[Mesa-dev] [PATCH mesa] move variable-sized struct at the end of parent struct

[andrey simiklit]

Hello,

Please find my comments below:

On Thu, Nov 1, 2018 at 12:24 PM Eric Engestrom <eric.engestrom at intel.com>
wrote:

>   warning: field 'base' with variable sized type 'struct
> drm_i915_query_topology_info'
>   not at the end of a struct or class is a GNU extension
> [-Wgnu-variable-sized-type-not-at-end]
>
> Signed-off-by: Eric Engestrom <eric.engestrom at intel.com>
> ---
>  src/intel/dev/gen_device_info.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/intel/dev/gen_device_info.c
> b/src/intel/dev/gen_device_info.c
> index 5dbd06075722f8cc644e..242fe163447a4265acfb 100644
> --- a/src/intel/dev/gen_device_info.c
> +++ b/src/intel/dev/gen_device_info.c
> @@ -991,8 +991,8 @@ gen_device_info_update_from_masks(struct
> gen_device_info *devinfo,
>                                    uint32_t n_eus)
>  {
>     struct {
> -      struct drm_i915_query_topology_info base;
>        uint8_t data[100];
> +      struct drm_i915_query_topology_info base;
>     } topology;
>

I can be wrong, but it seems like here the 'data[100]' field should rather
be placed after the 'base' field
because it was done as far as I understood to allocate memory on the stack
for the 'drm_i915_query_topology_info::data[]' field. I guess that this
patch
may introduce the stack corruption on the following line:
   for (int b = 0; b < topology.base.subslice_offset; b++)
      topology.base.data[b] = (slice_mask >> (b * 8)) & 0xff;



    assert((slice_mask & 0xff) == slice_mask);
> --
> Cheers,
>   Eric
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>

Regards,
Andrii.
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