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 /* 475 * TAINT_FORCED_RMMOD could be a per-module flag but the module 476 * is being removed anyway. 477 */ 478 const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { 479 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, 480 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, 481 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, 482 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, 483 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, 484 [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, 485 [ TAINT_USER ] = { 'U', ' ', false }, 486 [ TAINT_DIE ] = { 'D', ' ', false }, 487 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, 488 [ TAINT_WARN ] = { 'W', ' ', false }, 489 [ TAINT_CRAP ] = { 'C', ' ', true }, 490 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, 491 [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, 492 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, 493 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, 494 [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, 495 [ TAINT_AUX ] = { 'X', ' ', true }, 496 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, 497 [ TAINT_TEST ] = { 'N', ' ', true }, 498 }; 499 500 static void print_tainted_seq(struct seq_buf *s) 501 { 502 int i; 503 504 if (!tainted_mask) { 505 seq_buf_puts(s, "Not tainted"); 506 return; 507 } 508 509 seq_buf_printf(s, "Tainted: "); 510 for (i = 0; i < TAINT_FLAGS_COUNT; i++) { 511 const struct taint_flag *t = &taint_flags[i]; 512 bool is_set = test_bit(i, &tainted_mask); 513 char c = is_set ? t->c_true : t->c_false; 514 515 seq_buf_putc(s, c); 516 } 517 } 518 519 /** 520 * print_tainted - return a string to represent the kernel taint state. 521 * 522 * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst 523 * 524 * The string is overwritten by the next call to print_tainted(), 525 * but is always NULL terminated. 526 */ 527 const char *print_tainted(void) 528 { 529 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; 530 struct seq_buf s; 531 532 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); 533 534 seq_buf_init(&s, buf, sizeof(buf)); 535 536 print_tainted_seq(&s); 537 538 return seq_buf_str(&s); 539 } 540 541 int test_taint(unsigned flag) 542 { 543 return test_bit(flag, &tainted_mask); 544 } 545 EXPORT_SYMBOL(test_taint); 546 547 unsigned long get_taint(void) 548 { 549 return tainted_mask; 550 } 551 552 /** 553 * add_taint: add a taint flag if not already set. 554 * @flag: one of the TAINT_* constants. 555 * @lockdep_ok: whether lock debugging is still OK. 556 * 557 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for 558 * some notewortht-but-not-corrupting cases, it can be set to true. 559 */ 560 void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) 561 { 562 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) 563 pr_warn("Disabling lock debugging due to kernel taint\n"); 564 565 set_bit(flag, &tainted_mask); 566 567 if (tainted_mask & panic_on_taint) { 568 panic_on_taint = 0; 569 panic("panic_on_taint set ..."); 570 } 571 } 572 EXPORT_SYMBOL(add_taint); 573 574 static void spin_msec(int msecs) 575 { 576 int i; 577 578 for (i = 0; i < msecs; i++) { 579 touch_nmi_watchdog(); 580 mdelay(1); 581 } 582 } 583 584 /* 585 * It just happens that oops_enter() and oops_exit() are identically 586 * implemented... 587 */ 588 static void do_oops_enter_exit(void) 589 { 590 unsigned long flags; 591 static int spin_counter; 592 593 if (!pause_on_oops) 594 return; 595 596 spin_lock_irqsave(&pause_on_oops_lock, flags); 597 if (pause_on_oops_flag == 0) { 598 /* This CPU may now print the oops message */ 599 pause_on_oops_flag = 1; 600 } else { 601 /* We need to stall this CPU */ 602 if (!spin_counter) { 603 /* This CPU gets to do the counting */ 604 spin_counter = pause_on_oops; 605 do { 606 spin_unlock(&pause_on_oops_lock); 607 spin_msec(MSEC_PER_SEC); 608 spin_lock(&pause_on_oops_lock); 609 } while (--spin_counter); 610 pause_on_oops_flag = 0; 611 } else { 612 /* This CPU waits for a different one */ 613 while (spin_counter) { 614 spin_unlock(&pause_on_oops_lock); 615 spin_msec(1); 616 spin_lock(&pause_on_oops_lock); 617 } 618 } 619 } 620 spin_unlock_irqrestore(&pause_on_oops_lock, flags); 621 } 622 623 /* 624 * Return true if the calling CPU is allowed to print oops-related info. 625 * This is a bit racy.. 626 */ 627 bool oops_may_print(void) 628 { 629 return pause_on_oops_flag == 0; 630 } 631 632 /* 633 * Called when the architecture enters its oops handler, before it prints 634 * anything. If this is the first CPU to oops, and it's oopsing the first 635 * time then let it proceed. 636 * 637 * This is all enabled by the pause_on_oops kernel boot option. We do all 638 * this to ensure that oopses don't scroll off the screen. It has the 639 * side-effect of preventing later-oopsing CPUs from mucking up the display, 640 * too. 641 * 642 * It turns out that the CPU which is allowed to print ends up pausing for 643 * the right duration, whereas all the other CPUs pause for twice as long: 644 * once in oops_enter(), once in oops_exit(). 645 */ 646 void oops_enter(void) 647 { 648 tracing_off(); 649 /* can't trust the integrity of the kernel anymore: */ 650 debug_locks_off(); 651 do_oops_enter_exit(); 652 653 if (sysctl_oops_all_cpu_backtrace) 654 trigger_all_cpu_backtrace(); 655 } 656 657 static void print_oops_end_marker(void) 658 { 659 pr_warn("---[ end trace %016llx ]---\n", 0ULL); 660 } 661 662 /* 663 * Called when the architecture exits its oops handler, after printing 664 * everything. 665 */ 666 void oops_exit(void) 667 { 668 do_oops_enter_exit(); 669 print_oops_end_marker(); 670 kmsg_dump(KMSG_DUMP_OOPS); 671 } 672 673 struct warn_args { 674 const char *fmt; 675 va_list args; 676 }; 677 678 void __warn(const char *file, int line, void *caller, unsigned taint, 679 struct pt_regs *regs, struct warn_args *args) 680 { 681 disable_trace_on_warning(); 682 683 if (file) 684 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", 685 raw_smp_processor_id(), current->pid, file, line, 686 caller); 687 else 688 pr_warn("WARNING: CPU: %d PID: %d at %pS\n", 689 raw_smp_processor_id(), current->pid, caller); 690 691 #pragma GCC diagnostic push 692 #ifndef __clang__ 693 #pragma GCC diagnostic ignored "-Wsuggest-attribute=format" 694 #endif 695 if (args) 696 vprintk(args->fmt, args->args); 697 #pragma GCC diagnostic pop 698 699 print_modules(); 700 701 if (regs) 702 show_regs(regs); 703 704 check_panic_on_warn("kernel"); 705 706 if (!regs) 707 dump_stack(); 708 709 print_irqtrace_events(current); 710 711 print_oops_end_marker(); 712 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); 713 714 /* Just a warning, don't kill lockdep. */ 715 add_taint(taint, LOCKDEP_STILL_OK); 716 } 717 718 #ifdef CONFIG_BUG 719 #ifndef __WARN_FLAGS 720 void warn_slowpath_fmt(const char *file, int line, unsigned taint, 721 const char *fmt, ...) 722 { 723 bool rcu = warn_rcu_enter(); 724 struct warn_args args; 725 726 pr_warn(CUT_HERE); 727 728 if (!fmt) { 729 __warn(file, line, __builtin_return_address(0), taint, 730 NULL, NULL); 731 warn_rcu_exit(rcu); 732 return; 733 } 734 735 args.fmt = fmt; 736 va_start(args.args, fmt); 737 __warn(file, line, __builtin_return_address(0), taint, NULL, &args); 738 va_end(args.args); 739 warn_rcu_exit(rcu); 740 } 741 EXPORT_SYMBOL(warn_slowpath_fmt); 742 #else 743 void __warn_printk(const char *fmt, ...) 744 { 745 bool rcu = warn_rcu_enter(); 746 va_list args; 747 748 pr_warn(CUT_HERE); 749 750 va_start(args, fmt); 751 vprintk(fmt, args); 752 va_end(args); 753 warn_rcu_exit(rcu); 754 } 755 EXPORT_SYMBOL(__warn_printk); 756 #endif 757 758 /* Support resetting WARN*_ONCE state */ 759 760 static int clear_warn_once_set(void *data, u64 val) 761 { 762 generic_bug_clear_once(); 763 memset(__start_once, 0, __end_once - __start_once); 764 return 0; 765 } 766 767 DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, 768 "%lld\n"); 769 770 static __init int register_warn_debugfs(void) 771 { 772 /* Don't care about failure */ 773 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, 774 &clear_warn_once_fops); 775 return 0; 776 } 777 778 device_initcall(register_warn_debugfs); 779 #endif 780 781 #ifdef CONFIG_STACKPROTECTOR 782 783 /* 784 * Called when gcc's -fstack-protector feature is used, and 785 * gcc detects corruption of the on-stack canary value 786 */ 787 __visible noinstr void __stack_chk_fail(void) 788 { 789 instrumentation_begin(); 790 panic("stack-protector: Kernel stack is corrupted in: %pB", 791 __builtin_return_address(0)); 792 instrumentation_end(); 793 } 794 EXPORT_SYMBOL(__stack_chk_fail); 795 796 #endif 797 798 core_param(panic, panic_timeout, int, 0644); 799 core_param(panic_print, panic_print, ulong, 0644); 800 core_param(pause_on_oops, pause_on_oops, int, 0644); 801 core_param(panic_on_warn, panic_on_warn, int, 0644); 802 core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); 803 804 static int __init oops_setup(char *s) 805 { 806 if (!s) 807 return -EINVAL; 808 if (!strcmp(s, "panic")) 809 panic_on_oops = 1; 810 return 0; 811 } 812 early_param("oops", oops_setup); 813 814 static int __init panic_on_taint_setup(char *s) 815 { 816 char *taint_str; 817 818 if (!s) 819 return -EINVAL; 820 821 taint_str = strsep(&s, ","); 822 if (kstrtoul(taint_str, 16, &panic_on_taint)) 823 return -EINVAL; 824 825 /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ 826 panic_on_taint &= TAINT_FLAGS_MAX; 827 828 if (!panic_on_taint) 829 return -EINVAL; 830 831 if (s && !strcmp(s, "nousertaint")) 832 panic_on_taint_nousertaint = true; 833 834 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n", 835 panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint)); 836 837 return 0; 838 } 839 early_param("panic_on_taint", panic_on_taint_setup); 840