comes here, 326 * so go ahead. 327 * `old_cpu == this_cpu' means we came from nmi_panic() which sets 328 * panic_cpu to this CPU. In this case, this is also the 1st CPU. 329 */ 330 old_cpu = PANIC_CPU_INVALID; 331 this_cpu = raw_smp_processor_id(); 332 333 /* atomic_try_cmpxchg updates old_cpu on failure */ 334 if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) { 335 /* go ahead */ 336 } else if (old_cpu != this_cpu) 337 panic_smp_self_stop(); 338 339 console_verbose(); 340 bust_spinlocks(1); 341 va_start(args, fmt); 342 len = vscnprintf(buf, sizeof(buf), fmt, args); 343 va_end(args); 344 345 if (len && buf[len - 1] == '\n') 346 buf[len - 1] = '\0'; 347 348 pr_emerg("Kernel panic - not syncing: %s\n", buf); 349 #ifdef CONFIG_DEBUG_BUGVERBOSE 350 /* 351 * Avoid nested stack-dumping if a panic occurs during oops processing 352 */ 353 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) 354 dump_stack(); 355 #endif 356 357 /* 358 * If kgdb is enabled, give it a chance to run before we stop all 359 * the other CPUs or else we won't be able to debug processes left 360 * running on them. 361 */ 362 kgdb_panic(buf); 363 364 /* 365 * If we have crashed and we have a crash kernel loaded let it handle 366 * everything else. 367 * If we want to run this after calling panic_notifiers, pass 368 * the "crash_kexec_post_notifiers" option to the kernel. 369 * 370 * Bypass the panic_cpu check and call __crash_kexec directly. 371 */ 372 if (!_crash_kexec_post_notifiers) 373 __crash_kexec(NULL); 374 375 panic_other_cpus_shutdown(_crash_kexec_post_notifiers); 376 377 printk_legacy_allow_panic_sync(); 378 379 /* 380 * Run any panic handlers, including those that might need to 381 * add information to the kmsg dump output. 382 */ 383 atomic_notifier_call_chain(&panic_notifier_list, 0, buf); 384 385 panic_print_sys_info(false); 386 387 kmsg_dump_desc(KMSG_DUMP_PANIC, buf); 388 389 /* 390 * If you doubt kdump always works fine in any situation, 391 * "crash_kexec_post_notifiers" offers you a chance to run 392 * panic_notifiers and dumping kmsg before kdump. 393 * Note: since some panic_notifiers can make crashed kernel 394 * more unstable, it can increase risks of the kdump failure too. 395 * 396 * Bypass the panic_cpu check and call __crash_kexec directly. 397 */ 398 if (_crash_kexec_post_notifiers) 399 __crash_kexec(NULL); 400 401 console_unblank(); 402 403 /* 404 * We may have ended up stopping the CPU holding the lock (in 405 * smp_send_stop()) while still having some valuable data in the console 406 * buffer. Try to acquire the lock then release it regardless of the 407 * result. The release will also print the buffers out. Locks debug 408 * should be disabled to avoid reporting bad unlock balance when 409 * panic() is not being callled from OOPS. 410 */ 411 debug_locks_off(); 412 console_flush_on_panic(CONSOLE_FLUSH_PENDING); 413 414 panic_print_sys_info(true); 415 416 if (!panic_blink) 417 panic_blink = no_blink; 418 419 if (panic_timeout > 0) { 420 /* 421 * Delay timeout seconds before rebooting the machine. 422 * We can't use the "normal" timers since we just panicked. 423 */ 424 pr_emerg("Rebooting in %d seconds..\n", panic_timeout); 425 426 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { 427 touch_nmi_watchdog(); 428 if (i >= i_next) { 429 i += panic_blink(state ^= 1); 430 i_next = i + 3600 / PANIC_BLINK_SPD; 431 } 432 mdelay(PANIC_TIMER_STEP); 433 } 434 } 435 if (panic_timeout != 0) { 436 /* 437 * This will not be a clean reboot, with everything 438 * shutting down. But if there is a chance of 439 * rebooting the system it will be rebooted. 440 */ 441 if (panic_reboot_mode != REBOOT_UNDEFINED) 442 reboot_mode = panic_reboot_mode; 443 emergency_restart(); 444 } 445 #ifdef __sparc__ 446 { 447 extern int stop_a_enabled; 448 /* Make sure the user can actually press Stop-A (L1-A) */ 449 stop_a_enabled = 1; 450 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" 451 "twice on console to return to the boot prom\n"); 452 } 453 #endif 454 #if defined(CONFIG_S390) 455 disabled_wait(); 456 #endif 457 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); 458 459 /* Do not scroll important messages printed above */ 460 suppress_printk = 1; 461 462 /* 463 * The final messages may not have been printed if in a context that 464 * defers printing (such as NMI) and irq_work is not available. 465 * Explicitly flush the kernel log buffer one last time. 466 */ 467 console_flush_on_panic(CONSOLE_FLUSH_PENDING); 468 nbcon_atomic_flush_unsafe(); 469 470 local_irq_enable(); 471 for (i = 0; ; i += PANIC_TIMER_STEP) { 472 touch_softlockup_watchdog(); 473 if (i >= i_next) { 474 i += panic_blink(state ^= 1); 475 i_next = i + 3600 / PANIC_BLINK_SPD; 476 } 477 mdelay(PANIC_TIMER_STEP); 478 } 479 } 480 481 EXPORT_SYMBOL(panic); 482 483 #define TAINT_FLAG(taint, _c_true, _c_false, _module) \ 484 [ TAINT_##taint ] = { \ 485 .c_true = _c_true, .c_false = _c_false, \ 486 .module = _module, \ 487 .desc = #taint, \ 488 } 489 490 /* 491 * TAINT_FORCED_RMMOD could be a per-module flag but the module 492 * is being removed anyway. 493 */ 494 const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { 495 TAINT_FLAG(PROPRIETARY_MODULE, 'P', 'G', true), 496 TAINT_FLAG(FORCED_MODULE, 'F', ' ', true), 497 TAINT_FLAG(CPU_OUT_OF_SPEC, 'S', ' ', false), 498 TAINT_FLAG(FORCED_RMMOD, 'R', ' ', false), 499 TAINT_FLAG(MACHINE_CHECK, 'M', ' ', false), 500 TAINT_FLAG(BAD_PAGE, 'B', ' ', false), 501 TAINT_FLAG(USER, 'U', ' ', false), 502 TAINT_FLAG(DIE, 'D', ' ', false), 503 TAINT_FLAG(OVERRIDDEN_ACPI_TABLE, 'A', ' ', false), 504 TAINT_FLAG(WARN, 'W', ' ', false), 505 TAINT_FLAG(CRAP, 'C', ' ', true), 506 TAINT_FLAG(FIRMWARE_WORKAROUND, 'I', ' ', false), 507 TAINT_FLAG(OOT_MODULE, 'O', ' ', true), 508 TAINT_FLAG(UNSIGNED_MODULE, 'E', ' ', true), 509 TAINT_FLAG(SOFTLOCKUP, 'L', ' ', false), 510 TAINT_FLAG(LIVEPATCH, 'K', ' ', true), 511 TAINT_FLAG(AUX, 'X', ' ', true), 512 TAINT_FLAG(RANDSTRUCT, 'T', ' ', true), 513 TAINT_FLAG(TEST, 'N', ' ', true), 514 }; 515 516 #undef TAINT_FLAG 517 518 static void print_tainted_seq(struct seq_buf *s, bool verbose) 519 { 520 const char *sep = ""; 521 int i; 522 523 if (!tainted_mask) { 524 seq_buf_puts(s, "Not tainted"); 525 return; 526 } 527 528 seq_buf_printf(s, "Tainted: "); 529 for (i = 0; i < TAINT_FLAGS_COUNT; i++) { 530 const struct taint_flag *t = &taint_flags[i]; 531 bool is_set = test_bit(i, &tainted_mask); 532 char c = is_set ? t->c_true : t->c_false; 533 534 if (verbose) { 535 if (is_set) { 536 seq_buf_printf(s, "%s[%c]=%s", sep, c, t->desc); 537 sep = ", "; 538 } 539 } else { 540 seq_buf_putc(s, c); 541 } 542 } 543 } 544 545 static const char *_print_tainted(bool verbose) 546 { 547 /* FIXME: what should the size be? */ 548 static char buf[sizeof(taint_flags)]; 549 struct seq_buf s; 550 551 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); 552 553 seq_buf_init(&s, buf, sizeof(buf)); 554 555 print_tainted_seq(&s, verbose); 556 557 return seq_buf_str(&s); 558 } 559 560 /** 561 * print_tainted - return a string to represent the kernel taint state. 562 * 563 * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst 564 * 565 * The string is overwritten by the next call to print_tainted(), 566 * but is always NULL terminated. 567 */ 568 const char *print_tainted(void) 569 { 570 return _print_tainted(false); 571 } 572 573 /** 574 * print_tainted_verbose - A more verbose version of print_tainted() 575 */ 576 const char *print_tainted_verbose(void) 577 { 578 return _print_tainted(true); 579 } 580 581 int test_taint(unsigned flag) 582 { 583 return test_bit(flag, &tainted_mask); 584 } 585 EXPORT_SYMBOL(test_taint); 586 587 unsigned long get_taint(void) 588 { 589 return tainted_mask; 590 } 591 592 /** 593 * add_taint: add a taint flag if not already set. 594 * @flag: one of the TAINT_* constants. 595 * @lockdep_ok: whether lock debugging is still OK. 596 * 597 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for 598 * some notewortht-but-not-corrupting cases, it can be set to true. 599 */ 600 void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) 601 { 602 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) 603 pr_warn("Disabling lock debugging due to kernel taint\n"); 604 605 set_bit(flag, &tainted_mask); 606 607 if (tainted_mask & panic_on_taint) { 608 panic_on_taint = 0; 609 panic("panic_on_taint set ..."); 610 } 611 } 612 EXPORT_SYMBOL(add_taint); 613 614 static void spin_msec(int msecs) 615 { 616 int i; 617 618 for (i = 0; i < msecs; i++) { 619 touch_nmi_watchdog(); 620 mdelay(1); 621 } 622 } 623 624 /* 625 * It just happens that oops_enter() and oops_exit() are identically 626 * implemented... 627 */ 628 static void do_oops_enter_exit(void) 629 { 630 unsigned long flags; 631 static int spin_counter; 632 633 if (!pause_on_oops) 634 return; 635 636 spin_lock_irqsave(&pause_on_oops_lock, flags); 637 if (pause_on_oops_flag == 0) { 638 /* This CPU may now print the oops message */ 639 pause_on_oops_flag = 1; 640 } else { 641 /* We need to stall this CPU */ 642 if (!spin_counter) { 643 /* This CPU gets to do the counting */ 644 spin_counter = pause_on_oops; 645 do { 646 spin_unlock(&pause_on_oops_lock); 647 spin_msec(MSEC_PER_SEC); 648 spin_lock(&pause_on_oops_lock); 649 } while (--spin_counter); 650 pause_on_oops_flag = 0; 651 } else { 652 /* This CPU waits for a different one */ 653 while (spin_counter) { 654 spin_unlock(&pause_on_oops_lock); 655 spin_msec(1); 656 spin_lock(&pause_on_oops_lock); 657 } 658 } 659 } 660 spin_unlock_irqrestore(&pause_on_oops_lock, flags); 661 } 662 663 /* 664 * Return true if the calling CPU is allowed to print oops-related info. 665 * This is a bit racy.. 666 */ 667 bool oops_may_print(void) 668 { 669 return pause_on_oops_flag == 0; 670 } 671 672 /* 673 * Called when the architecture enters its oops handler, before it prints 674 * anything. If this is the first CPU to oops, and it's oopsing the first 675 * time then let it proceed. 676 * 677 * This is all enabled by the pause_on_oops kernel boot option. We do all 678 * this to ensure that oopses don't scroll off the screen. It has the 679 * side-effect of preventing later-oopsing CPUs from mucking up the display, 680 * too. 681 * 682 * It turns out that the CPU which is allowed to print ends up pausing for 683 * the right duration, whereas all the other CPUs pause for twice as long: 684 * once in oops_enter(), once in oops_exit(). 685 */ 686 void oops_enter(void) 687 { 688 nbcon_cpu_emergency_enter(); 689 tracing_off(); 690 /* can't trust the integrity of the kernel anymore: */ 691 debug_locks_off(); 692 do_oops_enter_exit(); 693 694 if (sysctl_oops_all_cpu_backtrace) 695 trigger_all_cpu_backtrace(); 696 } 697 698 static void print_oops_end_marker(void) 699 { 700 pr_warn("---[ end trace %016llx ]---\n", 0ULL); 701 } 702 703 /* 704 * Called when the architecture exits its oops handler, after printing 705 * everything. 706 */ 707 void oops_exit(void) 708 { 709 do_oops_enter_exit(); 710 print_oops_end_marker(); 711 nbcon_cpu_emergency_exit(); 712 kmsg_dump(KMSG_DUMP_OOPS); 713 } 714 715 struct warn_args { 716 const char *fmt; 717 va_list args; 718 }; 719 720 void __warn(const char *file, int line, void *caller, unsigned taint, 721 struct pt_regs *regs, struct warn_args *args) 722 { 723 nbcon_cpu_emergency_enter(); 724 725 disable_trace_on_warning(); 726 727 if (file) 728 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", 729 raw_smp_processor_id(), current->pid, file, line, 730 caller); 731 else 732 pr_warn("WARNING: CPU: %d PID: %d at %pS\n", 733 raw_smp_processor_id(), current->pid, caller); 734 735 #pragma GCC diagnostic push 736 #ifndef __clang__ 737 #pragma GCC diagnostic ignored "-Wsuggest-attribute=format" 738 #endif 739 if (args) 740 vprintk(args->fmt, args->args); 741 #pragma GCC diagnostic pop 742 743 print_modules(); 744 745 if (regs) 746 show_regs(regs); 747 748 check_panic_on_warn("kernel"); 749 750 if (!regs) 751 dump_stack(); 752 753 print_irqtrace_events(current); 754 755 print_oops_end_marker(); 756 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); 757 758 /* Just a warning, don't kill lockdep. */ 759 add_taint(taint, LOCKDEP_STILL_OK); 760 761 nbcon_cpu_emergency_exit(); 762 } 763 764 #ifdef CONFIG_BUG 765 #ifndef __WARN_FLAGS 766 void warn_slowpath_fmt(const char *file, int line, unsigned taint, 767 const char *fmt, ...) 768 { 769 bool rcu = warn_rcu_enter(); 770 struct warn_args args; 771 772 pr_warn(CUT_HERE); 773 774 if (!fmt) { 775 __warn(file, line, __builtin_return_address(0), taint, 776 NULL, NULL); 777 warn_rcu_exit(rcu); 778 return; 779 } 780 781 args.fmt = fmt; 782 va_start(args.args, fmt); 783 __warn(file, line, __builtin_return_address(0), taint, NULL, &args); 784 va_end(args.args); 785 warn_rcu_exit(rcu); 786 } 787 EXPORT_SYMBOL(warn_slowpath_fmt); 788 #else 789 void __warn_printk(const char *fmt, ...) 790 { 791 bool rcu = warn_rcu_enter(); 792 va_list args; 793 794 pr_warn(CUT_HERE); 795 796 va_start(args, fmt); 797 vprintk(fmt, args); 798 va_end(args); 799 warn_rcu_exit(rcu); 800 } 801 EXPORT_SYMBOL(__warn_printk); 802 #endif 803 804 /* Support resetting WARN*_ONCE state */ 805 806 static int clear_warn_once_set(void *data, u64 val) 807 { 808 generic_bug_clear_once(); 809 memset(__start_once, 0, __end_once - __start_once); 810 return 0; 811 } 812 813 DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, 814 "%lld\n"); 815 816 static __init int register_warn_debugfs(void) 817 { 818 /* Don't care about failure */ 819 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, 820 &clear_warn_once_fops); 821 return 0; 822 } 823 824 device_initcall(register_warn_debugfs); 825 #endif 826 827 #ifdef CONFIG_STACKPROTECTOR 828 829 /* 830 * Called when gcc's -fstack-protector feature is used, and 831 * gcc detects corruption of the on-stack canary value 832 */ 833 __visible noinstr void __stack_chk_fail(void) 834 { 835 instrumentation_begin(); 836 panic("stack-protector: Kernel stack is corrupted in: %pB", 837 __builtin_return_address(0)); 838 instrumentation_end(); 839 } 840 EXPORT_SYMBOL(__stack_chk_fail); 841 842 #endif 843 844 core_param(panic, panic_timeout, int, 0644); 845 core_param(panic_print, panic_print, ulong, 0644); 846 core_param(pause_on_oops, pause_on_oops, int, 0644); 847 core_param(panic_on_warn, panic_on_warn, int, 0644); 848 core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); 849 850 static int __init oops_setup(char *s) 851 { 852 if (!s) 853 return -EINVAL; 854 if (!strcmp(s, "panic")) 855 panic_on_oops = 1; 856 return 0; 857 } 858 early_param("oops", oops_setup); 859 860 static int __init panic_on_taint_setup(char *s) 861 { 862 char *taint_str; 863 864 if (!s) 865 return -EINVAL; 866 867 taint_str = strsep(&s, ","); 868 if (kstrtoul(taint_str, 16, &panic_on_taint)) 869 return -EINVAL; 870 871 /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ 872 panic_on_taint &= TAINT_FLAGS_MAX; 873 874 if (!panic_on_taint) 875 return -EINVAL; 876 877 if (s && !strcmp(s, "nousertaint")) 878 panic_on_taint_nousertaint = true; 879 880 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n", 881 panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint)); 882 883 return 0; 884 } 885 early_param("panic_on_taint", panic_on_taint_setup); 886