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Commit | Line | Data |
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58687acb DZ |
1 | /* |
2 | * Detect hard and soft lockups on a system | |
3 | * | |
4 | * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. | |
5 | * | |
6 | * this code detects hard lockups: incidents in where on a CPU | |
7 | * the kernel does not respond to anything except NMI. | |
8 | * | |
9 | * Note: Most of this code is borrowed heavily from softlockup.c, | |
10 | * so thanks to Ingo for the initial implementation. | |
11 | * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks | |
12 | * to those contributors as well. | |
13 | */ | |
14 | ||
15 | #include <linux/mm.h> | |
16 | #include <linux/cpu.h> | |
17 | #include <linux/nmi.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/freezer.h> | |
21 | #include <linux/kthread.h> | |
22 | #include <linux/lockdep.h> | |
23 | #include <linux/notifier.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/sysctl.h> | |
26 | ||
27 | #include <asm/irq_regs.h> | |
28 | #include <linux/perf_event.h> | |
29 | ||
4135038a | 30 | int watchdog_enabled = 1; |
4eec42f3 | 31 | int __read_mostly watchdog_thresh = 10; |
58687acb DZ |
32 | |
33 | static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts); | |
34 | static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog); | |
35 | static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer); | |
36 | static DEFINE_PER_CPU(bool, softlockup_touch_sync); | |
58687acb | 37 | static DEFINE_PER_CPU(bool, soft_watchdog_warn); |
23637d47 | 38 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
cafcd80d DZ |
39 | static DEFINE_PER_CPU(bool, hard_watchdog_warn); |
40 | static DEFINE_PER_CPU(bool, watchdog_nmi_touch); | |
58687acb DZ |
41 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); |
42 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved); | |
43 | static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); | |
44 | #endif | |
45 | ||
58687acb DZ |
46 | /* boot commands */ |
47 | /* | |
48 | * Should we panic when a soft-lockup or hard-lockup occurs: | |
49 | */ | |
23637d47 | 50 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
51 | static int hardlockup_panic = |
52 | CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE; | |
58687acb DZ |
53 | |
54 | static int __init hardlockup_panic_setup(char *str) | |
55 | { | |
56 | if (!strncmp(str, "panic", 5)) | |
57 | hardlockup_panic = 1; | |
fef2c9bc DZ |
58 | else if (!strncmp(str, "nopanic", 7)) |
59 | hardlockup_panic = 0; | |
5dc30558 | 60 | else if (!strncmp(str, "0", 1)) |
4135038a | 61 | watchdog_enabled = 0; |
58687acb DZ |
62 | return 1; |
63 | } | |
64 | __setup("nmi_watchdog=", hardlockup_panic_setup); | |
65 | #endif | |
66 | ||
67 | unsigned int __read_mostly softlockup_panic = | |
68 | CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE; | |
69 | ||
70 | static int __init softlockup_panic_setup(char *str) | |
71 | { | |
72 | softlockup_panic = simple_strtoul(str, NULL, 0); | |
73 | ||
74 | return 1; | |
75 | } | |
76 | __setup("softlockup_panic=", softlockup_panic_setup); | |
77 | ||
78 | static int __init nowatchdog_setup(char *str) | |
79 | { | |
4135038a | 80 | watchdog_enabled = 0; |
58687acb DZ |
81 | return 1; |
82 | } | |
83 | __setup("nowatchdog", nowatchdog_setup); | |
84 | ||
85 | /* deprecated */ | |
86 | static int __init nosoftlockup_setup(char *str) | |
87 | { | |
4135038a | 88 | watchdog_enabled = 0; |
58687acb DZ |
89 | return 1; |
90 | } | |
91 | __setup("nosoftlockup", nosoftlockup_setup); | |
92 | /* */ | |
93 | ||
4eec42f3 MSB |
94 | /* |
95 | * Hard-lockup warnings should be triggered after just a few seconds. Soft- | |
96 | * lockups can have false positives under extreme conditions. So we generally | |
97 | * want a higher threshold for soft lockups than for hard lockups. So we couple | |
98 | * the thresholds with a factor: we make the soft threshold twice the amount of | |
99 | * time the hard threshold is. | |
100 | */ | |
101 | static int get_softlockup_thresh() | |
102 | { | |
103 | return watchdog_thresh * 2; | |
104 | } | |
58687acb DZ |
105 | |
106 | /* | |
107 | * Returns seconds, approximately. We don't need nanosecond | |
108 | * resolution, and we don't need to waste time with a big divide when | |
109 | * 2^30ns == 1.074s. | |
110 | */ | |
111 | static unsigned long get_timestamp(int this_cpu) | |
112 | { | |
113 | return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */ | |
114 | } | |
115 | ||
116 | static unsigned long get_sample_period(void) | |
117 | { | |
118 | /* | |
586692a5 | 119 | * convert watchdog_thresh from seconds to ns |
58687acb DZ |
120 | * the divide by 5 is to give hrtimer 5 chances to |
121 | * increment before the hardlockup detector generates | |
122 | * a warning | |
123 | */ | |
4eec42f3 | 124 | return get_softlockup_thresh() * (NSEC_PER_SEC / 5); |
58687acb DZ |
125 | } |
126 | ||
127 | /* Commands for resetting the watchdog */ | |
128 | static void __touch_watchdog(void) | |
129 | { | |
26e09c6e | 130 | int this_cpu = smp_processor_id(); |
58687acb | 131 | |
909ea964 | 132 | __this_cpu_write(watchdog_touch_ts, get_timestamp(this_cpu)); |
58687acb DZ |
133 | } |
134 | ||
332fbdbc | 135 | void touch_softlockup_watchdog(void) |
58687acb | 136 | { |
909ea964 | 137 | __this_cpu_write(watchdog_touch_ts, 0); |
58687acb | 138 | } |
0167c781 | 139 | EXPORT_SYMBOL(touch_softlockup_watchdog); |
58687acb | 140 | |
332fbdbc | 141 | void touch_all_softlockup_watchdogs(void) |
58687acb DZ |
142 | { |
143 | int cpu; | |
144 | ||
145 | /* | |
146 | * this is done lockless | |
147 | * do we care if a 0 races with a timestamp? | |
148 | * all it means is the softlock check starts one cycle later | |
149 | */ | |
150 | for_each_online_cpu(cpu) | |
151 | per_cpu(watchdog_touch_ts, cpu) = 0; | |
152 | } | |
153 | ||
cafcd80d | 154 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb DZ |
155 | void touch_nmi_watchdog(void) |
156 | { | |
68d3f1d8 DZ |
157 | if (watchdog_enabled) { |
158 | unsigned cpu; | |
159 | ||
160 | for_each_present_cpu(cpu) { | |
161 | if (per_cpu(watchdog_nmi_touch, cpu) != true) | |
162 | per_cpu(watchdog_nmi_touch, cpu) = true; | |
163 | } | |
164 | } | |
332fbdbc | 165 | touch_softlockup_watchdog(); |
58687acb DZ |
166 | } |
167 | EXPORT_SYMBOL(touch_nmi_watchdog); | |
168 | ||
cafcd80d DZ |
169 | #endif |
170 | ||
58687acb DZ |
171 | void touch_softlockup_watchdog_sync(void) |
172 | { | |
173 | __raw_get_cpu_var(softlockup_touch_sync) = true; | |
174 | __raw_get_cpu_var(watchdog_touch_ts) = 0; | |
175 | } | |
176 | ||
23637d47 | 177 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb | 178 | /* watchdog detector functions */ |
26e09c6e | 179 | static int is_hardlockup(void) |
58687acb | 180 | { |
909ea964 | 181 | unsigned long hrint = __this_cpu_read(hrtimer_interrupts); |
58687acb | 182 | |
909ea964 | 183 | if (__this_cpu_read(hrtimer_interrupts_saved) == hrint) |
58687acb DZ |
184 | return 1; |
185 | ||
909ea964 | 186 | __this_cpu_write(hrtimer_interrupts_saved, hrint); |
58687acb DZ |
187 | return 0; |
188 | } | |
189 | #endif | |
190 | ||
26e09c6e | 191 | static int is_softlockup(unsigned long touch_ts) |
58687acb | 192 | { |
26e09c6e | 193 | unsigned long now = get_timestamp(smp_processor_id()); |
58687acb DZ |
194 | |
195 | /* Warn about unreasonable delays: */ | |
4eec42f3 | 196 | if (time_after(now, touch_ts + get_softlockup_thresh())) |
58687acb DZ |
197 | return now - touch_ts; |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
23637d47 | 202 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb DZ |
203 | static struct perf_event_attr wd_hw_attr = { |
204 | .type = PERF_TYPE_HARDWARE, | |
205 | .config = PERF_COUNT_HW_CPU_CYCLES, | |
206 | .size = sizeof(struct perf_event_attr), | |
207 | .pinned = 1, | |
208 | .disabled = 1, | |
209 | }; | |
210 | ||
211 | /* Callback function for perf event subsystem */ | |
277b1998 | 212 | static void watchdog_overflow_callback(struct perf_event *event, int nmi, |
58687acb DZ |
213 | struct perf_sample_data *data, |
214 | struct pt_regs *regs) | |
215 | { | |
c6db67cd PZ |
216 | /* Ensure the watchdog never gets throttled */ |
217 | event->hw.interrupts = 0; | |
218 | ||
909ea964 CL |
219 | if (__this_cpu_read(watchdog_nmi_touch) == true) { |
220 | __this_cpu_write(watchdog_nmi_touch, false); | |
58687acb DZ |
221 | return; |
222 | } | |
223 | ||
224 | /* check for a hardlockup | |
225 | * This is done by making sure our timer interrupt | |
226 | * is incrementing. The timer interrupt should have | |
227 | * fired multiple times before we overflow'd. If it hasn't | |
228 | * then this is a good indication the cpu is stuck | |
229 | */ | |
26e09c6e DZ |
230 | if (is_hardlockup()) { |
231 | int this_cpu = smp_processor_id(); | |
232 | ||
58687acb | 233 | /* only print hardlockups once */ |
909ea964 | 234 | if (__this_cpu_read(hard_watchdog_warn) == true) |
58687acb DZ |
235 | return; |
236 | ||
237 | if (hardlockup_panic) | |
238 | panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu); | |
239 | else | |
240 | WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu); | |
241 | ||
909ea964 | 242 | __this_cpu_write(hard_watchdog_warn, true); |
58687acb DZ |
243 | return; |
244 | } | |
245 | ||
909ea964 | 246 | __this_cpu_write(hard_watchdog_warn, false); |
58687acb DZ |
247 | return; |
248 | } | |
249 | static void watchdog_interrupt_count(void) | |
250 | { | |
909ea964 | 251 | __this_cpu_inc(hrtimer_interrupts); |
58687acb DZ |
252 | } |
253 | #else | |
254 | static inline void watchdog_interrupt_count(void) { return; } | |
23637d47 | 255 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
58687acb DZ |
256 | |
257 | /* watchdog kicker functions */ | |
258 | static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) | |
259 | { | |
909ea964 | 260 | unsigned long touch_ts = __this_cpu_read(watchdog_touch_ts); |
58687acb DZ |
261 | struct pt_regs *regs = get_irq_regs(); |
262 | int duration; | |
263 | ||
264 | /* kick the hardlockup detector */ | |
265 | watchdog_interrupt_count(); | |
266 | ||
267 | /* kick the softlockup detector */ | |
909ea964 | 268 | wake_up_process(__this_cpu_read(softlockup_watchdog)); |
58687acb DZ |
269 | |
270 | /* .. and repeat */ | |
271 | hrtimer_forward_now(hrtimer, ns_to_ktime(get_sample_period())); | |
272 | ||
273 | if (touch_ts == 0) { | |
909ea964 | 274 | if (unlikely(__this_cpu_read(softlockup_touch_sync))) { |
58687acb DZ |
275 | /* |
276 | * If the time stamp was touched atomically | |
277 | * make sure the scheduler tick is up to date. | |
278 | */ | |
909ea964 | 279 | __this_cpu_write(softlockup_touch_sync, false); |
58687acb DZ |
280 | sched_clock_tick(); |
281 | } | |
282 | __touch_watchdog(); | |
283 | return HRTIMER_RESTART; | |
284 | } | |
285 | ||
286 | /* check for a softlockup | |
287 | * This is done by making sure a high priority task is | |
288 | * being scheduled. The task touches the watchdog to | |
289 | * indicate it is getting cpu time. If it hasn't then | |
290 | * this is a good indication some task is hogging the cpu | |
291 | */ | |
26e09c6e | 292 | duration = is_softlockup(touch_ts); |
58687acb DZ |
293 | if (unlikely(duration)) { |
294 | /* only warn once */ | |
909ea964 | 295 | if (__this_cpu_read(soft_watchdog_warn) == true) |
58687acb DZ |
296 | return HRTIMER_RESTART; |
297 | ||
298 | printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", | |
26e09c6e | 299 | smp_processor_id(), duration, |
58687acb DZ |
300 | current->comm, task_pid_nr(current)); |
301 | print_modules(); | |
302 | print_irqtrace_events(current); | |
303 | if (regs) | |
304 | show_regs(regs); | |
305 | else | |
306 | dump_stack(); | |
307 | ||
308 | if (softlockup_panic) | |
309 | panic("softlockup: hung tasks"); | |
909ea964 | 310 | __this_cpu_write(soft_watchdog_warn, true); |
58687acb | 311 | } else |
909ea964 | 312 | __this_cpu_write(soft_watchdog_warn, false); |
58687acb DZ |
313 | |
314 | return HRTIMER_RESTART; | |
315 | } | |
316 | ||
317 | ||
318 | /* | |
319 | * The watchdog thread - touches the timestamp. | |
320 | */ | |
26e09c6e | 321 | static int watchdog(void *unused) |
58687acb | 322 | { |
fe7de49f | 323 | static struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; |
26e09c6e | 324 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); |
58687acb DZ |
325 | |
326 | sched_setscheduler(current, SCHED_FIFO, ¶m); | |
327 | ||
328 | /* initialize timestamp */ | |
329 | __touch_watchdog(); | |
330 | ||
331 | /* kick off the timer for the hardlockup detector */ | |
332 | /* done here because hrtimer_start can only pin to smp_processor_id() */ | |
333 | hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()), | |
334 | HRTIMER_MODE_REL_PINNED); | |
335 | ||
336 | set_current_state(TASK_INTERRUPTIBLE); | |
337 | /* | |
338 | * Run briefly once per second to reset the softlockup timestamp. | |
339 | * If this gets delayed for more than 60 seconds then the | |
26e09c6e | 340 | * debug-printout triggers in watchdog_timer_fn(). |
58687acb DZ |
341 | */ |
342 | while (!kthread_should_stop()) { | |
343 | __touch_watchdog(); | |
344 | schedule(); | |
345 | ||
346 | if (kthread_should_stop()) | |
347 | break; | |
348 | ||
349 | set_current_state(TASK_INTERRUPTIBLE); | |
350 | } | |
351 | __set_current_state(TASK_RUNNING); | |
352 | ||
353 | return 0; | |
354 | } | |
355 | ||
356 | ||
23637d47 | 357 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb DZ |
358 | static int watchdog_nmi_enable(int cpu) |
359 | { | |
360 | struct perf_event_attr *wd_attr; | |
361 | struct perf_event *event = per_cpu(watchdog_ev, cpu); | |
362 | ||
363 | /* is it already setup and enabled? */ | |
364 | if (event && event->state > PERF_EVENT_STATE_OFF) | |
365 | goto out; | |
366 | ||
367 | /* it is setup but not enabled */ | |
368 | if (event != NULL) | |
369 | goto out_enable; | |
370 | ||
371 | /* Try to register using hardware perf events */ | |
372 | wd_attr = &wd_hw_attr; | |
4eec42f3 | 373 | wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); |
38a81da2 | 374 | event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback); |
58687acb DZ |
375 | if (!IS_ERR(event)) { |
376 | printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n"); | |
377 | goto out_save; | |
378 | } | |
379 | ||
5651f7f4 DZ |
380 | |
381 | /* vary the KERN level based on the returned errno */ | |
382 | if (PTR_ERR(event) == -EOPNOTSUPP) | |
383 | printk(KERN_INFO "NMI watchdog disabled (cpu%i): not supported (no LAPIC?)\n", cpu); | |
384 | else if (PTR_ERR(event) == -ENOENT) | |
385 | printk(KERN_WARNING "NMI watchdog disabled (cpu%i): hardware events not enabled\n", cpu); | |
386 | else | |
387 | printk(KERN_ERR "NMI watchdog disabled (cpu%i): unable to create perf event: %ld\n", cpu, PTR_ERR(event)); | |
eac24335 | 388 | return PTR_ERR(event); |
58687acb DZ |
389 | |
390 | /* success path */ | |
391 | out_save: | |
392 | per_cpu(watchdog_ev, cpu) = event; | |
393 | out_enable: | |
394 | perf_event_enable(per_cpu(watchdog_ev, cpu)); | |
395 | out: | |
396 | return 0; | |
397 | } | |
398 | ||
399 | static void watchdog_nmi_disable(int cpu) | |
400 | { | |
401 | struct perf_event *event = per_cpu(watchdog_ev, cpu); | |
402 | ||
403 | if (event) { | |
404 | perf_event_disable(event); | |
405 | per_cpu(watchdog_ev, cpu) = NULL; | |
406 | ||
407 | /* should be in cleanup, but blocks oprofile */ | |
408 | perf_event_release_kernel(event); | |
409 | } | |
410 | return; | |
411 | } | |
412 | #else | |
413 | static int watchdog_nmi_enable(int cpu) { return 0; } | |
414 | static void watchdog_nmi_disable(int cpu) { return; } | |
23637d47 | 415 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
58687acb DZ |
416 | |
417 | /* prepare/enable/disable routines */ | |
418 | static int watchdog_prepare_cpu(int cpu) | |
419 | { | |
420 | struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu); | |
421 | ||
422 | WARN_ON(per_cpu(softlockup_watchdog, cpu)); | |
423 | hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
424 | hrtimer->function = watchdog_timer_fn; | |
425 | ||
426 | return 0; | |
427 | } | |
428 | ||
429 | static int watchdog_enable(int cpu) | |
430 | { | |
431 | struct task_struct *p = per_cpu(softlockup_watchdog, cpu); | |
f99a9933 | 432 | int err = 0; |
58687acb DZ |
433 | |
434 | /* enable the perf event */ | |
eac24335 | 435 | err = watchdog_nmi_enable(cpu); |
f99a9933 DZ |
436 | |
437 | /* Regardless of err above, fall through and start softlockup */ | |
58687acb DZ |
438 | |
439 | /* create the watchdog thread */ | |
440 | if (!p) { | |
441 | p = kthread_create(watchdog, (void *)(unsigned long)cpu, "watchdog/%d", cpu); | |
442 | if (IS_ERR(p)) { | |
443 | printk(KERN_ERR "softlockup watchdog for %i failed\n", cpu); | |
1409f141 | 444 | if (!err) { |
f99a9933 DZ |
445 | /* if hardlockup hasn't already set this */ |
446 | err = PTR_ERR(p); | |
1409f141 HD |
447 | /* and disable the perf event */ |
448 | watchdog_nmi_disable(cpu); | |
449 | } | |
f99a9933 | 450 | goto out; |
58687acb DZ |
451 | } |
452 | kthread_bind(p, cpu); | |
453 | per_cpu(watchdog_touch_ts, cpu) = 0; | |
454 | per_cpu(softlockup_watchdog, cpu) = p; | |
455 | wake_up_process(p); | |
456 | } | |
457 | ||
f99a9933 DZ |
458 | out: |
459 | return err; | |
58687acb DZ |
460 | } |
461 | ||
462 | static void watchdog_disable(int cpu) | |
463 | { | |
464 | struct task_struct *p = per_cpu(softlockup_watchdog, cpu); | |
465 | struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu); | |
466 | ||
467 | /* | |
468 | * cancel the timer first to stop incrementing the stats | |
469 | * and waking up the kthread | |
470 | */ | |
471 | hrtimer_cancel(hrtimer); | |
472 | ||
473 | /* disable the perf event */ | |
474 | watchdog_nmi_disable(cpu); | |
475 | ||
476 | /* stop the watchdog thread */ | |
477 | if (p) { | |
478 | per_cpu(softlockup_watchdog, cpu) = NULL; | |
479 | kthread_stop(p); | |
480 | } | |
58687acb DZ |
481 | } |
482 | ||
483 | static void watchdog_enable_all_cpus(void) | |
484 | { | |
485 | int cpu; | |
39735766 MS |
486 | |
487 | watchdog_enabled = 0; | |
58687acb DZ |
488 | |
489 | for_each_online_cpu(cpu) | |
39735766 MS |
490 | if (!watchdog_enable(cpu)) |
491 | /* if any cpu succeeds, watchdog is considered | |
492 | enabled for the system */ | |
493 | watchdog_enabled = 1; | |
58687acb | 494 | |
39735766 | 495 | if (!watchdog_enabled) |
58687acb DZ |
496 | printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n"); |
497 | ||
498 | } | |
499 | ||
500 | static void watchdog_disable_all_cpus(void) | |
501 | { | |
502 | int cpu; | |
503 | ||
504 | for_each_online_cpu(cpu) | |
505 | watchdog_disable(cpu); | |
506 | ||
507 | /* if all watchdogs are disabled, then they are disabled for the system */ | |
508 | watchdog_enabled = 0; | |
509 | } | |
510 | ||
511 | ||
512 | /* sysctl functions */ | |
513 | #ifdef CONFIG_SYSCTL | |
514 | /* | |
586692a5 | 515 | * proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh |
58687acb DZ |
516 | */ |
517 | ||
586692a5 MSB |
518 | int proc_dowatchdog(struct ctl_table *table, int write, |
519 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
58687acb | 520 | { |
e04ab2bc | 521 | int ret; |
58687acb | 522 | |
586692a5 | 523 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
e04ab2bc MSB |
524 | if (ret || !write) |
525 | goto out; | |
526 | ||
586692a5 | 527 | if (watchdog_enabled && watchdog_thresh) |
e04ab2bc MSB |
528 | watchdog_enable_all_cpus(); |
529 | else | |
530 | watchdog_disable_all_cpus(); | |
531 | ||
532 | out: | |
533 | return ret; | |
58687acb | 534 | } |
58687acb DZ |
535 | #endif /* CONFIG_SYSCTL */ |
536 | ||
537 | ||
538 | /* | |
539 | * Create/destroy watchdog threads as CPUs come and go: | |
540 | */ | |
541 | static int __cpuinit | |
542 | cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
543 | { | |
544 | int hotcpu = (unsigned long)hcpu; | |
eac24335 | 545 | int err = 0; |
58687acb DZ |
546 | |
547 | switch (action) { | |
548 | case CPU_UP_PREPARE: | |
549 | case CPU_UP_PREPARE_FROZEN: | |
eac24335 | 550 | err = watchdog_prepare_cpu(hotcpu); |
58687acb DZ |
551 | break; |
552 | case CPU_ONLINE: | |
553 | case CPU_ONLINE_FROZEN: | |
4135038a MS |
554 | if (watchdog_enabled) |
555 | err = watchdog_enable(hotcpu); | |
58687acb DZ |
556 | break; |
557 | #ifdef CONFIG_HOTPLUG_CPU | |
558 | case CPU_UP_CANCELED: | |
559 | case CPU_UP_CANCELED_FROZEN: | |
560 | watchdog_disable(hotcpu); | |
561 | break; | |
562 | case CPU_DEAD: | |
563 | case CPU_DEAD_FROZEN: | |
564 | watchdog_disable(hotcpu); | |
565 | break; | |
566 | #endif /* CONFIG_HOTPLUG_CPU */ | |
567 | } | |
f99a9933 DZ |
568 | |
569 | /* | |
570 | * hardlockup and softlockup are not important enough | |
571 | * to block cpu bring up. Just always succeed and | |
572 | * rely on printk output to flag problems. | |
573 | */ | |
574 | return NOTIFY_OK; | |
58687acb DZ |
575 | } |
576 | ||
577 | static struct notifier_block __cpuinitdata cpu_nfb = { | |
578 | .notifier_call = cpu_callback | |
579 | }; | |
580 | ||
004417a6 | 581 | void __init lockup_detector_init(void) |
58687acb DZ |
582 | { |
583 | void *cpu = (void *)(long)smp_processor_id(); | |
584 | int err; | |
585 | ||
58687acb | 586 | err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); |
eac24335 | 587 | WARN_ON(notifier_to_errno(err)); |
58687acb DZ |
588 | |
589 | cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); | |
590 | register_cpu_notifier(&cpu_nfb); | |
591 | ||
004417a6 | 592 | return; |
58687acb | 593 | } |