From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754346Ab1IFNNi (ORCPT ); Tue, 6 Sep 2011 09:13:38 -0400 Received: from smtp-vbr9.xs4all.nl ([194.109.24.29]:1677 "EHLO smtp-vbr9.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753470Ab1IFNNb (ORCPT ); Tue, 6 Sep 2011 09:13:31 -0400 From: Hans Verkuil To: Laurent Pinchart Subject: Re: [PATCH] v4l2: uvcvideo use after free bug fix Date: Tue, 6 Sep 2011 15:02:54 +0200 User-Agent: KMail/1.13.7 (Linux/3.0-3.slh.1-aptosid-amd64; KDE/4.6.5; x86_64; ; ) Cc: Dave Young , Sitsofe Wheeler , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Guennadi Liakhovetski , Mauro Carvalho Chehab References: <20110906120808.GC2321@darkstar> <201109061412.16088.laurent.pinchart@ideasonboard.com> In-Reply-To: <201109061412.16088.laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201109061502.54340.hverkuil@xs4all.nl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, September 06, 2011 14:12:14 Laurent Pinchart wrote: > Hans, > > On Tuesday 06 September 2011 14:08:08 Dave Young wrote: > > Reported-by: Sitsofe Wheeler > > Signed-off-by: Dave Young > > Tested-by: Sitsofe Wheeler > > Acked-by: Laurent Pinchart > > > > Unplugging uvc video camera trigger following oops: > > > > eeepc kernel: [ 1393.500719] usb 3-2: USB disconnect, device number 4 > > eeepc kernel: [ 1393.504351] uvcvideo: Failed to resubmit video URB (-19). > > eeepc kernel: [ 1495.428853] BUG: unable to handle kernel paging request at > > 6b6b6bcb eeepc kernel: [ 1495.429017] IP: [] > > dev_get_drvdata+0x17/0x20 eeepc kernel: [ 1495.429017] *pde = 00000000 > > eeepc kernel: [ 1495.429017] Oops: 0000 [#1] DEBUG_PAGEALLOC > > eeepc kernel: [ 1495.429017] > > eeepc kernel: [ 1495.429017] Pid: 3476, comm: cheese Not tainted > > 3.1.0-rc3-00270-g7a54f5e-dirty #485 ASUSTeK Computer INC. 900/900 eeepc > > kernel: [ 1495.429017] EIP: 0060:[] EFLAGS: 00010202 CPU: 0 > > eeepc kernel: [ 1495.429017] EIP is at dev_get_drvdata+0x17/0x20 > > eeepc kernel: [ 1495.429017] EAX: 6b6b6b6b EBX: eb08d870 ECX: 00000000 EDX: > > eb08d930 eeepc kernel: [ 1495.429017] ESI: eb08d870 EDI: eb08d870 EBP: > > d3249cac ESP: d3249cac eeepc kernel: [ 1495.429017] DS: 007b ES: 007b FS: > > 0000 GS: 00e0 SS: 0068 eeepc kernel: [ 1495.429017] Process cheese (pid: > > 3476, ti=d3248000 task=df46d870 task.ti=d3248000) eeepc kernel: [ > > 1495.429017] Stack: > > eeepc kernel: [ 1495.429017] d3249cb8 b03e77a1 d307b840 d3249ccc b03e77d1 > > d307b840 eb08d870 eb08d830 eeepc kernel: [ 1495.429017] d3249ce4 b03ed3b7 > > 00000246 d307b840 eb08d870 d3021b80 d3249cec b03ed565 eeepc kernel: [ > > 1495.429017] d3249cfc b03e044d e8323d10 b06e013c d3249d18 b0355fb9 > > fffffffe d3249d1c eeepc kernel: [ 1495.429017] Call Trace: > > eeepc kernel: [ 1495.429017] [] v4l2_device_disconnect+0x11/0x30 > > eeepc kernel: [ 1495.429017] [] v4l2_device_unregister+0x11/0x50 > > eeepc kernel: [ 1495.429017] [] uvc_delete+0x37/0x110 > > eeepc kernel: [ 1495.429017] [] uvc_release+0x25/0x30 > > eeepc kernel: [ 1495.429017] [] v4l2_device_release+0x9d/0xc0 > > eeepc kernel: [ 1495.429017] [] device_release+0x19/0x90 > > eeepc kernel: [ 1495.429017] [] ? usb_hcd_unlink_urb+0x7c/0x90 > > eeepc kernel: [ 1495.429017] [] kobject_release+0x3c/0x90 > > eeepc kernel: [ 1495.429017] [] ? kobject_del+0x30/0x30 > > eeepc kernel: [ 1495.429017] [] kref_put+0x2c/0x60 > > eeepc kernel: [ 1495.429017] [] kobject_put+0x1d/0x50 > > eeepc kernel: [ 1495.429017] [] ? > > usb_autopm_put_interface+0x25/0x30 eeepc kernel: [ 1495.429017] > > [] ? uvc_v4l2_release+0x5d/0xd0 eeepc kernel: [ 1495.429017] > > [] put_device+0xf/0x20 > > eeepc kernel: [ 1495.429017] [] v4l2_release+0x56/0x60 > > eeepc kernel: [ 1495.429017] [] fput+0xcc/0x220 > > eeepc kernel: [ 1495.429017] [] filp_close+0x44/0x70 > > eeepc kernel: [ 1495.429017] [] put_files_struct+0x158/0x180 > > eeepc kernel: [ 1495.429017] [] ? put_files_struct+0x20/0x180 > > eeepc kernel: [ 1495.429017] [] exit_files+0x40/0x50 > > eeepc kernel: [ 1495.429017] [] do_exit+0x5a7/0x660 > > eeepc kernel: [ 1495.429017] [] ? __dequeue_signal+0x12/0x120 > > eeepc kernel: [ 1495.429017] [] ? _raw_spin_unlock_irq+0x22/0x30 > > eeepc kernel: [ 1495.429017] [] do_group_exit+0x3c/0xb0 > > eeepc kernel: [ 1495.429017] [] ? trace_hardirqs_on+0xb/0x10 > > eeepc kernel: [ 1495.429017] [] > > get_signal_to_deliver+0x18f/0x570 eeepc kernel: [ 1495.429017] > > [] do_signal+0x47/0x9e0 > > eeepc kernel: [ 1495.429017] [] ? _raw_spin_unlock_irq+0x22/0x30 > > eeepc kernel: [ 1495.429017] [] ? trace_hardirqs_on+0xb/0x10 > > eeepc kernel: [ 1495.429017] [] ? T.1034+0x30/0xc0 > > eeepc kernel: [ 1495.429017] [] ? schedule+0x29f/0x640 > > eeepc kernel: [ 1495.429017] [] do_notify_resume+0x38/0x40 > > eeepc kernel: [ 1495.429017] [] work_notifysig+0x9/0x11 > > eeepc kernel: [ 1495.429017] Code: e5 5d 83 f8 01 19 c0 f7 d0 83 e0 f0 c3 > > 8d b4 26 00 00 00 00 55 85 c0 89 e5 75 09 31 c0 5d c3 90 8d 74 26 00 8b 40 > > 04 85 c0 74 f0 <8b> 40 60 5d c3 8d 74 26 00 55 89 e5 53 89 c3 83 ec 04 8b > > 40 04 eeepc kernel: [ 1495.429017] EIP: [] > > dev_get_drvdata+0x17/0x20 SS:ESP 0068:d3249cac eeepc kernel: [ > > 1495.429017] CR2: 000000006b6b6bcb > > eeepc kernel: [ 1495.466975] uvcvideo: Failed to resubmit video URB (-27). > > eeepc kernel: [ 1495.467860] uvcvideo: Failed to resubmit video URB (-27). > > eeepc kernel: last message repeated 3 times > > eeepc kernel: [ 1495.512610] ---[ end trace 73ec16848794e5a5 ]--- > > > > For uvc device, dev->vdev.dev is the &intf->dev, > > uvc_delete code is as below: > > usb_put_intf(dev->intf); > > usb_put_dev(dev->udev); > > > > uvc_status_cleanup(dev); > > uvc_ctrl_cleanup_device(dev); > > > > ## the intf dev is released above, so below code will oops. > > > > if (dev->vdev.dev) > > v4l2_device_unregister(&dev->vdev); > > > > Fix it by get_device in v4l2_device_register and put_device in > > v4l2_device_disconnect --- > > drivers/media/video/v4l2-device.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/media/video/v4l2-device.c > > b/drivers/media/video/v4l2-device.c index c72856c..e6a2c3b 100644 > > --- a/drivers/media/video/v4l2-device.c > > +++ b/drivers/media/video/v4l2-device.c > > @@ -38,6 +38,7 @@ int v4l2_device_register(struct device *dev, struct > > v4l2_device *v4l2_dev) mutex_init(&v4l2_dev->ioctl_lock); > > v4l2_prio_init(&v4l2_dev->prio); > > kref_init(&v4l2_dev->ref); > > + get_device(dev); > > v4l2_dev->dev = dev; > > We store a reference to the device in v4l2_dev, and we use it later. We thus > need either get a reference to the device (like done by this patch), or > mandate drivers not to release their reference to the device before calling > v4l2_device_unregister and/or v4l2_device_disconnect (in this case that would > mean moving the usb_put_intf call after the v4l2_device_unregister call in the > uvcvideo driver). > > Do you have a preference ? My preference would be to get a reference ourselves, but I don't have the time to fully analyze this. So I leave that to you. Regards, Hans > > > if (dev == NULL) { > > /* If dev == NULL, then name must be filled in by the caller */ > > @@ -93,6 +94,7 @@ void v4l2_device_disconnect(struct v4l2_device *v4l2_dev) > > > > if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev) > > dev_set_drvdata(v4l2_dev->dev, NULL); > > + put_device(v4l2_dev->dev); > > v4l2_dev->dev = NULL; > > } > > EXPORT_SYMBOL_GPL(v4l2_device_disconnect); > >