[Intel-gfx] GPU hang with kernel 4.10rc3

[Chris Wilson]

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.

Is this a new bug? Bisection would be the fastest way to triage it.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre