On 5/2/2022 2:50 PM, 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().

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

---

drivers/gpu/drm/msm/dp/dp_display.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c index c388323..5200a58 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -1106,12 +1106,17 @@ static int hpd_event_thread(void *data) while (!kthread_should_stop()) { 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) {