From mboxrd@z Thu Jan 1 00:00:00 1970 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 88B06C433EF for ; Thu, 17 Feb 2022 04:50:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233961AbiBQEuy (ORCPT ); Wed, 16 Feb 2022 23:50:54 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:37700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229697AbiBQEux (ORCPT ); Wed, 16 Feb 2022 23:50:53 -0500 X-Greylist: delayed 613 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 16 Feb 2022 20:50:39 PST Received: from hust.edu.cn (unknown [202.114.0.240]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05F1929ADED; Wed, 16 Feb 2022 20:50:38 -0800 (PST) Received: from localhost.localdomain ([172.16.0.254]) (user=dzm91@hust.edu.cn mech=LOGIN bits=0) by mx1.hust.edu.cn with ESMTP id 21H4dsXQ007777-21H4dsXT007777 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Thu, 17 Feb 2022 12:40:01 +0800 From: Dongliang Mu To: Hans Verkuil , Mauro Carvalho Chehab , Dongliang Mu Cc: syzkaller , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] media: hdpvr: call flush_work only if initialized Date: Thu, 17 Feb 2022 12:39:40 +0800 Message-Id: <20220217043950.749343-1-dzm91@hust.edu.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-FEAS-AUTH-USER: dzm91@hust.edu.cn Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dongliang Mu flush_work will throw one WARN if worker->func is NULL. So we should always initialize one worker before calling flush_work. When hdpvr_probe does not initialize its worker, the hdpvr_disconnect will encounter one WARN. The stack trace is in the following: hdpvr_disconnect+0xb8/0xf2 drivers/media/usb/hdpvr/hdpvr-core.c:425 usb_unbind_interface+0xbf/0x3a0 drivers/usb/core/driver.c:458 __device_release_driver drivers/base/dd.c:1206 [inline] device_release_driver_internal+0x22a/0x230 drivers/base/dd.c:1237 bus_remove_device+0x108/0x160 drivers/base/bus.c:529 device_del+0x1fe/0x510 drivers/base/core.c:3592 usb_disable_device+0xd1/0x1d0 drivers/usb/core/message.c:1419 usb_disconnect+0x109/0x330 drivers/usb/core/hub.c:2228 Fix this by adding a sanity check of the worker before flush_work. Reported-by: syzkaller Signed-off-by: Dongliang Mu --- drivers/media/usb/hdpvr/hdpvr-core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/hdpvr/hdpvr-core.c b/drivers/media/usb/hdpvr/hdpvr-core.c index 52e05a69c46e..d102b459d45d 100644 --- a/drivers/media/usb/hdpvr/hdpvr-core.c +++ b/drivers/media/usb/hdpvr/hdpvr-core.c @@ -422,7 +422,8 @@ static void hdpvr_disconnect(struct usb_interface *interface) mutex_unlock(&dev->io_mutex); v4l2_device_disconnect(&dev->v4l2_dev); msleep(100); - flush_work(&dev->worker); + if (dev->worker.func) + flush_work(&dev->worker); mutex_lock(&dev->io_mutex); hdpvr_cancel_queue(dev); mutex_unlock(&dev->io_mutex); -- 2.25.1