From: Oliver Neukum <oliver@neukum.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Valentine Barshak <vbarshak@mvista.com>,
Jiri Kosina <jkosina@suse.cz>,
linux-usb@vger.kernel.org, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: USBHID: Fix race between disconnect and hiddev_ioctl
Date: Sat, 4 Dec 2010 21:22:23 +0100 [thread overview]
Message-ID: <201012042122.23852.oliver@neukum.org> (raw)
In-Reply-To: <20101203231611.GB22969@core.coreip.homeip.net>
Am Samstag, 4. Dezember 2010, 00:16:12 schrieb Dmitry Torokhov:
> > Since disconnect can happen at any time, we can't initialize
> > struct hid_device *hid = hiddev->hid at the beginning of ioctl
> > and then use it.
> >
> > This change checks hiddev->exist flag while holding
> > the existancelock and uses hid_device only if it exists.
>
> Why didn't you take the lock and check hiddev->exist at the beginning of
> ioctl handler instead of pushing it down into individual command
> handlers? I guess it would slow down HIDIOCGVERSION but I think we could
> pay this price for code that is more clear ;)
Strictly speaking you'd change the semantics. Right now you can execute
the ioctl even if you know you are holding an fd to a disconnected device
open.
Regards
Oliver
next prev parent reply other threads:[~2010-12-04 20:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-03 17:27 Valentine Barshak
2010-12-03 23:16 ` Dmitry Torokhov
2010-12-03 23:31 ` Valentine Barshak
2010-12-04 20:22 ` Oliver Neukum [this message]
2010-12-04 20:37 ` Dmitry Torokhov
2010-12-06 14:03 ` Valentine Barshak
2010-12-06 15:25 ` Valentine Barshak
2010-12-03 17:52 Valentine Barshak
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