The lockup detector (watchdog) affinity is initially set based on the HK_TYPE_TIMER housekeeping mask. However, if this mask is updated at runtime, the watchdog threads remain on their original CPUs.
Register a housekeeping notifier to update watchdog_cpumask and trigger a reconfiguration via proc_watchdog_update() when the HK_TYPE_TIMER housekeeping mask changes. This ensures that watchdog threads are synchronized with the new isolation boundaries. Signed-off-by: Qiliang Yuan <[email protected]> Signed-off-by: Qiliang Yuan <[email protected]> --- kernel/watchdog.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 366122f4a0f8..2922d7f93d61 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -26,6 +26,7 @@ #include <linux/sysctl.h> #include <linux/tick.h> #include <linux/sys_info.h> +#include <linux/sched/isolation.h> #include <linux/sched/clock.h> #include <linux/sched/debug.h> @@ -1359,6 +1360,28 @@ static int __init lockup_detector_check(void) } late_initcall_sync(lockup_detector_check); +static int watchdog_housekeeping_reconfigure(struct notifier_block *nb, + unsigned long action, void *data) +{ + if (action == HK_UPDATE_MASK) { + unsigned int type = (unsigned long)data; + + if (type == HK_TYPE_TIMER) { + mutex_lock(&watchdog_mutex); + cpumask_copy(&watchdog_cpumask, + housekeeping_cpumask(HK_TYPE_TIMER)); + proc_watchdog_update(false); + mutex_unlock(&watchdog_mutex); + } + } + + return NOTIFY_OK; +} + +static struct notifier_block watchdog_housekeeping_nb = { + .notifier_call = watchdog_housekeeping_reconfigure, +}; + void __init lockup_detector_init(void) { if (tick_nohz_full_enabled()) @@ -1373,4 +1396,5 @@ void __init lockup_detector_init(void) allow_lockup_detector_init_retry = true; lockup_detector_setup(); + housekeeping_register_notifier(&watchdog_housekeeping_nb); } -- 2.51.0
