Re: [PATCH] usb: gadget: mv_u3d_core: fix violation of lockingdiscipline in mv_u3d_ep_disable()

From: Felipe Balbi
Date: Mon Jul 29 2013 - 09:59:50 EST


On Mon, Jul 29, 2013 at 05:15:58PM +0400, Alexey Khoroshilov wrote:
> On 07/29/2013 04:52 PM, Felipe Balbi wrote:
> > Hi,
> >
> > On Fri, Jul 26, 2013 at 07:26:05PM +0400, Alexey Khoroshilov wrote:
> >> On 07/25/2013 09:30 PM, Felipe Balbi wrote:
> >>> On Wed, Jul 24, 2013 at 12:20:17AM +0400, Alexey Khoroshilov wrote:
> >>>> mv_u3d_nuke() expects to be calles with ep->u3d->lock held,
> >>>> because mv_u3d_done() does. But mv_u3d_ep_disable() calls it
> >>>> without lock that can lead to unpleasant consequences.
> >>>>
> >>>> Found by Linux Driver Verification project (linuxtesting.org).
> >>>>
> >>>> Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
> >>> which commit introduced the bug ? Which kernels are affected by this bug ?
> >> The bug is present from the very beginning: commit 3d4eb9d of 15 June 2012.
> >> So it is in the mainline since v3.5.
> > Alright, do you want to have the same fix in stable kernels ? Is it
> > necessary at all or do we consider it 'never worked before' and send it
> > in the next merge window ?
>
> It is a tricky point. From one point of view it 'never worked before',
> but as far as the bug leads to a data race with unpredictable
> consequences I would prefer to have it fixed within 3.11 timeframe.

Alright, I have already sent my pull request for v3.11-rc3, so once -rc4
is tagged (in about a week) I'll send this patch.

--
balbi

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