On 03/05/2022 19:25, Kuogee Hsieh wrote:
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>
Let's do it properly:
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
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 c388323..da5c03a 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1103,15 +1103,20 @@ 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) {
--
With best wishes
Dmitry
