FAILED: patch "[PATCH] clockevents: Add missing resets of the next_event_forced flag" failed to apply to 7.0-stable tree

FAILED: patch "[PATCH] clockevents: Add missing resets of the next_event_forced flag" failed to apply to 7.0-stable tree

[gregkh]

The patch below does not apply to the 7.0-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-7.0.y
git checkout FETCH_HEAD
git cherry-pick -x 4096fd0e8eaea13ebe5206700b33f49635ae18e5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026051258-schedule-parcel-c95c@gregkh' --subject-prefix 'PATCH 7.0.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4096fd0e8eaea13ebe5206700b33f49635ae18e5 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@kernel.org>
Date: Tue, 14 Apr 2026 22:55:01 +0200
Subject: [PATCH] clockevents: Add missing resets of the next_event_forced flag

The prevention mechanism against timer interrupt starvation missed to reset
the next_event_forced flag in a couple of places:

    - When the clock event state changes. That can cause the flag to be
      stale over a shutdown/startup sequence

    - When a non-forced event is armed, which then prevents rearming before
      that event. If that event is far out in the future this will cause
      missed timer interrupts.

    - In the suspend wakeup handler.

That led to stalls which have been reported by several people.

Add the missing resets, which fixes the problems for the reporters.

Fixes: d6e152d905bd ("clockevents: Prevent timer interrupt starvation")
Reported-by: Hanabishi <i.r.e.c.c.a.k.u.n+kernel.org@gmail.com>
Reported-by: Eric Naim <dnaim@cachyos.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Hanabishi <i.r.e.c.c.a.k.u.n+kernel.org@gmail.com>
Tested-by: Eric Naim <dnaim@cachyos.org>
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/68d1e9ac-2780-4be3-8ee3-0788062dd3a4@gmail.com
Link: https://patch.msgid.link/87340xfeje.ffs@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.

Re: FAILED: patch "[PATCH] clockevents: Add missing resets of the next_event_forced flag" failed to apply to 7.0-stable tree

[Thomas Gleixner]

On Tue, May 12 2026 at 15:50, gregkh@linuxfoundation.org wrote:
> The patch below does not apply to the 7.0-stable tree.

Obviously not. It's in linux-7.0.y since April 22:

commit 9401b593fa48218d2667df1610b0ebc518554880
Author:     Thomas Gleixner <tglx@kernel.org>
AuthorDate: Tue Apr 21 08:26:19 2026 +0200
Commit:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CommitDate: Wed Apr 22 13:32:23 2026 +0200

    clockevents: Add missing resets of the next_event_forced flag
    
    commit 4096fd0e8eaea13ebe5206700b33f49635ae18e5 upstream.

Re: FAILED: patch "[PATCH] clockevents: Add missing resets of the next_event_forced flag" failed to apply to 7.0-stable tree

[Greg KH]

On Thu, May 14, 2026 at 12:50:32PM +0200, Thomas Gleixner wrote:
> On Tue, May 12 2026 at 15:50, gregkh@linuxfoundation.org wrote:
> > The patch below does not apply to the 7.0-stable tree.
> 
> Obviously not. It's in linux-7.0.y since April 22:
> 
> commit 9401b593fa48218d2667df1610b0ebc518554880
> Author:     Thomas Gleixner <tglx@kernel.org>
> AuthorDate: Tue Apr 21 08:26:19 2026 +0200
> Commit:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> CommitDate: Wed Apr 22 13:32:23 2026 +0200
> 
>     clockevents: Add missing resets of the next_event_forced flag
>     
>     commit 4096fd0e8eaea13ebe5206700b33f49635ae18e5 upstream.
> 

Sorry about that, my fault :(