The hardlockup detector threads are affined to CPUs based on the HK_TYPE_TIMER housekeeping mask at boot. If this mask is updated at runtime, these threads remain on their original CPUs, potentially running on isolated cores.
Synchronize watchdog thread affinity with HK_TYPE_TIMER updates. This ensures that hardlockup detector threads correctly follow the dynamic housekeeping boundaries for timers. Signed-off-by: Qiliang Yuan <[email protected]> --- kernel/watchdog.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 366122f4a0f87..ef93795729697 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 +1360,29 @@ 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) { + struct housekeeping_update *upd = data; + unsigned int type = upd->type; + + 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 +1397,5 @@ void __init lockup_detector_init(void) allow_lockup_detector_init_retry = true; lockup_detector_setup(); + housekeeping_register_notifier(&watchdog_housekeeping_nb); } -- 2.43.0
