Commit | Line | Data |
---|---|---|
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 | * | |
86f5e6a7 FLVC |
6 | * Note: Most of this code is borrowed heavily from the original softlockup |
7 | * detector, so thanks to Ingo for the initial implementation. | |
8 | * Some chunks also taken from the old x86-specific nmi watchdog code, thanks | |
58687acb DZ |
9 | * to those contributors as well. |
10 | */ | |
11 | ||
4501980a AM |
12 | #define pr_fmt(fmt) "NMI watchdog: " fmt |
13 | ||
58687acb DZ |
14 | #include <linux/mm.h> |
15 | #include <linux/cpu.h> | |
16 | #include <linux/nmi.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/delay.h> | |
19 | #include <linux/freezer.h> | |
20 | #include <linux/kthread.h> | |
21 | #include <linux/lockdep.h> | |
22 | #include <linux/notifier.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/sysctl.h> | |
25 | ||
26 | #include <asm/irq_regs.h> | |
27 | #include <linux/perf_event.h> | |
28 | ||
4135038a | 29 | int watchdog_enabled = 1; |
4eec42f3 | 30 | int __read_mostly watchdog_thresh = 10; |
58687acb DZ |
31 | |
32 | static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts); | |
33 | static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog); | |
34 | static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer); | |
35 | static DEFINE_PER_CPU(bool, softlockup_touch_sync); | |
58687acb | 36 | static DEFINE_PER_CPU(bool, soft_watchdog_warn); |
23637d47 | 37 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
cafcd80d DZ |
38 | static DEFINE_PER_CPU(bool, hard_watchdog_warn); |
39 | static DEFINE_PER_CPU(bool, watchdog_nmi_touch); | |
58687acb DZ |
40 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); |
41 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved); | |
42 | static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); | |
43 | #endif | |
44 | ||
58687acb DZ |
45 | /* boot commands */ |
46 | /* | |
47 | * Should we panic when a soft-lockup or hard-lockup occurs: | |
48 | */ | |
23637d47 | 49 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
50 | static int hardlockup_panic = |
51 | CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE; | |
58687acb DZ |
52 | |
53 | static int __init hardlockup_panic_setup(char *str) | |
54 | { | |
55 | if (!strncmp(str, "panic", 5)) | |
56 | hardlockup_panic = 1; | |
fef2c9bc DZ |
57 | else if (!strncmp(str, "nopanic", 7)) |
58 | hardlockup_panic = 0; | |
5dc30558 | 59 | else if (!strncmp(str, "0", 1)) |
4135038a | 60 | watchdog_enabled = 0; |
58687acb DZ |
61 | return 1; |
62 | } | |
63 | __setup("nmi_watchdog=", hardlockup_panic_setup); | |
64 | #endif | |
65 | ||
66 | unsigned int __read_mostly softlockup_panic = | |
67 | CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE; | |
68 | ||
69 | static int __init softlockup_panic_setup(char *str) | |
70 | { | |
71 | softlockup_panic = simple_strtoul(str, NULL, 0); | |
72 | ||
73 | return 1; | |
74 | } | |
75 | __setup("softlockup_panic=", softlockup_panic_setup); | |
76 | ||
77 | static int __init nowatchdog_setup(char *str) | |
78 | { | |
4135038a | 79 | watchdog_enabled = 0; |
58687acb DZ |
80 | return 1; |
81 | } | |
82 | __setup("nowatchdog", nowatchdog_setup); | |
83 | ||
84 | /* deprecated */ | |
85 | static int __init nosoftlockup_setup(char *str) | |
86 | { | |
4135038a | 87 | watchdog_enabled = 0; |
58687acb DZ |
88 | return 1; |
89 | } | |
90 | __setup("nosoftlockup", nosoftlockup_setup); | |
91 | /* */ | |
92 | ||
4eec42f3 MSB |
93 | /* |
94 | * Hard-lockup warnings should be triggered after just a few seconds. Soft- | |
95 | * lockups can have false positives under extreme conditions. So we generally | |
96 | * want a higher threshold for soft lockups than for hard lockups. So we couple | |
97 | * the thresholds with a factor: we make the soft threshold twice the amount of | |
98 | * time the hard threshold is. | |
99 | */ | |
6e9101ae | 100 | static int get_softlockup_thresh(void) |
4eec42f3 MSB |
101 | { |
102 | return watchdog_thresh * 2; | |
103 | } | |
58687acb DZ |
104 | |
105 | /* | |
106 | * Returns seconds, approximately. We don't need nanosecond | |
107 | * resolution, and we don't need to waste time with a big divide when | |
108 | * 2^30ns == 1.074s. | |
109 | */ | |
110 | static unsigned long get_timestamp(int this_cpu) | |
111 | { | |
112 | return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */ | |
113 | } | |
114 | ||
115 | static unsigned long get_sample_period(void) | |
116 | { | |
117 | /* | |
586692a5 | 118 | * convert watchdog_thresh from seconds to ns |
86f5e6a7 FLVC |
119 | * the divide by 5 is to give hrtimer several chances (two |
120 | * or three with the current relation between the soft | |
121 | * and hard thresholds) to increment before the | |
122 | * hardlockup detector generates a warning | |
58687acb | 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 |
1880c4ae | 203 | |
58687acb DZ |
204 | static struct perf_event_attr wd_hw_attr = { |
205 | .type = PERF_TYPE_HARDWARE, | |
206 | .config = PERF_COUNT_HW_CPU_CYCLES, | |
207 | .size = sizeof(struct perf_event_attr), | |
208 | .pinned = 1, | |
209 | .disabled = 1, | |
210 | }; | |
211 | ||
212 | /* Callback function for perf event subsystem */ | |
a8b0ca17 | 213 | static void watchdog_overflow_callback(struct perf_event *event, |
58687acb DZ |
214 | struct perf_sample_data *data, |
215 | struct pt_regs *regs) | |
216 | { | |
c6db67cd PZ |
217 | /* Ensure the watchdog never gets throttled */ |
218 | event->hw.interrupts = 0; | |
219 | ||
909ea964 CL |
220 | if (__this_cpu_read(watchdog_nmi_touch) == true) { |
221 | __this_cpu_write(watchdog_nmi_touch, false); | |
58687acb DZ |
222 | return; |
223 | } | |
224 | ||
225 | /* check for a hardlockup | |
226 | * This is done by making sure our timer interrupt | |
227 | * is incrementing. The timer interrupt should have | |
228 | * fired multiple times before we overflow'd. If it hasn't | |
229 | * then this is a good indication the cpu is stuck | |
230 | */ | |
26e09c6e DZ |
231 | if (is_hardlockup()) { |
232 | int this_cpu = smp_processor_id(); | |
233 | ||
58687acb | 234 | /* only print hardlockups once */ |
909ea964 | 235 | if (__this_cpu_read(hard_watchdog_warn) == true) |
58687acb DZ |
236 | return; |
237 | ||
238 | if (hardlockup_panic) | |
239 | panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu); | |
240 | else | |
241 | WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu); | |
242 | ||
909ea964 | 243 | __this_cpu_write(hard_watchdog_warn, true); |
58687acb DZ |
244 | return; |
245 | } | |
246 | ||
909ea964 | 247 | __this_cpu_write(hard_watchdog_warn, false); |
58687acb DZ |
248 | return; |
249 | } | |
250 | static void watchdog_interrupt_count(void) | |
251 | { | |
909ea964 | 252 | __this_cpu_inc(hrtimer_interrupts); |
58687acb DZ |
253 | } |
254 | #else | |
255 | static inline void watchdog_interrupt_count(void) { return; } | |
23637d47 | 256 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
58687acb DZ |
257 | |
258 | /* watchdog kicker functions */ | |
259 | static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) | |
260 | { | |
909ea964 | 261 | unsigned long touch_ts = __this_cpu_read(watchdog_touch_ts); |
58687acb DZ |
262 | struct pt_regs *regs = get_irq_regs(); |
263 | int duration; | |
264 | ||
265 | /* kick the hardlockup detector */ | |
266 | watchdog_interrupt_count(); | |
267 | ||
268 | /* kick the softlockup detector */ | |
909ea964 | 269 | wake_up_process(__this_cpu_read(softlockup_watchdog)); |
58687acb DZ |
270 | |
271 | /* .. and repeat */ | |
272 | hrtimer_forward_now(hrtimer, ns_to_ktime(get_sample_period())); | |
273 | ||
274 | if (touch_ts == 0) { | |
909ea964 | 275 | if (unlikely(__this_cpu_read(softlockup_touch_sync))) { |
58687acb DZ |
276 | /* |
277 | * If the time stamp was touched atomically | |
278 | * make sure the scheduler tick is up to date. | |
279 | */ | |
909ea964 | 280 | __this_cpu_write(softlockup_touch_sync, false); |
58687acb DZ |
281 | sched_clock_tick(); |
282 | } | |
283 | __touch_watchdog(); | |
284 | return HRTIMER_RESTART; | |
285 | } | |
286 | ||
287 | /* check for a softlockup | |
288 | * This is done by making sure a high priority task is | |
289 | * being scheduled. The task touches the watchdog to | |
290 | * indicate it is getting cpu time. If it hasn't then | |
291 | * this is a good indication some task is hogging the cpu | |
292 | */ | |
26e09c6e | 293 | duration = is_softlockup(touch_ts); |
58687acb DZ |
294 | if (unlikely(duration)) { |
295 | /* only warn once */ | |
909ea964 | 296 | if (__this_cpu_read(soft_watchdog_warn) == true) |
58687acb DZ |
297 | return HRTIMER_RESTART; |
298 | ||
b0f4c4b3 | 299 | printk(KERN_EMERG "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", |
26e09c6e | 300 | smp_processor_id(), duration, |
58687acb DZ |
301 | current->comm, task_pid_nr(current)); |
302 | print_modules(); | |
303 | print_irqtrace_events(current); | |
304 | if (regs) | |
305 | show_regs(regs); | |
306 | else | |
307 | dump_stack(); | |
308 | ||
309 | if (softlockup_panic) | |
310 | panic("softlockup: hung tasks"); | |
909ea964 | 311 | __this_cpu_write(soft_watchdog_warn, true); |
58687acb | 312 | } else |
909ea964 | 313 | __this_cpu_write(soft_watchdog_warn, false); |
58687acb DZ |
314 | |
315 | return HRTIMER_RESTART; | |
316 | } | |
317 | ||
318 | ||
319 | /* | |
320 | * The watchdog thread - touches the timestamp. | |
321 | */ | |
26e09c6e | 322 | static int watchdog(void *unused) |
58687acb | 323 | { |
7a05c0f7 | 324 | struct sched_param param = { .sched_priority = 0 }; |
26e09c6e | 325 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); |
58687acb | 326 | |
58687acb DZ |
327 | /* initialize timestamp */ |
328 | __touch_watchdog(); | |
329 | ||
330 | /* kick off the timer for the hardlockup detector */ | |
331 | /* done here because hrtimer_start can only pin to smp_processor_id() */ | |
332 | hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()), | |
333 | HRTIMER_MODE_REL_PINNED); | |
334 | ||
335 | set_current_state(TASK_INTERRUPTIBLE); | |
336 | /* | |
86f5e6a7 FLVC |
337 | * Run briefly (kicked by the hrtimer callback function) once every |
338 | * get_sample_period() seconds (4 seconds by default) to reset the | |
339 | * softlockup timestamp. If this gets delayed for more than | |
340 | * 2*watchdog_thresh seconds then the debug-printout triggers in | |
341 | * watchdog_timer_fn(). | |
58687acb DZ |
342 | */ |
343 | while (!kthread_should_stop()) { | |
344 | __touch_watchdog(); | |
345 | schedule(); | |
346 | ||
347 | if (kthread_should_stop()) | |
348 | break; | |
349 | ||
350 | set_current_state(TASK_INTERRUPTIBLE); | |
351 | } | |
b60f796c AM |
352 | /* |
353 | * Drop the policy/priority elevation during thread exit to avoid a | |
354 | * scheduling latency spike. | |
355 | */ | |
58687acb | 356 | __set_current_state(TASK_RUNNING); |
cba9bd22 | 357 | sched_setscheduler(current, SCHED_NORMAL, ¶m); |
58687acb DZ |
358 | return 0; |
359 | } | |
360 | ||
361 | ||
23637d47 | 362 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb DZ |
363 | static int watchdog_nmi_enable(int cpu) |
364 | { | |
365 | struct perf_event_attr *wd_attr; | |
366 | struct perf_event *event = per_cpu(watchdog_ev, cpu); | |
367 | ||
368 | /* is it already setup and enabled? */ | |
369 | if (event && event->state > PERF_EVENT_STATE_OFF) | |
370 | goto out; | |
371 | ||
372 | /* it is setup but not enabled */ | |
373 | if (event != NULL) | |
374 | goto out_enable; | |
375 | ||
58687acb | 376 | wd_attr = &wd_hw_attr; |
4eec42f3 | 377 | wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); |
1880c4ae CG |
378 | |
379 | /* Try to register using hardware perf events */ | |
4dc0da86 | 380 | event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL); |
58687acb | 381 | if (!IS_ERR(event)) { |
4501980a | 382 | pr_info("enabled, takes one hw-pmu counter.\n"); |
58687acb DZ |
383 | goto out_save; |
384 | } | |
385 | ||
5651f7f4 DZ |
386 | |
387 | /* vary the KERN level based on the returned errno */ | |
388 | if (PTR_ERR(event) == -EOPNOTSUPP) | |
4501980a | 389 | pr_info("disabled (cpu%i): not supported (no LAPIC?)\n", cpu); |
5651f7f4 | 390 | else if (PTR_ERR(event) == -ENOENT) |
4501980a AM |
391 | pr_warning("disabled (cpu%i): hardware events not enabled\n", |
392 | cpu); | |
5651f7f4 | 393 | else |
4501980a AM |
394 | pr_err("disabled (cpu%i): unable to create perf event: %ld\n", |
395 | cpu, PTR_ERR(event)); | |
eac24335 | 396 | return PTR_ERR(event); |
58687acb DZ |
397 | |
398 | /* success path */ | |
399 | out_save: | |
400 | per_cpu(watchdog_ev, cpu) = event; | |
401 | out_enable: | |
402 | perf_event_enable(per_cpu(watchdog_ev, cpu)); | |
403 | out: | |
404 | return 0; | |
405 | } | |
406 | ||
407 | static void watchdog_nmi_disable(int cpu) | |
408 | { | |
409 | struct perf_event *event = per_cpu(watchdog_ev, cpu); | |
410 | ||
411 | if (event) { | |
412 | perf_event_disable(event); | |
413 | per_cpu(watchdog_ev, cpu) = NULL; | |
414 | ||
415 | /* should be in cleanup, but blocks oprofile */ | |
416 | perf_event_release_kernel(event); | |
417 | } | |
418 | return; | |
419 | } | |
420 | #else | |
421 | static int watchdog_nmi_enable(int cpu) { return 0; } | |
422 | static void watchdog_nmi_disable(int cpu) { return; } | |
23637d47 | 423 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
58687acb DZ |
424 | |
425 | /* prepare/enable/disable routines */ | |
6e9101ae | 426 | static void watchdog_prepare_cpu(int cpu) |
58687acb DZ |
427 | { |
428 | struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu); | |
429 | ||
430 | WARN_ON(per_cpu(softlockup_watchdog, cpu)); | |
431 | hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
432 | hrtimer->function = watchdog_timer_fn; | |
58687acb DZ |
433 | } |
434 | ||
435 | static int watchdog_enable(int cpu) | |
436 | { | |
437 | struct task_struct *p = per_cpu(softlockup_watchdog, cpu); | |
f99a9933 | 438 | int err = 0; |
58687acb DZ |
439 | |
440 | /* enable the perf event */ | |
eac24335 | 441 | err = watchdog_nmi_enable(cpu); |
f99a9933 DZ |
442 | |
443 | /* Regardless of err above, fall through and start softlockup */ | |
58687acb DZ |
444 | |
445 | /* create the watchdog thread */ | |
446 | if (!p) { | |
7a05c0f7 | 447 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; |
18e5a45d | 448 | p = kthread_create_on_node(watchdog, NULL, cpu_to_node(cpu), "watchdog/%d", cpu); |
58687acb | 449 | if (IS_ERR(p)) { |
4501980a | 450 | pr_err("softlockup watchdog for %i failed\n", cpu); |
1409f141 | 451 | if (!err) { |
f99a9933 DZ |
452 | /* if hardlockup hasn't already set this */ |
453 | err = PTR_ERR(p); | |
1409f141 HD |
454 | /* and disable the perf event */ |
455 | watchdog_nmi_disable(cpu); | |
456 | } | |
f99a9933 | 457 | goto out; |
58687acb | 458 | } |
7a05c0f7 | 459 | sched_setscheduler(p, SCHED_FIFO, ¶m); |
58687acb DZ |
460 | kthread_bind(p, cpu); |
461 | per_cpu(watchdog_touch_ts, cpu) = 0; | |
462 | per_cpu(softlockup_watchdog, cpu) = p; | |
463 | wake_up_process(p); | |
464 | } | |
465 | ||
f99a9933 DZ |
466 | out: |
467 | return err; | |
58687acb DZ |
468 | } |
469 | ||
470 | static void watchdog_disable(int cpu) | |
471 | { | |
472 | struct task_struct *p = per_cpu(softlockup_watchdog, cpu); | |
473 | struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu); | |
474 | ||
475 | /* | |
476 | * cancel the timer first to stop incrementing the stats | |
477 | * and waking up the kthread | |
478 | */ | |
479 | hrtimer_cancel(hrtimer); | |
480 | ||
481 | /* disable the perf event */ | |
482 | watchdog_nmi_disable(cpu); | |
483 | ||
484 | /* stop the watchdog thread */ | |
485 | if (p) { | |
486 | per_cpu(softlockup_watchdog, cpu) = NULL; | |
487 | kthread_stop(p); | |
488 | } | |
58687acb DZ |
489 | } |
490 | ||
4ff81951 VA |
491 | /* sysctl functions */ |
492 | #ifdef CONFIG_SYSCTL | |
58687acb DZ |
493 | static void watchdog_enable_all_cpus(void) |
494 | { | |
495 | int cpu; | |
39735766 MS |
496 | |
497 | watchdog_enabled = 0; | |
58687acb DZ |
498 | |
499 | for_each_online_cpu(cpu) | |
39735766 MS |
500 | if (!watchdog_enable(cpu)) |
501 | /* if any cpu succeeds, watchdog is considered | |
502 | enabled for the system */ | |
503 | watchdog_enabled = 1; | |
58687acb | 504 | |
39735766 | 505 | if (!watchdog_enabled) |
4501980a | 506 | pr_err("failed to be enabled on some cpus\n"); |
58687acb DZ |
507 | |
508 | } | |
509 | ||
510 | static void watchdog_disable_all_cpus(void) | |
511 | { | |
512 | int cpu; | |
513 | ||
514 | for_each_online_cpu(cpu) | |
515 | watchdog_disable(cpu); | |
516 | ||
517 | /* if all watchdogs are disabled, then they are disabled for the system */ | |
518 | watchdog_enabled = 0; | |
519 | } | |
520 | ||
521 | ||
58687acb | 522 | /* |
586692a5 | 523 | * proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh |
58687acb DZ |
524 | */ |
525 | ||
586692a5 MSB |
526 | int proc_dowatchdog(struct ctl_table *table, int write, |
527 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
58687acb | 528 | { |
e04ab2bc | 529 | int ret; |
58687acb | 530 | |
586692a5 | 531 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
e04ab2bc MSB |
532 | if (ret || !write) |
533 | goto out; | |
534 | ||
586692a5 | 535 | if (watchdog_enabled && watchdog_thresh) |
e04ab2bc MSB |
536 | watchdog_enable_all_cpus(); |
537 | else | |
538 | watchdog_disable_all_cpus(); | |
539 | ||
540 | out: | |
541 | return ret; | |
58687acb | 542 | } |
58687acb DZ |
543 | #endif /* CONFIG_SYSCTL */ |
544 | ||
545 | ||
546 | /* | |
547 | * Create/destroy watchdog threads as CPUs come and go: | |
548 | */ | |
549 | static int __cpuinit | |
550 | cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
551 | { | |
552 | int hotcpu = (unsigned long)hcpu; | |
553 | ||
554 | switch (action) { | |
555 | case CPU_UP_PREPARE: | |
556 | case CPU_UP_PREPARE_FROZEN: | |
6e9101ae | 557 | watchdog_prepare_cpu(hotcpu); |
58687acb DZ |
558 | break; |
559 | case CPU_ONLINE: | |
560 | case CPU_ONLINE_FROZEN: | |
4135038a | 561 | if (watchdog_enabled) |
6e9101ae | 562 | watchdog_enable(hotcpu); |
58687acb DZ |
563 | break; |
564 | #ifdef CONFIG_HOTPLUG_CPU | |
565 | case CPU_UP_CANCELED: | |
566 | case CPU_UP_CANCELED_FROZEN: | |
567 | watchdog_disable(hotcpu); | |
568 | break; | |
569 | case CPU_DEAD: | |
570 | case CPU_DEAD_FROZEN: | |
571 | watchdog_disable(hotcpu); | |
572 | break; | |
573 | #endif /* CONFIG_HOTPLUG_CPU */ | |
574 | } | |
f99a9933 DZ |
575 | |
576 | /* | |
577 | * hardlockup and softlockup are not important enough | |
578 | * to block cpu bring up. Just always succeed and | |
579 | * rely on printk output to flag problems. | |
580 | */ | |
581 | return NOTIFY_OK; | |
58687acb DZ |
582 | } |
583 | ||
584 | static struct notifier_block __cpuinitdata cpu_nfb = { | |
585 | .notifier_call = cpu_callback | |
586 | }; | |
587 | ||
004417a6 | 588 | void __init lockup_detector_init(void) |
58687acb DZ |
589 | { |
590 | void *cpu = (void *)(long)smp_processor_id(); | |
591 | int err; | |
592 | ||
58687acb | 593 | err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); |
eac24335 | 594 | WARN_ON(notifier_to_errno(err)); |
58687acb DZ |
595 | |
596 | cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); | |
597 | register_cpu_notifier(&cpu_nfb); | |
598 | ||
004417a6 | 599 | return; |
58687acb | 600 | } |