From: Oliver Neukum <oneukum@suse.de>
To: Jiri Kosina <jkosina@suse.cz>
Cc: linux-input@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: possible race between reset and error handling in usbhid
Date: Fri, 14 Oct 2011 08:37:29 +0200 [thread overview]
Message-ID: <201110140837.29660.oneukum@suse.de> (raw)
In-Reply-To: <alpine.LNX.2.00.1110131819500.14768@pobox.suse.cz>
Am Donnerstag, 13. Oktober 2011, 18:20:52 schrieb Jiri Kosina:
> On Wed, 12 Oct 2011, Oliver Neukum wrote:
>
> > looking at the usbhid code it seems to me that there is no protection
> > between the error handling code and pre_reset() racing.
> >
> > In particular there seems to be no protection from hid_retry_timeout() calling
> > hid_start_in() which would start IO after hid_pre_reset() has already called
> > hid_cease_io() because that uses del_timer(), not del_timer_sync()
> >
> > What do you think about this patch?
>
> Looks like you made a good catch, thanks. Out of curiosity -- did you
> encounter this happening for real, or have you find out by code reading?
A bit of both. I was looking for causes of a mysterious bug report that
just mentions HID devices and resets and is known to be a race.
So I may have indirectly encountered it.
Regards
Oliver
prev parent reply other threads:[~2011-10-14 6:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-12 14:14 possible race between reset and error handling in usbhid Oliver Neukum
2011-10-13 16:20 ` Jiri Kosina
2011-10-14 6:37 ` Oliver Neukum [this message]
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