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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
27#define PANIC_TIMER_STEP 100
28#define PANIC_BLINK_SPD 18
29
30int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
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 = CONFIG_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 * Stop ourself in panic -- architecture code may override this
54 */
55void __weak panic_smp_self_stop(void)
56{
57 while (1)
58 cpu_relax();
59}
60
61/**
62 * panic - halt the system
63 * @fmt: The text string to print
64 *
65 * Display a message, then perform cleanups.
66 *
67 * This function never returns.
68 */
69void panic(const char *fmt, ...)
70{
71 static DEFINE_SPINLOCK(panic_lock);
72 static char buf[1024];
73 va_list args;
74 long i, i_next = 0;
75 int state = 0;
76
77 /*
78 * Disable local interrupts. This will prevent panic_smp_self_stop
79 * from deadlocking the first cpu that invokes the panic, since
80 * there is nothing to prevent an interrupt handler (that runs
81 * after the panic_lock is acquired) from invoking panic again.
82 */
83 local_irq_disable();
84
85 /*
86 * It's possible to come here directly from a panic-assertion and
87 * not have preempt disabled. Some functions called from here want
88 * preempt to be disabled. No point enabling it later though...
89 *
90 * Only one CPU is allowed to execute the panic code from here. For
91 * multiple parallel invocations of panic, all other CPUs either
92 * stop themself or will wait until they are stopped by the 1st CPU
93 * with smp_send_stop().
94 */
95 if (!spin_trylock(&panic_lock))
96 panic_smp_self_stop();
97
98 console_verbose();
99 bust_spinlocks(1);
100 va_start(args, fmt);
101 vsnprintf(buf, sizeof(buf), fmt, args);
102 va_end(args);
103 pr_emerg("Kernel panic - not syncing: %s\n", buf);
104#ifdef CONFIG_DEBUG_BUGVERBOSE
105 /*
106 * Avoid nested stack-dumping if a panic occurs during oops processing
107 */
108 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
109 dump_stack();
110#endif
111
112 /*
113 * If we have crashed and we have a crash kernel loaded let it handle
114 * everything else.
115 * Do we want to call this before we try to display a message?
116 */
117 crash_kexec(NULL);
118
119 /*
120 * Note smp_send_stop is the usual smp shutdown function, which
121 * unfortunately means it may not be hardened to work in a panic
122 * situation.
123 */
124 smp_send_stop();
125
126 /*
127 * Run any panic handlers, including those that might need to
128 * add information to the kmsg dump output.
129 */
130 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
131
132 kmsg_dump(KMSG_DUMP_PANIC);
133
134 bust_spinlocks(0);
135
136 if (!panic_blink)
137 panic_blink = no_blink;
138
139 if (panic_timeout > 0) {
140 /*
141 * Delay timeout seconds before rebooting the machine.
142 * We can't use the "normal" timers since we just panicked.
143 */
144 pr_emerg("Rebooting in %d seconds..", panic_timeout);
145
146 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
147 touch_nmi_watchdog();
148 if (i >= i_next) {
149 i += panic_blink(state ^= 1);
150 i_next = i + 3600 / PANIC_BLINK_SPD;
151 }
152 mdelay(PANIC_TIMER_STEP);
153 }
154 }
155 if (panic_timeout != 0) {
156 /*
157 * This will not be a clean reboot, with everything
158 * shutting down. But if there is a chance of
159 * rebooting the system it will be rebooted.
160 */
161 emergency_restart();
162 }
163#ifdef __sparc__
164 {
165 extern int stop_a_enabled;
166 /* Make sure the user can actually press Stop-A (L1-A) */
167 stop_a_enabled = 1;
168 pr_emerg("Press Stop-A (L1-A) to return to the boot prom\n");
169 }
170#endif
171#if defined(CONFIG_S390)
172 {
173 unsigned long caller;
174
175 caller = (unsigned long)__builtin_return_address(0);
176 disabled_wait(caller);
177 }
178#endif
179 pr_emerg("---[ end Kernel panic - not syncing: %s\n", buf);
180 local_irq_enable();
181 for (i = 0; ; i += PANIC_TIMER_STEP) {
182 touch_softlockup_watchdog();
183 if (i >= i_next) {
184 i += panic_blink(state ^= 1);
185 i_next = i + 3600 / PANIC_BLINK_SPD;
186 }
187 mdelay(PANIC_TIMER_STEP);
188 }
189}
190
191EXPORT_SYMBOL(panic);
192
193
194struct tnt {
195 u8 bit;
196 char true;
197 char false;
198};
199
200static const struct tnt tnts[] = {
201 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
202 { TAINT_FORCED_MODULE, 'F', ' ' },
203 { TAINT_CPU_OUT_OF_SPEC, 'S', ' ' },
204 { TAINT_FORCED_RMMOD, 'R', ' ' },
205 { TAINT_MACHINE_CHECK, 'M', ' ' },
206 { TAINT_BAD_PAGE, 'B', ' ' },
207 { TAINT_USER, 'U', ' ' },
208 { TAINT_DIE, 'D', ' ' },
209 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
210 { TAINT_WARN, 'W', ' ' },
211 { TAINT_CRAP, 'C', ' ' },
212 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
213 { TAINT_OOT_MODULE, 'O', ' ' },
214 { TAINT_UNSIGNED_MODULE, 'E', ' ' },
215};
216
217/**
218 * print_tainted - return a string to represent the kernel taint state.
219 *
220 * 'P' - Proprietary module has been loaded.
221 * 'F' - Module has been forcibly loaded.
222 * 'S' - SMP with CPUs not designed for SMP.
223 * 'R' - User forced a module unload.
224 * 'M' - System experienced a machine check exception.
225 * 'B' - System has hit bad_page.
226 * 'U' - Userspace-defined naughtiness.
227 * 'D' - Kernel has oopsed before
228 * 'A' - ACPI table overridden.
229 * 'W' - Taint on warning.
230 * 'C' - modules from drivers/staging are loaded.
231 * 'I' - Working around severe firmware bug.
232 * 'O' - Out-of-tree module has been loaded.
233 * 'E' - Unsigned module has been loaded.
234 *
235 * The string is overwritten by the next call to print_tainted().
236 */
237const char *print_tainted(void)
238{
239 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ")];
240
241 if (tainted_mask) {
242 char *s;
243 int i;
244
245 s = buf + sprintf(buf, "Tainted: ");
246 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
247 const struct tnt *t = &tnts[i];
248 *s++ = test_bit(t->bit, &tainted_mask) ?
249 t->true : t->false;
250 }
251 *s = 0;
252 } else
253 snprintf(buf, sizeof(buf), "Not tainted");
254
255 return buf;
256}
257
258int test_taint(unsigned flag)
259{
260 return test_bit(flag, &tainted_mask);
261}
262EXPORT_SYMBOL(test_taint);
263
264unsigned long get_taint(void)
265{
266 return tainted_mask;
267}
268
269/**
270 * add_taint: add a taint flag if not already set.
271 * @flag: one of the TAINT_* constants.
272 * @lockdep_ok: whether lock debugging is still OK.
273 *
274 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
275 * some notewortht-but-not-corrupting cases, it can be set to true.
276 */
277void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
278{
279 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
280 pr_warn("Disabling lock debugging due to kernel taint\n");
281
282 set_bit(flag, &tainted_mask);
283}
284EXPORT_SYMBOL(add_taint);
285
286static void spin_msec(int msecs)
287{
288 int i;
289
290 for (i = 0; i < msecs; i++) {
291 touch_nmi_watchdog();
292 mdelay(1);
293 }
294}
295
296/*
297 * It just happens that oops_enter() and oops_exit() are identically
298 * implemented...
299 */
300static void do_oops_enter_exit(void)
301{
302 unsigned long flags;
303 static int spin_counter;
304
305 if (!pause_on_oops)
306 return;
307
308 spin_lock_irqsave(&pause_on_oops_lock, flags);
309 if (pause_on_oops_flag == 0) {
310 /* This CPU may now print the oops message */
311 pause_on_oops_flag = 1;
312 } else {
313 /* We need to stall this CPU */
314 if (!spin_counter) {
315 /* This CPU gets to do the counting */
316 spin_counter = pause_on_oops;
317 do {
318 spin_unlock(&pause_on_oops_lock);
319 spin_msec(MSEC_PER_SEC);
320 spin_lock(&pause_on_oops_lock);
321 } while (--spin_counter);
322 pause_on_oops_flag = 0;
323 } else {
324 /* This CPU waits for a different one */
325 while (spin_counter) {
326 spin_unlock(&pause_on_oops_lock);
327 spin_msec(1);
328 spin_lock(&pause_on_oops_lock);
329 }
330 }
331 }
332 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
333}
334
335/*
336 * Return true if the calling CPU is allowed to print oops-related info.
337 * This is a bit racy..
338 */
339int oops_may_print(void)
340{
341 return pause_on_oops_flag == 0;
342}
343
344/*
345 * Called when the architecture enters its oops handler, before it prints
346 * anything. If this is the first CPU to oops, and it's oopsing the first
347 * time then let it proceed.
348 *
349 * This is all enabled by the pause_on_oops kernel boot option. We do all
350 * this to ensure that oopses don't scroll off the screen. It has the
351 * side-effect of preventing later-oopsing CPUs from mucking up the display,
352 * too.
353 *
354 * It turns out that the CPU which is allowed to print ends up pausing for
355 * the right duration, whereas all the other CPUs pause for twice as long:
356 * once in oops_enter(), once in oops_exit().
357 */
358void oops_enter(void)
359{
360 tracing_off();
361 /* can't trust the integrity of the kernel anymore: */
362 debug_locks_off();
363 do_oops_enter_exit();
364}
365
366/*
367 * 64-bit random ID for oopses:
368 */
369static u64 oops_id;
370
371static int init_oops_id(void)
372{
373 if (!oops_id)
374 get_random_bytes(&oops_id, sizeof(oops_id));
375 else
376 oops_id++;
377
378 return 0;
379}
380late_initcall(init_oops_id);
381
382void print_oops_end_marker(void)
383{
384 init_oops_id();
385 pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
386}
387
388/*
389 * Called when the architecture exits its oops handler, after printing
390 * everything.
391 */
392void oops_exit(void)
393{
394 do_oops_enter_exit();
395 print_oops_end_marker();
396 kmsg_dump(KMSG_DUMP_OOPS);
397}
398
399#ifdef WANT_WARN_ON_SLOWPATH
400struct slowpath_args {
401 const char *fmt;
402 va_list args;
403};
404
405static void warn_slowpath_common(const char *file, int line, void *caller,
406 unsigned taint, struct slowpath_args *args)
407{
408 disable_trace_on_warning();
409
410 pr_warn("------------[ cut here ]------------\n");
411 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS()\n",
412 raw_smp_processor_id(), current->pid, file, line, caller);
413
414 if (args)
415 vprintk(args->fmt, args->args);
416
417 print_modules();
418 dump_stack();
419 print_oops_end_marker();
420 /* Just a warning, don't kill lockdep. */
421 add_taint(taint, LOCKDEP_STILL_OK);
422}
423
424void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
425{
426 struct slowpath_args args;
427
428 args.fmt = fmt;
429 va_start(args.args, fmt);
430 warn_slowpath_common(file, line, __builtin_return_address(0),
431 TAINT_WARN, &args);
432 va_end(args.args);
433}
434EXPORT_SYMBOL(warn_slowpath_fmt);
435
436void warn_slowpath_fmt_taint(const char *file, int line,
437 unsigned taint, const char *fmt, ...)
438{
439 struct slowpath_args args;
440
441 args.fmt = fmt;
442 va_start(args.args, fmt);
443 warn_slowpath_common(file, line, __builtin_return_address(0),
444 taint, &args);
445 va_end(args.args);
446}
447EXPORT_SYMBOL(warn_slowpath_fmt_taint);
448
449void warn_slowpath_null(const char *file, int line)
450{
451 warn_slowpath_common(file, line, __builtin_return_address(0),
452 TAINT_WARN, NULL);
453}
454EXPORT_SYMBOL(warn_slowpath_null);
455#endif
456
457#ifdef CONFIG_CC_STACKPROTECTOR
458
459/*
460 * Called when gcc's -fstack-protector feature is used, and
461 * gcc detects corruption of the on-stack canary value
462 */
463__visible void __stack_chk_fail(void)
464{
465 panic("stack-protector: Kernel stack is corrupted in: %p\n",
466 __builtin_return_address(0));
467}
468EXPORT_SYMBOL(__stack_chk_fail);
469
470#endif
471
472core_param(panic, panic_timeout, int, 0644);
473core_param(pause_on_oops, pause_on_oops, int, 0644);
474
475static int __init oops_setup(char *s)
476{
477 if (!s)
478 return -EINVAL;
479 if (!strcmp(s, "panic"))
480 panic_on_oops = 1;
481 return 0;
482}
483early_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 = CONFIG_PANIC_ON_OOPS_VALUE;
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 * Stop ourself in panic -- architecture code may override this
54 */
55void __weak panic_smp_self_stop(void)
56{
57 while (1)
58 cpu_relax();
59}
60
61/**
62 * panic - halt the system
63 * @fmt: The text string to print
64 *
65 * Display a message, then perform cleanups.
66 *
67 * This function never returns.
68 */
69void panic(const char *fmt, ...)
70{
71 static DEFINE_SPINLOCK(panic_lock);
72 static char buf[1024];
73 va_list args;
74 long i, i_next = 0;
75 int state = 0;
76
77 /*
78 * It's possible to come here directly from a panic-assertion and
79 * not have preempt disabled. Some functions called from here want
80 * preempt to be disabled. No point enabling it later though...
81 *
82 * Only one CPU is allowed to execute the panic code from here. For
83 * multiple parallel invocations of panic, all other CPUs either
84 * stop themself or will wait until they are stopped by the 1st CPU
85 * with smp_send_stop().
86 */
87 if (!spin_trylock(&panic_lock))
88 panic_smp_self_stop();
89
90 console_verbose();
91 bust_spinlocks(1);
92 va_start(args, fmt);
93 vsnprintf(buf, sizeof(buf), fmt, args);
94 va_end(args);
95 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
96#ifdef CONFIG_DEBUG_BUGVERBOSE
97 /*
98 * Avoid nested stack-dumping if a panic occurs during oops processing
99 */
100 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
101 dump_stack();
102#endif
103
104 /*
105 * If we have crashed and we have a crash kernel loaded let it handle
106 * everything else.
107 * Do we want to call this before we try to display a message?
108 */
109 crash_kexec(NULL);
110
111 /*
112 * Note smp_send_stop is the usual smp shutdown function, which
113 * unfortunately means it may not be hardened to work in a panic
114 * situation.
115 */
116 smp_send_stop();
117
118 kmsg_dump(KMSG_DUMP_PANIC);
119
120 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
121
122 bust_spinlocks(0);
123
124 if (!panic_blink)
125 panic_blink = no_blink;
126
127 if (panic_timeout > 0) {
128 /*
129 * Delay timeout seconds before rebooting the machine.
130 * We can't use the "normal" timers since we just panicked.
131 */
132 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
133
134 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
135 touch_nmi_watchdog();
136 if (i >= i_next) {
137 i += panic_blink(state ^= 1);
138 i_next = i + 3600 / PANIC_BLINK_SPD;
139 }
140 mdelay(PANIC_TIMER_STEP);
141 }
142 }
143 if (panic_timeout != 0) {
144 /*
145 * This will not be a clean reboot, with everything
146 * shutting down. But if there is a chance of
147 * rebooting the system it will be rebooted.
148 */
149 emergency_restart();
150 }
151#ifdef __sparc__
152 {
153 extern int stop_a_enabled;
154 /* Make sure the user can actually press Stop-A (L1-A) */
155 stop_a_enabled = 1;
156 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
157 }
158#endif
159#if defined(CONFIG_S390)
160 {
161 unsigned long caller;
162
163 caller = (unsigned long)__builtin_return_address(0);
164 disabled_wait(caller);
165 }
166#endif
167 local_irq_enable();
168 for (i = 0; ; i += PANIC_TIMER_STEP) {
169 touch_softlockup_watchdog();
170 if (i >= i_next) {
171 i += panic_blink(state ^= 1);
172 i_next = i + 3600 / PANIC_BLINK_SPD;
173 }
174 mdelay(PANIC_TIMER_STEP);
175 }
176}
177
178EXPORT_SYMBOL(panic);
179
180
181struct tnt {
182 u8 bit;
183 char true;
184 char false;
185};
186
187static const struct tnt tnts[] = {
188 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
189 { TAINT_FORCED_MODULE, 'F', ' ' },
190 { TAINT_UNSAFE_SMP, 'S', ' ' },
191 { TAINT_FORCED_RMMOD, 'R', ' ' },
192 { TAINT_MACHINE_CHECK, 'M', ' ' },
193 { TAINT_BAD_PAGE, 'B', ' ' },
194 { TAINT_USER, 'U', ' ' },
195 { TAINT_DIE, 'D', ' ' },
196 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
197 { TAINT_WARN, 'W', ' ' },
198 { TAINT_CRAP, 'C', ' ' },
199 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
200 { TAINT_OOT_MODULE, 'O', ' ' },
201};
202
203/**
204 * print_tainted - return a string to represent the kernel taint state.
205 *
206 * 'P' - Proprietary module has been loaded.
207 * 'F' - Module has been forcibly loaded.
208 * 'S' - SMP with CPUs not designed for SMP.
209 * 'R' - User forced a module unload.
210 * 'M' - System experienced a machine check exception.
211 * 'B' - System has hit bad_page.
212 * 'U' - Userspace-defined naughtiness.
213 * 'D' - Kernel has oopsed before
214 * 'A' - ACPI table overridden.
215 * 'W' - Taint on warning.
216 * 'C' - modules from drivers/staging are loaded.
217 * 'I' - Working around severe firmware bug.
218 * 'O' - Out-of-tree module has been loaded.
219 *
220 * The string is overwritten by the next call to print_tainted().
221 */
222const char *print_tainted(void)
223{
224 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
225
226 if (tainted_mask) {
227 char *s;
228 int i;
229
230 s = buf + sprintf(buf, "Tainted: ");
231 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
232 const struct tnt *t = &tnts[i];
233 *s++ = test_bit(t->bit, &tainted_mask) ?
234 t->true : t->false;
235 }
236 *s = 0;
237 } else
238 snprintf(buf, sizeof(buf), "Not tainted");
239
240 return buf;
241}
242
243int test_taint(unsigned flag)
244{
245 return test_bit(flag, &tainted_mask);
246}
247EXPORT_SYMBOL(test_taint);
248
249unsigned long get_taint(void)
250{
251 return tainted_mask;
252}
253
254void add_taint(unsigned flag)
255{
256 /*
257 * Can't trust the integrity of the kernel anymore.
258 * We don't call directly debug_locks_off() because the issue
259 * is not necessarily serious enough to set oops_in_progress to 1
260 * Also we want to keep up lockdep for staging/out-of-tree
261 * development and post-warning case.
262 */
263 switch (flag) {
264 case TAINT_CRAP:
265 case TAINT_OOT_MODULE:
266 case TAINT_WARN:
267 case TAINT_FIRMWARE_WORKAROUND:
268 break;
269
270 default:
271 if (__debug_locks_off())
272 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
273 }
274
275 set_bit(flag, &tainted_mask);
276}
277EXPORT_SYMBOL(add_taint);
278
279static void spin_msec(int msecs)
280{
281 int i;
282
283 for (i = 0; i < msecs; i++) {
284 touch_nmi_watchdog();
285 mdelay(1);
286 }
287}
288
289/*
290 * It just happens that oops_enter() and oops_exit() are identically
291 * implemented...
292 */
293static void do_oops_enter_exit(void)
294{
295 unsigned long flags;
296 static int spin_counter;
297
298 if (!pause_on_oops)
299 return;
300
301 spin_lock_irqsave(&pause_on_oops_lock, flags);
302 if (pause_on_oops_flag == 0) {
303 /* This CPU may now print the oops message */
304 pause_on_oops_flag = 1;
305 } else {
306 /* We need to stall this CPU */
307 if (!spin_counter) {
308 /* This CPU gets to do the counting */
309 spin_counter = pause_on_oops;
310 do {
311 spin_unlock(&pause_on_oops_lock);
312 spin_msec(MSEC_PER_SEC);
313 spin_lock(&pause_on_oops_lock);
314 } while (--spin_counter);
315 pause_on_oops_flag = 0;
316 } else {
317 /* This CPU waits for a different one */
318 while (spin_counter) {
319 spin_unlock(&pause_on_oops_lock);
320 spin_msec(1);
321 spin_lock(&pause_on_oops_lock);
322 }
323 }
324 }
325 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
326}
327
328/*
329 * Return true if the calling CPU is allowed to print oops-related info.
330 * This is a bit racy..
331 */
332int oops_may_print(void)
333{
334 return pause_on_oops_flag == 0;
335}
336
337/*
338 * Called when the architecture enters its oops handler, before it prints
339 * anything. If this is the first CPU to oops, and it's oopsing the first
340 * time then let it proceed.
341 *
342 * This is all enabled by the pause_on_oops kernel boot option. We do all
343 * this to ensure that oopses don't scroll off the screen. It has the
344 * side-effect of preventing later-oopsing CPUs from mucking up the display,
345 * too.
346 *
347 * It turns out that the CPU which is allowed to print ends up pausing for
348 * the right duration, whereas all the other CPUs pause for twice as long:
349 * once in oops_enter(), once in oops_exit().
350 */
351void oops_enter(void)
352{
353 tracing_off();
354 /* can't trust the integrity of the kernel anymore: */
355 debug_locks_off();
356 do_oops_enter_exit();
357}
358
359/*
360 * 64-bit random ID for oopses:
361 */
362static u64 oops_id;
363
364static int init_oops_id(void)
365{
366 if (!oops_id)
367 get_random_bytes(&oops_id, sizeof(oops_id));
368 else
369 oops_id++;
370
371 return 0;
372}
373late_initcall(init_oops_id);
374
375void print_oops_end_marker(void)
376{
377 init_oops_id();
378 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
379 (unsigned long long)oops_id);
380}
381
382/*
383 * Called when the architecture exits its oops handler, after printing
384 * everything.
385 */
386void oops_exit(void)
387{
388 do_oops_enter_exit();
389 print_oops_end_marker();
390 kmsg_dump(KMSG_DUMP_OOPS);
391}
392
393#ifdef WANT_WARN_ON_SLOWPATH
394struct slowpath_args {
395 const char *fmt;
396 va_list args;
397};
398
399static void warn_slowpath_common(const char *file, int line, void *caller,
400 unsigned taint, struct slowpath_args *args)
401{
402 const char *board;
403
404 printk(KERN_WARNING "------------[ cut here ]------------\n");
405 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
406 board = dmi_get_system_info(DMI_PRODUCT_NAME);
407 if (board)
408 printk(KERN_WARNING "Hardware name: %s\n", board);
409
410 if (args)
411 vprintk(args->fmt, args->args);
412
413 print_modules();
414 dump_stack();
415 print_oops_end_marker();
416 add_taint(taint);
417}
418
419void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
420{
421 struct slowpath_args args;
422
423 args.fmt = fmt;
424 va_start(args.args, fmt);
425 warn_slowpath_common(file, line, __builtin_return_address(0),
426 TAINT_WARN, &args);
427 va_end(args.args);
428}
429EXPORT_SYMBOL(warn_slowpath_fmt);
430
431void warn_slowpath_fmt_taint(const char *file, int line,
432 unsigned taint, const char *fmt, ...)
433{
434 struct slowpath_args args;
435
436 args.fmt = fmt;
437 va_start(args.args, fmt);
438 warn_slowpath_common(file, line, __builtin_return_address(0),
439 taint, &args);
440 va_end(args.args);
441}
442EXPORT_SYMBOL(warn_slowpath_fmt_taint);
443
444void warn_slowpath_null(const char *file, int line)
445{
446 warn_slowpath_common(file, line, __builtin_return_address(0),
447 TAINT_WARN, NULL);
448}
449EXPORT_SYMBOL(warn_slowpath_null);
450#endif
451
452#ifdef CONFIG_CC_STACKPROTECTOR
453
454/*
455 * Called when gcc's -fstack-protector feature is used, and
456 * gcc detects corruption of the on-stack canary value
457 */
458void __stack_chk_fail(void)
459{
460 panic("stack-protector: Kernel stack is corrupted in: %p\n",
461 __builtin_return_address(0));
462}
463EXPORT_SYMBOL(__stack_chk_fail);
464
465#endif
466
467core_param(panic, panic_timeout, int, 0644);
468core_param(pause_on_oops, pause_on_oops, int, 0644);
469
470static int __init oops_setup(char *s)
471{
472 if (!s)
473 return -EINVAL;
474 if (!strcmp(s, "panic"))
475 panic_on_oops = 1;
476 return 0;
477}
478early_param("oops", oops_setup);