From patchwork Sun Aug 30 15:04:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 11745193 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A263F1751 for ; Sun, 30 Aug 2020 15:05:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88B2020720 for ; Sun, 30 Aug 2020 15:05:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="h8YR4hed" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727078AbgH3PFx (ORCPT ); Sun, 30 Aug 2020 11:05:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726388AbgH3PEv (ORCPT ); Sun, 30 Aug 2020 11:04:51 -0400 Received: from mail-oi1-x242.google.com (mail-oi1-x242.google.com [IPv6:2607:f8b0:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1FE3C061573; Sun, 30 Aug 2020 08:04:50 -0700 (PDT) Received: by mail-oi1-x242.google.com with SMTP id j7so4986886oij.9; Sun, 30 Aug 2020 08:04:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=OYzNNlQnqbfdrR5BIEiLRBleJJxXkTs1ZX+qGsGLh84=; b=h8YR4hedSi8kp7nYNZN7j/BPhMClAEoyXxVj33nY231jl6DtXzhAWk52ftw1kGvj4H l2TFZ0egurTwgfPeAXv4ySlV4KmK7W7TeY/2Yb+cQAJlERF63uPSGz5XDLUwK3S/mMMu 5Ud3oIHE6GTv3eKFqVTtE0Kmpq9ty2AYAg4qItPaf4kvYZZQv3r5gwqq5oHo0K3rgHBN suJz8sVzirqw6yBCJp1Nci0/suOKUYEAl0thM+5EN216NX6sbktHP5HWFV4LpIYvxvP5 mX0jNA/idyX6Paq8l6YtOW0v6NFQx5GPVP5lxjGn2IKI7awLa3DYZl6q6tMjVTm+8tM7 gBWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=OYzNNlQnqbfdrR5BIEiLRBleJJxXkTs1ZX+qGsGLh84=; b=INryj1UCUcIC8t7G4w4Gv/+77hLWXLapUAhkVe/s11/HHRL5RKAbthazPWpdf0QAe7 Q68KwyxP3uaDvf9iNm7VZ/SiJjqvt+EsRXLfQAdu9rpF9f0LFixpA+QBItSjExPyAq3I ntS/DsenK6AzWdSixbFqa3QmEqsDOMAgKLrvb3j+IZaiFO+Q/iQzIog2PkMpjwQyNOPD 0XVPkZH7qej6FSjjPFxUiBCP0e4mS2tjhiZLPuFCgNQlm3NZ60LnZmew+pq+iNMxTxu6 OUjicN++RqpKzzw4K62DusVHdfeA7tyUO3e0aw5ebn3JIp3e68YER0Wkfjs+Bs+4YTic tg9w== X-Gm-Message-State: AOAM530C99QwJKYcqdBLzpGlaRzmBn8jRRFlAAAgfveV3NU6rIc0v9jX iwqVeu6aRKtMNfwaMYHtVRk= X-Google-Smtp-Source: ABdhPJwOfWD7+aGHr0WUHi0M8wt0arY6aznSeE7vZseyiAI0QaYuT0UPhOeyhcOIY3epqg3aPohAVA== X-Received: by 2002:a05:6808:7c8:: with SMTP id f8mr1242699oij.119.1598799889315; Sun, 30 Aug 2020 08:04:49 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id q9sm882356ooe.33.2020.08.30.08.04.48 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 30 Aug 2020 08:04:48 -0700 (PDT) From: Guenter Roeck To: Laurent Pinchart Cc: Mauro Carvalho Chehab , Sakari Ailus , linux-uvc-devel@lists.sourceforge.net, linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck , Alan Stern , Hans Verkuil Subject: [PATCH 1/5] media: uvcvideo: Cancel async worker earlier Date: Sun, 30 Aug 2020 08:04:39 -0700 Message-Id: <20200830150443.167286-2-linux@roeck-us.net> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200830150443.167286-1-linux@roeck-us.net> References: <20200830150443.167286-1-linux@roeck-us.net> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org So far the asynchronous control worker was canceled only in uvc_ctrl_cleanup_device. This is much later than the call to uvc_disconnect. However, after the call to uvc_disconnect returns, there must be no more USB activity. This can result in all kinds of problems in the USB code. One observed example: URB ffff993e83d0bc00 submitted while active WARNING: CPU: 0 PID: 4046 at drivers/usb/core/urb.c:364 usb_submit_urb+0x4ba/0x55e Modules linked in: <...> CPU: 0 PID: 4046 Comm: kworker/0:35 Not tainted 4.19.139 #18 Hardware name: Google Phaser/Phaser, BIOS Google_Phaser.10952.0.0 08/09/2018 Workqueue: events uvc_ctrl_status_event_work [uvcvideo] RIP: 0010:usb_submit_urb+0x4ba/0x55e Code: <...> RSP: 0018:ffffb08d471ebde8 EFLAGS: 00010246 RAX: a6da85d923ea5d00 RBX: ffff993e71985928 RCX: 0000000000000000 RDX: ffff993f37a1de90 RSI: ffff993f37a153d0 RDI: ffff993f37a153d0 RBP: ffffb08d471ebe28 R08: 000000000000003b R09: 001424bf85822e96 R10: 0000001000000000 R11: ffffffff975a4398 R12: ffff993e83d0b000 R13: ffff993e83d0bc00 R14: 0000000000000000 R15: 00000000fffffff0 FS: 0000000000000000(0000) GS:ffff993f37a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000ec9c0000 CR3: 000000025b160000 CR4: 0000000000340ef0 Call Trace: uvc_ctrl_status_event_work+0xd6/0x107 [uvcvideo] process_one_work+0x19b/0x4c5 worker_thread+0x10d/0x286 kthread+0x138/0x140 ? process_one_work+0x4c5/0x4c5 ? kthread_associate_blkcg+0xc1/0xc1 ret_from_fork+0x1f/0x40 Introduce new function uvc_ctrl_stop_device() to cancel the worker and call it from uvc_unregister_video() to solve the problem. Cc: Laurent Pinchart Cc: Alan Stern Cc: Hans Verkuil Signed-off-by: Guenter Roeck --- drivers/media/usb/uvc/uvc_ctrl.c | 11 +++++++---- drivers/media/usb/uvc/uvc_driver.c | 1 + drivers/media/usb/uvc/uvcvideo.h | 1 + 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index e399b9fad757..130c56e0063d 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -2340,14 +2340,17 @@ static void uvc_ctrl_cleanup_mappings(struct uvc_device *dev, } } -void uvc_ctrl_cleanup_device(struct uvc_device *dev) +void uvc_ctrl_stop_device(struct uvc_device *dev) { - struct uvc_entity *entity; - unsigned int i; - /* Can be uninitialized if we are aborting on probe error. */ if (dev->async_ctrl.work.func) cancel_work_sync(&dev->async_ctrl.work); +} + +void uvc_ctrl_cleanup_device(struct uvc_device *dev) +{ + struct uvc_entity *entity; + unsigned int i; /* Free controls and control mappings for all entities. */ list_for_each_entry(entity, &dev->entities, list) { diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 431d86e1c94b..bfba67a69185 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1952,6 +1952,7 @@ static void uvc_unregister_video(struct uvc_device *dev) } uvc_status_unregister(dev); + uvc_ctrl_stop_device(dev); if (dev->vdev.dev) v4l2_device_unregister(&dev->vdev); diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h index 6ab972c643e3..543afcd9fd26 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -830,6 +830,7 @@ int uvc_query_v4l2_menu(struct uvc_video_chain *chain, int uvc_ctrl_add_mapping(struct uvc_video_chain *chain, const struct uvc_control_mapping *mapping); int uvc_ctrl_init_device(struct uvc_device *dev); +void uvc_ctrl_stop_device(struct uvc_device *dev); void uvc_ctrl_cleanup_device(struct uvc_device *dev); int uvc_ctrl_restore_values(struct uvc_device *dev); bool uvc_ctrl_status_event(struct urb *urb, struct uvc_video_chain *chain, From patchwork Sun Aug 30 15:04:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 11745183 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 00FB7739 for ; Sun, 30 Aug 2020 15:05:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D52FF20757 for ; Sun, 30 Aug 2020 15:05:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XnhYXd4o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726589AbgH3PFN (ORCPT ); Sun, 30 Aug 2020 11:05:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726404AbgH3PEw (ORCPT ); Sun, 30 Aug 2020 11:04:52 -0400 Received: from mail-oi1-x242.google.com (mail-oi1-x242.google.com [IPv6:2607:f8b0:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE371C061575; Sun, 30 Aug 2020 08:04:51 -0700 (PDT) Received: by mail-oi1-x242.google.com with SMTP id y6so1783000oie.5; Sun, 30 Aug 2020 08:04:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=EA6cVmvUSvTNBygQ//XKPSrIb6L3Na4NjlVN7lTwXxg=; b=XnhYXd4owlC48q5pHppL8pWHP5eIa4NA+vZjkreSJx5XrzXu/D+uOyVtG13Qg+/8vo ZeWGKOAIgfGhJGp/4tsfzfAfcbtgW5sieQwRuJQG4j51GclVbX+YE8l3Q3fz7nwyKh0b pgIXArNjOQ9C5e9Aw1Au7TfRq5DCkoH6Ifd50pTXNQIl85QoCf2Kcut2tmm6Zfhfskj7 kekMi01qR5+iZMRFg2fEz0dJSMoqN+FRc6fis4bXxizOcEpRjpIyBvDDSULKVV0SJ6jI 5QpfG3lsvNgvunJYAU/NbPJfzG2S46wmMYU+h4P+UEANhJZAXEJh8oO1vMrNlNkDDMW0 ROAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=EA6cVmvUSvTNBygQ//XKPSrIb6L3Na4NjlVN7lTwXxg=; b=PnKFkvWd489b9UlKj1PQo+9r9tkqd4Vhb+hh48JBmTgByZJ+faJsBNc+qF8hNqfdTx Rt/I5UqSQmeuGMnn+21TMiusRPq4ijbInJvRjCiXtly+UZ0Rl86z9JPmLl/c2D+SPXFa AaTt3dQ7vlgNUyJSvQSHDBdTqdxxvib3KT6xeb4WeG+YrgvOK+ypiTQN7PuSHR14Fghi NUFy3VlN8GS2kxPdt3/xh88OeHx8GOdVU1XuJajOg6JLeFlO1Eu+E2q+TP/PXEGyfnqp MDeOHZHKf6kSxv8qF6j4pboa5b7uDCNj8vdMr4b6iP7kymWQBM6udR60VHPinSs9KNsN m++Q== X-Gm-Message-State: AOAM531AvwDIgLiQFvrB2BB+4ruR+9PAq3kuOhrF2DuqAtOH5SMFa00d d/yiBTObpOpFTCTgtLgFCdk= X-Google-Smtp-Source: ABdhPJyjiyp/u2wu+8G/I/KCDNXt4GO4vFz3W1cns6AhTEUFrg+p04IunHBMIk5k5HWKPfLJeujM+A== X-Received: by 2002:a05:6808:7dc:: with SMTP id f28mr1364574oij.26.1598799891024; Sun, 30 Aug 2020 08:04:51 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id z10sm1198394otk.6.2020.08.30.08.04.50 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 30 Aug 2020 08:04:50 -0700 (PDT) From: Guenter Roeck To: Laurent Pinchart Cc: Mauro Carvalho Chehab , Sakari Ailus , linux-uvc-devel@lists.sourceforge.net, linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck , Alan Stern , Hans Verkuil Subject: [PATCH 2/5] media: uvcvideo: Lock video streams and queues while unregistering Date: Sun, 30 Aug 2020 08:04:40 -0700 Message-Id: <20200830150443.167286-3-linux@roeck-us.net> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200830150443.167286-1-linux@roeck-us.net> References: <20200830150443.167286-1-linux@roeck-us.net> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The call to uvc_disconnect() is not protected by any mutex. This means it can and will be called while other accesses to the video device are in progress. This can cause all kinds of race conditions, including crashes such as the following. usb 1-4: USB disconnect, device number 3 BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 5633 Comm: V4L2CaptureThre Not tainted 4.19.113-08536-g5d29ca36db06 #1 Hardware name: GOOGLE Edgar, BIOS Google_Edgar.7287.167.156 03/25/2019 RIP: 0010:usb_ifnum_to_if+0x29/0x40 Code: <...> RSP: 0018:ffffa46f42a47a80 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff904a396c9000 RDX: ffff904a39641320 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffa46f42a47a80 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000009975 R11: 0000000000000009 R12: 0000000000000000 R13: ffff904a396b3800 R14: ffff904a39e88000 R15: 0000000000000000 FS: 00007f396448e700(0000) GS:ffff904a3ba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000016cb46000 CR4: 00000000001006f0 Call Trace: usb_hcd_alloc_bandwidth+0x1ee/0x30f usb_set_interface+0x1a3/0x2b7 uvc_video_start_transfer+0x29b/0x4b8 [uvcvideo] uvc_video_start_streaming+0x91/0xdd [uvcvideo] uvc_start_streaming+0x28/0x5d [uvcvideo] vb2_start_streaming+0x61/0x143 [videobuf2_common] vb2_core_streamon+0xf7/0x10f [videobuf2_common] uvc_queue_streamon+0x2e/0x41 [uvcvideo] uvc_ioctl_streamon+0x42/0x5c [uvcvideo] __video_do_ioctl+0x33d/0x42a video_usercopy+0x34e/0x5ff ? video_ioctl2+0x16/0x16 v4l2_ioctl+0x46/0x53 do_vfs_ioctl+0x50a/0x76f ksys_ioctl+0x58/0x83 __x64_sys_ioctl+0x1a/0x1e do_syscall_64+0x54/0xde usb_set_interface() should not be called after the USB device has been unregistered. However, in the above case the disconnect happened after v4l2_ioctl() was called, but before the call to usb_ifnum_to_if(). Acquire various mutexes in uvc_unregister_video() to fix the majority (maybe all) of the observed race conditions. The uvc_device lock prevents races against suspend and resume calls and the poll function. The uvc_streaming lock prevents races against stream related functions; for the most part, those are ioctls. This lock also requires other functions using this lock to check if a video device is still registered after acquiring it. For example, it was observed that the video device was already unregistered by the time the stream lock was acquired in uvc_ioctl_streamon(). The uvc_queue lock prevents races against queue functions, Most of those are already protected by the uvc_streaming lock, but some are called directly. This is done as added protection; an actual race was not (yet) observed. Cc: Laurent Pinchart Cc: Alan Stern Cc: Hans Verkuil Signed-off-by: Guenter Roeck --- drivers/media/usb/uvc/uvc_driver.c | 9 +++++++ drivers/media/usb/uvc/uvc_v4l2.c | 39 +++++++++++++++++++++++++++++- 2 files changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index bfba67a69185..a5808305f1e3 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1941,14 +1941,22 @@ static void uvc_unregister_video(struct uvc_device *dev) { struct uvc_streaming *stream; + mutex_lock(&dev->lock); + list_for_each_entry(stream, &dev->streams, list) { if (!video_is_registered(&stream->vdev)) continue; + mutex_lock(&stream->mutex); + mutex_lock(&stream->queue.mutex); + video_unregister_device(&stream->vdev); video_unregister_device(&stream->meta.vdev); uvc_debugfs_cleanup_stream(stream); + + mutex_unlock(&stream->queue.mutex); + mutex_unlock(&stream->mutex); } uvc_status_unregister(dev); @@ -1960,6 +1968,7 @@ static void uvc_unregister_video(struct uvc_device *dev) if (media_devnode_is_registered(dev->mdev.devnode)) media_device_unregister(&dev->mdev); #endif + mutex_unlock(&dev->lock); } int uvc_register_video_device(struct uvc_device *dev, diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 0335e69b70ab..7e5e583dae5e 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -237,6 +237,12 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream, * the Windows driver). */ mutex_lock(&stream->mutex); + if (!video_is_registered(&stream->vdev)) { + mutex_unlock(&stream->mutex); + ret = -ENODEV; + goto done; + } + if (stream->dev->quirks & UVC_QUIRK_PROBE_EXTRAFIELDS) probe->dwMaxVideoFrameSize = stream->ctrl.dwMaxVideoFrameSize; @@ -274,6 +280,12 @@ static int uvc_v4l2_get_format(struct uvc_streaming *stream, return -EINVAL; mutex_lock(&stream->mutex); + + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto done; + } + format = stream->cur_format; frame = stream->cur_frame; @@ -312,6 +324,11 @@ static int uvc_v4l2_set_format(struct uvc_streaming *stream, mutex_lock(&stream->mutex); + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto done; + } + if (uvc_queue_allocated(&stream->queue)) { ret = -EBUSY; goto done; @@ -387,6 +404,11 @@ static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream, mutex_lock(&stream->mutex); + if (!video_is_registered(&stream->vdev)) { + mutex_unlock(&stream->mutex); + return -ENODEV; + } + if (uvc_queue_streaming(&stream->queue)) { mutex_unlock(&stream->mutex); return -EBUSY; @@ -713,6 +735,10 @@ static int uvc_ioctl_reqbufs(struct file *file, void *fh, return ret; mutex_lock(&stream->mutex); + if (!video_is_registered(&stream->vdev)) { + mutex_unlock(&stream->mutex); + return -ENODEV; + } ret = uvc_request_buffers(&stream->queue, rb); mutex_unlock(&stream->mutex); if (ret < 0) @@ -797,7 +823,12 @@ static int uvc_ioctl_streamon(struct file *file, void *fh, return -EBUSY; mutex_lock(&stream->mutex); + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto unlock; + } ret = uvc_queue_streamon(&stream->queue, type); +unlock: mutex_unlock(&stream->mutex); return ret; @@ -808,15 +839,21 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh, { struct uvc_fh *handle = fh; struct uvc_streaming *stream = handle->stream; + int ret = 0; if (!uvc_has_privileges(handle)) return -EBUSY; mutex_lock(&stream->mutex); + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto unlock; + } uvc_queue_streamoff(&stream->queue, type); +unlock: mutex_unlock(&stream->mutex); - return 0; + return ret; } static int uvc_ioctl_enum_input(struct file *file, void *fh, From patchwork Sun Aug 30 15:04:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 11745187 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9CE7C1709 for ; Sun, 30 Aug 2020 15:05:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8470120EDD for ; Sun, 30 Aug 2020 15:05:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oIywOkO7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726845AbgH3PFQ (ORCPT ); Sun, 30 Aug 2020 11:05:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726430AbgH3PEy (ORCPT ); Sun, 30 Aug 2020 11:04:54 -0400 Received: from mail-ot1-x343.google.com (mail-ot1-x343.google.com [IPv6:2607:f8b0:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48CAAC061236; Sun, 30 Aug 2020 08:04:53 -0700 (PDT) Received: by mail-ot1-x343.google.com with SMTP id i4so270069ota.2; Sun, 30 Aug 2020 08:04:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=pMRtD6tzB0RfchkgrwI0vaPh8EOiJQaXxLNReVAOoxQ=; b=oIywOkO7Lkwid5PbB8cZGWceW9jnT9dfHQdi7ZtIXdTVRSXFVnaOMrg7SLMadALZME JJ+m1bxfgn+QY3zfwNicERjnkWt2wVP4ZcjkWP/g+jL7r7RoW992yxpcd4vIAIo7Havg 24o4uXcPGfkIx/d/sgVrMQ50b5THtqJJznnJFtmfzxSDLHutc/7rcL+q5Lb+PTwzGGds Pxuq+f/7FylqQR7/SUaoWeuPBfULol4t3p9tgZHjTVFFUekoqC94D1pXDRP3XjnEXbS4 95XOIWJ3aA1cUqkZJE7WVS2rxkma2E8yl5FJ3tKt5thOBcvoHTQda2oUDGS8d0fZK39z mWxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=pMRtD6tzB0RfchkgrwI0vaPh8EOiJQaXxLNReVAOoxQ=; b=qgnfq8C11aPelUJ0wlIrGNt+ySLeE0G+JhVBhR2hK4LvVusIHCknfL5NvtPkHqGoUs lmOteu/c9xUUymFcgh1MNiB2ftNRBsFmraDEF/7X87oO9brMi/n9U8GAcQEIHRPEXsx5 1Xp7axW4nmxWXKnXdqAy1n5bNAEgfMpx6OXzmTn3kgQ+TPReVVTiKS5fOBNw1wye2gl9 1jc9pbvYVvMX32kpNm9ODyHDGeXJE8a3bmQtdXimw4SKOecctvxv4we7DeUfxYRaITfC 8DNcra6ihkVTRbmIMNNAnjH9eA35CbeMGV16PBCPCZirSYfSYHosj/Gal0GvET/48PN/ 27lA== X-Gm-Message-State: AOAM530kkx8MgkU6R2zPjPOKxRWSJS+rM3rmRpLkORXOkGrH9C3mvOKr xWpbBjmz8pePXPG3vCwGRfU= X-Google-Smtp-Source: ABdhPJzNXaJe84a7D3sO9IMj6DbCTnxSY+tjf3ivhYJjiaQTI++KHW5i280YyO85VME/1Gp3NeJi/g== X-Received: by 2002:a9d:620d:: with SMTP id g13mr4863159otj.165.1598799892727; Sun, 30 Aug 2020 08:04:52 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id z6sm1310838oot.18.2020.08.30.08.04.52 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 30 Aug 2020 08:04:52 -0700 (PDT) From: Guenter Roeck To: Laurent Pinchart Cc: Mauro Carvalho Chehab , Sakari Ailus , linux-uvc-devel@lists.sourceforge.net, linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck , Alan Stern , Hans Verkuil Subject: [PATCH 3/5] media: uvcvideo: Release stream queue when unregistering video device Date: Sun, 30 Aug 2020 08:04:41 -0700 Message-Id: <20200830150443.167286-4-linux@roeck-us.net> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200830150443.167286-1-linux@roeck-us.net> References: <20200830150443.167286-1-linux@roeck-us.net> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The following traceback was observed when stress testing the uvcvideo driver. config->interface[0] is NULL WARNING: CPU: 0 PID: 2757 at drivers/usb/core/usb.c:285 usb_ifnum_to_if+0x81/0x85 ^^^ added log message and WARN() to prevent crash Modules linked in: <...> CPU: 0 PID: 2757 Comm: inotify_reader Not tainted 4.19.139 #20 Hardware name: Google Phaser/Phaser, BIOS Google_Phaser.10952.0.0 08/09/2018 RIP: 0010:usb_ifnum_to_if+0x81/0x85 Code: <...> RSP: 0018:ffff9ee20141fa58 EFLAGS: 00010246 RAX: 438a0e5a525f1800 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff975477a1de90 RSI: ffff975477a153d0 RDI: ffff975477a153d0 RBP: ffff9ee20141fa70 R08: 000000000000002c R09: 002daec189138d78 R10: 0000001000000000 R11: ffffffffa7da42e6 R12: ffff975459594800 R13: 0000000000000001 R14: 0000000000000001 R15: ffff975465376400 FS: 00007ddebffd6700(0000) GS:ffff975477a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000012c83000 CR3: 00000001bbaf8000 CR4: 0000000000340ef0 Call Trace: usb_set_interface+0x3b/0x2f3 uvc_video_stop_streaming+0x38/0x81 [uvcvideo] uvc_stop_streaming+0x21/0x49 [uvcvideo] __vb2_queue_cancel+0x33/0x249 [videobuf2_common] vb2_core_queue_release+0x1c/0x45 [videobuf2_common] uvc_queue_release+0x26/0x32 [uvcvideo] uvc_v4l2_release+0x41/0xdd [uvcvideo] v4l2_release+0x99/0xed __fput+0xf0/0x1ea task_work_run+0x7f/0xa7 do_exit+0x1d1/0x6eb do_group_exit+0x9d/0xac get_signal+0x135/0x482 do_signal+0x4a/0x63c exit_to_usermode_loop+0x86/0xa5 do_syscall_64+0x171/0x269 ? __do_page_fault+0x272/0x474 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7ddec156dc26 Code: Bad RIP value. RSP: 002b:00007ddebffd5c10 EFLAGS: 00000293 ORIG_RAX: 0000000000000017 RAX: fffffffffffffdfe RBX: 000000000000000a RCX: 00007ddec156dc26 RDX: 0000000000000000 RSI: 00007ddebffd5d28 RDI: 000000000000000a RBP: 00007ddebffd5c50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007ddebffd5d28 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 When this was observed, a USB disconnect was in progress, uvc_disconnect() had returned, but usb_disable_device() was still running. Drivers are not supposed to call any USB functions after the driver disconnect function has been called. The uvcvideo driver does not follow that convention and tries to write to the disconnected USB interface anyway. This results in a variety of race conditions. To solve this specific problem, release the uvc queue from uvc_unregister_video() after the associated video devices have been unregistered. Since the function already holds the uvc queue mutex, bypass uvc_queue_release() and call vb2_queue_release() directly. Cc: Laurent Pinchart Cc: Alan Stern Cc: Hans Verkuil Signed-off-by: Guenter Roeck --- drivers/media/usb/uvc/uvc_driver.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index a5808305f1e3..27b72806b9b9 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1955,6 +1955,8 @@ static void uvc_unregister_video(struct uvc_device *dev) uvc_debugfs_cleanup_stream(stream); + vb2_queue_release(&stream->queue.queue); + mutex_unlock(&stream->queue.mutex); mutex_unlock(&stream->mutex); } From patchwork Sun Aug 30 15:04:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 11745201 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1FD4313A4 for ; Sun, 30 Aug 2020 15:06:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07CC120738 for ; Sun, 30 Aug 2020 15:06:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UpO3YKI6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727031AbgH3PFw (ORCPT ); Sun, 30 Aug 2020 11:05:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726479AbgH3PE5 (ORCPT ); Sun, 30 Aug 2020 11:04:57 -0400 Received: from mail-oi1-x244.google.com (mail-oi1-x244.google.com [IPv6:2607:f8b0:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75339C06123A; Sun, 30 Aug 2020 08:04:57 -0700 (PDT) Received: by mail-oi1-x244.google.com with SMTP id j7so4987008oij.9; Sun, 30 Aug 2020 08:04:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=ZkNcNHVU6ZdU0VSPf8SeudCLMA4dEM0Dg2KzNaFvtGE=; b=UpO3YKI6UQgD7Xdn2rcCT/uQz+L2twkbkTjDy+RojmAPSG+Gp4QIzNuK+DvVrIDVOJ eSo0BabTjvvpoWIgIGg3zxLBQ41gPRLZJXZ2MnzKWwp8S2DyMdnz5fmSb/0/d0alctqy rDJ2fMioRGlUtb7qkJInnbBD0CBQDIdkJt5sf4bU3E+94eQkP4gxDw9RCWFiyilego5D uikWnuZyngSfMiLP4XfFpx4/jJ3kNdxhjUNU9KylWY2aLlIZwFz0NS0qtS140N/Oa2ja x5+9MpHYWuSMtu0+5wAdfP3x7PWDZk1xs37OHDYgk4H4/aKHwpbeguwRaGOhMlnosBXd O1SA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=ZkNcNHVU6ZdU0VSPf8SeudCLMA4dEM0Dg2KzNaFvtGE=; b=tBYgxEGMfM33cDWIT5sEgNKLsmuLiWfpIRrzDoIeZFfwxW+W63HKTSK2OHbIgXFEP0 CIxClmnBITwi9uO1xdkY/X34DJo8A0/fGn396QYvY7wnNl2ZcKLWAg8if0lO4XTQYUH4 v3bLcpbIvfNhh4SD8ziFpmwEwTS1MaXm2f6spB7QO8o4Bv4ztntY5iOKUoudIoCtCrCl LCd7doDMRkENYYD194YGIhU4jq8FXUZxfrJ7Dr9BOfBLgC+WMbVCKA6rE4CpzBQ5BKZi nzVLPArBzVjFIfsuznpSZ3pr7nupYgeGluDV79WqNmbYSo1TkD9XR1ECwuyGDUFkXce9 Y3Bw== X-Gm-Message-State: AOAM531ESF2iH5/fAN24nFOAkV6glMz3zR6BA2/gXD8z8VROIk+PEsQD qBH7cF+TMWwf6LWYTp1hBxLvHaOuCVE= X-Google-Smtp-Source: ABdhPJwpwH5meTO8EaihTTnsgJ8Qc+B2Ncdt52ZwH/k3pp5avUFLREigtVwA9WXPHX1mCx7ZpeWqxQ== X-Received: by 2002:aca:4a13:: with SMTP id x19mr1474406oia.17.1598799894300; Sun, 30 Aug 2020 08:04:54 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id 111sm1192674otc.15.2020.08.30.08.04.53 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 30 Aug 2020 08:04:53 -0700 (PDT) From: Guenter Roeck To: Laurent Pinchart Cc: Mauro Carvalho Chehab , Sakari Ailus , linux-uvc-devel@lists.sourceforge.net, linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck , Alan Stern , Hans Verkuil Subject: [PATCH 4/5] media: uvcvideo: Protect uvc queue file operations against disconnect Date: Sun, 30 Aug 2020 08:04:42 -0700 Message-Id: <20200830150443.167286-5-linux@roeck-us.net> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200830150443.167286-1-linux@roeck-us.net> References: <20200830150443.167286-1-linux@roeck-us.net> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org uvc queue file operations have no mutex protection against USB disconnect. This is questionable at least for the poll operation, which has to wait for the uvc queue mutex. By the time that mutex has been acquired, is it possible that the video device has been unregistered. Protect all file operations by using the queue mutex to avoid possible race conditions. After acquiring the mutex, check if the video device is still registered, and bail out if not. Cc: Laurent Pinchart Cc: Alan Stern Cc: Hans Verkuil Signed-off-by: Guenter Roeck Reported-by: kernel test robot --- drivers/media/usb/uvc/uvc_queue.c | 32 +++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c index cd60c6c1749e..c7964177a99d 100644 --- a/drivers/media/usb/uvc/uvc_queue.c +++ b/drivers/media/usb/uvc/uvc_queue.c @@ -358,24 +358,52 @@ int uvc_queue_streamoff(struct uvc_video_queue *queue, enum v4l2_buf_type type) int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma) { - return vb2_mmap(&queue->queue, vma); + struct uvc_streaming *stream = uvc_queue_to_stream(queue); + int ret; + + mutex_lock(&queue->mutex); + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto unlock; + } + ret = vb2_mmap(&queue->queue, vma); +unlock: + mutex_unlock(&queue->mutex); + return ret; } #ifndef CONFIG_MMU unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue, unsigned long pgoff) { - return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0); + struct uvc_streaming *stream = uvc_queue_to_stream(queue); + unsigned long ret; + + mutex_lock(&queue->mutex); + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto unlock; + } + ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0); +unlock: + mutex_unlock(&queue->mutex); + return ret; } #endif __poll_t uvc_queue_poll(struct uvc_video_queue *queue, struct file *file, poll_table *wait) { + struct uvc_streaming *stream = uvc_queue_to_stream(queue); __poll_t ret; mutex_lock(&queue->mutex); + if (!video_is_registered(&stream->vdev)) { + ret = -ENODEV; + goto unlock; + } ret = vb2_poll(&queue->queue, file, wait); +unlock: mutex_unlock(&queue->mutex); return ret; From patchwork Sun Aug 30 15:04:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 11745197 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 634A21751 for ; Sun, 30 Aug 2020 15:06:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48104208DB for ; Sun, 30 Aug 2020 15:06:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MEaZJ54k" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727783AbgH3PFz (ORCPT ); Sun, 30 Aug 2020 11:05:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726454AbgH3PE4 (ORCPT ); Sun, 30 Aug 2020 11:04:56 -0400 Received: from mail-ot1-x343.google.com (mail-ot1-x343.google.com [IPv6:2607:f8b0:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CB05C061239; Sun, 30 Aug 2020 08:04:56 -0700 (PDT) Received: by mail-ot1-x343.google.com with SMTP id t7so3297445otp.0; Sun, 30 Aug 2020 08:04:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=Es4kZEIMvRU2zV/gMiYhHOsFVc+QsyIoOtUdccLtNdo=; b=MEaZJ54kn8cL89PvsI0AHlm+W5xJuRyQGLHXQJBrL4I3fuaJXmCbyZ6nZhjAW/rVVl ioztRcHskqevxCjpaGAy3vwF1LnJUUzrRJJGpWzAWW3w/eTle3LELOI8LrqBdzGPKHXo Z3oxCGg05PS088Jdi3J0thU5UPNJTPYI9LPOw41SgdwRZDtz5utlHAbcjF9NCX/cLJMU VZzdmibml4IJSpqRye+BN/PwYXl0q1Eut8+eeLC8IqB1DvW7VH72pF56b0hOP5WnKVMn TgrojcB2EPTt4s3uON8pytz3MsQu1SYqihc0dZKGjc4PnRP33oaqMJX//MoHX1bDAvHp gVXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=Es4kZEIMvRU2zV/gMiYhHOsFVc+QsyIoOtUdccLtNdo=; b=uX8nDeostAwKPdeRVgG7qUDiz58l8sx7ctkXd4XgG83igEvyXnEkIFGyxFNj0hNRIJ RFAa04+ftcZ48+n7OwPHZlerS5jVp4fQPZnJTzpnt6GpnjHOjY/8oFirKn1+ICozyduL gr+wrHyOyEiJ3uWTvwER7j2cJVAV6BSwPvhIxw16D+jWyQxYpiU2jAEqVcNI9njikpJ5 XTV3hjcD8BSEmEPE8QwbKM+cQz4NxVkapcW2cctGFiIZlW+toJR+5OGja5uj5u/qMSas UZi0HXuniCpMjvLX0HAnzl7IhbDhe4V1H0mh1UH2suTSCv7+fNtp/7ruLr4/7++uIZhE 5geg== X-Gm-Message-State: AOAM530AUhe+uRkBzwI7SgwUDYJc060C51P9/OYA/wHJva+FQ3owGoRS jXTn5Rm98HA/JMAfm5jVFfU= X-Google-Smtp-Source: ABdhPJzR6UopvhKv4I7vbbBAESp6f/cDqIX8GkcmhOErrU7gTQXke3+AEaBRjNvgANgCyyRAvjgugA== X-Received: by 2002:a9d:5e0c:: with SMTP id d12mr4761399oti.239.1598799895933; Sun, 30 Aug 2020 08:04:55 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id c15sm1101354oiy.13.2020.08.30.08.04.55 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sun, 30 Aug 2020 08:04:55 -0700 (PDT) From: Guenter Roeck To: Laurent Pinchart Cc: Mauro Carvalho Chehab , Sakari Ailus , linux-uvc-devel@lists.sourceforge.net, linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck , Alan Stern , Hans Verkuil Subject: [PATCH 5/5] media: uvcvideo: In uvc_v4l2_open, check if video device is registered Date: Sun, 30 Aug 2020 08:04:43 -0700 Message-Id: <20200830150443.167286-6-linux@roeck-us.net> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200830150443.167286-1-linux@roeck-us.net> References: <20200830150443.167286-1-linux@roeck-us.net> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org uvc_v4l2_open() acquires the uvc device mutex. After doing so, it does not check if the video device is still registered. This may result in race conditions and can result in an attempt to submit an urb to a disconnected USB interface (from uvc_v4l2_open). The problem was observed after adding a call to msleep() just before acquiring the mutex and disconnecting the camera during the sleep. Check if the video device is still registered after acquiring the mutex to avoid the problem. In the release function, only call uvc_status_stop() if the video device is still registered. If the video device has been unregistered, the urb associated with uvc status has already been killed in uvc_status_unregister(). Trying to kill it again won't do any good and might have unexpected side effects. Cc: Laurent Pinchart Cc: Alan Stern Cc: Hans Verkuil Signed-off-by: Guenter Roeck --- drivers/media/usb/uvc/uvc_v4l2.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 7e5e583dae5e..1f7d454557b9 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -548,6 +548,10 @@ static int uvc_v4l2_open(struct file *file) } mutex_lock(&stream->dev->lock); + if (!video_is_registered(&stream->vdev)) { + mutex_unlock(&stream->dev->lock); + return -ENODEV; + } if (stream->dev->users == 0) { ret = uvc_status_start(stream->dev, GFP_KERNEL); if (ret < 0) { @@ -590,7 +594,7 @@ static int uvc_v4l2_release(struct file *file) file->private_data = NULL; mutex_lock(&stream->dev->lock); - if (--stream->dev->users == 0) + if (--stream->dev->users == 0 && video_is_registered(&stream->vdev)) uvc_status_stop(stream->dev); mutex_unlock(&stream->dev->lock);