linux-kernel - Re: [PATCH v3] drm/msm/dp: fix event thread stuck in wait_event after kthread

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Message-ID: <CAE-0n50P4G1gwKmdzKR-ezHwmN3_BfBC5eWTC852oww75Zen6g@mail.gmail.com>
Date:   Wed, 4 May 2022 14:44:11 -0400
From:   Stephen Boyd <swboyd@...omium.org>
To:     Kuogee Hsieh <quic_khsieh@...cinc.com>, agross@...nel.org,
        airlied@...ux.ie, bjorn.andersson@...aro.org, daniel@...ll.ch,
        dianders@...omium.org, dmitry.baryshkov@...aro.org,
        robdclark@...il.com, sean@...rly.run, vkoul@...nel.org
Cc:     quic_abhinavk@...cinc.com, quic_aravindh@...cinc.com,
        quic_sbillaka@...cinc.com, freedreno@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] drm/msm/dp: fix event thread stuck in wait_event after kthread_stop()

Quoting Kuogee Hsieh (2022-05-03 09:25:36)
> Event thread supposed to exit from its while loop after kthread_stop().
> However there may has possibility that event thread is pending in the
> middle of wait_event due to condition checking never become true.
> To make sure event thread exit its loop after kthread_stop(), this
> patch OR kthread_should_stop() into wait_event's condition checking
> so that event thread will exit its loop after kernal_stop().
>
> Changes in v2:
> --  correct spelling error at commit title
>
> Changes in v3:
> -- remove unnecessary parenthesis
> -- while(1) to replace while (!kthread_should_stop())
>
> Reported-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> Fixes: 570d3e5d28db ("drm/msm/dp: stop event kernel thread when DP unbind")
> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
> ---

Reviewed-by: Stephen Boyd <swboyd@...omium.org>