[Mesa-dev] [PATCH] svga: Prevent use after free.

[Emil Velikov]

On 22 January 2018 at 15:13, Jose Fonseca <jfonseca at vmware.com> wrote:
> Courtesy of clang static analyzer.
>
> I was hunting for potential sources of memory corruption using Mesa with
> a GL trace, and happened to find this (unrelated) issue.
> ---
>  src/gallium/drivers/svga/svga_context.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/src/gallium/drivers/svga/svga_context.c b/src/gallium/drivers/svga/svga_context.c
> index 546b9f48b1..af16a99b72 100644
> --- a/src/gallium/drivers/svga/svga_context.c
> +++ b/src/gallium/drivers/svga/svga_context.c
> @@ -327,6 +327,7 @@ cleanup:
>     util_bitmask_destroy(svga->stream_output_id_bm);
>     util_bitmask_destroy(svga->query_id_bm);
>     FREE(svga);
> +   svga = NULL;
>
>  done:
>     SVGA_STATS_TIME_POP(svgascreen->sws);

Seems like the most important line is just outside of context. Namely:

return svga ? &svga->pipe:NULL;

Cc: mesa-stable at lists.freedesktop.org
Reviewed-by: Emil Velikov <emil.l.velikov at gmail.com>

-Emil