linux-kernel - Re: [PATCH v4] media: ucvideo: Add quirk for Logitech Rally Bar

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Mon, 12 Feb 2024 13:22:42 +0100
From: Oliver Neukum <oneukum@...e.com>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Ricardo Ribalda <ribalda@...omium.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Alan Stern <stern@...land.harvard.edu>,
 Mauro Carvalho Chehab <mchehab@...nel.org>, linux-usb@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
 stable@...r.kernel.org
Subject: Re: [PATCH v4] media: ucvideo: Add quirk for Logitech Rally Bar

On 04.02.24 11:52, Laurent Pinchart wrote:
> Hi Ricardo,
> 
> Thank you for the patch.

Hi,

sorry for commenting on this late, but this patch has
a fundamental issue. In fact this issue is the reason the
handling for quirks is in usbcore at all.

If you leave the setting/clearing of this flag to a driver you
are introducing a race condition. The driver may or may not be
present at the time a device is enumerated. And you have
no idea how long the autosuspend delay is on a system
and what its default policy is regarding suspending
devices.
That means that a device can have been suspended and
resumed before it is probed. On a device that needs
RESET_RESUME, we are in trouble.
The inverse issue will arise if a device does not react
well to RESET_RESUME. You cannot rule out that a device
that must not be reset will be reset.

I am sorry, but it seems to me that the exceptions need
to go into usbcore.

	Regards
		Oliver