From: Kuogee Hsieh quic_khsieh@quicinc.com
stable inclusion from stable-v5.10.121 commit a10092dabae6a3536c60c9c0b16d1135aba0ef74 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 2f9b5b3ae2eb625b75a898212a76f3b8c6d0d2b0 ]
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@linaro.org Fixes: 570d3e5d28db ("drm/msm/dp: stop event kernel thread when DP unbind") Signed-off-by: Kuogee Hsieh quic_khsieh@quicinc.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Reviewed-by: Stephen Boyd swboyd@chromium.org Patchwork: https://patchwork.freedesktop.org/patch/484576/ Link: https://lore.kernel.org/r/1651595136-24312-1-git-send-email-quic_khsieh@quic... Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/gpu/drm/msm/dp/dp_display.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c index 09c8e50da68d..ebd05678a27b 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -998,15 +998,20 @@ static int hpd_event_thread(void *data)
dp_priv = (struct dp_display_private *)data;
- while (!kthread_should_stop()) { + while (1) { if (timeout_mode) { wait_event_timeout(dp_priv->event_q, - (dp_priv->event_pndx == dp_priv->event_gndx), - EVENT_TIMEOUT); + (dp_priv->event_pndx == dp_priv->event_gndx) || + kthread_should_stop(), EVENT_TIMEOUT); } else { wait_event_interruptible(dp_priv->event_q, - (dp_priv->event_pndx != dp_priv->event_gndx)); + (dp_priv->event_pndx != dp_priv->event_gndx) || + kthread_should_stop()); } + + if (kthread_should_stop()) + break; + spin_lock_irqsave(&dp_priv->event_lock, flag); todo = &dp_priv->event_list[dp_priv->event_gndx]; if (todo->delay) {