linux/kernel/watchdog.c

1 // SPDX-License-Identifier: GPL-2.0
8  * detector, so thanks to Ingo for the initial implementation.
9  * Some chunks also taken from the old x86-specific nmi watchdog code, thanks
55  * Should we panic when a soft-lockup or hard-lockup occurs:
172 		 * Perform multi-CPU dump only once to avoid multiple  in watchdog_hardlockup_check()
195  * These functions can be overridden based on the configured hardlockdup detector.
198  * softlockup watchdog start and stop. The detector must select the
206  * Watchdog-detector specific API.
214 	return -ENODEV;  in watchdog_hardlockup_probe()
218  * watchdog_hardlockup_stop - Stop the watchdog for reconfiguration
228  * watchdog_hardlockup_start - Start the watchdog after reconfiguration
234  * - watchdog_enabled
235  * - watchdog_thresh
236  * - watchdog_cpumask
241  * lockup_detector_update_enable - Update the sysctl enable bit
317  * Hard-lockup warnings should be triggered after just a few seconds. Soft-
319  * want a higher threshold for soft lockups than for hard lockups. So we couple
320  * the thresholds with a factor: we make the soft threshold twice the amount of
321  * time the hard threshold is.
345 	 * hardlockup detector generates a warning  in set_sample_period()
364  * touch_softlockup_watchdog_sched - touch watchdog on scheduler stalls
367  * preventing the watchdog task from executing - e.g. the scheduler
419 			return now - touch_ts;  in is_softlockup()
424 /* watchdog detector functions */
429  * The watchdog feed function - touches the timestamp.
433  * for more than 2*watchdog_thresh seconds then the debug-printout
457 	/* kick the softlockup detector */  in watchdog_timer_fn()
506 		 * Prevent multiple soft-lockup reports if one cpu is already  in watchdog_timer_fn()
517 		pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",  in watchdog_timer_fn()
519 			current->comm, task_pid_nr(current));  in watchdog_timer_fn()
555 	hrtimer->function = watchdog_timer_fn;  in watchdog_enable()
561 	/* Enable the hardlockup detector */  in watchdog_enable()
573 	 * Disable the hardlockup detector first. That prevents that a large  in watchdog_disable()
575 	 * detector causes a false positive.  in watchdog_disable()
658  * Create the watchdog infrastructure and configure the detector(s).
704  * lockup_detector_cleanup - Cleanup after cpu hotplug or sysctl changes
716  * lockup_detector_soft_poweroff - Interface to stop lockup detector(s)
718  * Special interface for parisc. It prevents lockup detector warnings from
739  * caller             | table->data points to            | 'which'
740  * -------------------|----------------------------------|-------------------------------
743  * -------------------|----------------------------------|-------------------------------
745  * -------------------|----------------------------------|-------------------------------
751 	int err, old, *param = table->data;  in proc_watchdog_common()
790 		return -ENOTSUPP;  in proc_nmi_watchdog()
968 		pr_info("Delayed init of the lockup detector failed: %d\n", ret);  in lockup_detector_delay_init()
980  * lockup_detector_retry_init - retry init lockup detector if possible.
982  * Retry hardlockup detector init. It is useful when it requires some