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

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

[gregkh]

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 <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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 94cff94634e506a4a44684bee1875d2dbf782722
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --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 <bigeasy@linutronix.de>
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() ]

Fixes: c8c4076723dac ("x86/timer: Skip PIT initialization on modern chipsets")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250404133116.p-XRWJXf@linutronix.de

diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c
index 39f7c2d736d1..b603c25f3dfa 100644
--- a/drivers/clocksource/i8253.c
+++ b/drivers/clocksource/i8253.c
@@ -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)

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

[Sebastian Andrzej Siewior]

On 2025-05-12 12:31:56 [+0200], gregkh@linuxfoundation.org wrote:
> 
> 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 <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-6.1.y
> git checkout FETCH_HEAD
> git cherry-pick -x 94cff94634e506a4a44684bee1875d2dbf782722
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025051256-encrust-scribe-9996@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
> 
…

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

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

[Greg KH]

On Tue, May 13, 2025 at 08:53:26AM +0200, Sebastian Andrzej Siewior wrote:
> On 2025-05-12 12:31:56 [+0200], gregkh@linuxfoundation.org wrote:
> > 
> > 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 <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-6.1.y
> > git checkout FETCH_HEAD
> > git cherry-pick -x 94cff94634e506a4a44684bee1875d2dbf782722
> > # <resolve conflicts, build, test, etc.>
> > git commit -s
> > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025051256-encrust-scribe-9996@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
> > 
> …
> 
> 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.

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

thanks,

greg k-h

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

[Sebastian Andrzej Siewior]

On 2025-05-13 08:55:13 [+0200], Greg KH wrote:
> > 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.
> 
> Did you build the result?  Many times FAILED reports are due to that.

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

> thanks,
> 
> greg k-h

Sebastian