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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3A94C00A89 for ; Thu, 5 Nov 2020 05:29:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B9562087D for ; Thu, 5 Nov 2020 05:29:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="fTWthj3L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726996AbgKEF3s (ORCPT ); Thu, 5 Nov 2020 00:29:48 -0500 Received: from z5.mailgun.us ([104.130.96.5]:59425 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726307AbgKEF3s (ORCPT ); Thu, 5 Nov 2020 00:29:48 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1604554186; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=7Fgplp/vGedVzY7LkgXnQph8/xJaGqTQde+yVz6mUJc=; b=fTWthj3La94fL2zB2/z5ZZUd2f4TsuwmsovoQuxu4B5fvQ19MYI4TbLDnkoTM+mX6mZDF4U7 NGEP/s98IlR/nKHzMtjFkPwVAAsZiu95WKEnB7OhtQ0EcrEyV6d0IZmbKimG04/4Wsj7wtSq 5Z8z27lG8grhq9k3U25iSfNmhO0= X-Mailgun-Sending-Ip: 104.130.96.5 X-Mailgun-Sid: WyIxZTE2YSIsICJsaW51eC11c2JAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n03.prod.us-west-2.postgun.com with SMTP id 5fa38dc846e8885ab887edaa (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 05 Nov 2020 05:29:44 GMT Sender: sallenki=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 1392AC433CB; Thu, 5 Nov 2020 05:29:44 +0000 (UTC) Received: from [192.168.0.105] (unknown [103.110.145.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: sallenki) by smtp.codeaurora.org (Postfix) with ESMTPSA id 564BCC433C6; Thu, 5 Nov 2020 05:29:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 564BCC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=sallenki@codeaurora.org Subject: Re: strange call stack when running uvc-gadget application To: Peter Chen Cc: "linux-usb@vger.kernel.org" , "laurent.pinchart@ideasonboard.com" References: <20201102094936.GA29581@b29397-desktop> <20201104100511.GA16946@b29397-desktop> From: Sriharsha Allenki Message-ID: <51accf3a-6fe8-4d3d-2773-7d0756dab806@codeaurora.org> Date: Thu, 5 Nov 2020 10:59:39 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201104100511.GA16946@b29397-desktop> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hi Peter, On 11/4/2020 3:35 PM, Peter Chen wrote: > On 20-11-03 11:50:17, Sriharsha Allenki wrote: >> Hi Peter, >> >> On 11/2/2020 3:20 PM, Peter Chen wrote: >>> Hi all, >>> >>> When running run uvc-gadget application at HS using dwc3 gadget at Linux >>> v5.10-rc1, the video stream will be stopped after 1-2 minutes running. The >>> trace log like below, I wonder how _raw_spin_lock_irqsave calls __switch_to? >>> Any hints? Thanks. >>> >>> usb_test# [ 4757.322728] configfs-gadget gadget: uvc: VS request completed with status -18. >>> [ 4757.329971] configfs-gadget gadget: uvc: VS request completed with status -18. >>> UVC: Possible USB shutdown requested from Host, seen during VIDIOC_DQBUF >>> >>> usb_test# [ 4812.376465] check_interval: 37 callbacks suppressed >>> [ 4825.307665] configfs-gadget gadget: uvc: VS request completed with status -18. >>> [ 4825.314912] configfs-gadget gadget: uvc: VS request completed with status -18. >>> UVC: Possible USB shutdown requested from Host, seen during VIDIOC_DQBUF >>> [ 4826.231392] check_interval: 3 callbacks suppressed >>> select timeout >>> [ 4827.336088] dwc3 38100000.dwc3: request 0000000080ebefd3 was not queued to ep2in >>> [ 4827.343547] dwc3 38100000.dwc3: request 00000000b578605c was not queued to ep2in >>> [ 4827.350989] dwc3 38100000.dwc3: request 00000000c6d191cd was not queued to ep2in >>> [ 4827.358422] dwc3 38100000.dwc3: request 0000000085205409 was not queued to ep2in >>> UVC: Stopping video stream. >>> >>> [ 4848.381718] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: >>> [ 4848.387824] rcu: 3-...0: (1 GPs behind) idle=162/1/0x4000000000000000 softirq=10819/10819 fqs=2356 >>> [ 4848.396956] (detected by 2, t=5252 jiffies, g=20129, q=3770) >>> [ 4848.396959] Task dump for CPU 3: >>> [ 4848.405925] task:uvc-gadget_wlhe state:R running task stack: 0 pid: 674 ppid: 636 flags:0x00000202 >>> [ 4848.415842] Call trace: >>> [ 4848.418294] __switch_to+0xc0/0x170 >>> [ 4848.421785] _raw_spin_lock_irqsave+0x84/0xb0 >>> [ 4848.426143] composite_disconnect+0x28/0x78 >>> [ 4848.430327] configfs_composite_disconnect+0x68/0x70 >>> [ 4848.435290] usb_gadget_disconnect+0x10c/0x128 >>> [ 4848.439733] usb_gadget_deactivate+0xd4/0x108 >>> [ 4848.444089] usb_function_deactivate+0x6c/0x80 >>> [ 4848.448534] uvc_function_disconnect+0x20/0x58 >>> [ 4848.452976] uvc_v4l2_release+0x30/0x88 >>> [ 4848.456812] v4l2_release+0xbc/0xf0 >>> [ 4848.460301] __fput+0x7c/0x230 >>> [ 4848.463353] ____fput+0x14/0x20 >>> [ 4848.466495] task_work_run+0x88/0x140 >>> [ 4848.470157] do_notify_resume+0x240/0x6f0 >>> [ 4848.474166] work_pending+0x8/0x200 >> The reason for this seems to be that the usb_gadget_deactivate is being called with >> spinlock held from the usb_function_deactivate and the same lock is being used >> in the composite_disconnect (&cdev->lock). >> >> This should be able to resolve it. >> >> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c >> index 05b176c82cc5..5fced737e4ef 100644 >> --- a/drivers/usb/gadget/composite.c >> +++ b/drivers/usb/gadget/composite.c >> @@ -392,8 +392,11 @@ int usb_function_deactivate(struct usb_function *function) >> >>         spin_lock_irqsave(&cdev->lock, flags); >> >> -       if (cdev->deactivations == 0) >> +       if (cdev->deactivations == 0) { >> +               spin_unlock_irqrestore(&cdev->lock, flags); >>                 status = usb_gadget_deactivate(cdev->gadget); >> +               spin_lock_irqsave(&cdev->lock, flags); >> +       } >>         if (status == 0) >>                 cdev->deactivations++; >> >> @@ -424,8 +427,11 @@ int usb_function_activate(struct usb_function *function) >>                 status = -EINVAL; >>         else { >>                 cdev->deactivations--; >> -               if (cdev->deactivations == 0) >> +               if (cdev->deactivations == 0) { >> +                       spin_unlock_irqrestore(&cdev->lock, flags); >>                         status = usb_gadget_activate(cdev->gadget); >> +                       spin_lock_irqsave(&cdev->lock, flags); >> +               } >>         } >> >>         spin_unlock_irqrestore(&cdev->lock, flags); >> > Thanks, Sriharsha. It fixed the kernel dump after video stream has > stopped, I did not check the whole trace carefully, and not found this > spin recursion issue. You could add my Tested-by for it. Meanwhile, > this issue was reported before, and unlock at usb_function_activate > could also fix the possible sleep at atomic context issue for dwc3. > > https://lore.kernel.org/linux-usb/20191115070122.GF30608@b29397-desktop/T/ Thanks for the testing and confirmation, will raise the patch soon. Regards, Sriharsha > -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project