Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
58687acb DZ |
2 | /* |
3 | * Detect hard and soft lockups on a system | |
4 | * | |
5 | * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. | |
6 | * | |
86f5e6a7 FLVC |
7 | * Note: Most of this code is borrowed heavily from the original softlockup |
8 | * detector, so thanks to Ingo for the initial implementation. | |
9 | * Some chunks also taken from the old x86-specific nmi watchdog code, thanks | |
58687acb DZ |
10 | * to those contributors as well. |
11 | */ | |
12 | ||
5f92a7b0 | 13 | #define pr_fmt(fmt) "watchdog: " fmt |
4501980a | 14 | |
58687acb DZ |
15 | #include <linux/mm.h> |
16 | #include <linux/cpu.h> | |
17 | #include <linux/nmi.h> | |
18 | #include <linux/init.h> | |
58687acb DZ |
19 | #include <linux/module.h> |
20 | #include <linux/sysctl.h> | |
fe4ba3c3 | 21 | #include <linux/tick.h> |
e6017571 | 22 | #include <linux/sched/clock.h> |
b17b0153 | 23 | #include <linux/sched/debug.h> |
78634061 | 24 | #include <linux/sched/isolation.h> |
9cf57731 | 25 | #include <linux/stop_machine.h> |
58687acb DZ |
26 | |
27 | #include <asm/irq_regs.h> | |
5d1c0f4a | 28 | #include <linux/kvm_para.h> |
58687acb | 29 | |
946d1977 | 30 | static DEFINE_MUTEX(watchdog_mutex); |
ab992dc3 | 31 | |
47f4cb43 | 32 | #if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64) |
df95d308 | 33 | # define WATCHDOG_HARDLOCKUP_DEFAULT 1 |
84d56e66 | 34 | #else |
df95d308 | 35 | # define WATCHDOG_HARDLOCKUP_DEFAULT 0 |
84d56e66 | 36 | #endif |
05a4a952 | 37 | |
09154985 TG |
38 | unsigned long __read_mostly watchdog_enabled; |
39 | int __read_mostly watchdog_user_enabled = 1; | |
df95d308 DA |
40 | static int __read_mostly watchdog_hardlockup_user_enabled = WATCHDOG_HARDLOCKUP_DEFAULT; |
41 | static int __read_mostly watchdog_softlockup_user_enabled = 1; | |
7feeb9cd | 42 | int __read_mostly watchdog_thresh = 10; |
df95d308 | 43 | static int __read_mostly watchdog_hardlockup_available; |
7feeb9cd | 44 | |
7feeb9cd TG |
45 | struct cpumask watchdog_cpumask __read_mostly; |
46 | unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask); | |
47 | ||
05a4a952 | 48 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
f117955a GP |
49 | |
50 | # ifdef CONFIG_SMP | |
51 | int __read_mostly sysctl_hardlockup_all_cpu_backtrace; | |
52 | # endif /* CONFIG_SMP */ | |
53 | ||
05a4a952 NP |
54 | /* |
55 | * Should we panic when a soft-lockup or hard-lockup occurs: | |
56 | */ | |
57 | unsigned int __read_mostly hardlockup_panic = | |
67fca000 | 58 | IS_ENABLED(CONFIG_BOOTPARAM_HARDLOCKUP_PANIC); |
05a4a952 NP |
59 | /* |
60 | * We may not want to enable hard lockup detection by default in all cases, | |
61 | * for example when running the kernel as a guest on a hypervisor. In these | |
62 | * cases this function can be called to disable hard lockup detection. This | |
63 | * function should only be executed once by the boot processor before the | |
64 | * kernel command line parameters are parsed, because otherwise it is not | |
65 | * possible to override this in hardlockup_panic_setup(). | |
66 | */ | |
7a355820 | 67 | void __init hardlockup_detector_disable(void) |
05a4a952 | 68 | { |
df95d308 | 69 | watchdog_hardlockup_user_enabled = 0; |
05a4a952 NP |
70 | } |
71 | ||
72 | static int __init hardlockup_panic_setup(char *str) | |
73 | { | |
74 | if (!strncmp(str, "panic", 5)) | |
75 | hardlockup_panic = 1; | |
76 | else if (!strncmp(str, "nopanic", 7)) | |
77 | hardlockup_panic = 0; | |
78 | else if (!strncmp(str, "0", 1)) | |
df95d308 | 79 | watchdog_hardlockup_user_enabled = 0; |
05a4a952 | 80 | else if (!strncmp(str, "1", 1)) |
df95d308 | 81 | watchdog_hardlockup_user_enabled = 1; |
05a4a952 NP |
82 | return 1; |
83 | } | |
84 | __setup("nmi_watchdog=", hardlockup_panic_setup); | |
85 | ||
368a7e2c | 86 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
05a4a952 | 87 | |
1f423c90 | 88 | #if defined(CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER) |
81972551 | 89 | |
77c12fc9 DA |
90 | static DEFINE_PER_CPU(atomic_t, hrtimer_interrupts); |
91 | static DEFINE_PER_CPU(int, hrtimer_interrupts_saved); | |
1610611a | 92 | static DEFINE_PER_CPU(bool, watchdog_hardlockup_warned); |
ed92e1ef | 93 | static DEFINE_PER_CPU(bool, watchdog_hardlockup_touched); |
6dcde5d5 | 94 | static unsigned long hard_lockup_nmi_warn; |
81972551 | 95 | |
ed92e1ef DA |
96 | notrace void arch_touch_nmi_watchdog(void) |
97 | { | |
98 | /* | |
99 | * Using __raw here because some code paths have | |
100 | * preemption enabled. If preemption is enabled | |
101 | * then interrupts should be enabled too, in which | |
102 | * case we shouldn't have to worry about the watchdog | |
103 | * going off. | |
104 | */ | |
105 | raw_cpu_write(watchdog_hardlockup_touched, true); | |
106 | } | |
107 | EXPORT_SYMBOL(arch_touch_nmi_watchdog); | |
108 | ||
1f423c90 DA |
109 | void watchdog_hardlockup_touch_cpu(unsigned int cpu) |
110 | { | |
111 | per_cpu(watchdog_hardlockup_touched, cpu) = true; | |
1f423c90 DA |
112 | } |
113 | ||
77c12fc9 | 114 | static bool is_hardlockup(unsigned int cpu) |
81972551 | 115 | { |
77c12fc9 | 116 | int hrint = atomic_read(&per_cpu(hrtimer_interrupts, cpu)); |
81972551 | 117 | |
77c12fc9 | 118 | if (per_cpu(hrtimer_interrupts_saved, cpu) == hrint) |
81972551 DA |
119 | return true; |
120 | ||
77c12fc9 DA |
121 | /* |
122 | * NOTE: we don't need any fancy atomic_t or READ_ONCE/WRITE_ONCE | |
123 | * for hrtimer_interrupts_saved. hrtimer_interrupts_saved is | |
124 | * written/read by a single CPU. | |
125 | */ | |
126 | per_cpu(hrtimer_interrupts_saved, cpu) = hrint; | |
1610611a | 127 | |
81972551 DA |
128 | return false; |
129 | } | |
130 | ||
d3b62ace | 131 | static void watchdog_hardlockup_kick(void) |
81972551 | 132 | { |
d3b62ace DA |
133 | int new_interrupts; |
134 | ||
135 | new_interrupts = atomic_inc_return(this_cpu_ptr(&hrtimer_interrupts)); | |
136 | watchdog_buddy_check_hardlockup(new_interrupts); | |
81972551 DA |
137 | } |
138 | ||
77c12fc9 | 139 | void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) |
81972551 | 140 | { |
ed92e1ef DA |
141 | if (per_cpu(watchdog_hardlockup_touched, cpu)) { |
142 | per_cpu(watchdog_hardlockup_touched, cpu) = false; | |
143 | return; | |
144 | } | |
145 | ||
1610611a DA |
146 | /* |
147 | * Check for a hardlockup by making sure the CPU's timer | |
148 | * interrupt is incrementing. The timer interrupt should have | |
149 | * fired multiple times before we overflow'd. If it hasn't | |
81972551 DA |
150 | * then this is a good indication the cpu is stuck |
151 | */ | |
77c12fc9 | 152 | if (is_hardlockup(cpu)) { |
1610611a | 153 | unsigned int this_cpu = smp_processor_id(); |
ee6bdb3f | 154 | unsigned long flags; |
81972551 | 155 | |
1610611a | 156 | /* Only print hardlockups once. */ |
77c12fc9 | 157 | if (per_cpu(watchdog_hardlockup_warned, cpu)) |
81972551 DA |
158 | return; |
159 | ||
6dcde5d5 DA |
160 | /* |
161 | * Prevent multiple hard-lockup reports if one cpu is already | |
162 | * engaged in dumping all cpu back traces. | |
163 | */ | |
164 | if (sysctl_hardlockup_all_cpu_backtrace) { | |
165 | if (test_and_set_bit_lock(0, &hard_lockup_nmi_warn)) | |
166 | return; | |
167 | } | |
168 | ||
ee6bdb3f DA |
169 | /* |
170 | * NOTE: we call printk_cpu_sync_get_irqsave() after printing | |
171 | * the lockup message. While it would be nice to serialize | |
172 | * that printout, we really want to make sure that if some | |
173 | * other CPU somehow locked up while holding the lock associated | |
174 | * with printk_cpu_sync_get_irqsave() that we can still at least | |
175 | * get the message about the lockup out. | |
176 | */ | |
77c12fc9 | 177 | pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n", cpu); |
ee6bdb3f DA |
178 | printk_cpu_sync_get_irqsave(flags); |
179 | ||
81972551 DA |
180 | print_modules(); |
181 | print_irqtrace_events(current); | |
77c12fc9 DA |
182 | if (cpu == this_cpu) { |
183 | if (regs) | |
184 | show_regs(regs); | |
185 | else | |
186 | dump_stack(); | |
ee6bdb3f | 187 | printk_cpu_sync_put_irqrestore(flags); |
77c12fc9 | 188 | } else { |
ee6bdb3f | 189 | printk_cpu_sync_put_irqrestore(flags); |
1f38c86b | 190 | trigger_single_cpu_backtrace(cpu); |
77c12fc9 | 191 | } |
81972551 | 192 | |
6dcde5d5 | 193 | if (sysctl_hardlockup_all_cpu_backtrace) { |
1f38c86b | 194 | trigger_allbutcpu_cpu_backtrace(cpu); |
6dcde5d5 DA |
195 | clear_bit_unlock(0, &hard_lockup_nmi_warn); |
196 | } | |
81972551 DA |
197 | |
198 | if (hardlockup_panic) | |
199 | nmi_panic(regs, "Hard LOCKUP"); | |
200 | ||
77c12fc9 | 201 | per_cpu(watchdog_hardlockup_warned, cpu) = true; |
1610611a | 202 | } else { |
77c12fc9 | 203 | per_cpu(watchdog_hardlockup_warned, cpu) = false; |
81972551 | 204 | } |
81972551 DA |
205 | } |
206 | ||
1f423c90 | 207 | #else /* CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */ |
81972551 | 208 | |
d3b62ace | 209 | static inline void watchdog_hardlockup_kick(void) { } |
81972551 | 210 | |
1f423c90 | 211 | #endif /* !CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */ |
81972551 | 212 | |
05a4a952 | 213 | /* |
d9b3629a | 214 | * These functions can be overridden based on the configured hardlockdup detector. |
a10a842f | 215 | * |
df95d308 | 216 | * watchdog_hardlockup_enable/disable can be implemented to start and stop when |
d9b3629a | 217 | * softlockup watchdog start and stop. The detector must select the |
a10a842f | 218 | * SOFTLOCKUP_DETECTOR Kconfig. |
05a4a952 | 219 | */ |
d9b3629a | 220 | void __weak watchdog_hardlockup_enable(unsigned int cpu) { } |
941154bd | 221 | |
d9b3629a | 222 | void __weak watchdog_hardlockup_disable(unsigned int cpu) { } |
05a4a952 | 223 | |
930d8f8d LC |
224 | /* |
225 | * Watchdog-detector specific API. | |
226 | * | |
227 | * Return 0 when hardlockup watchdog is available, negative value otherwise. | |
228 | * Note that the negative value means that a delayed probe might | |
229 | * succeed later. | |
230 | */ | |
df95d308 | 231 | int __weak __init watchdog_hardlockup_probe(void) |
a994a314 | 232 | { |
d9b3629a | 233 | return -ENODEV; |
a994a314 TG |
234 | } |
235 | ||
6592ad2f | 236 | /** |
df95d308 | 237 | * watchdog_hardlockup_stop - Stop the watchdog for reconfiguration |
6592ad2f | 238 | * |
6b9dc480 | 239 | * The reconfiguration steps are: |
df95d308 | 240 | * watchdog_hardlockup_stop(); |
6592ad2f | 241 | * update_variables(); |
df95d308 | 242 | * watchdog_hardlockup_start(); |
6b9dc480 | 243 | */ |
df95d308 | 244 | void __weak watchdog_hardlockup_stop(void) { } |
6b9dc480 TG |
245 | |
246 | /** | |
df95d308 | 247 | * watchdog_hardlockup_start - Start the watchdog after reconfiguration |
6592ad2f | 248 | * |
df95d308 | 249 | * Counterpart to watchdog_hardlockup_stop(). |
6b9dc480 TG |
250 | * |
251 | * The following variables have been updated in update_variables() and | |
252 | * contain the currently valid configuration: | |
7feeb9cd | 253 | * - watchdog_enabled |
a10a842f NP |
254 | * - watchdog_thresh |
255 | * - watchdog_cpumask | |
a10a842f | 256 | */ |
df95d308 | 257 | void __weak watchdog_hardlockup_start(void) { } |
a10a842f | 258 | |
09154985 TG |
259 | /** |
260 | * lockup_detector_update_enable - Update the sysctl enable bit | |
261 | * | |
df95d308 DA |
262 | * Caller needs to make sure that the hard watchdogs are off, so this |
263 | * can't race with watchdog_hardlockup_disable(). | |
09154985 TG |
264 | */ |
265 | static void lockup_detector_update_enable(void) | |
266 | { | |
267 | watchdog_enabled = 0; | |
268 | if (!watchdog_user_enabled) | |
269 | return; | |
df95d308 DA |
270 | if (watchdog_hardlockup_available && watchdog_hardlockup_user_enabled) |
271 | watchdog_enabled |= WATCHDOG_HARDLOCKUP_ENABLED; | |
272 | if (watchdog_softlockup_user_enabled) | |
273 | watchdog_enabled |= WATCHDOG_SOFTOCKUP_ENABLED; | |
09154985 TG |
274 | } |
275 | ||
05a4a952 NP |
276 | #ifdef CONFIG_SOFTLOCKUP_DETECTOR |
277 | ||
fef06efc PM |
278 | /* |
279 | * Delay the soflockup report when running a known slow code. | |
280 | * It does _not_ affect the timestamp of the last successdul reschedule. | |
281 | */ | |
282 | #define SOFTLOCKUP_DELAY_REPORT ULONG_MAX | |
11e31f60 | 283 | |
f117955a GP |
284 | #ifdef CONFIG_SMP |
285 | int __read_mostly sysctl_softlockup_all_cpu_backtrace; | |
286 | #endif | |
287 | ||
e7e04615 SS |
288 | static struct cpumask watchdog_allowed_mask __read_mostly; |
289 | ||
2b9d7f23 TG |
290 | /* Global variables, exported for sysctl */ |
291 | unsigned int __read_mostly softlockup_panic = | |
67fca000 | 292 | IS_ENABLED(CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC); |
2eb2527f | 293 | |
9cf57731 | 294 | static bool softlockup_initialized __read_mostly; |
0f34c400 | 295 | static u64 __read_mostly sample_period; |
58687acb | 296 | |
fef06efc | 297 | /* Timestamp taken after the last successful reschedule. */ |
58687acb | 298 | static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts); |
fef06efc PM |
299 | /* Timestamp of the last softlockup report. */ |
300 | static DEFINE_PER_CPU(unsigned long, watchdog_report_ts); | |
58687acb DZ |
301 | static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer); |
302 | static DEFINE_PER_CPU(bool, softlockup_touch_sync); | |
ed235875 | 303 | static unsigned long soft_lockup_nmi_warn; |
58687acb | 304 | |
8b793bcd KJ |
305 | static int __init softlockup_panic_setup(char *str) |
306 | { | |
307 | softlockup_panic = simple_strtoul(str, NULL, 0); | |
308 | return 1; | |
309 | } | |
310 | __setup("softlockup_panic=", softlockup_panic_setup); | |
311 | ||
58687acb DZ |
312 | static int __init nowatchdog_setup(char *str) |
313 | { | |
09154985 | 314 | watchdog_user_enabled = 0; |
58687acb DZ |
315 | return 1; |
316 | } | |
317 | __setup("nowatchdog", nowatchdog_setup); | |
318 | ||
58687acb DZ |
319 | static int __init nosoftlockup_setup(char *str) |
320 | { | |
df95d308 | 321 | watchdog_softlockup_user_enabled = 0; |
58687acb DZ |
322 | return 1; |
323 | } | |
324 | __setup("nosoftlockup", nosoftlockup_setup); | |
195daf66 | 325 | |
11295055 LO |
326 | static int __init watchdog_thresh_setup(char *str) |
327 | { | |
328 | get_option(&str, &watchdog_thresh); | |
329 | return 1; | |
330 | } | |
331 | __setup("watchdog_thresh=", watchdog_thresh_setup); | |
332 | ||
941154bd TG |
333 | static void __lockup_detector_cleanup(void); |
334 | ||
4eec42f3 MSB |
335 | /* |
336 | * Hard-lockup warnings should be triggered after just a few seconds. Soft- | |
337 | * lockups can have false positives under extreme conditions. So we generally | |
338 | * want a higher threshold for soft lockups than for hard lockups. So we couple | |
339 | * the thresholds with a factor: we make the soft threshold twice the amount of | |
340 | * time the hard threshold is. | |
341 | */ | |
6e9101ae | 342 | static int get_softlockup_thresh(void) |
4eec42f3 MSB |
343 | { |
344 | return watchdog_thresh * 2; | |
345 | } | |
58687acb DZ |
346 | |
347 | /* | |
348 | * Returns seconds, approximately. We don't need nanosecond | |
349 | * resolution, and we don't need to waste time with a big divide when | |
350 | * 2^30ns == 1.074s. | |
351 | */ | |
c06b4f19 | 352 | static unsigned long get_timestamp(void) |
58687acb | 353 | { |
545a2bf7 | 354 | return running_clock() >> 30LL; /* 2^30 ~= 10^9 */ |
58687acb DZ |
355 | } |
356 | ||
0f34c400 | 357 | static void set_sample_period(void) |
58687acb DZ |
358 | { |
359 | /* | |
586692a5 | 360 | * convert watchdog_thresh from seconds to ns |
86f5e6a7 FLVC |
361 | * the divide by 5 is to give hrtimer several chances (two |
362 | * or three with the current relation between the soft | |
363 | * and hard thresholds) to increment before the | |
364 | * hardlockup detector generates a warning | |
58687acb | 365 | */ |
0f34c400 | 366 | sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5); |
7edaeb68 | 367 | watchdog_update_hrtimer_threshold(sample_period); |
58687acb DZ |
368 | } |
369 | ||
fef06efc PM |
370 | static void update_report_ts(void) |
371 | { | |
372 | __this_cpu_write(watchdog_report_ts, get_timestamp()); | |
373 | } | |
374 | ||
58687acb | 375 | /* Commands for resetting the watchdog */ |
7c0012f5 | 376 | static void update_touch_ts(void) |
58687acb | 377 | { |
c06b4f19 | 378 | __this_cpu_write(watchdog_touch_ts, get_timestamp()); |
fef06efc | 379 | update_report_ts(); |
58687acb DZ |
380 | } |
381 | ||
03e0d461 TH |
382 | /** |
383 | * touch_softlockup_watchdog_sched - touch watchdog on scheduler stalls | |
384 | * | |
385 | * Call when the scheduler may have stalled for legitimate reasons | |
386 | * preventing the watchdog task from executing - e.g. the scheduler | |
387 | * entering idle state. This should only be used for scheduler events. | |
388 | * Use touch_softlockup_watchdog() for everything else. | |
389 | */ | |
cb9d7fd5 | 390 | notrace void touch_softlockup_watchdog_sched(void) |
58687acb | 391 | { |
7861144b | 392 | /* |
fef06efc PM |
393 | * Preemption can be enabled. It doesn't matter which CPU's watchdog |
394 | * report period gets restarted here, so use the raw_ operation. | |
7861144b | 395 | */ |
fef06efc | 396 | raw_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT); |
58687acb | 397 | } |
03e0d461 | 398 | |
cb9d7fd5 | 399 | notrace void touch_softlockup_watchdog(void) |
03e0d461 TH |
400 | { |
401 | touch_softlockup_watchdog_sched(); | |
82607adc | 402 | wq_watchdog_touch(raw_smp_processor_id()); |
03e0d461 | 403 | } |
0167c781 | 404 | EXPORT_SYMBOL(touch_softlockup_watchdog); |
58687acb | 405 | |
332fbdbc | 406 | void touch_all_softlockup_watchdogs(void) |
58687acb DZ |
407 | { |
408 | int cpu; | |
409 | ||
410 | /* | |
d57108d4 TG |
411 | * watchdog_mutex cannpt be taken here, as this might be called |
412 | * from (soft)interrupt context, so the access to | |
413 | * watchdog_allowed_cpumask might race with a concurrent update. | |
414 | * | |
415 | * The watchdog time stamp can race against a concurrent real | |
416 | * update as well, the only side effect might be a cycle delay for | |
417 | * the softlockup check. | |
58687acb | 418 | */ |
89e28ce6 | 419 | for_each_cpu(cpu, &watchdog_allowed_mask) { |
fef06efc | 420 | per_cpu(watchdog_report_ts, cpu) = SOFTLOCKUP_DELAY_REPORT; |
89e28ce6 WQ |
421 | wq_watchdog_touch(cpu); |
422 | } | |
58687acb DZ |
423 | } |
424 | ||
58687acb DZ |
425 | void touch_softlockup_watchdog_sync(void) |
426 | { | |
f7f66b05 | 427 | __this_cpu_write(softlockup_touch_sync, true); |
fef06efc | 428 | __this_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT); |
58687acb DZ |
429 | } |
430 | ||
0f90b88d PM |
431 | static int is_softlockup(unsigned long touch_ts, |
432 | unsigned long period_ts, | |
433 | unsigned long now) | |
58687acb | 434 | { |
df95d308 | 435 | if ((watchdog_enabled & WATCHDOG_SOFTOCKUP_ENABLED) && watchdog_thresh) { |
195daf66 | 436 | /* Warn about unreasonable delays. */ |
fef06efc | 437 | if (time_after(now, period_ts + get_softlockup_thresh())) |
195daf66 UO |
438 | return now - touch_ts; |
439 | } | |
58687acb DZ |
440 | return 0; |
441 | } | |
442 | ||
05a4a952 | 443 | /* watchdog detector functions */ |
be45bf53 PZ |
444 | static DEFINE_PER_CPU(struct completion, softlockup_completion); |
445 | static DEFINE_PER_CPU(struct cpu_stop_work, softlockup_stop_work); | |
446 | ||
9cf57731 | 447 | /* |
b124ac45 | 448 | * The watchdog feed function - touches the timestamp. |
9cf57731 PZ |
449 | * |
450 | * It only runs once every sample_period seconds (4 seconds by | |
451 | * default) to reset the softlockup timestamp. If this gets delayed | |
452 | * for more than 2*watchdog_thresh seconds then the debug-printout | |
453 | * triggers in watchdog_timer_fn(). | |
454 | */ | |
455 | static int softlockup_fn(void *data) | |
456 | { | |
7c0012f5 | 457 | update_touch_ts(); |
be45bf53 | 458 | complete(this_cpu_ptr(&softlockup_completion)); |
9cf57731 PZ |
459 | |
460 | return 0; | |
461 | } | |
462 | ||
58687acb DZ |
463 | /* watchdog kicker functions */ |
464 | static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) | |
465 | { | |
0f90b88d | 466 | unsigned long touch_ts, period_ts, now; |
58687acb DZ |
467 | struct pt_regs *regs = get_irq_regs(); |
468 | int duration; | |
ed235875 | 469 | int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace; |
896260a6 | 470 | unsigned long flags; |
58687acb | 471 | |
01f0a027 | 472 | if (!watchdog_enabled) |
b94f5118 DZ |
473 | return HRTIMER_NORESTART; |
474 | ||
d3b62ace | 475 | watchdog_hardlockup_kick(); |
58687acb DZ |
476 | |
477 | /* kick the softlockup detector */ | |
be45bf53 PZ |
478 | if (completion_done(this_cpu_ptr(&softlockup_completion))) { |
479 | reinit_completion(this_cpu_ptr(&softlockup_completion)); | |
480 | stop_one_cpu_nowait(smp_processor_id(), | |
481 | softlockup_fn, NULL, | |
482 | this_cpu_ptr(&softlockup_stop_work)); | |
483 | } | |
58687acb DZ |
484 | |
485 | /* .. and repeat */ | |
0f34c400 | 486 | hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period)); |
58687acb | 487 | |
0f90b88d PM |
488 | /* |
489 | * Read the current timestamp first. It might become invalid anytime | |
490 | * when a virtual machine is stopped by the host or when the watchog | |
491 | * is touched from NMI. | |
492 | */ | |
493 | now = get_timestamp(); | |
9bf3bc94 PM |
494 | /* |
495 | * If a virtual machine is stopped by the host it can look to | |
0f90b88d | 496 | * the watchdog like a soft lockup. This function touches the watchdog. |
9bf3bc94 PM |
497 | */ |
498 | kvm_check_and_clear_guest_paused(); | |
0f90b88d PM |
499 | /* |
500 | * The stored timestamp is comparable with @now only when not touched. | |
501 | * It might get touched anytime from NMI. Make sure that is_softlockup() | |
502 | * uses the same (valid) value. | |
503 | */ | |
504 | period_ts = READ_ONCE(*this_cpu_ptr(&watchdog_report_ts)); | |
9bf3bc94 PM |
505 | |
506 | /* Reset the interval when touched by known problematic code. */ | |
fef06efc | 507 | if (period_ts == SOFTLOCKUP_DELAY_REPORT) { |
909ea964 | 508 | if (unlikely(__this_cpu_read(softlockup_touch_sync))) { |
58687acb DZ |
509 | /* |
510 | * If the time stamp was touched atomically | |
511 | * make sure the scheduler tick is up to date. | |
512 | */ | |
909ea964 | 513 | __this_cpu_write(softlockup_touch_sync, false); |
58687acb DZ |
514 | sched_clock_tick(); |
515 | } | |
5d1c0f4a | 516 | |
fef06efc | 517 | update_report_ts(); |
58687acb DZ |
518 | return HRTIMER_RESTART; |
519 | } | |
520 | ||
0f90b88d PM |
521 | /* Check for a softlockup. */ |
522 | touch_ts = __this_cpu_read(watchdog_touch_ts); | |
523 | duration = is_softlockup(touch_ts, period_ts, now); | |
58687acb | 524 | if (unlikely(duration)) { |
9f113bf7 PM |
525 | /* |
526 | * Prevent multiple soft-lockup reports if one cpu is already | |
527 | * engaged in dumping all cpu back traces. | |
528 | */ | |
ed235875 | 529 | if (softlockup_all_cpu_backtrace) { |
9f113bf7 | 530 | if (test_and_set_bit_lock(0, &soft_lockup_nmi_warn)) |
ed235875 | 531 | return HRTIMER_RESTART; |
ed235875 AT |
532 | } |
533 | ||
c9ad17c9 | 534 | /* Start period for the next softlockup warning. */ |
fef06efc | 535 | update_report_ts(); |
c9ad17c9 | 536 | |
896260a6 | 537 | printk_cpu_sync_get_irqsave(flags); |
656c3b79 | 538 | pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", |
26e09c6e | 539 | smp_processor_id(), duration, |
58687acb DZ |
540 | current->comm, task_pid_nr(current)); |
541 | print_modules(); | |
542 | print_irqtrace_events(current); | |
543 | if (regs) | |
544 | show_regs(regs); | |
545 | else | |
546 | dump_stack(); | |
896260a6 | 547 | printk_cpu_sync_put_irqrestore(flags); |
58687acb | 548 | |
ed235875 | 549 | if (softlockup_all_cpu_backtrace) { |
8d539b84 | 550 | trigger_allbutcpu_cpu_backtrace(smp_processor_id()); |
9f113bf7 | 551 | clear_bit_unlock(0, &soft_lockup_nmi_warn); |
ed235875 AT |
552 | } |
553 | ||
69361eef | 554 | add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK); |
58687acb DZ |
555 | if (softlockup_panic) |
556 | panic("softlockup: hung tasks"); | |
1bc503cb | 557 | } |
58687acb DZ |
558 | |
559 | return HRTIMER_RESTART; | |
560 | } | |
561 | ||
bcd951cf | 562 | static void watchdog_enable(unsigned int cpu) |
58687acb | 563 | { |
01f0a027 | 564 | struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer); |
be45bf53 | 565 | struct completion *done = this_cpu_ptr(&softlockup_completion); |
58687acb | 566 | |
9cf57731 PZ |
567 | WARN_ON_ONCE(cpu != smp_processor_id()); |
568 | ||
be45bf53 PZ |
569 | init_completion(done); |
570 | complete(done); | |
571 | ||
01f0a027 | 572 | /* |
df95d308 | 573 | * Start the timer first to prevent the hardlockup watchdog triggering |
01f0a027 TG |
574 | * before the timer has a chance to fire. |
575 | */ | |
d2ab4cf4 | 576 | hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
3935e895 | 577 | hrtimer->function = watchdog_timer_fn; |
01f0a027 | 578 | hrtimer_start(hrtimer, ns_to_ktime(sample_period), |
d2ab4cf4 | 579 | HRTIMER_MODE_REL_PINNED_HARD); |
3935e895 | 580 | |
01f0a027 | 581 | /* Initialize timestamp */ |
7c0012f5 | 582 | update_touch_ts(); |
df95d308 DA |
583 | /* Enable the hardlockup detector */ |
584 | if (watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED) | |
585 | watchdog_hardlockup_enable(cpu); | |
bcd951cf | 586 | } |
58687acb | 587 | |
bcd951cf TG |
588 | static void watchdog_disable(unsigned int cpu) |
589 | { | |
01f0a027 | 590 | struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer); |
58687acb | 591 | |
9cf57731 PZ |
592 | WARN_ON_ONCE(cpu != smp_processor_id()); |
593 | ||
01f0a027 | 594 | /* |
df95d308 DA |
595 | * Disable the hardlockup detector first. That prevents that a large |
596 | * delay between disabling the timer and disabling the hardlockup | |
597 | * detector causes a false positive. | |
01f0a027 | 598 | */ |
df95d308 | 599 | watchdog_hardlockup_disable(cpu); |
01f0a027 | 600 | hrtimer_cancel(hrtimer); |
be45bf53 | 601 | wait_for_completion(this_cpu_ptr(&softlockup_completion)); |
58687acb DZ |
602 | } |
603 | ||
9cf57731 | 604 | static int softlockup_stop_fn(void *data) |
b8900bc0 | 605 | { |
9cf57731 PZ |
606 | watchdog_disable(smp_processor_id()); |
607 | return 0; | |
b8900bc0 FW |
608 | } |
609 | ||
9cf57731 | 610 | static void softlockup_stop_all(void) |
bcd951cf | 611 | { |
9cf57731 PZ |
612 | int cpu; |
613 | ||
614 | if (!softlockup_initialized) | |
615 | return; | |
616 | ||
617 | for_each_cpu(cpu, &watchdog_allowed_mask) | |
618 | smp_call_on_cpu(cpu, softlockup_stop_fn, NULL, false); | |
619 | ||
620 | cpumask_clear(&watchdog_allowed_mask); | |
bcd951cf TG |
621 | } |
622 | ||
9cf57731 | 623 | static int softlockup_start_fn(void *data) |
bcd951cf | 624 | { |
9cf57731 PZ |
625 | watchdog_enable(smp_processor_id()); |
626 | return 0; | |
bcd951cf | 627 | } |
58687acb | 628 | |
9cf57731 | 629 | static void softlockup_start_all(void) |
2eb2527f | 630 | { |
9cf57731 | 631 | int cpu; |
2eb2527f | 632 | |
9cf57731 PZ |
633 | cpumask_copy(&watchdog_allowed_mask, &watchdog_cpumask); |
634 | for_each_cpu(cpu, &watchdog_allowed_mask) | |
635 | smp_call_on_cpu(cpu, softlockup_start_fn, NULL, false); | |
2eb2527f TG |
636 | } |
637 | ||
9cf57731 | 638 | int lockup_detector_online_cpu(unsigned int cpu) |
2eb2527f | 639 | { |
7dd47617 TG |
640 | if (cpumask_test_cpu(cpu, &watchdog_allowed_mask)) |
641 | watchdog_enable(cpu); | |
9cf57731 | 642 | return 0; |
2eb2527f TG |
643 | } |
644 | ||
9cf57731 | 645 | int lockup_detector_offline_cpu(unsigned int cpu) |
2eb2527f | 646 | { |
7dd47617 TG |
647 | if (cpumask_test_cpu(cpu, &watchdog_allowed_mask)) |
648 | watchdog_disable(cpu); | |
9cf57731 | 649 | return 0; |
2eb2527f TG |
650 | } |
651 | ||
7c56a873 | 652 | static void __lockup_detector_reconfigure(void) |
2eb2527f | 653 | { |
e31d6883 | 654 | cpus_read_lock(); |
df95d308 | 655 | watchdog_hardlockup_stop(); |
9cf57731 PZ |
656 | |
657 | softlockup_stop_all(); | |
2eb2527f | 658 | set_sample_period(); |
09154985 TG |
659 | lockup_detector_update_enable(); |
660 | if (watchdog_enabled && watchdog_thresh) | |
9cf57731 PZ |
661 | softlockup_start_all(); |
662 | ||
df95d308 | 663 | watchdog_hardlockup_start(); |
e31d6883 TG |
664 | cpus_read_unlock(); |
665 | /* | |
666 | * Must be called outside the cpus locked section to prevent | |
667 | * recursive locking in the perf code. | |
668 | */ | |
669 | __lockup_detector_cleanup(); | |
2eb2527f TG |
670 | } |
671 | ||
7c56a873 LD |
672 | void lockup_detector_reconfigure(void) |
673 | { | |
674 | mutex_lock(&watchdog_mutex); | |
675 | __lockup_detector_reconfigure(); | |
676 | mutex_unlock(&watchdog_mutex); | |
677 | } | |
678 | ||
2eb2527f | 679 | /* |
b124ac45 | 680 | * Create the watchdog infrastructure and configure the detector(s). |
2eb2527f | 681 | */ |
5587185d | 682 | static __init void lockup_detector_setup(void) |
2eb2527f | 683 | { |
2eb2527f TG |
684 | /* |
685 | * If sysctl is off and watchdog got disabled on the command line, | |
686 | * nothing to do here. | |
687 | */ | |
09154985 TG |
688 | lockup_detector_update_enable(); |
689 | ||
2eb2527f TG |
690 | if (!IS_ENABLED(CONFIG_SYSCTL) && |
691 | !(watchdog_enabled && watchdog_thresh)) | |
692 | return; | |
693 | ||
2eb2527f | 694 | mutex_lock(&watchdog_mutex); |
7c56a873 | 695 | __lockup_detector_reconfigure(); |
9cf57731 | 696 | softlockup_initialized = true; |
2eb2527f TG |
697 | mutex_unlock(&watchdog_mutex); |
698 | } | |
699 | ||
2b9d7f23 | 700 | #else /* CONFIG_SOFTLOCKUP_DETECTOR */ |
7c56a873 | 701 | static void __lockup_detector_reconfigure(void) |
6592ad2f | 702 | { |
e31d6883 | 703 | cpus_read_lock(); |
df95d308 | 704 | watchdog_hardlockup_stop(); |
09154985 | 705 | lockup_detector_update_enable(); |
df95d308 | 706 | watchdog_hardlockup_start(); |
e31d6883 | 707 | cpus_read_unlock(); |
6592ad2f | 708 | } |
7c56a873 LD |
709 | void lockup_detector_reconfigure(void) |
710 | { | |
711 | __lockup_detector_reconfigure(); | |
712 | } | |
5587185d | 713 | static inline void lockup_detector_setup(void) |
34ddaa3e | 714 | { |
7c56a873 | 715 | __lockup_detector_reconfigure(); |
34ddaa3e | 716 | } |
2b9d7f23 | 717 | #endif /* !CONFIG_SOFTLOCKUP_DETECTOR */ |
05a4a952 | 718 | |
941154bd TG |
719 | static void __lockup_detector_cleanup(void) |
720 | { | |
721 | lockdep_assert_held(&watchdog_mutex); | |
722 | hardlockup_detector_perf_cleanup(); | |
723 | } | |
724 | ||
725 | /** | |
726 | * lockup_detector_cleanup - Cleanup after cpu hotplug or sysctl changes | |
727 | * | |
728 | * Caller must not hold the cpu hotplug rwsem. | |
729 | */ | |
730 | void lockup_detector_cleanup(void) | |
731 | { | |
732 | mutex_lock(&watchdog_mutex); | |
733 | __lockup_detector_cleanup(); | |
734 | mutex_unlock(&watchdog_mutex); | |
735 | } | |
736 | ||
6554fd8c TG |
737 | /** |
738 | * lockup_detector_soft_poweroff - Interface to stop lockup detector(s) | |
739 | * | |
740 | * Special interface for parisc. It prevents lockup detector warnings from | |
741 | * the default pm_poweroff() function which busy loops forever. | |
742 | */ | |
743 | void lockup_detector_soft_poweroff(void) | |
744 | { | |
745 | watchdog_enabled = 0; | |
746 | } | |
747 | ||
58cf690a UO |
748 | #ifdef CONFIG_SYSCTL |
749 | ||
b124ac45 | 750 | /* Propagate any changes to the watchdog infrastructure */ |
d57108d4 | 751 | static void proc_watchdog_update(void) |
a0c9cbb9 | 752 | { |
e8b62b2d TG |
753 | /* Remove impossible cpus to keep sysctl output clean. */ |
754 | cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask); | |
7c56a873 | 755 | __lockup_detector_reconfigure(); |
a0c9cbb9 UO |
756 | } |
757 | ||
ef246a21 UO |
758 | /* |
759 | * common function for watchdog, nmi_watchdog and soft_watchdog parameter | |
760 | * | |
df95d308 DA |
761 | * caller | table->data points to | 'which' |
762 | * -------------------|----------------------------------|------------------------------- | |
763 | * proc_watchdog | watchdog_user_enabled | WATCHDOG_HARDLOCKUP_ENABLED | | |
764 | * | | WATCHDOG_SOFTOCKUP_ENABLED | |
765 | * -------------------|----------------------------------|------------------------------- | |
766 | * proc_nmi_watchdog | watchdog_hardlockup_user_enabled | WATCHDOG_HARDLOCKUP_ENABLED | |
767 | * -------------------|----------------------------------|------------------------------- | |
768 | * proc_soft_watchdog | watchdog_softlockup_user_enabled | WATCHDOG_SOFTOCKUP_ENABLED | |
ef246a21 UO |
769 | */ |
770 | static int proc_watchdog_common(int which, struct ctl_table *table, int write, | |
32927393 | 771 | void *buffer, size_t *lenp, loff_t *ppos) |
ef246a21 | 772 | { |
09154985 | 773 | int err, old, *param = table->data; |
ef246a21 | 774 | |
946d1977 | 775 | mutex_lock(&watchdog_mutex); |
ef246a21 | 776 | |
ef246a21 | 777 | if (!write) { |
09154985 TG |
778 | /* |
779 | * On read synchronize the userspace interface. This is a | |
780 | * racy snapshot. | |
781 | */ | |
782 | *param = (watchdog_enabled & which) != 0; | |
ef246a21 UO |
783 | err = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
784 | } else { | |
09154985 | 785 | old = READ_ONCE(*param); |
ef246a21 | 786 | err = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
09154985 | 787 | if (!err && old != READ_ONCE(*param)) |
d57108d4 | 788 | proc_watchdog_update(); |
ef246a21 | 789 | } |
946d1977 | 790 | mutex_unlock(&watchdog_mutex); |
ef246a21 UO |
791 | return err; |
792 | } | |
793 | ||
83a80a39 UO |
794 | /* |
795 | * /proc/sys/kernel/watchdog | |
796 | */ | |
797 | int proc_watchdog(struct ctl_table *table, int write, | |
32927393 | 798 | void *buffer, size_t *lenp, loff_t *ppos) |
83a80a39 | 799 | { |
df95d308 DA |
800 | return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED | |
801 | WATCHDOG_SOFTOCKUP_ENABLED, | |
83a80a39 UO |
802 | table, write, buffer, lenp, ppos); |
803 | } | |
804 | ||
805 | /* | |
806 | * /proc/sys/kernel/nmi_watchdog | |
58687acb | 807 | */ |
83a80a39 | 808 | int proc_nmi_watchdog(struct ctl_table *table, int write, |
32927393 | 809 | void *buffer, size_t *lenp, loff_t *ppos) |
83a80a39 | 810 | { |
df95d308 | 811 | if (!watchdog_hardlockup_available && write) |
a994a314 | 812 | return -ENOTSUPP; |
df95d308 | 813 | return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED, |
83a80a39 UO |
814 | table, write, buffer, lenp, ppos); |
815 | } | |
816 | ||
817 | /* | |
818 | * /proc/sys/kernel/soft_watchdog | |
819 | */ | |
820 | int proc_soft_watchdog(struct ctl_table *table, int write, | |
32927393 | 821 | void *buffer, size_t *lenp, loff_t *ppos) |
83a80a39 | 822 | { |
df95d308 | 823 | return proc_watchdog_common(WATCHDOG_SOFTOCKUP_ENABLED, |
83a80a39 UO |
824 | table, write, buffer, lenp, ppos); |
825 | } | |
58687acb | 826 | |
83a80a39 UO |
827 | /* |
828 | * /proc/sys/kernel/watchdog_thresh | |
829 | */ | |
830 | int proc_watchdog_thresh(struct ctl_table *table, int write, | |
32927393 | 831 | void *buffer, size_t *lenp, loff_t *ppos) |
58687acb | 832 | { |
d57108d4 | 833 | int err, old; |
58687acb | 834 | |
946d1977 | 835 | mutex_lock(&watchdog_mutex); |
bcd951cf | 836 | |
d57108d4 | 837 | old = READ_ONCE(watchdog_thresh); |
b8900bc0 | 838 | err = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
83a80a39 | 839 | |
d57108d4 TG |
840 | if (!err && write && old != READ_ONCE(watchdog_thresh)) |
841 | proc_watchdog_update(); | |
e04ab2bc | 842 | |
946d1977 | 843 | mutex_unlock(&watchdog_mutex); |
b8900bc0 | 844 | return err; |
58687acb | 845 | } |
fe4ba3c3 CM |
846 | |
847 | /* | |
848 | * The cpumask is the mask of possible cpus that the watchdog can run | |
849 | * on, not the mask of cpus it is actually running on. This allows the | |
850 | * user to specify a mask that will include cpus that have not yet | |
851 | * been brought online, if desired. | |
852 | */ | |
853 | int proc_watchdog_cpumask(struct ctl_table *table, int write, | |
32927393 | 854 | void *buffer, size_t *lenp, loff_t *ppos) |
fe4ba3c3 CM |
855 | { |
856 | int err; | |
857 | ||
946d1977 | 858 | mutex_lock(&watchdog_mutex); |
8c073d27 | 859 | |
fe4ba3c3 | 860 | err = proc_do_large_bitmap(table, write, buffer, lenp, ppos); |
05ba3de7 | 861 | if (!err && write) |
e8b62b2d | 862 | proc_watchdog_update(); |
5490125d | 863 | |
946d1977 | 864 | mutex_unlock(&watchdog_mutex); |
fe4ba3c3 CM |
865 | return err; |
866 | } | |
dd0693fd XN |
867 | |
868 | static const int sixty = 60; | |
869 | ||
870 | static struct ctl_table watchdog_sysctls[] = { | |
871 | { | |
872 | .procname = "watchdog", | |
873 | .data = &watchdog_user_enabled, | |
874 | .maxlen = sizeof(int), | |
875 | .mode = 0644, | |
876 | .proc_handler = proc_watchdog, | |
877 | .extra1 = SYSCTL_ZERO, | |
878 | .extra2 = SYSCTL_ONE, | |
879 | }, | |
880 | { | |
881 | .procname = "watchdog_thresh", | |
882 | .data = &watchdog_thresh, | |
883 | .maxlen = sizeof(int), | |
884 | .mode = 0644, | |
885 | .proc_handler = proc_watchdog_thresh, | |
886 | .extra1 = SYSCTL_ZERO, | |
887 | .extra2 = (void *)&sixty, | |
888 | }, | |
dd0693fd XN |
889 | { |
890 | .procname = "watchdog_cpumask", | |
891 | .data = &watchdog_cpumask_bits, | |
892 | .maxlen = NR_CPUS, | |
893 | .mode = 0644, | |
894 | .proc_handler = proc_watchdog_cpumask, | |
895 | }, | |
896 | #ifdef CONFIG_SOFTLOCKUP_DETECTOR | |
897 | { | |
898 | .procname = "soft_watchdog", | |
df95d308 | 899 | .data = &watchdog_softlockup_user_enabled, |
dd0693fd XN |
900 | .maxlen = sizeof(int), |
901 | .mode = 0644, | |
902 | .proc_handler = proc_soft_watchdog, | |
903 | .extra1 = SYSCTL_ZERO, | |
904 | .extra2 = SYSCTL_ONE, | |
905 | }, | |
906 | { | |
907 | .procname = "softlockup_panic", | |
908 | .data = &softlockup_panic, | |
909 | .maxlen = sizeof(int), | |
910 | .mode = 0644, | |
911 | .proc_handler = proc_dointvec_minmax, | |
912 | .extra1 = SYSCTL_ZERO, | |
913 | .extra2 = SYSCTL_ONE, | |
914 | }, | |
915 | #ifdef CONFIG_SMP | |
916 | { | |
917 | .procname = "softlockup_all_cpu_backtrace", | |
918 | .data = &sysctl_softlockup_all_cpu_backtrace, | |
919 | .maxlen = sizeof(int), | |
920 | .mode = 0644, | |
921 | .proc_handler = proc_dointvec_minmax, | |
922 | .extra1 = SYSCTL_ZERO, | |
923 | .extra2 = SYSCTL_ONE, | |
924 | }, | |
925 | #endif /* CONFIG_SMP */ | |
926 | #endif | |
927 | #ifdef CONFIG_HARDLOCKUP_DETECTOR | |
928 | { | |
929 | .procname = "hardlockup_panic", | |
930 | .data = &hardlockup_panic, | |
931 | .maxlen = sizeof(int), | |
932 | .mode = 0644, | |
933 | .proc_handler = proc_dointvec_minmax, | |
934 | .extra1 = SYSCTL_ZERO, | |
935 | .extra2 = SYSCTL_ONE, | |
936 | }, | |
937 | #ifdef CONFIG_SMP | |
938 | { | |
939 | .procname = "hardlockup_all_cpu_backtrace", | |
940 | .data = &sysctl_hardlockup_all_cpu_backtrace, | |
941 | .maxlen = sizeof(int), | |
942 | .mode = 0644, | |
943 | .proc_handler = proc_dointvec_minmax, | |
944 | .extra1 = SYSCTL_ZERO, | |
945 | .extra2 = SYSCTL_ONE, | |
946 | }, | |
947 | #endif /* CONFIG_SMP */ | |
948 | #endif | |
949 | {} | |
950 | }; | |
951 | ||
9ec272c5 DA |
952 | static struct ctl_table watchdog_hardlockup_sysctl[] = { |
953 | { | |
954 | .procname = "nmi_watchdog", | |
955 | .data = &watchdog_hardlockup_user_enabled, | |
956 | .maxlen = sizeof(int), | |
957 | .mode = 0444, | |
958 | .proc_handler = proc_nmi_watchdog, | |
959 | .extra1 = SYSCTL_ZERO, | |
960 | .extra2 = SYSCTL_ONE, | |
961 | }, | |
962 | {} | |
963 | }; | |
964 | ||
dd0693fd XN |
965 | static void __init watchdog_sysctl_init(void) |
966 | { | |
967 | register_sysctl_init("kernel", watchdog_sysctls); | |
9ec272c5 DA |
968 | |
969 | if (watchdog_hardlockup_available) | |
970 | watchdog_hardlockup_sysctl[0].mode = 0644; | |
971 | register_sysctl_init("kernel", watchdog_hardlockup_sysctl); | |
dd0693fd | 972 | } |
9ec272c5 | 973 | |
dd0693fd XN |
974 | #else |
975 | #define watchdog_sysctl_init() do { } while (0) | |
58687acb DZ |
976 | #endif /* CONFIG_SYSCTL */ |
977 | ||
930d8f8d LC |
978 | static void __init lockup_detector_delay_init(struct work_struct *work); |
979 | static bool allow_lockup_detector_init_retry __initdata; | |
980 | ||
981 | static struct work_struct detector_work __initdata = | |
982 | __WORK_INITIALIZER(detector_work, lockup_detector_delay_init); | |
983 | ||
984 | static void __init lockup_detector_delay_init(struct work_struct *work) | |
985 | { | |
986 | int ret; | |
987 | ||
988 | ret = watchdog_hardlockup_probe(); | |
989 | if (ret) { | |
990 | pr_info("Delayed init of the lockup detector failed: %d\n", ret); | |
991 | pr_info("Hard watchdog permanently disabled\n"); | |
992 | return; | |
993 | } | |
994 | ||
995 | allow_lockup_detector_init_retry = false; | |
996 | ||
997 | watchdog_hardlockup_available = true; | |
998 | lockup_detector_setup(); | |
999 | } | |
1000 | ||
1001 | /* | |
1002 | * lockup_detector_retry_init - retry init lockup detector if possible. | |
1003 | * | |
1004 | * Retry hardlockup detector init. It is useful when it requires some | |
1005 | * functionality that has to be initialized later on a particular | |
1006 | * platform. | |
1007 | */ | |
1008 | void __init lockup_detector_retry_init(void) | |
1009 | { | |
1010 | /* Must be called before late init calls */ | |
1011 | if (!allow_lockup_detector_init_retry) | |
1012 | return; | |
1013 | ||
1014 | schedule_work(&detector_work); | |
1015 | } | |
1016 | ||
1017 | /* | |
1018 | * Ensure that optional delayed hardlockup init is proceed before | |
1019 | * the init code and memory is freed. | |
1020 | */ | |
1021 | static int __init lockup_detector_check(void) | |
1022 | { | |
1023 | /* Prevent any later retry. */ | |
1024 | allow_lockup_detector_init_retry = false; | |
1025 | ||
1026 | /* Make sure no work is pending. */ | |
1027 | flush_work(&detector_work); | |
1028 | ||
9ec272c5 DA |
1029 | watchdog_sysctl_init(); |
1030 | ||
930d8f8d LC |
1031 | return 0; |
1032 | ||
1033 | } | |
1034 | late_initcall_sync(lockup_detector_check); | |
1035 | ||
004417a6 | 1036 | void __init lockup_detector_init(void) |
58687acb | 1037 | { |
13316b31 | 1038 | if (tick_nohz_full_enabled()) |
314b08ff | 1039 | pr_info("Disabling watchdog on nohz_full cores by default\n"); |
13316b31 | 1040 | |
de201559 | 1041 | cpumask_copy(&watchdog_cpumask, |
04d4e665 | 1042 | housekeeping_cpumask(HK_TYPE_TIMER)); |
fe4ba3c3 | 1043 | |
df95d308 DA |
1044 | if (!watchdog_hardlockup_probe()) |
1045 | watchdog_hardlockup_available = true; | |
930d8f8d LC |
1046 | else |
1047 | allow_lockup_detector_init_retry = true; | |
1048 | ||
5587185d | 1049 | lockup_detector_setup(); |
58687acb | 1050 | } |