Re: The "clockevents: Prevent timer interrupt starvation" patch causes lockups

[Thomas Gleixner <tglx@kernel.org>]

On Tue, Apr 14 2026 at 18:25, Hanabishi wrote:
> On 14/04/2026 18:04, Frederic Weisbecker wrote:
>
> This patch doesn't help me unfortunately. Thanks.

The one below should cover all possible holes.

Thanks,

        tglx
---
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index b4d730604972..5e22697b098d 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -94,6 +94,9 @@ static int __clockevents_switch_state(struct clock_event_device *dev,
 	if (dev->features & CLOCK_EVT_FEAT_DUMMY)
 		return 0;
 
+	/* On state transitions clear the forced flag unconditionally */
+	dev->next_event_forced = 0;
+
 	/* Transition with new state-specific callbacks */
 	switch (state) {
 	case CLOCK_EVT_STATE_DETACHED:
@@ -366,8 +369,10 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, b
 	if (delta > (int64_t)dev->min_delta_ns) {
 		delta = min(delta, (int64_t) dev->max_delta_ns);
 		cycles = ((u64)delta * dev->mult) >> dev->shift;
-		if (!dev->set_next_event((unsigned long) cycles, dev))
+		if (!dev->set_next_event((unsigned long) cycles, dev)) {
+			dev->next_event_forced = 0;
 			return 0;
+		}
 	}
 
 	if (dev->next_event_forced)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 7e57fa31ee26..115e0bf01276 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -108,6 +108,7 @@ static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu)
 
 static void tick_oneshot_wakeup_handler(struct clock_event_device *wd)
 {
+	wd->next_event_forced = 0;
 	/*
 	 * If we woke up early and the tick was reprogrammed in the
 	 * meantime then this may be spurious but harmless.