From nobody Wed Sep 17 22:19:01 2025 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 25A5AC4167B for ; Wed, 14 Dec 2022 16:34:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239065AbiLNQeL (ORCPT ); Wed, 14 Dec 2022 11:34:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238982AbiLNQdk (ORCPT ); Wed, 14 Dec 2022 11:33:40 -0500 Received: from mail-ed1-x52c.google.com (mail-ed1-x52c.google.com [IPv6:2a00:1450:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73DFF2A436 for ; Wed, 14 Dec 2022 08:32:22 -0800 (PST) Received: by mail-ed1-x52c.google.com with SMTP id i15so23292947edf.2 for ; Wed, 14 Dec 2022 08:32:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:from:to:cc:subject:date:message-id:reply-to; bh=MVrlltRx17nfXTGhP7yPJwRU3y4M8/9HTbuxEEs49iU=; b=aXv6T3ty9OZD4OYRcWL5+4mKME8v/e1WDdI9AA+KQJzPhv03AdE8drDDUqdiblA3yP s3/zhNBDtfTEYSkUNDB0AoiAz16cuPGibNxtKMzRSH9ilTXaJbDoVQ2FCuMzaGR2CKlx ERlbbfHgFDDGKgxdZXQ7Jy8oTG0/idZ4EWhqs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=MVrlltRx17nfXTGhP7yPJwRU3y4M8/9HTbuxEEs49iU=; b=2Pps8jqq63aWJWU5exAAYio4JldIxeRctdJcYKmljXYkuE+7xYrRt9hdceCQx1ViRQ TbM3YBSuSdmGfjqucpTAIOcE1Z3PYbjOAL9RN3tntop7EhlwmNeM7wpUiGpfzxjB4jxg WQ0CvtNBDeYkOaeX8wgPIItUWIW//Agc8y3q3bKyQArVC9mt59qTJ9zml9QL6EYGTRUk TSAZQ7Ji8sTOmxTR4Veh19TuK0cObb6YXAqJfN2/qYBNnOe/hSMYrdKxnvr3uHMSQ2/r XJalbakLD7hiYPC1ts1JSAlKxEK/SkCjLlpl91DWZdSKaYWUqo26CHMfxGlHrxNk0NZv a3Tg== X-Gm-Message-State: ANoB5pnUJttQNWnZZaYuAemFD2TU8UYta8gA+rRFPQU7l2bf9qam318e OX8/G7HW9GaqPcBfAc9Zr9wLAg== X-Google-Smtp-Source: AA0mqf41+3D5Js+uQP1l7WfEZEbOf6NiTJkGvwte5sA62Fzt/SILgjAyev/3jho0mOvjeKhWFRtVfA== X-Received: by 2002:aa7:cd46:0:b0:46d:e3f8:4ed4 with SMTP id v6-20020aa7cd46000000b0046de3f84ed4mr17653967edw.21.1671035541045; Wed, 14 Dec 2022 08:32:21 -0800 (PST) Received: from alco.roam.corp.google.com ([100.104.168.209]) by smtp.gmail.com with ESMTPSA id ee48-20020a056402293000b004615f7495e0sm6395908edb.8.2022.12.14.08.32.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Dec 2022 08:32:20 -0800 (PST) From: Ricardo Ribalda Date: Wed, 14 Dec 2022 17:31:55 +0100 Subject: [PATCH v4] media: uvcvideo: Fix race condition with usb_kill_urb MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20221212-uvc-race-v4-0-38d7075b03f5@chromium.org> To: Laurent Pinchart , Sergey Senozhatsky , Mauro Carvalho Chehab , Max Staudt Cc: linux-media@vger.kernel.org, stable@vger.kernel.org, Yunke Cao , Ricardo Ribalda , linux-kernel@vger.kernel.org X-Mailer: b4 0.11.0-dev-696ae X-Developer-Signature: v=1; a=openpgp-sha256; l=4414; i=ribalda@chromium.org; h=from:subject:message-id; bh=ogVdjybS9LEoywx0YwN/okaYfuH/y03AYQsWkydp3kQ=; b=owEBbQKS/ZANAwAKAdE30T7POsSIAcsmYgBjmfqNKqeDuIPruv3HRUGHzLrKhw0xXerfWXVR/oWJ Mh7m06eJAjMEAAEKAB0WIQREDzjr+/4oCDLSsx7RN9E+zzrEiAUCY5n6jQAKCRDRN9E+zzrEiGEBD/ 9paXuRWZxtIqzclORW4HCZGYi73FtH4rtSGo1FNlEq1R7vGpC1gQ796/GNRy0vTNoPO+QxaG6poI5J 8vAFLwLc3YCxAUXzcN/QuRqSznplWWU+TiGxWm/I2x+dlNbE0tk30rBktBkJ0rYvQev/gODgWCgghN JKnkI1XV3lxO9nCa/7WllWLHsNpjcGE0reWbaPRdpmwgQxUZyQsn0v1UjsGkI2EPfhhCBA9pLym2ie qJguxwajBM0LmK/ds6p5rVXdEmdz1BoOTa91s5QN89Qfu2n9gPljroekcxObhSEAR7A+TH4JCenRYJ zfstu4W4xhtU5LdCrdBumpkkOmxjw4mDZR4yYtH/asavDzAMEM98ceXIkSRT4ipCkbcQCeDfcD3339 e7BLYFB+fh7dO0R2dEZdw/i0vmr0gxk79TPbMbp/21RZutJPl/Ht2JMQfGOLfv/tojT7MT35xsEjqi ZTlGsBuRhEjLFLnjSEmAKs+AITV2Js6CV0xeCPwkwVkyyS/D4qhsv3NNxGuKjqvutOAcTKVaKNx7OD M75UhkjEUu9w2EF9WyCuIrjRO3YLkRQUrDrN9vqCGLuElX71HVPqqCTn9zxpYlYwQ2RnzYpt+fQe7k 4LxOvbbN2nLIE8NqmuMp9hiq5+moqyLr+SNq2O3Nlg0YoGQiXc424GQnJdlA== X-Developer-Key: i=ribalda@chromium.org; a=openpgp; fpr=9EC3BB66E2FC129A6F90B39556A0D81F9F782DA9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org usb_kill_urb warranties that all the handlers are finished when it returns, but does not protect against threads that might be handling asynchronously the urb. For UVC, the function uvc_ctrl_status_event_async() takes care of control changes asynchronously. If the code is executed in the following order: CPU 0 CPU 1 =3D=3D=3D=3D=3D =3D=3D=3D=3D=3D uvc_status_complete() uvc_status_stop() uvc_ctrl_status_event_work() uvc_status_start() -> FAIL Then uvc_status_start will keep failing and this error will be shown: <4>[ 5.540139] URB 0000000000000000 submitted while active drivers/usb/core/urb.c:378 usb_submit_urb+0x4c3/0x528 Let's improve the current situation, by not re-submiting the urb if we are stopping the status event. Also process the queued work (if any) during stop. CPU 0 CPU 1 =3D=3D=3D=3D=3D =3D=3D=3D=3D=3D uvc_status_complete() uvc_status_stop() uvc_status_start() uvc_ctrl_status_event_work() -> FAIL Hopefully, with the usb layer protection this should be enough to cover all the cases. Cc: stable@vger.kernel.org Fixes: e5225c820c05 ("media: uvcvideo: Send a control event when a Control = Change interrupt arrives") Reviewed-by: Yunke Cao Signed-off-by: Ricardo Ribalda --- uvc: Fix race condition on uvc Make sure that all the async work is finished when we stop the status urb. To: Yunke Cao To: Sergey Senozhatsky To: Max Staudt To: Laurent Pinchart To: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- Changes in v4: - Replace bool with atomic_t to avoid compiler reordering - First complete the async work and then kill the urb to avoid race (Thanks= Laurent!) - Link to v3: https://lore.kernel.org/r/20221212-uvc-race-v3-0-954efc752c9a= @chromium.org Changes in v3: - Remove the patch for dev->status, makes more sense in another series, and= makes the zero day less nervous. - Update reviewed-by (thanks Yunke!). - Link to v2: https://lore.kernel.org/r/20221212-uvc-race-v2-0-54496cc3b8ab= @chromium.org Changes in v2: - Add a patch for not kalloc dev->status - Redo the logic mechanism, so it also works with suspend (Thanks Yunke!) - Link to v1: https://lore.kernel.org/r/20221212-uvc-race-v1-0-c52e1783c31d= @chromium.org --- drivers/media/usb/uvc/uvc_ctrl.c | 3 +++ drivers/media/usb/uvc/uvc_status.c | 6 ++++++ drivers/media/usb/uvc/uvcvideo.h | 1 + 3 files changed, 10 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_c= trl.c index c95a2229f4fa..1be6897a7d6d 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1442,6 +1442,9 @@ static void uvc_ctrl_status_event_work(struct work_st= ruct *work) =20 uvc_ctrl_status_event(w->chain, w->ctrl, w->data); =20 + if (atomic_read(&dev->flush_status)) + return; + /* Resubmit the URB. */ w->urb->interval =3D dev->int_ep->desc.bInterval; ret =3D usb_submit_urb(w->urb, GFP_KERNEL); diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc= _status.c index 7518ffce22ed..4a95850cdc1b 100644 --- a/drivers/media/usb/uvc/uvc_status.c +++ b/drivers/media/usb/uvc/uvc_status.c @@ -304,10 +304,16 @@ int uvc_status_start(struct uvc_device *dev, gfp_t fl= ags) if (dev->int_urb =3D=3D NULL) return 0; =20 + atomic_set(&dev->flush_status, 0); return usb_submit_urb(dev->int_urb, flags); } =20 void uvc_status_stop(struct uvc_device *dev) { + struct uvc_ctrl_work *w =3D &dev->async_ctrl; + + atomic_set(&dev->flush_status, 1); + if (cancel_work_sync(&w->work)) + uvc_ctrl_status_event(w->chain, w->ctrl, w->data); usb_kill_urb(dev->int_urb); } diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvi= deo.h index df93db259312..1274691f157f 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -560,6 +560,7 @@ struct uvc_device { struct usb_host_endpoint *int_ep; struct urb *int_urb; u8 *status; + atomic_t flush_status; struct input_dev *input; char input_phys[64]; =20 --- base-commit: 0ec5a38bf8499f403f81cb81a0e3a60887d1993c change-id: 20221212-uvc-race-09276ea68bf8 Best regards, --=20 Ricardo Ribalda