[Mesa-dev] [PATCH 2/2] mesa: reference shared state in glPushAttrib(GL_TEXTURE_BIT)

[Jose Fonseca]

Looks good. Good find!

Jose

----- Original Message -----
> This fixes a dangling texture object pointer bug hit via
> wglShareLists().
> When we push the GL_TEXTURE_BIT state we may push references to the
> default
> texture objects which are owned by the gl_shared_state object.  We
> don't
> want to accidentally delete that shared state while the attribute
> stack
> references shared objects.  So keep a reference to it.
> 
> NOTE: This is a candidate for the 8.0 branch.
> ---
>  src/mesa/main/attrib.c |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/src/mesa/main/attrib.c b/src/mesa/main/attrib.c
> index 01e7945..1068dd8 100644
> --- a/src/mesa/main/attrib.c
> +++ b/src/mesa/main/attrib.c
> @@ -47,6 +47,7 @@
>  #include "multisample.h"
>  #include "points.h"
>  #include "polygon.h"
> +#include "shared.h"
>  #include "scissor.h"
>  #include "stencil.h"
>  #include "texenv.h"
> @@ -165,6 +166,13 @@ struct texture_state
>      * deleted while saved in the attribute stack).
>      */
>     struct gl_texture_object
>     *SavedTexRef[MAX_TEXTURE_UNITS][NUM_TEXTURE_TARGETS];
> +
> +   /* We need to keep a reference to the shared state.  That's where
> the
> +    * default texture objects are kept.  We don't want that state to
> be
> +    * freed while the attribute stack contains pointers to any
> default
> +    * texture objects.
> +    */
> +   struct gl_shared_state *SharedRef;
>  };
>  
>  
> @@ -437,6 +445,8 @@ _mesa_PushAttrib(GLbitfield mask)
>           }
>        }
>  
> +      _mesa_reference_shared_state(ctx, &texstate->SharedRef,
> ctx->Shared);
> +
>        _mesa_unlock_context_textures(ctx);
>  
>        save_attrib_data(&head, GL_TEXTURE_BIT, texstate);
> @@ -806,6 +816,8 @@ pop_texture_group(struct gl_context *ctx, struct
> texture_state *texstate)
>  
>     _mesa_ActiveTextureARB(GL_TEXTURE0_ARB +
>     texstate->Texture.CurrentUnit);
>  
> +   _mesa_reference_shared_state(ctx, &texstate->SharedRef, NULL);
> +
>     _mesa_unlock_context_textures(ctx);
>  }
>  
> @@ -1605,6 +1617,7 @@ _mesa_free_attrib_data(struct gl_context *ctx)
>                    _mesa_reference_texobj(&texstate->SavedTexRef[u][tgt],
>                    NULL);
>                 }
>              }
> +            _mesa_reference_shared_state(ctx, &texstate->SharedRef,
> NULL);
>           }
>           else {
>              /* any other chunks of state that requires special
>              handling? */
> --
> 1.7.3.4
> 
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