[Mesa-dev] [PATCH] mesa: remove usage of alloca in externalobjects.c v3

[Emil Velikov]

On 31 January 2018 at 19:03, Andres Rodriguez <andresx7 at gmail.com> wrote:
> Don't want an overly large numBufferBarriers/numTextureBarriers to blow
> up the stack.
>
> v2: handle malloc errors
> v3: fix patch
>
> Suggested-by: Emil Velikov <emil.velikov at collabora.com>
> Signed-off-by: Andres Rodriguez <andresx7 at gmail.com>
> ---
>  src/mesa/main/externalobjects.c | 48 +++++++++++++++++++++++++++++++++++------
>  1 file changed, 42 insertions(+), 6 deletions(-)
>
> diff --git a/src/mesa/main/externalobjects.c b/src/mesa/main/externalobjects.c
> index 463debd268..a28d6dba6f 100644
> --- a/src/mesa/main/externalobjects.c
> +++ b/src/mesa/main/externalobjects.c
> @@ -713,91 +713,127 @@ _mesa_WaitSemaphoreEXT(GLuint semaphore,
>                         const GLuint *buffers,
>                         GLuint numTextureBarriers,
>                         const GLuint *textures,
>                         const GLenum *srcLayouts)
>  {
>     GET_CURRENT_CONTEXT(ctx);
>     struct gl_semaphore_object *semObj;
>     struct gl_buffer_object **bufObjs;
>     struct gl_texture_object **texObjs;
Initialize texObjs (might as well do bufObjs) since on bufObjs
allocation failure we'll end up feeding junk to free().

> -   bufObjs = alloca(sizeof(struct gl_buffer_object **) * numBufferBarriers);
> +   bufObjs = malloc(sizeof(struct gl_buffer_object **) * numBufferBarriers);
> +   if (!bufObjs) {
> +      _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s(numBufferBarriers=%u)",
> +                  func, numBufferBarriers);
> +      goto end;
> +   }
> +

> +end:
> +   free(bufObjs);
> +   free(texObjs);
>  }
>
>  void GLAPIENTRY
>  _mesa_SignalSemaphoreEXT(GLuint semaphore,
>                           GLuint numBufferBarriers,
>                           const GLuint *buffers,
>                           GLuint numTextureBarriers,
>                           const GLuint *textures,
>                           const GLenum *dstLayouts)
>  {
>     GET_CURRENT_CONTEXT(ctx);
>     struct gl_semaphore_object *semObj;
>     struct gl_buffer_object **bufObjs;
>     struct gl_texture_object **texObjs;
>
Ditto.

With the above nitpicks, patch is
Reviewed-by: Emil Velikov <emil.velikov at collabora.com>

-Emil