[Mesa-dev] [PATCH] gallium/util: avoid unreferencing random memory on buffer alloc failure

[Albert Freeman]

On 27 September 2015 at 03:46, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> Found by Coverity
>
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  src/gallium/auxiliary/util/u_blitter.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/gallium/auxiliary/util/u_blitter.c b/src/gallium/auxiliary/util/u_blitter.c
> index 2fbf69c..b7b1ece 100644
> --- a/src/gallium/auxiliary/util/u_blitter.c
> +++ b/src/gallium/auxiliary/util/u_blitter.c
> @@ -2065,7 +2065,7 @@ void util_blitter_clear_buffer(struct blitter_context *blitter,
>     struct blitter_context_priv *ctx = (struct blitter_context_priv*)blitter;
>     struct pipe_context *pipe = ctx->base.pipe;
>     struct pipe_vertex_buffer vb = {0};
> -   struct pipe_stream_output_target *so_target;
> +   struct pipe_stream_output_target *so_target = NULL;
>     unsigned offsets[PIPE_MAX_SO_BUFFERS] = {0};
>
>     assert(num_channels >= 1);
> --
> 2.4.9
>
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"so_target = pipe->create_stream_output_target(pipe, dst, offset,
size);" unconditionally assigns to so_target before first use (unless
I am reading something incorrectly).

Perhaps all function pointers that don't get implemented by a driver
should be zeroed? I am trying to think where this could be done (in
the gallium drivers themselves? (although that doesn’t seem the ideal
solution)). Perhaps in a function that is part of gallium itself
(outside drivers/[state trackers]/etc) that gets called upon driver
shared library load.