From: Kevin Hilman <khilman@baylibre.com>
To: Jerome Brunet <jbrunet@baylibre.com>,
Jassi Brar <jassisinghbrar@gmail.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>,
linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
Da Xue <da@libre.computer>
Subject: Re: [PATCH] mailbox: cancel timer before starting it
Date: Thu, 24 Sep 2020 09:50:55 -0700 [thread overview]
Message-ID: <7hr1qr9l00.fsf@baylibre.com> (raw)
In-Reply-To: <20200923123916.1115962-1-jbrunet@baylibre.com>
Jerome Brunet <jbrunet@baylibre.com> writes:
> If the txdone is done by polling, it is possible for msg_submit() to start
> the timer while txdone_hrtimer() callback is running. If the timer needs
> recheduling, it could already be enqueued by the time hrtimer_forward_now()
> is called, leading hrtimer to loudly complain.
>
> WARNING: CPU: 3 PID: 74 at kernel/time/hrtimer.c:932 hrtimer_forward+0xc4/0x110
> CPU: 3 PID: 74 Comm: kworker/u8:1 Not tainted 5.9.0-rc2-00236-gd3520067d01c-dirty #5
> Hardware name: Libre Computer AML-S805X-AC (DT)
> Workqueue: events_freezable_power_ thermal_zone_device_check
> pstate: 20000085 (nzCv daIf -PAN -UAO BTYPE=--)
> pc : hrtimer_forward+0xc4/0x110
> lr : txdone_hrtimer+0xf8/0x118
> [...]
>
> Canceling the timer before starting it ensure that the timer callback is
> not running when the timer is started, solving this race condition.
>
> Fixes: 0cc67945ea59 ("mailbox: switch to hrtimer for tx_complete polling")
> Reported-by: Da Xue <da@libre.computer>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Kevin
next prev parent reply other threads:[~2020-09-24 16:50 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 12:39 [PATCH] mailbox: cancel timer before starting it Jerome Brunet
2020-09-24 16:50 ` Kevin Hilman [this message]
2020-10-15 13:46 ` Ionela Voinescu
2020-10-15 13:58 ` Jerome Brunet
2020-10-15 14:29 ` Ionela Voinescu
2020-10-16 8:44 ` Sudeep Holla
2020-10-16 9:02 ` Jerome Brunet
2020-10-16 9:34 ` Sudeep Holla
2020-10-16 11:47 ` Sudeep Holla
2020-10-15 18:45 ` Jassi Brar
2020-10-16 8:52 ` Ionela Voinescu
2020-10-16 9:00 ` Jerome Brunet
2020-10-16 13:52 ` Sudeep Holla
2020-10-16 17:33 ` Jassi Brar
2020-10-16 18:54 ` Jerome Brunet
2020-10-16 19:27 ` Jassi Brar
2022-07-19 7:08 ` Da Xue
2020-10-16 11:52 ` Sudeep Holla
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