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]
Message-ID: <20150301093001.GA1696@nest>
Date:	Sun, 1 Mar 2015 12:30:01 +0300
From:	Andrey Skvortsov <andrej.skvortzov@...il.com>
To:	Chris Wilson <chris@...is-wilson.co.uk>,
	Daniel Vetter <daniel.vetter@...el.com>,
	Jani Nikula <jani.nikula@...ux.intel.com>,
	David Airlie <airlied@...ux.ie>,
	intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, Sitsofe Wheeler <sitsofe@...il.com>
Subject: Re: [Intel-gfx] [Regression] BUG: unable to handle kernel NULL
 pointer dereference

On 01 Mar, Chris Wilson wrote:
> On Sun, Mar 01, 2015 at 12:57:01AM +0300, Andrey Skvortsov wrote:
> > On 28 Feb, Chris Wilson wrote:
> > > On Sat, Feb 28, 2015 at 03:20:37PM +0300, Andrey Skvortsov wrote:
> > > > Unfortunately this is not the last bug, that breaks i915/drm working
> > > > on my laptop. Sometimes system successfully loads with couple warnings mentioned in
> > > > previous mail:
> > > > 
> > > > [   26.922953] WARNING: CPU: 1 PID: 767 at drivers/gpu/drm/i915/i915_gem.c:4525 i915_gem_free_object+0x13f/0x288 [i915]()
> > > > [   26.922954] WARN_ON(obj->frontbuffer_bits)
> > > 
> > > That's inocuous, but for the serious hang, you may want to try
> > > video=SVIDEO-1:d on the kernel commandline to workaround the hang. (Check
> > > /sys/class/drm/card/ for the actual name of the connector for TV). I
> > > think Ville mentioned he was looking/looked at the atomic-vs-load_detect
> > > changes that is at the heart of the issue here. (Admittedly he did say
> > > it was worthy of a drink or two.)
> > > -Chris
> > 
> > Thank you for the help. I've tried to add to the kernel command line
> > 'video=card0-SVIDEO-1:d video=card0-VGA-1:d'. But despite of that
> > kernel crashes with 'BUG: unable to handle kernel NULL pointer
> > dereference at' occasionally.
> 
> Remove the card0- and combine both into a single video= stanza:
> video=SVIDEO-1:d,VGA-1:d

I've just tried that, but the crash with NULL pointer dereference still happens.

-- 
Best regards,
Andrey Skvortsov

Secure e-mail with gnupg: See http://www.gnupg.org/
PGP Key ID: 0x57A3AEAD



Download attachment "signature.asc" of type "application/pgp-signature" (820 bytes)

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ