Re: [tip: timers/urgent] timekeeping: Use READ/WRITE_ONCE() for tick_do_timer_cpu

From: Ingo Molnar <mingo@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org,
	Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sean Anderson <sean.anderson@seco.com>,
	x86@kernel.org
Subject: Re: [tip: timers/urgent] timekeeping: Use READ/WRITE_ONCE() for tick_do_timer_cpu
Date: Wed, 10 Apr 2024 10:15:04 +0200	[thread overview]
Message-ID: <ZhZKiKyXsgSeABvD@gmail.com> (raw)
In-Reply-To: <171269748856.10875.3911619468870441338.tip-bot2@tip-bot2>


* tip-bot2 for Thomas Gleixner <tip-bot2@linutronix.de> wrote:

> The following commit has been merged into the timers/urgent branch of tip:
> 
> Commit-ID:     0200ddd723d6056d0b1c1ebde4b11e75a0f2ed7e
> Gitweb:        https://git.kernel.org/tip/0200ddd723d6056d0b1c1ebde4b11e75a0f2ed7e
> Author:        Thomas Gleixner <tglx@linutronix.de>
> AuthorDate:    Tue, 09 Apr 2024 12:29:12 +02:00
> Committer:     Thomas Gleixner <tglx@linutronix.de>
> CommitterDate: Tue, 09 Apr 2024 23:09:44 +02:00
> 
> timekeeping: Use READ/WRITE_ONCE() for tick_do_timer_cpu

> @@ -232,7 +233,7 @@ static void tick_setup_device(struct tick_device *td,
>  						!tick_nohz_full_cpu(cpu)) {
>  			tick_take_do_timer_from_boot();
>  			tick_do_timer_boot_cpu = -1;
> -			WARN_ON(tick_do_timer_cpu != cpu);
> +			WARN_ON(READ_ON_ONCE(tick_do_timer_cpu) != cpu);

So there's no such thing as READ_ON_ONCE() - I've amended the commit with 
the fix below.

Thanks,

	Ingo


 kernel/time/tick-common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index a285f4deb96d..d88b13076b79 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -233,7 +233,7 @@ static void tick_setup_device(struct tick_device *td,
 						!tick_nohz_full_cpu(cpu)) {
 			tick_take_do_timer_from_boot();
 			tick_do_timer_boot_cpu = -1;
-			WARN_ON(READ_ON_ONCE(tick_do_timer_cpu) != cpu);
+			WARN_ON(READ_ONCE(tick_do_timer_cpu) != cpu);
 #endif
 		}
 
