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1/*
2 * linux/kernel/panic.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * This function is used through-out the kernel (including mm and fs)
9 * to indicate a major problem.
10 */
11#include <linux/debug_locks.h>
12#include <linux/interrupt.h>
13#include <linux/kmsg_dump.h>
14#include <linux/kallsyms.h>
15#include <linux/notifier.h>
16#include <linux/module.h>
17#include <linux/random.h>
18#include <linux/ftrace.h>
19#include <linux/reboot.h>
20#include <linux/delay.h>
21#include <linux/kexec.h>
22#include <linux/sched.h>
23#include <linux/sysrq.h>
24#include <linux/init.h>
25#include <linux/nmi.h>
26#include <linux/console.h>
27#include <linux/bug.h>
28
29#define PANIC_TIMER_STEP 100
30#define PANIC_BLINK_SPD 18
31
32int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
33static unsigned long tainted_mask;
34static int pause_on_oops;
35static int pause_on_oops_flag;
36static DEFINE_SPINLOCK(pause_on_oops_lock);
37bool crash_kexec_post_notifiers;
38int panic_on_warn __read_mostly;
39
40int panic_timeout = CONFIG_PANIC_TIMEOUT;
41EXPORT_SYMBOL_GPL(panic_timeout);
42
43ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
44
45EXPORT_SYMBOL(panic_notifier_list);
46
47static long no_blink(int state)
48{
49 return 0;
50}
51
52/* Returns how long it waited in ms */
53long (*panic_blink)(int state);
54EXPORT_SYMBOL(panic_blink);
55
56/*
57 * Stop ourself in panic -- architecture code may override this
58 */
59void __weak panic_smp_self_stop(void)
60{
61 while (1)
62 cpu_relax();
63}
64
65/*
66 * Stop ourselves in NMI context if another CPU has already panicked. Arch code
67 * may override this to prepare for crash dumping, e.g. save regs info.
68 */
69void __weak nmi_panic_self_stop(struct pt_regs *regs)
70{
71 panic_smp_self_stop();
72}
73
74atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
75
76/*
77 * A variant of panic() called from NMI context. We return if we've already
78 * panicked on this CPU. If another CPU already panicked, loop in
79 * nmi_panic_self_stop() which can provide architecture dependent code such
80 * as saving register state for crash dump.
81 */
82void nmi_panic(struct pt_regs *regs, const char *msg)
83{
84 int old_cpu, cpu;
85
86 cpu = raw_smp_processor_id();
87 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
88
89 if (old_cpu == PANIC_CPU_INVALID)
90 panic("%s", msg);
91 else if (old_cpu != cpu)
92 nmi_panic_self_stop(regs);
93}
94EXPORT_SYMBOL(nmi_panic);
95
96/**
97 * panic - halt the system
98 * @fmt: The text string to print
99 *
100 * Display a message, then perform cleanups.
101 *
102 * This function never returns.
103 */
104void panic(const char *fmt, ...)
105{
106 static char buf[1024];
107 va_list args;
108 long i, i_next = 0;
109 int state = 0;
110 int old_cpu, this_cpu;
111
112 /*
113 * Disable local interrupts. This will prevent panic_smp_self_stop
114 * from deadlocking the first cpu that invokes the panic, since
115 * there is nothing to prevent an interrupt handler (that runs
116 * after setting panic_cpu) from invoking panic() again.
117 */
118 local_irq_disable();
119
120 /*
121 * It's possible to come here directly from a panic-assertion and
122 * not have preempt disabled. Some functions called from here want
123 * preempt to be disabled. No point enabling it later though...
124 *
125 * Only one CPU is allowed to execute the panic code from here. For
126 * multiple parallel invocations of panic, all other CPUs either
127 * stop themself or will wait until they are stopped by the 1st CPU
128 * with smp_send_stop().
129 *
130 * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
131 * comes here, so go ahead.
132 * `old_cpu == this_cpu' means we came from nmi_panic() which sets
133 * panic_cpu to this CPU. In this case, this is also the 1st CPU.
134 */
135 this_cpu = raw_smp_processor_id();
136 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
137
138 if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
139 panic_smp_self_stop();
140
141 console_verbose();
142 bust_spinlocks(1);
143 va_start(args, fmt);
144 vsnprintf(buf, sizeof(buf), fmt, args);
145 va_end(args);
146 pr_emerg("Kernel panic - not syncing: %s\n", buf);
147#ifdef CONFIG_DEBUG_BUGVERBOSE
148 /*
149 * Avoid nested stack-dumping if a panic occurs during oops processing
150 */
151 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
152 dump_stack();
153#endif
154
155 /*
156 * If we have crashed and we have a crash kernel loaded let it handle
157 * everything else.
158 * If we want to run this after calling panic_notifiers, pass
159 * the "crash_kexec_post_notifiers" option to the kernel.
160 *
161 * Bypass the panic_cpu check and call __crash_kexec directly.
162 */
163 if (!crash_kexec_post_notifiers)
164 __crash_kexec(NULL);
165
166 /*
167 * Note smp_send_stop is the usual smp shutdown function, which
168 * unfortunately means it may not be hardened to work in a panic
169 * situation.
170 */
171 smp_send_stop();
172
173 /*
174 * Run any panic handlers, including those that might need to
175 * add information to the kmsg dump output.
176 */
177 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
178
179 kmsg_dump(KMSG_DUMP_PANIC);
180
181 /*
182 * If you doubt kdump always works fine in any situation,
183 * "crash_kexec_post_notifiers" offers you a chance to run
184 * panic_notifiers and dumping kmsg before kdump.
185 * Note: since some panic_notifiers can make crashed kernel
186 * more unstable, it can increase risks of the kdump failure too.
187 *
188 * Bypass the panic_cpu check and call __crash_kexec directly.
189 */
190 if (crash_kexec_post_notifiers)
191 __crash_kexec(NULL);
192
193 bust_spinlocks(0);
194
195 /*
196 * We may have ended up stopping the CPU holding the lock (in
197 * smp_send_stop()) while still having some valuable data in the console
198 * buffer. Try to acquire the lock then release it regardless of the
199 * result. The release will also print the buffers out. Locks debug
200 * should be disabled to avoid reporting bad unlock balance when
201 * panic() is not being callled from OOPS.
202 */
203 debug_locks_off();
204 console_flush_on_panic();
205
206 if (!panic_blink)
207 panic_blink = no_blink;
208
209 if (panic_timeout > 0) {
210 /*
211 * Delay timeout seconds before rebooting the machine.
212 * We can't use the "normal" timers since we just panicked.
213 */
214 pr_emerg("Rebooting in %d seconds..", panic_timeout);
215
216 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
217 touch_nmi_watchdog();
218 if (i >= i_next) {
219 i += panic_blink(state ^= 1);
220 i_next = i + 3600 / PANIC_BLINK_SPD;
221 }
222 mdelay(PANIC_TIMER_STEP);
223 }
224 }
225 if (panic_timeout != 0) {
226 /*
227 * This will not be a clean reboot, with everything
228 * shutting down. But if there is a chance of
229 * rebooting the system it will be rebooted.
230 */
231 emergency_restart();
232 }
233#ifdef __sparc__
234 {
235 extern int stop_a_enabled;
236 /* Make sure the user can actually press Stop-A (L1-A) */
237 stop_a_enabled = 1;
238 pr_emerg("Press Stop-A (L1-A) to return to the boot prom\n");
239 }
240#endif
241#if defined(CONFIG_S390)
242 {
243 unsigned long caller;
244
245 caller = (unsigned long)__builtin_return_address(0);
246 disabled_wait(caller);
247 }
248#endif
249 pr_emerg("---[ end Kernel panic - not syncing: %s\n", buf);
250 local_irq_enable();
251 for (i = 0; ; i += PANIC_TIMER_STEP) {
252 touch_softlockup_watchdog();
253 if (i >= i_next) {
254 i += panic_blink(state ^= 1);
255 i_next = i + 3600 / PANIC_BLINK_SPD;
256 }
257 mdelay(PANIC_TIMER_STEP);
258 }
259}
260
261EXPORT_SYMBOL(panic);
262
263
264struct tnt {
265 u8 bit;
266 char true;
267 char false;
268};
269
270static const struct tnt tnts[] = {
271 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
272 { TAINT_FORCED_MODULE, 'F', ' ' },
273 { TAINT_CPU_OUT_OF_SPEC, 'S', ' ' },
274 { TAINT_FORCED_RMMOD, 'R', ' ' },
275 { TAINT_MACHINE_CHECK, 'M', ' ' },
276 { TAINT_BAD_PAGE, 'B', ' ' },
277 { TAINT_USER, 'U', ' ' },
278 { TAINT_DIE, 'D', ' ' },
279 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
280 { TAINT_WARN, 'W', ' ' },
281 { TAINT_CRAP, 'C', ' ' },
282 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
283 { TAINT_OOT_MODULE, 'O', ' ' },
284 { TAINT_UNSIGNED_MODULE, 'E', ' ' },
285 { TAINT_SOFTLOCKUP, 'L', ' ' },
286 { TAINT_LIVEPATCH, 'K', ' ' },
287};
288
289/**
290 * print_tainted - return a string to represent the kernel taint state.
291 *
292 * 'P' - Proprietary module has been loaded.
293 * 'F' - Module has been forcibly loaded.
294 * 'S' - SMP with CPUs not designed for SMP.
295 * 'R' - User forced a module unload.
296 * 'M' - System experienced a machine check exception.
297 * 'B' - System has hit bad_page.
298 * 'U' - Userspace-defined naughtiness.
299 * 'D' - Kernel has oopsed before
300 * 'A' - ACPI table overridden.
301 * 'W' - Taint on warning.
302 * 'C' - modules from drivers/staging are loaded.
303 * 'I' - Working around severe firmware bug.
304 * 'O' - Out-of-tree module has been loaded.
305 * 'E' - Unsigned module has been loaded.
306 * 'L' - A soft lockup has previously occurred.
307 * 'K' - Kernel has been live patched.
308 *
309 * The string is overwritten by the next call to print_tainted().
310 */
311const char *print_tainted(void)
312{
313 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ")];
314
315 if (tainted_mask) {
316 char *s;
317 int i;
318
319 s = buf + sprintf(buf, "Tainted: ");
320 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
321 const struct tnt *t = &tnts[i];
322 *s++ = test_bit(t->bit, &tainted_mask) ?
323 t->true : t->false;
324 }
325 *s = 0;
326 } else
327 snprintf(buf, sizeof(buf), "Not tainted");
328
329 return buf;
330}
331
332int test_taint(unsigned flag)
333{
334 return test_bit(flag, &tainted_mask);
335}
336EXPORT_SYMBOL(test_taint);
337
338unsigned long get_taint(void)
339{
340 return tainted_mask;
341}
342
343/**
344 * add_taint: add a taint flag if not already set.
345 * @flag: one of the TAINT_* constants.
346 * @lockdep_ok: whether lock debugging is still OK.
347 *
348 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
349 * some notewortht-but-not-corrupting cases, it can be set to true.
350 */
351void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
352{
353 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
354 pr_warn("Disabling lock debugging due to kernel taint\n");
355
356 set_bit(flag, &tainted_mask);
357}
358EXPORT_SYMBOL(add_taint);
359
360static void spin_msec(int msecs)
361{
362 int i;
363
364 for (i = 0; i < msecs; i++) {
365 touch_nmi_watchdog();
366 mdelay(1);
367 }
368}
369
370/*
371 * It just happens that oops_enter() and oops_exit() are identically
372 * implemented...
373 */
374static void do_oops_enter_exit(void)
375{
376 unsigned long flags;
377 static int spin_counter;
378
379 if (!pause_on_oops)
380 return;
381
382 spin_lock_irqsave(&pause_on_oops_lock, flags);
383 if (pause_on_oops_flag == 0) {
384 /* This CPU may now print the oops message */
385 pause_on_oops_flag = 1;
386 } else {
387 /* We need to stall this CPU */
388 if (!spin_counter) {
389 /* This CPU gets to do the counting */
390 spin_counter = pause_on_oops;
391 do {
392 spin_unlock(&pause_on_oops_lock);
393 spin_msec(MSEC_PER_SEC);
394 spin_lock(&pause_on_oops_lock);
395 } while (--spin_counter);
396 pause_on_oops_flag = 0;
397 } else {
398 /* This CPU waits for a different one */
399 while (spin_counter) {
400 spin_unlock(&pause_on_oops_lock);
401 spin_msec(1);
402 spin_lock(&pause_on_oops_lock);
403 }
404 }
405 }
406 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
407}
408
409/*
410 * Return true if the calling CPU is allowed to print oops-related info.
411 * This is a bit racy..
412 */
413int oops_may_print(void)
414{
415 return pause_on_oops_flag == 0;
416}
417
418/*
419 * Called when the architecture enters its oops handler, before it prints
420 * anything. If this is the first CPU to oops, and it's oopsing the first
421 * time then let it proceed.
422 *
423 * This is all enabled by the pause_on_oops kernel boot option. We do all
424 * this to ensure that oopses don't scroll off the screen. It has the
425 * side-effect of preventing later-oopsing CPUs from mucking up the display,
426 * too.
427 *
428 * It turns out that the CPU which is allowed to print ends up pausing for
429 * the right duration, whereas all the other CPUs pause for twice as long:
430 * once in oops_enter(), once in oops_exit().
431 */
432void oops_enter(void)
433{
434 tracing_off();
435 /* can't trust the integrity of the kernel anymore: */
436 debug_locks_off();
437 do_oops_enter_exit();
438}
439
440/*
441 * 64-bit random ID for oopses:
442 */
443static u64 oops_id;
444
445static int init_oops_id(void)
446{
447 if (!oops_id)
448 get_random_bytes(&oops_id, sizeof(oops_id));
449 else
450 oops_id++;
451
452 return 0;
453}
454late_initcall(init_oops_id);
455
456void print_oops_end_marker(void)
457{
458 init_oops_id();
459 pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
460}
461
462/*
463 * Called when the architecture exits its oops handler, after printing
464 * everything.
465 */
466void oops_exit(void)
467{
468 do_oops_enter_exit();
469 print_oops_end_marker();
470 kmsg_dump(KMSG_DUMP_OOPS);
471}
472
473struct warn_args {
474 const char *fmt;
475 va_list args;
476};
477
478void __warn(const char *file, int line, void *caller, unsigned taint,
479 struct pt_regs *regs, struct warn_args *args)
480{
481 disable_trace_on_warning();
482
483 pr_warn("------------[ cut here ]------------\n");
484
485 if (file)
486 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
487 raw_smp_processor_id(), current->pid, file, line,
488 caller);
489 else
490 pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
491 raw_smp_processor_id(), current->pid, caller);
492
493 if (args)
494 vprintk(args->fmt, args->args);
495
496 if (panic_on_warn) {
497 /*
498 * This thread may hit another WARN() in the panic path.
499 * Resetting this prevents additional WARN() from panicking the
500 * system on this thread. Other threads are blocked by the
501 * panic_mutex in panic().
502 */
503 panic_on_warn = 0;
504 panic("panic_on_warn set ...\n");
505 }
506
507 print_modules();
508
509 if (regs)
510 show_regs(regs);
511 else
512 dump_stack();
513
514 print_oops_end_marker();
515
516 /* Just a warning, don't kill lockdep. */
517 add_taint(taint, LOCKDEP_STILL_OK);
518}
519
520#ifdef WANT_WARN_ON_SLOWPATH
521void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
522{
523 struct warn_args args;
524
525 args.fmt = fmt;
526 va_start(args.args, fmt);
527 __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL,
528 &args);
529 va_end(args.args);
530}
531EXPORT_SYMBOL(warn_slowpath_fmt);
532
533void warn_slowpath_fmt_taint(const char *file, int line,
534 unsigned taint, const char *fmt, ...)
535{
536 struct warn_args args;
537
538 args.fmt = fmt;
539 va_start(args.args, fmt);
540 __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
541 va_end(args.args);
542}
543EXPORT_SYMBOL(warn_slowpath_fmt_taint);
544
545void warn_slowpath_null(const char *file, int line)
546{
547 __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, NULL);
548}
549EXPORT_SYMBOL(warn_slowpath_null);
550#endif
551
552#ifdef CONFIG_CC_STACKPROTECTOR
553
554/*
555 * Called when gcc's -fstack-protector feature is used, and
556 * gcc detects corruption of the on-stack canary value
557 */
558__visible void __stack_chk_fail(void)
559{
560 panic("stack-protector: Kernel stack is corrupted in: %p\n",
561 __builtin_return_address(0));
562}
563EXPORT_SYMBOL(__stack_chk_fail);
564
565#endif
566
567core_param(panic, panic_timeout, int, 0644);
568core_param(pause_on_oops, pause_on_oops, int, 0644);
569core_param(panic_on_warn, panic_on_warn, int, 0644);
570
571static int __init setup_crash_kexec_post_notifiers(char *s)
572{
573 crash_kexec_post_notifiers = true;
574 return 0;
575}
576early_param("crash_kexec_post_notifiers", setup_crash_kexec_post_notifiers);
577
578static int __init oops_setup(char *s)
579{
580 if (!s)
581 return -EINVAL;
582 if (!strcmp(s, "panic"))
583 panic_on_oops = 1;
584 return 0;
585}
586early_param("oops", oops_setup);
1/*
2 * linux/kernel/panic.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * This function is used through-out the kernel (including mm and fs)
9 * to indicate a major problem.
10 */
11#include <linux/debug_locks.h>
12#include <linux/interrupt.h>
13#include <linux/kmsg_dump.h>
14#include <linux/kallsyms.h>
15#include <linux/notifier.h>
16#include <linux/module.h>
17#include <linux/random.h>
18#include <linux/reboot.h>
19#include <linux/delay.h>
20#include <linux/kexec.h>
21#include <linux/sched.h>
22#include <linux/sysrq.h>
23#include <linux/init.h>
24#include <linux/nmi.h>
25#include <linux/dmi.h>
26
27#define PANIC_TIMER_STEP 100
28#define PANIC_BLINK_SPD 18
29
30int panic_on_oops;
31static unsigned long tainted_mask;
32static int pause_on_oops;
33static int pause_on_oops_flag;
34static DEFINE_SPINLOCK(pause_on_oops_lock);
35
36int panic_timeout;
37EXPORT_SYMBOL_GPL(panic_timeout);
38
39ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
40
41EXPORT_SYMBOL(panic_notifier_list);
42
43static long no_blink(int state)
44{
45 return 0;
46}
47
48/* Returns how long it waited in ms */
49long (*panic_blink)(int state);
50EXPORT_SYMBOL(panic_blink);
51
52/**
53 * panic - halt the system
54 * @fmt: The text string to print
55 *
56 * Display a message, then perform cleanups.
57 *
58 * This function never returns.
59 */
60NORET_TYPE void panic(const char * fmt, ...)
61{
62 static char buf[1024];
63 va_list args;
64 long i, i_next = 0;
65 int state = 0;
66
67 /*
68 * It's possible to come here directly from a panic-assertion and
69 * not have preempt disabled. Some functions called from here want
70 * preempt to be disabled. No point enabling it later though...
71 */
72 preempt_disable();
73
74 console_verbose();
75 bust_spinlocks(1);
76 va_start(args, fmt);
77 vsnprintf(buf, sizeof(buf), fmt, args);
78 va_end(args);
79 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
80#ifdef CONFIG_DEBUG_BUGVERBOSE
81 dump_stack();
82#endif
83
84 /*
85 * If we have crashed and we have a crash kernel loaded let it handle
86 * everything else.
87 * Do we want to call this before we try to display a message?
88 */
89 crash_kexec(NULL);
90
91 kmsg_dump(KMSG_DUMP_PANIC);
92
93 /*
94 * Note smp_send_stop is the usual smp shutdown function, which
95 * unfortunately means it may not be hardened to work in a panic
96 * situation.
97 */
98 smp_send_stop();
99
100 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
101
102 bust_spinlocks(0);
103
104 if (!panic_blink)
105 panic_blink = no_blink;
106
107 if (panic_timeout > 0) {
108 /*
109 * Delay timeout seconds before rebooting the machine.
110 * We can't use the "normal" timers since we just panicked.
111 */
112 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
113
114 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
115 touch_nmi_watchdog();
116 if (i >= i_next) {
117 i += panic_blink(state ^= 1);
118 i_next = i + 3600 / PANIC_BLINK_SPD;
119 }
120 mdelay(PANIC_TIMER_STEP);
121 }
122 }
123 if (panic_timeout != 0) {
124 /*
125 * This will not be a clean reboot, with everything
126 * shutting down. But if there is a chance of
127 * rebooting the system it will be rebooted.
128 */
129 emergency_restart();
130 }
131#ifdef __sparc__
132 {
133 extern int stop_a_enabled;
134 /* Make sure the user can actually press Stop-A (L1-A) */
135 stop_a_enabled = 1;
136 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
137 }
138#endif
139#if defined(CONFIG_S390)
140 {
141 unsigned long caller;
142
143 caller = (unsigned long)__builtin_return_address(0);
144 disabled_wait(caller);
145 }
146#endif
147 local_irq_enable();
148 for (i = 0; ; i += PANIC_TIMER_STEP) {
149 touch_softlockup_watchdog();
150 if (i >= i_next) {
151 i += panic_blink(state ^= 1);
152 i_next = i + 3600 / PANIC_BLINK_SPD;
153 }
154 mdelay(PANIC_TIMER_STEP);
155 }
156}
157
158EXPORT_SYMBOL(panic);
159
160
161struct tnt {
162 u8 bit;
163 char true;
164 char false;
165};
166
167static const struct tnt tnts[] = {
168 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
169 { TAINT_FORCED_MODULE, 'F', ' ' },
170 { TAINT_UNSAFE_SMP, 'S', ' ' },
171 { TAINT_FORCED_RMMOD, 'R', ' ' },
172 { TAINT_MACHINE_CHECK, 'M', ' ' },
173 { TAINT_BAD_PAGE, 'B', ' ' },
174 { TAINT_USER, 'U', ' ' },
175 { TAINT_DIE, 'D', ' ' },
176 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
177 { TAINT_WARN, 'W', ' ' },
178 { TAINT_CRAP, 'C', ' ' },
179 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
180};
181
182/**
183 * print_tainted - return a string to represent the kernel taint state.
184 *
185 * 'P' - Proprietary module has been loaded.
186 * 'F' - Module has been forcibly loaded.
187 * 'S' - SMP with CPUs not designed for SMP.
188 * 'R' - User forced a module unload.
189 * 'M' - System experienced a machine check exception.
190 * 'B' - System has hit bad_page.
191 * 'U' - Userspace-defined naughtiness.
192 * 'D' - Kernel has oopsed before
193 * 'A' - ACPI table overridden.
194 * 'W' - Taint on warning.
195 * 'C' - modules from drivers/staging are loaded.
196 * 'I' - Working around severe firmware bug.
197 *
198 * The string is overwritten by the next call to print_tainted().
199 */
200const char *print_tainted(void)
201{
202 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
203
204 if (tainted_mask) {
205 char *s;
206 int i;
207
208 s = buf + sprintf(buf, "Tainted: ");
209 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
210 const struct tnt *t = &tnts[i];
211 *s++ = test_bit(t->bit, &tainted_mask) ?
212 t->true : t->false;
213 }
214 *s = 0;
215 } else
216 snprintf(buf, sizeof(buf), "Not tainted");
217
218 return buf;
219}
220
221int test_taint(unsigned flag)
222{
223 return test_bit(flag, &tainted_mask);
224}
225EXPORT_SYMBOL(test_taint);
226
227unsigned long get_taint(void)
228{
229 return tainted_mask;
230}
231
232void add_taint(unsigned flag)
233{
234 /*
235 * Can't trust the integrity of the kernel anymore.
236 * We don't call directly debug_locks_off() because the issue
237 * is not necessarily serious enough to set oops_in_progress to 1
238 * Also we want to keep up lockdep for staging development and
239 * post-warning case.
240 */
241 if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
242 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
243
244 set_bit(flag, &tainted_mask);
245}
246EXPORT_SYMBOL(add_taint);
247
248static void spin_msec(int msecs)
249{
250 int i;
251
252 for (i = 0; i < msecs; i++) {
253 touch_nmi_watchdog();
254 mdelay(1);
255 }
256}
257
258/*
259 * It just happens that oops_enter() and oops_exit() are identically
260 * implemented...
261 */
262static void do_oops_enter_exit(void)
263{
264 unsigned long flags;
265 static int spin_counter;
266
267 if (!pause_on_oops)
268 return;
269
270 spin_lock_irqsave(&pause_on_oops_lock, flags);
271 if (pause_on_oops_flag == 0) {
272 /* This CPU may now print the oops message */
273 pause_on_oops_flag = 1;
274 } else {
275 /* We need to stall this CPU */
276 if (!spin_counter) {
277 /* This CPU gets to do the counting */
278 spin_counter = pause_on_oops;
279 do {
280 spin_unlock(&pause_on_oops_lock);
281 spin_msec(MSEC_PER_SEC);
282 spin_lock(&pause_on_oops_lock);
283 } while (--spin_counter);
284 pause_on_oops_flag = 0;
285 } else {
286 /* This CPU waits for a different one */
287 while (spin_counter) {
288 spin_unlock(&pause_on_oops_lock);
289 spin_msec(1);
290 spin_lock(&pause_on_oops_lock);
291 }
292 }
293 }
294 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
295}
296
297/*
298 * Return true if the calling CPU is allowed to print oops-related info.
299 * This is a bit racy..
300 */
301int oops_may_print(void)
302{
303 return pause_on_oops_flag == 0;
304}
305
306/*
307 * Called when the architecture enters its oops handler, before it prints
308 * anything. If this is the first CPU to oops, and it's oopsing the first
309 * time then let it proceed.
310 *
311 * This is all enabled by the pause_on_oops kernel boot option. We do all
312 * this to ensure that oopses don't scroll off the screen. It has the
313 * side-effect of preventing later-oopsing CPUs from mucking up the display,
314 * too.
315 *
316 * It turns out that the CPU which is allowed to print ends up pausing for
317 * the right duration, whereas all the other CPUs pause for twice as long:
318 * once in oops_enter(), once in oops_exit().
319 */
320void oops_enter(void)
321{
322 tracing_off();
323 /* can't trust the integrity of the kernel anymore: */
324 debug_locks_off();
325 do_oops_enter_exit();
326}
327
328/*
329 * 64-bit random ID for oopses:
330 */
331static u64 oops_id;
332
333static int init_oops_id(void)
334{
335 if (!oops_id)
336 get_random_bytes(&oops_id, sizeof(oops_id));
337 else
338 oops_id++;
339
340 return 0;
341}
342late_initcall(init_oops_id);
343
344void print_oops_end_marker(void)
345{
346 init_oops_id();
347 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
348 (unsigned long long)oops_id);
349}
350
351/*
352 * Called when the architecture exits its oops handler, after printing
353 * everything.
354 */
355void oops_exit(void)
356{
357 do_oops_enter_exit();
358 print_oops_end_marker();
359 kmsg_dump(KMSG_DUMP_OOPS);
360}
361
362#ifdef WANT_WARN_ON_SLOWPATH
363struct slowpath_args {
364 const char *fmt;
365 va_list args;
366};
367
368static void warn_slowpath_common(const char *file, int line, void *caller,
369 unsigned taint, struct slowpath_args *args)
370{
371 const char *board;
372
373 printk(KERN_WARNING "------------[ cut here ]------------\n");
374 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
375 board = dmi_get_system_info(DMI_PRODUCT_NAME);
376 if (board)
377 printk(KERN_WARNING "Hardware name: %s\n", board);
378
379 if (args)
380 vprintk(args->fmt, args->args);
381
382 print_modules();
383 dump_stack();
384 print_oops_end_marker();
385 add_taint(taint);
386}
387
388void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
389{
390 struct slowpath_args args;
391
392 args.fmt = fmt;
393 va_start(args.args, fmt);
394 warn_slowpath_common(file, line, __builtin_return_address(0),
395 TAINT_WARN, &args);
396 va_end(args.args);
397}
398EXPORT_SYMBOL(warn_slowpath_fmt);
399
400void warn_slowpath_fmt_taint(const char *file, int line,
401 unsigned taint, const char *fmt, ...)
402{
403 struct slowpath_args args;
404
405 args.fmt = fmt;
406 va_start(args.args, fmt);
407 warn_slowpath_common(file, line, __builtin_return_address(0),
408 taint, &args);
409 va_end(args.args);
410}
411EXPORT_SYMBOL(warn_slowpath_fmt_taint);
412
413void warn_slowpath_null(const char *file, int line)
414{
415 warn_slowpath_common(file, line, __builtin_return_address(0),
416 TAINT_WARN, NULL);
417}
418EXPORT_SYMBOL(warn_slowpath_null);
419#endif
420
421#ifdef CONFIG_CC_STACKPROTECTOR
422
423/*
424 * Called when gcc's -fstack-protector feature is used, and
425 * gcc detects corruption of the on-stack canary value
426 */
427void __stack_chk_fail(void)
428{
429 panic("stack-protector: Kernel stack is corrupted in: %p\n",
430 __builtin_return_address(0));
431}
432EXPORT_SYMBOL(__stack_chk_fail);
433
434#endif
435
436core_param(panic, panic_timeout, int, 0644);
437core_param(pause_on_oops, pause_on_oops, int, 0644);
438
439static int __init oops_setup(char *s)
440{
441 if (!s)
442 return -EINVAL;
443 if (!strcmp(s, "panic"))
444 panic_on_oops = 1;
445 return 0;
446}
447early_param("oops", oops_setup);