FAILED: patch "[PATCH] clocksource/i8253: Use raw_spinlock_irqsave() in" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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 <[email protected]>.

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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 94cff94634e506a4a44684bee1875d2dbf782722
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025051256-encrust-scribe-9996@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 94cff94634e506a4a44684bee1875d2dbf782722 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <[email protected]>
Date: Fri, 4 Apr 2025 15:31:16 +0200
Subject: [PATCH] clocksource/i8253: Use raw_spinlock_irqsave() in
clockevent_i8253_disable()

On x86 during boot, clockevent_i8253_disable() can be invoked via x86_late_time_init -> hpet_time_init() -> pit_timer_init() which happens with enabled interrupts.

If some of the old i8253 hardware is actually used then lockdep will notice that i8253_lock is used in hard interrupt context. This causes lockdep to complain because it observed the lock being acquired with interrupts enabled and in hard interrupt context.

Make clockevent_i8253_disable() acquire the lock with raw_spinlock_irqsave() to cure this.

[ tglx: Massage change log and use guard() ]

index 39f7c2d736d1..b603c25f3dfa 100644
@@ -103,7 +103,7 @@ int __init clocksource_i8253_init(void)
 #ifdef CONFIG_CLKEVT_I8253
 void clockevent_i8253_disable(void)
 {
-	raw_spin_lock(&i8253_lock);
+	guard(raw_spinlock_irqsave)(&i8253_lock);
 
 	/*
 	 * Writing the MODE register should stop the counter, according to

@@ -132,8 +132,6 @@ void clockevent_i8253_disable(void)
 	outb_p(0, PIT_CH0);
 
 	outb_p(0x30, PIT_MODE);
-
-	raw_spin_unlock(&i8253_lock);
 }
 
 static int pit_shutdown(struct clock_event_device *evt)

…

I performed these steps and the patch applied. The diff is the same so git did not attempt to resolve a conflict on its own. HEAD was at v6.1.138 at the time.

Sebastian

Did you build the result? Many times FAILED reports are due to that.

thanks,

greg k-h

Yes. I just sent a fixed version for v5.10 which failed to compile due to missing guard notation.

Sebastian