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 56339C4332F for ; Thu, 2 Nov 2023 09:06:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229776AbjKBJGD (ORCPT ); Thu, 2 Nov 2023 05:06:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44284 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229609AbjKBJGB (ORCPT ); Thu, 2 Nov 2023 05:06:01 -0400 Received: from mx01.omp.ru (mx01.omp.ru [90.154.21.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E31AF137; Thu, 2 Nov 2023 02:05:56 -0700 (PDT) Received: from [192.168.1.103] (178.176.78.246) by msexch01.omp.ru (10.188.4.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.1258.12; Thu, 2 Nov 2023 12:05:46 +0300 Subject: Re: [PATCH] usb: gadget: uvc_video: unlock before submitting a request to ep To: Piyush Mehta , , , , CC: , , , References: <20231102071138.828126-1-piyush.mehta@amd.com> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: <4661c898-2520-96b5-2f1c-8b013abd2a5c@omp.ru> Date: Thu, 2 Nov 2023 12:05:45 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20231102071138.828126-1-piyush.mehta@amd.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [178.176.78.246] X-ClientProxiedBy: msexch01.omp.ru (10.188.4.12) To msexch01.omp.ru (10.188.4.12) X-KSE-ServerInfo: msexch01.omp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 6.0.0, Database issued on: 11/02/2023 08:52:39 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 181066 [Nov 02 2023] X-KSE-AntiSpam-Info: Version: 6.0.0.2 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 543 543 1e3516af5cdd92079dfeb0e292c8747a62cb1ee4 X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: {relay has no DNS name} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 178.176.78.246 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;127.0.0.199:7.1.2;omp.ru:7.1.1 X-KSE-AntiSpam-Info: ApMailHostAddress: 178.176.78.246 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 59 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-AntiSpam-Info: Auth:dmarc=temperror header.from=omp.ru;spf=temperror smtp.mailfrom=omp.ru;dkim=none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Heuristic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 11/02/2023 08:56:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 11/2/2023 6:00:00 AM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! On 11/2/23 10:11 AM, Piyush Mehta wrote: > There could be chances where the usb_ep_queue() could fail and trigger > complete() handler with error status. In this case, if usb_ep_queue() > is called with lock held and the triggered complete() handler is waiting > for the same lock to be cleared could result in a deadlock situation and > could result in system hang. To aviod this scenerio, call usb_ep_queue() Scenario. :-) > with lock removed. This patch does the same. The last sentence is hardly needed. > Signed-off-by: Piyush Mehta > --- > drivers/usb/gadget/function/uvc_video.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c > index 91af3b1ef0d4..0a5d9ac145e7 100644 > --- a/drivers/usb/gadget/function/uvc_video.c > +++ b/drivers/usb/gadget/function/uvc_video.c > @@ -460,11 +460,12 @@ static void uvcg_video_pump(struct work_struct *work) > req->no_interrupt = 1; > } > > - /* Queue the USB request */ > - ret = uvcg_video_ep_queue(video, req); > spin_unlock_irqrestore(&queue->irqlock, flags); > > + /* Queue the USB request */ > + ret = uvcg_video_ep_queue(video, req); > if (ret < 0) { > + usb_ep_set_halt(video->ep); Hm, you don't say anything about this change in the patch description... [...] MBR, Sergey