From patchwork Tue May 3 16:25:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuogee Hsieh X-Patchwork-Id: 12835963 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D83EBC433F5 for ; Tue, 3 May 2022 16:25:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239526AbiECQ3Y (ORCPT ); Tue, 3 May 2022 12:29:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236784AbiECQ3U (ORCPT ); Tue, 3 May 2022 12:29:20 -0400 Received: from alexa-out-sd-02.qualcomm.com (alexa-out-sd-02.qualcomm.com [199.106.114.39]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90C09245AF; Tue, 3 May 2022 09:25:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1651595145; x=1683131145; h=from:to:cc:subject:date:message-id:mime-version; bh=XUNvuxnwMARaOjUov73VAGop00ml9m7FBckSe+F8Mus=; b=FBY/g70hH0lhUAuDHrsUUtQQYmbVZmC6vrIRbpqMeWU9hnER6GLv7YOe DBNaHEYs+L5ivmgZ9RU4X1jiareyu7bCTrONy0GmSYrBDYs7XFkMCTBjB lrxurUFuaJ0FoPW+WsjVzpOopeE2kVucL1CarC76s3AmsJLDCyUau+aMi Y=; Received: from unknown (HELO ironmsg03-sd.qualcomm.com) ([10.53.140.143]) by alexa-out-sd-02.qualcomm.com with ESMTP; 03 May 2022 09:25:45 -0700 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg03-sd.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 May 2022 09:25:44 -0700 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Tue, 3 May 2022 09:25:44 -0700 Received: from khsieh-linux1.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Tue, 3 May 2022 09:25:43 -0700 From: Kuogee Hsieh To: , , , , , , , , , CC: , , , , , , , Subject: [PATCH v3] drm/msm/dp: fix event thread stuck in wait_event after kthread_stop() Date: Tue, 3 May 2022 09:25:36 -0700 Message-ID: <1651595136-24312-1-git-send-email-quic_khsieh@quicinc.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 Fixes: 570d3e5d28db ("drm/msm/dp: stop event kernel thread when DP unbind") Signed-off-by: Kuogee Hsieh Reviewed-by: Dmitry Baryshkov Reviewed-by: Stephen Boyd --- 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) {