From: Andy Whitcroft <apw@canonical.com>
To: Dave Airlie <airlied@gmail.com>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/1] [RFC] DRM locking issues during early open
Date: Fri, 20 Apr 2012 18:25:40 +0100 [thread overview]
Message-ID: <20120420172540.GF3467@shadowen.org> (raw)
In-Reply-To: <CAPM=9txRi3=0=211S7RO=OqJwVPkFfQTtMC=DAhxZUUAW3voww@mail.gmail.com>
On Fri, Apr 20, 2012 at 11:34:43AM +0100, Dave Airlie wrote:
> >
> > I may be reading things wrong but the initialisation does indeed hold
> > drm_global_mutex, but and back when this first occured we would have
> > been using kernel_lock() which was at least partially reentrant right?
>
> Yup if we slept with the BKL held we'd have allowed others to get past it,
> but also I introduced the global mutex in pci a while back
Yeah I have managed to get access to more details on the bug, and
actually we are opening the drm device successfully, we then attempt a
DRM_SETVERSION ioctl on it and it is that that appears to fail both for
1.4 and 1.1.
It is somewhat perplexing to understand how that is possible, though I
will note that the stub f_ops do not contain an ioctl op but I cannot
see any mechanism by which we might return a validly open file without
putting the driver specific ops in it.
-apw
WARNING: multiple messages have this Message-ID (diff)
From: Andy Whitcroft <apw@canonical.com>
To: Dave Airlie <airlied@gmail.com>
Cc: David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org,
Jesse Barnes <jbarnes@virtuousgeek.org>,
Bryce Harrington <bryce@canonical.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/1] [RFC] DRM locking issues during early open
Date: Fri, 20 Apr 2012 18:25:40 +0100 [thread overview]
Message-ID: <20120420172540.GF3467@shadowen.org> (raw)
In-Reply-To: <CAPM=9txRi3=0=211S7RO=OqJwVPkFfQTtMC=DAhxZUUAW3voww@mail.gmail.com>
On Fri, Apr 20, 2012 at 11:34:43AM +0100, Dave Airlie wrote:
> >
> > I may be reading things wrong but the initialisation does indeed hold
> > drm_global_mutex, but and back when this first occured we would have
> > been using kernel_lock() which was at least partially reentrant right?
>
> Yup if we slept with the BKL held we'd have allowed others to get past it,
> but also I introduced the global mutex in pci a while back
Yeah I have managed to get access to more details on the bug, and
actually we are opening the drm device successfully, we then attempt a
DRM_SETVERSION ioctl on it and it is that that appears to fail both for
1.4 and 1.1.
It is somewhat perplexing to understand how that is possible, though I
will note that the stub f_ops do not contain an ioctl op but I cannot
see any mechanism by which we might return a validly open file without
putting the driver specific ops in it.
-apw
next prev parent reply other threads:[~2012-04-20 17:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-19 16:22 [PATCH 0/1] [RFC] DRM locking issues during early open Andy Whitcroft
2012-04-19 16:22 ` [PATCH 1/1] drm -- stop early access to drm devices Andy Whitcroft
2012-04-19 16:30 ` [PATCH 0/1] [RFC] DRM locking issues during early open Dave Airlie
2012-04-19 16:41 ` Andy Whitcroft
2012-04-19 16:47 ` Dave Airlie
2012-04-19 16:47 ` Dave Airlie
2012-04-19 16:52 ` Dave Airlie
2012-04-19 16:55 ` Jesse Barnes
2012-04-19 16:56 ` Dave Airlie
2012-04-19 17:00 ` Dave Airlie
2012-04-19 16:41 ` Daniel Vetter
2012-04-20 9:40 ` Dave Airlie
2012-04-20 10:31 ` Andy Whitcroft
2012-04-20 10:34 ` Dave Airlie
2012-04-20 17:25 ` Andy Whitcroft [this message]
2012-04-20 17:25 ` Andy Whitcroft
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