This is a note to let you know that I've just added the patch titled
drm/msm/dp: fix event thread stuck in wait_event after kthread_stop()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-msm-dp-fix-event-thread-stuck-in-wait_event-afte.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c15891ccc536f34c85a0b2ab268788b7da968239
Author: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
Date: Tue May 3 09:25:36 2022 -0700
drm/msm/dp: fix event thread stuck in wait_event after kthread_stop()
[ 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@xxxxxxxxxx>
Fixes: 570d3e5d28db ("drm/msm/dp: stop event kernel thread when DP unbind")
Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Patchwork: https://patchwork.freedesktop.org/patch/484576/
Link: https://lore.kernel.org/r/1651595136-24312-1-git-send-email-quic_khsieh@xxxxxxxxxxx
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 00e7d9db6199..7b624191abf1 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1069,15 +1069,20 @@ 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) {
