linux-kernel - Re: linux-next: Tree for Aug 13 [ screen corruption in graphical mode ]

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]

Date:	Tue, 13 Aug 2013 19:53:25 +0200
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	Chris Wilson <chris@...is-wilson.co.uk>,
	Sedat Dilek <sedat.dilek@...il.com>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Dave Airlie <airlied@...il.com>,
	DRI <dri-devel@...ts.freedesktop.org>,
	intel-gfx <intel-gfx@...ts.freedesktop.org>,
	"s.dilek" <s.dilek@...erlin.de>
Subject: Re: linux-next: Tree for Aug 13 [ screen corruption in graphical mode ]

On Tue, Aug 13, 2013 at 7:13 PM, Chris Wilson <chris@...is-wilson.co.uk> wrote:
> On Tue, Aug 13, 2013 at 07:03:44PM +0200, Sedat Dilek wrote:
>> On Tue, Aug 13, 2013 at 6:37 PM, Sedat Dilek <sedat.dilek@...il.com> wrote:
>> > On Tue, Aug 13, 2013 at 6:34 PM, Chris Wilson <chris@...is-wilson.co.uk> wrote:
>> >> On Tue, Aug 13, 2013 at 06:23:29PM +0200, Sedat Dilek wrote:
>> >>> On Tue, Aug 13, 2013 at 5:59 PM, Sedat Dilek <sedat.dilek@...il.com> wrote:
>> >>> > I have bisected the issue on Linux v3.11-rc5 + drm-intel-nightly:
>> >>> >
>> >>> > 5456fe3882812aba251886e36fe55bfefb8e8829 is the first bad commit
>> >>> > commit 5456fe3882812aba251886e36fe55bfefb8e8829
>> >>> > Author: Chris Wilson <chris@...is-wilson.co.uk>
>> >>> > Date:   Thu Aug 8 14:41:07 2013 +0100
>> >>> >
>> >>> >     drm/i915: Allocate LLC ringbuffers from stolen
>> >>> >
>> >>> >     As stolen objects now behave identically (wrt to default LLC cacheing)
>> >>> >     as their normal system counterparts, we no longer have to differentiate
>> >>> >     our usage for ringbuffers. So allocate them from stolen on SNB+ as well.
>> >>> >
>> >>> >     Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
>> >>> >     Reviewed-by: Ville Syrjälä <ville.syrjala@...ux.intel.com>
>> >>> >     Signed-off-by: Daniel Vetter <daniel.vetter@...ll.ch>
>> >>> >
>> >>> > :040000 040000 de063a052f39095f4d2f51b49caef9f827df41e8
>> >>> > 1c819aa5501a9fcc9912a5c7c037c71b9b9e9a6b M      drivers
>> >>> >
>> >>> > See also attached files!
>> >>> >
>> >>>
>> >>> With the attached revert-patch my system is OK (with my customized X stack).
>> >>
>> >> No indication of a GPU hang? I'm puzzled as to how this ends up with the
>> >> scanout being misread.
>> >>
>> >> cat /sys/kernel/debug/dri/0/i915_gem_stolen
>> >> cat /sys/kernel/debug/dri/0/i915_gem_framebuffer
>> >>
>> >> would be interesting.
>
>> Attached both outputs with GOOD and BAD (BROKEN) kernel.
>
> ggtt offset is the same for both setups, the only difference between the
> two is the location of fbcon in stolen memory.
>
> Can you please attach the output of intel_reg_dumper for good/bad? It's
> a long shot...
>
> Speaking of long shots, try this (slightly different to the earlier patch):
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a21f935..37ad772 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -1850,6 +1850,9 @@ intel_pin_and_fence_fb_obj(struct drm_device *dev,
>                 BUG();
>         }
>
> +       if (obj->stolen && INTEL_INFO(dev)->gen >= 6)
> +               alignment = 256 * 1024;
> +
>         /* Note that the w/a also requires 64 PTE of padding following the
>          * bo. We currently fill all unused PTE with the shadow page and so
>          * we should always have valid PTE following the scanout preventing
>
>
> --

Files attached.

- Sedat -

View attachment "i915_gem_framebuffer_BROKEN_with-ickle-patch.txt" of type "text/plain" (454 bytes)

View attachment "i915_gem_framebuffer_with-ickle-patch.txt" of type "text/plain" (452 bytes)

View attachment "i915_gem_stolen_BROKEN_with-ickle-patch.txt" of type "text/plain" (685 bytes)

View attachment "i915_gem_stolen_with-ickle-patch.txt" of type "text/plain" (220 bytes)