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