[Mesa-dev] [PATCH 3/3] i965: if DEBUG_OUT_OF_BOUND_CHK is up, check that noise padding for each bo used in batchbuffer is correct

[Jason Ekstrand]

On Fri, Dec 8, 2017 at 2:54 AM, <kevin.rogovin at intel.com> wrote:

> From: Kevin Rogovin <kevin.rogovin at intel.com>
>
> Signed-off-by: Kevin Rogovin <kevin.rogovin at intel.com>
> ---
>  src/mesa/drivers/dri/i965/intel_batchbuffer.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> index 91a6506..549ea3e 100644
> --- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> +++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> @@ -758,6 +758,7 @@ execbuffer(int fd,
>     };
>
>     unsigned long cmd = DRM_IOCTL_I915_GEM_EXECBUFFER2;
> +   bool detected_out_of_bounds_write = false;
>
>     if (in_fence != -1) {
>        execbuf.rsvd2 = in_fence;
> @@ -787,6 +788,20 @@ execbuffer(int fd,
>               batch->validation_list[i].offset);
>           bo->gtt_offset = batch->validation_list[i].offset;
>        }
> +
> +      if (unlikely(INTEL_DEBUG & DEBUG_OUT_OF_BOUND_CHK)) {
> +         if (!brw_bo_padding_is_good(bo)) {
> +            detected_out_of_bounds_write = true;
> +            fprintf(stderr,
> +                    "Detected buffer out-of-bounds write from brw_bo %p "
> +                    "(GEM %u, label = \"%s\")\n",
> +                    bo, bo->gem_handle, bo->name);
> +         }
> +      }
> +   }
>

I think you want to do this at the end of submit_batch instead and add a
brw_bo_wait_rendering on the batch.  Otherwise, your bounds checking is
racing with the GPU.


> +
> +   if (unlikely(detected_out_of_bounds_write)) {
> +      abort();
>     }
>
>     if (ret == 0 && out_fence != NULL)
> --
> 2.7.4
>
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