Re: [PATCH] drm/i915: fix crash in error state readout on non-execlist platforms v2

Daniel Vetter
2015-09-23T08:32:05Z

On Tue, Sep 15, 2015 at 10:03:01AM -0700, Jesse Barnes wrote:
> Looks like this was introduced in:
> commit d1675198ed1f21aec6e036336e4340c40b726497
> Author: Alex Dai <yu.dai@intel.com>
> Date: Wed Aug 12 15:43:43 2015 +0100
>
> drm/i915: Integrate GuC-based command submission
>
> This patch assumed LRC contexts and HWS layout, which is incorrect on
> platforms without execlists. This can lead to a crash in GPU error
> state readout on those platforms.
>
> I don't see a bug filed for this, but there may be one that I haven't
> found.
>
> v2: fixup offset handling for error capture fix (Dave)
>
> Cc: Alex Dai <yu.dai@intel.com>
> Reviewed-by: Dave Gordon <david.s.gordon@intel.com>
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Queued for -next, thanks for the patch.
-Daniel

> ---
> drivers/gpu/drm/i915/i915_gpu_error.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> index 3379f9c..f95de05 100644
> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> @@ -457,17 +457,23 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
> }
>
> if ((obj = error->ring[i].hws_page)) {
> + u64 hws_offset = obj->gtt_offset;
> + u32 *hws_page = &obj->pages[0][0];
> +
> + if (i915.enable_execlists) {
> + hws_offset += LRC_PPHWSP_PN * PAGE_SIZE;
> + hws_page = &obj->pages[LRC_PPHWSP_PN][0];
> + }
> err_printf(m, "%s --- HW Status = 0x%08llx\n",
> - dev_priv->ring[i].name,
> - obj->gtt_offset + LRC_PPHWSP_PN * PAGE_SIZE);
> + dev_priv->ring[i].name, hws_offset);
> offset = 0;
> for (elt = 0; elt < PAGE_SIZE/16; elt += 4) {
> err_printf(m, "[%04x] %08x %08x %08x %08x\n",
> offset,
> - obj->pages[LRC_PPHWSP_PN][elt],
> - obj->pages[LRC_PPHWSP_PN][elt+1],
> - obj->pages[LRC_PPHWSP_PN][elt+2],
> - obj->pages[LRC_PPHWSP_PN][elt+3]);
> + hws_page[elt],
> + hws_page[elt+1],
> + hws_page[elt+2],
> + hws_page[elt+3]);
> offset += 16;
> }
> }
> --
> 1.9.1
>
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--
Daniel Vetter
Software Engineer, Intel Corporation