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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 | * | |
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> | |
bcd951cf | 25 | #include <linux/smpboot.h> |
58687acb DZ |
26 | |
27 | #include <asm/irq_regs.h> | |
5d1c0f4a | 28 | #include <linux/kvm_para.h> |
58687acb DZ |
29 | #include <linux/perf_event.h> |
30 | ||
4135038a | 31 | int watchdog_enabled = 1; |
4eec42f3 | 32 | int __read_mostly watchdog_thresh = 10; |
bcd951cf | 33 | static int __read_mostly watchdog_disabled; |
0f34c400 | 34 | static u64 __read_mostly sample_period; |
58687acb DZ |
35 | |
36 | static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts); | |
37 | static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog); | |
38 | static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer); | |
39 | static DEFINE_PER_CPU(bool, softlockup_touch_sync); | |
58687acb | 40 | static DEFINE_PER_CPU(bool, soft_watchdog_warn); |
bcd951cf TG |
41 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); |
42 | static DEFINE_PER_CPU(unsigned long, soft_lockup_hrtimer_cnt); | |
23637d47 | 43 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
cafcd80d DZ |
44 | static DEFINE_PER_CPU(bool, hard_watchdog_warn); |
45 | static DEFINE_PER_CPU(bool, watchdog_nmi_touch); | |
58687acb DZ |
46 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved); |
47 | static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); | |
48 | #endif | |
49 | ||
58687acb DZ |
50 | /* boot commands */ |
51 | /* | |
52 | * Should we panic when a soft-lockup or hard-lockup occurs: | |
53 | */ | |
23637d47 | 54 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
55 | static int hardlockup_panic = |
56 | CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE; | |
58687acb DZ |
57 | |
58 | static int __init hardlockup_panic_setup(char *str) | |
59 | { | |
60 | if (!strncmp(str, "panic", 5)) | |
61 | hardlockup_panic = 1; | |
fef2c9bc DZ |
62 | else if (!strncmp(str, "nopanic", 7)) |
63 | hardlockup_panic = 0; | |
5dc30558 | 64 | else if (!strncmp(str, "0", 1)) |
4135038a | 65 | watchdog_enabled = 0; |
58687acb DZ |
66 | return 1; |
67 | } | |
68 | __setup("nmi_watchdog=", hardlockup_panic_setup); | |
69 | #endif | |
70 | ||
71 | unsigned int __read_mostly softlockup_panic = | |
72 | CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE; | |
73 | ||
74 | static int __init softlockup_panic_setup(char *str) | |
75 | { | |
76 | softlockup_panic = simple_strtoul(str, NULL, 0); | |
77 | ||
78 | return 1; | |
79 | } | |
80 | __setup("softlockup_panic=", softlockup_panic_setup); | |
81 | ||
82 | static int __init nowatchdog_setup(char *str) | |
83 | { | |
4135038a | 84 | watchdog_enabled = 0; |
58687acb DZ |
85 | return 1; |
86 | } | |
87 | __setup("nowatchdog", nowatchdog_setup); | |
88 | ||
89 | /* deprecated */ | |
90 | static int __init nosoftlockup_setup(char *str) | |
91 | { | |
4135038a | 92 | watchdog_enabled = 0; |
58687acb DZ |
93 | return 1; |
94 | } | |
95 | __setup("nosoftlockup", nosoftlockup_setup); | |
96 | /* */ | |
97 | ||
4eec42f3 MSB |
98 | /* |
99 | * Hard-lockup warnings should be triggered after just a few seconds. Soft- | |
100 | * lockups can have false positives under extreme conditions. So we generally | |
101 | * want a higher threshold for soft lockups than for hard lockups. So we couple | |
102 | * the thresholds with a factor: we make the soft threshold twice the amount of | |
103 | * time the hard threshold is. | |
104 | */ | |
6e9101ae | 105 | static int get_softlockup_thresh(void) |
4eec42f3 MSB |
106 | { |
107 | return watchdog_thresh * 2; | |
108 | } | |
58687acb DZ |
109 | |
110 | /* | |
111 | * Returns seconds, approximately. We don't need nanosecond | |
112 | * resolution, and we don't need to waste time with a big divide when | |
113 | * 2^30ns == 1.074s. | |
114 | */ | |
115 | static unsigned long get_timestamp(int this_cpu) | |
116 | { | |
117 | return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */ | |
118 | } | |
119 | ||
0f34c400 | 120 | static void set_sample_period(void) |
58687acb DZ |
121 | { |
122 | /* | |
586692a5 | 123 | * convert watchdog_thresh from seconds to ns |
86f5e6a7 FLVC |
124 | * the divide by 5 is to give hrtimer several chances (two |
125 | * or three with the current relation between the soft | |
126 | * and hard thresholds) to increment before the | |
127 | * hardlockup detector generates a warning | |
58687acb | 128 | */ |
0f34c400 | 129 | sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5); |
58687acb DZ |
130 | } |
131 | ||
132 | /* Commands for resetting the watchdog */ | |
133 | static void __touch_watchdog(void) | |
134 | { | |
26e09c6e | 135 | int this_cpu = smp_processor_id(); |
58687acb | 136 | |
909ea964 | 137 | __this_cpu_write(watchdog_touch_ts, get_timestamp(this_cpu)); |
58687acb DZ |
138 | } |
139 | ||
332fbdbc | 140 | void touch_softlockup_watchdog(void) |
58687acb | 141 | { |
909ea964 | 142 | __this_cpu_write(watchdog_touch_ts, 0); |
58687acb | 143 | } |
0167c781 | 144 | EXPORT_SYMBOL(touch_softlockup_watchdog); |
58687acb | 145 | |
332fbdbc | 146 | void touch_all_softlockup_watchdogs(void) |
58687acb DZ |
147 | { |
148 | int cpu; | |
149 | ||
150 | /* | |
151 | * this is done lockless | |
152 | * do we care if a 0 races with a timestamp? | |
153 | * all it means is the softlock check starts one cycle later | |
154 | */ | |
155 | for_each_online_cpu(cpu) | |
156 | per_cpu(watchdog_touch_ts, cpu) = 0; | |
157 | } | |
158 | ||
cafcd80d | 159 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb DZ |
160 | void touch_nmi_watchdog(void) |
161 | { | |
68d3f1d8 DZ |
162 | if (watchdog_enabled) { |
163 | unsigned cpu; | |
164 | ||
165 | for_each_present_cpu(cpu) { | |
166 | if (per_cpu(watchdog_nmi_touch, cpu) != true) | |
167 | per_cpu(watchdog_nmi_touch, cpu) = true; | |
168 | } | |
169 | } | |
332fbdbc | 170 | touch_softlockup_watchdog(); |
58687acb DZ |
171 | } |
172 | EXPORT_SYMBOL(touch_nmi_watchdog); | |
173 | ||
cafcd80d DZ |
174 | #endif |
175 | ||
58687acb DZ |
176 | void touch_softlockup_watchdog_sync(void) |
177 | { | |
178 | __raw_get_cpu_var(softlockup_touch_sync) = true; | |
179 | __raw_get_cpu_var(watchdog_touch_ts) = 0; | |
180 | } | |
181 | ||
23637d47 | 182 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
58687acb | 183 | /* watchdog detector functions */ |
26e09c6e | 184 | static int is_hardlockup(void) |
58687acb | 185 | { |
909ea964 | 186 | unsigned long hrint = __this_cpu_read(hrtimer_interrupts); |
58687acb | 187 | |
909ea964 | 188 | if (__this_cpu_read(hrtimer_interrupts_saved) == hrint) |
58687acb DZ |
189 | return 1; |
190 | ||
909ea964 | 191 | __this_cpu_write(hrtimer_interrupts_saved, hrint); |
58687acb DZ |
192 | return 0; |
193 | } | |
194 | #endif | |
195 | ||
26e09c6e | 196 | static int is_softlockup(unsigned long touch_ts) |
58687acb | 197 | { |
26e09c6e | 198 | unsigned long now = get_timestamp(smp_processor_id()); |
58687acb DZ |
199 | |
200 | /* Warn about unreasonable delays: */ | |
4eec42f3 | 201 | if (time_after(now, touch_ts + get_softlockup_thresh())) |
58687acb DZ |
202 | return now - touch_ts; |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
23637d47 | 207 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
1880c4ae | 208 | |
58687acb DZ |
209 | static struct perf_event_attr wd_hw_attr = { |
210 | .type = PERF_TYPE_HARDWARE, | |
211 | .config = PERF_COUNT_HW_CPU_CYCLES, | |
212 | .size = sizeof(struct perf_event_attr), | |
213 | .pinned = 1, | |
214 | .disabled = 1, | |
215 | }; | |
216 | ||
217 | /* Callback function for perf event subsystem */ | |
a8b0ca17 | 218 | static void watchdog_overflow_callback(struct perf_event *event, |
58687acb DZ |
219 | struct perf_sample_data *data, |
220 | struct pt_regs *regs) | |
221 | { | |
c6db67cd PZ |
222 | /* Ensure the watchdog never gets throttled */ |
223 | event->hw.interrupts = 0; | |
224 | ||
909ea964 CL |
225 | if (__this_cpu_read(watchdog_nmi_touch) == true) { |
226 | __this_cpu_write(watchdog_nmi_touch, false); | |
58687acb DZ |
227 | return; |
228 | } | |
229 | ||
230 | /* check for a hardlockup | |
231 | * This is done by making sure our timer interrupt | |
232 | * is incrementing. The timer interrupt should have | |
233 | * fired multiple times before we overflow'd. If it hasn't | |
234 | * then this is a good indication the cpu is stuck | |
235 | */ | |
26e09c6e DZ |
236 | if (is_hardlockup()) { |
237 | int this_cpu = smp_processor_id(); | |
238 | ||
58687acb | 239 | /* only print hardlockups once */ |
909ea964 | 240 | if (__this_cpu_read(hard_watchdog_warn) == true) |
58687acb DZ |
241 | return; |
242 | ||
243 | if (hardlockup_panic) | |
244 | panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu); | |
245 | else | |
246 | WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu); | |
247 | ||
909ea964 | 248 | __this_cpu_write(hard_watchdog_warn, true); |
58687acb DZ |
249 | return; |
250 | } | |
251 | ||
909ea964 | 252 | __this_cpu_write(hard_watchdog_warn, false); |
58687acb DZ |
253 | return; |
254 | } | |
bcd951cf TG |
255 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
256 | ||
58687acb DZ |
257 | static void watchdog_interrupt_count(void) |
258 | { | |
909ea964 | 259 | __this_cpu_inc(hrtimer_interrupts); |
58687acb | 260 | } |
bcd951cf TG |
261 | |
262 | static int watchdog_nmi_enable(unsigned int cpu); | |
263 | static void watchdog_nmi_disable(unsigned int cpu); | |
58687acb DZ |
264 | |
265 | /* watchdog kicker functions */ | |
266 | static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) | |
267 | { | |
909ea964 | 268 | unsigned long touch_ts = __this_cpu_read(watchdog_touch_ts); |
58687acb DZ |
269 | struct pt_regs *regs = get_irq_regs(); |
270 | int duration; | |
271 | ||
272 | /* kick the hardlockup detector */ | |
273 | watchdog_interrupt_count(); | |
274 | ||
275 | /* kick the softlockup detector */ | |
909ea964 | 276 | wake_up_process(__this_cpu_read(softlockup_watchdog)); |
58687acb DZ |
277 | |
278 | /* .. and repeat */ | |
0f34c400 | 279 | hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period)); |
58687acb DZ |
280 | |
281 | if (touch_ts == 0) { | |
909ea964 | 282 | if (unlikely(__this_cpu_read(softlockup_touch_sync))) { |
58687acb DZ |
283 | /* |
284 | * If the time stamp was touched atomically | |
285 | * make sure the scheduler tick is up to date. | |
286 | */ | |
909ea964 | 287 | __this_cpu_write(softlockup_touch_sync, false); |
58687acb DZ |
288 | sched_clock_tick(); |
289 | } | |
5d1c0f4a EM |
290 | |
291 | /* Clear the guest paused flag on watchdog reset */ | |
292 | kvm_check_and_clear_guest_paused(); | |
58687acb DZ |
293 | __touch_watchdog(); |
294 | return HRTIMER_RESTART; | |
295 | } | |
296 | ||
297 | /* check for a softlockup | |
298 | * This is done by making sure a high priority task is | |
299 | * being scheduled. The task touches the watchdog to | |
300 | * indicate it is getting cpu time. If it hasn't then | |
301 | * this is a good indication some task is hogging the cpu | |
302 | */ | |
26e09c6e | 303 | duration = is_softlockup(touch_ts); |
58687acb | 304 | if (unlikely(duration)) { |
5d1c0f4a EM |
305 | /* |
306 | * If a virtual machine is stopped by the host it can look to | |
307 | * the watchdog like a soft lockup, check to see if the host | |
308 | * stopped the vm before we issue the warning | |
309 | */ | |
310 | if (kvm_check_and_clear_guest_paused()) | |
311 | return HRTIMER_RESTART; | |
312 | ||
58687acb | 313 | /* only warn once */ |
909ea964 | 314 | if (__this_cpu_read(soft_watchdog_warn) == true) |
58687acb DZ |
315 | return HRTIMER_RESTART; |
316 | ||
b0f4c4b3 | 317 | printk(KERN_EMERG "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", |
26e09c6e | 318 | smp_processor_id(), duration, |
58687acb DZ |
319 | current->comm, task_pid_nr(current)); |
320 | print_modules(); | |
321 | print_irqtrace_events(current); | |
322 | if (regs) | |
323 | show_regs(regs); | |
324 | else | |
325 | dump_stack(); | |
326 | ||
327 | if (softlockup_panic) | |
328 | panic("softlockup: hung tasks"); | |
909ea964 | 329 | __this_cpu_write(soft_watchdog_warn, true); |
58687acb | 330 | } else |
909ea964 | 331 | __this_cpu_write(soft_watchdog_warn, false); |
58687acb DZ |
332 | |
333 | return HRTIMER_RESTART; | |
334 | } | |
335 | ||
bcd951cf TG |
336 | static void watchdog_set_prio(unsigned int policy, unsigned int prio) |
337 | { | |
338 | struct sched_param param = { .sched_priority = prio }; | |
58687acb | 339 | |
bcd951cf TG |
340 | sched_setscheduler(current, policy, ¶m); |
341 | } | |
342 | ||
343 | static void watchdog_enable(unsigned int cpu) | |
58687acb | 344 | { |
26e09c6e | 345 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); |
58687acb | 346 | |
bcd951cf TG |
347 | if (!watchdog_enabled) { |
348 | kthread_park(current); | |
349 | return; | |
350 | } | |
351 | ||
352 | /* Enable the perf event */ | |
353 | watchdog_nmi_enable(cpu); | |
58687acb DZ |
354 | |
355 | /* kick off the timer for the hardlockup detector */ | |
bcd951cf TG |
356 | hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
357 | hrtimer->function = watchdog_timer_fn; | |
358 | ||
58687acb | 359 | /* done here because hrtimer_start can only pin to smp_processor_id() */ |
0f34c400 | 360 | hrtimer_start(hrtimer, ns_to_ktime(sample_period), |
58687acb DZ |
361 | HRTIMER_MODE_REL_PINNED); |
362 | ||
bcd951cf TG |
363 | /* initialize timestamp */ |
364 | watchdog_set_prio(SCHED_FIFO, MAX_RT_PRIO - 1); | |
365 | __touch_watchdog(); | |
366 | } | |
58687acb | 367 | |
bcd951cf TG |
368 | static void watchdog_disable(unsigned int cpu) |
369 | { | |
370 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); | |
58687acb | 371 | |
8d451690 TG |
372 | if (!watchdog_enabled) |
373 | return; | |
374 | ||
bcd951cf TG |
375 | watchdog_set_prio(SCHED_NORMAL, 0); |
376 | hrtimer_cancel(hrtimer); | |
377 | /* disable the perf event */ | |
378 | watchdog_nmi_disable(cpu); | |
58687acb DZ |
379 | } |
380 | ||
bcd951cf TG |
381 | static int watchdog_should_run(unsigned int cpu) |
382 | { | |
383 | return __this_cpu_read(hrtimer_interrupts) != | |
384 | __this_cpu_read(soft_lockup_hrtimer_cnt); | |
385 | } | |
386 | ||
387 | /* | |
388 | * The watchdog thread function - touches the timestamp. | |
389 | * | |
0f34c400 | 390 | * It only runs once every sample_period seconds (4 seconds by |
bcd951cf TG |
391 | * default) to reset the softlockup timestamp. If this gets delayed |
392 | * for more than 2*watchdog_thresh seconds then the debug-printout | |
393 | * triggers in watchdog_timer_fn(). | |
394 | */ | |
395 | static void watchdog(unsigned int cpu) | |
396 | { | |
397 | __this_cpu_write(soft_lockup_hrtimer_cnt, | |
398 | __this_cpu_read(hrtimer_interrupts)); | |
399 | __touch_watchdog(); | |
400 | } | |
58687acb | 401 | |
23637d47 | 402 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
a7027046 DZ |
403 | /* |
404 | * People like the simple clean cpu node info on boot. | |
405 | * Reduce the watchdog noise by only printing messages | |
406 | * that are different from what cpu0 displayed. | |
407 | */ | |
408 | static unsigned long cpu0_err; | |
409 | ||
bcd951cf | 410 | static int watchdog_nmi_enable(unsigned int cpu) |
58687acb DZ |
411 | { |
412 | struct perf_event_attr *wd_attr; | |
413 | struct perf_event *event = per_cpu(watchdog_ev, cpu); | |
414 | ||
415 | /* is it already setup and enabled? */ | |
416 | if (event && event->state > PERF_EVENT_STATE_OFF) | |
417 | goto out; | |
418 | ||
419 | /* it is setup but not enabled */ | |
420 | if (event != NULL) | |
421 | goto out_enable; | |
422 | ||
58687acb | 423 | wd_attr = &wd_hw_attr; |
4eec42f3 | 424 | wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); |
1880c4ae CG |
425 | |
426 | /* Try to register using hardware perf events */ | |
4dc0da86 | 427 | event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL); |
a7027046 DZ |
428 | |
429 | /* save cpu0 error for future comparision */ | |
430 | if (cpu == 0 && IS_ERR(event)) | |
431 | cpu0_err = PTR_ERR(event); | |
432 | ||
58687acb | 433 | if (!IS_ERR(event)) { |
a7027046 DZ |
434 | /* only print for cpu0 or different than cpu0 */ |
435 | if (cpu == 0 || cpu0_err) | |
436 | pr_info("enabled on all CPUs, permanently consumes one hw-PMU counter.\n"); | |
58687acb DZ |
437 | goto out_save; |
438 | } | |
439 | ||
a7027046 DZ |
440 | /* skip displaying the same error again */ |
441 | if (cpu > 0 && (PTR_ERR(event) == cpu0_err)) | |
442 | return PTR_ERR(event); | |
5651f7f4 DZ |
443 | |
444 | /* vary the KERN level based on the returned errno */ | |
445 | if (PTR_ERR(event) == -EOPNOTSUPP) | |
4501980a | 446 | pr_info("disabled (cpu%i): not supported (no LAPIC?)\n", cpu); |
5651f7f4 | 447 | else if (PTR_ERR(event) == -ENOENT) |
4501980a AM |
448 | pr_warning("disabled (cpu%i): hardware events not enabled\n", |
449 | cpu); | |
5651f7f4 | 450 | else |
4501980a AM |
451 | pr_err("disabled (cpu%i): unable to create perf event: %ld\n", |
452 | cpu, PTR_ERR(event)); | |
eac24335 | 453 | return PTR_ERR(event); |
58687acb DZ |
454 | |
455 | /* success path */ | |
456 | out_save: | |
457 | per_cpu(watchdog_ev, cpu) = event; | |
458 | out_enable: | |
459 | perf_event_enable(per_cpu(watchdog_ev, cpu)); | |
460 | out: | |
461 | return 0; | |
462 | } | |
463 | ||
bcd951cf | 464 | static void watchdog_nmi_disable(unsigned int cpu) |
58687acb DZ |
465 | { |
466 | struct perf_event *event = per_cpu(watchdog_ev, cpu); | |
467 | ||
468 | if (event) { | |
469 | perf_event_disable(event); | |
470 | per_cpu(watchdog_ev, cpu) = NULL; | |
471 | ||
472 | /* should be in cleanup, but blocks oprofile */ | |
473 | perf_event_release_kernel(event); | |
474 | } | |
475 | return; | |
476 | } | |
477 | #else | |
bcd951cf TG |
478 | static int watchdog_nmi_enable(unsigned int cpu) { return 0; } |
479 | static void watchdog_nmi_disable(unsigned int cpu) { return; } | |
23637d47 | 480 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
58687acb DZ |
481 | |
482 | /* prepare/enable/disable routines */ | |
4ff81951 VA |
483 | /* sysctl functions */ |
484 | #ifdef CONFIG_SYSCTL | |
58687acb DZ |
485 | static void watchdog_enable_all_cpus(void) |
486 | { | |
bcd951cf | 487 | unsigned int cpu; |
58687acb | 488 | |
bcd951cf TG |
489 | if (watchdog_disabled) { |
490 | watchdog_disabled = 0; | |
491 | for_each_online_cpu(cpu) | |
492 | kthread_unpark(per_cpu(softlockup_watchdog, cpu)); | |
493 | } | |
58687acb DZ |
494 | } |
495 | ||
496 | static void watchdog_disable_all_cpus(void) | |
497 | { | |
bcd951cf | 498 | unsigned int cpu; |
58687acb | 499 | |
bcd951cf TG |
500 | if (!watchdog_disabled) { |
501 | watchdog_disabled = 1; | |
502 | for_each_online_cpu(cpu) | |
503 | kthread_park(per_cpu(softlockup_watchdog, cpu)); | |
504 | } | |
58687acb DZ |
505 | } |
506 | ||
58687acb | 507 | /* |
586692a5 | 508 | * proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh |
58687acb DZ |
509 | */ |
510 | ||
586692a5 MSB |
511 | int proc_dowatchdog(struct ctl_table *table, int write, |
512 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
58687acb | 513 | { |
e04ab2bc | 514 | int ret; |
58687acb | 515 | |
bcd951cf TG |
516 | if (watchdog_disabled < 0) |
517 | return -ENODEV; | |
518 | ||
586692a5 | 519 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
e04ab2bc | 520 | if (ret || !write) |
bcd951cf | 521 | return ret; |
e04ab2bc | 522 | |
0f34c400 | 523 | set_sample_period(); |
586692a5 | 524 | if (watchdog_enabled && watchdog_thresh) |
e04ab2bc MSB |
525 | watchdog_enable_all_cpus(); |
526 | else | |
527 | watchdog_disable_all_cpus(); | |
528 | ||
e04ab2bc | 529 | return ret; |
58687acb | 530 | } |
58687acb DZ |
531 | #endif /* CONFIG_SYSCTL */ |
532 | ||
bcd951cf TG |
533 | static struct smp_hotplug_thread watchdog_threads = { |
534 | .store = &softlockup_watchdog, | |
535 | .thread_should_run = watchdog_should_run, | |
536 | .thread_fn = watchdog, | |
537 | .thread_comm = "watchdog/%u", | |
538 | .setup = watchdog_enable, | |
539 | .park = watchdog_disable, | |
540 | .unpark = watchdog_enable, | |
58687acb DZ |
541 | }; |
542 | ||
004417a6 | 543 | void __init lockup_detector_init(void) |
58687acb | 544 | { |
0f34c400 | 545 | set_sample_period(); |
bcd951cf TG |
546 | if (smpboot_register_percpu_thread(&watchdog_threads)) { |
547 | pr_err("Failed to create watchdog threads, disabled\n"); | |
548 | watchdog_disabled = -ENODEV; | |
549 | } | |
58687acb | 550 | } |