Re: [Intel-gfx] GPU hang with kernel 4.10rc3

[Chris Wilson]

On Thu, Jan 12, 2017 at 07:03:25AM +0100, Juergen Gross wrote:
> On 11/01/17 18:08, Chris Wilson wrote:
> > On Wed, Jan 11, 2017 at 05:33:34PM +0100, Juergen Gross wrote:
> >> With kernel 4.10rc3 running as Xen dm0 I get at each boot:
> >>
> >> [   49.213697] [drm] GPU HANG: ecode 7:0:0x3d1d3d3d, in gnome-shell
> >> [1431], reason: Hang on render ring, action: reset
> >> [   49.213699] [drm] GPU hangs can indicate a bug anywhere in the entire
> >> gfx stack, including userspace.
> >> [   49.213700] [drm] Please file a _new_ bug report on
> >> bugs.freedesktop.org against DRI -> DRM/Intel
> >> [   49.213700] [drm] drm/i915 developers can then reassign to the right
> >> component if it's not a kernel issue.
> >> [   49.213700] [drm] The gpu crash dump is required to analyze gpu
> >> hangs, so please always attach it.
> >> [   49.213701] [drm] GPU crash dump saved to /sys/class/drm/card0/error
> >> [   49.213755] drm/i915: Resetting chip after gpu hang
> >> [   60.213769] drm/i915: Resetting chip after gpu hang
> >> [   71.189737] drm/i915: Resetting chip after gpu hang
> >> [   82.165747] drm/i915: Resetting chip after gpu hang
> >> [   93.205727] drm/i915: Resetting chip after gpu hang
> >>
> >> The dump is attached.
> > 
> > That's a nasty one. The first couple of pages of the batchbuffer appear
> > to be overwritten. (Full of 0xc2c2c2c2, i.e. probably pixel data.) That
> > may be a concurrent write by either the GPU or CPU, or we may have
> > incorrected mapped a set of pages. That it doesn't recovered suggests
> > that the corruption occurs frequently, probably on every request/batch.
> 
> I hoped someone would have an idea already.

Sorry, first report of something like this in a long time (that I can
remember at least). And the problem is that it can be anything from a
coherency to a concurrency issue, so no one patch springs to mind.
Thankfully it appears to be kernel related.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre