From: MyungJoo Ham <myungjoo.ham@samsung.com>
To: Mukesh Ojha <quic_mojha@quicinc.com>,
Chanwoo Choi <cw00.choi@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"huangzaiyang@oppo.com" <huangzaiyang@oppo.com>,
CPGS <cpgs@samsung.com>
Subject: RE: Re: [PATCH v4] PM / devfreq: Synchronize device_monitor_[start/stop]
Date: Tue, 12 Dec 2023 09:27:02 +0900 [thread overview]
Message-ID: <1296674576.21702343402595.JavaMail.epsvc@epcpadp3> (raw)
In-Reply-To: CGME20231206105023epcas1p443ebecc35010d2577b86c3fa23e24e45@epcms1p6
On 11/25/2023 2:41 AM, Mukesh Ojha wrote:
> There is a chance if a frequent switch of the governor
> done in a loop result in timer list corruption where
> timer cancel being done from two place one from
> cancel_delayed_work_sync() and followed by expire_timers()
> can be seen from the traces[1].
>
> while true
> do
> echo "simple_ondemand" > /sys/class/devfreq/1d84000.ufshc/governor
> echo "performance" > /sys/class/devfreq/1d84000.ufshc/governor
> done
>
> It looks to be issue with devfreq driver where
> device_monitor_[start/stop] need to synchronized so that
> delayed work should get corrupted while it is either
> being queued or running or being cancelled.
>
> Let's use polling flag and devfreq lock to synchronize the
> queueing the timer instance twice and work data being
> corrupted.
Would you please identify the resources to be protected by this lock
and specify them in the devfreq->lock declaration?
(it seems the list of protected resources is growing, and
we need to track them.)
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
parent reply other threads:[~2023-12-12 1:10 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <CGME20231206105023epcas1p443ebecc35010d2577b86c3fa23e24e45@epcms1p6>]
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