[Mesa-dev] [PATCH] st/mesa: destroy pipe_context before destroying st_context

[Nicolai Hähnle]

Looks like there's a problem with the error path at the end of 
st_create_context_priv (line ~506): it calls st_destroy_context_priv 
which will now destroy the pipe, which then leads to a double-destroy by 
the caller.

Just setting st->pipe = NULL; would be enough.

Nicolai

On 20.01.2017 20:00, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> If radeonsi starts compiling an optimized shader variant for asynchronously
> with a GL debug callback set and the application destroys the GL context,
> radeonsi crashes when trying to write shader stats into the debug output
> of a non-existent context after compilation, because st/mesa was destroyed
> before pipe_context.
>
> Firefox with WebGL2 enabled hits this bug.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99456
>
> Cc: 17.0 <mesa-stable at lists.freedesktop.org>
> ---
>  src/mesa/state_tracker/st_context.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
> index 0eae971..7a99e82 100644
> --- a/src/mesa/state_tracker/st_context.c
> +++ b/src/mesa/state_tracker/st_context.c
> @@ -307,20 +307,24 @@ st_destroy_context_priv(struct st_context *st)
>     }
>
>     /* free glDrawPixels cache data */
>     free(st->drawpix_cache.image);
>     pipe_resource_reference(&st->drawpix_cache.texture, NULL);
>
>     /* free glReadPixels cache data */
>     st_invalidate_readpix_cache(st);
>
>     cso_destroy_context(st->cso_context);
> +
> +   if (st->pipe)
> +      st->pipe->destroy(st->pipe);
> +
>     free( st );
>  }
>
>
>  static struct st_context *
>  st_create_context_priv( struct gl_context *ctx, struct pipe_context *pipe,
>  		const struct st_config_options *options)
>  {
>     struct pipe_screen *screen = pipe->screen;
>     uint i;
> @@ -572,21 +576,20 @@ static void
>  destroy_tex_sampler_cb(GLuint id, void *data, void *userData)
>  {
>     struct gl_texture_object *texObj = (struct gl_texture_object *) data;
>     struct st_context *st = (struct st_context *) userData;
>
>     st_texture_release_sampler_view(st, st_texture_object(texObj));
>  }
>
>  void st_destroy_context( struct st_context *st )
>  {
> -   struct pipe_context *pipe = st->pipe;
>     struct gl_context *ctx = st->ctx;
>     GLuint i;
>
>     _mesa_HashWalk(ctx->Shared->TexObjects, destroy_tex_sampler_cb, st);
>
>     st_reference_fragprog(st, &st->fp, NULL);
>     st_reference_geomprog(st, &st->gp, NULL);
>     st_reference_vertprog(st, &st->vp, NULL);
>     st_reference_tesscprog(st, &st->tcp, NULL);
>     st_reference_tesseprog(st, &st->tep, NULL);
> @@ -604,22 +607,20 @@ void st_destroy_context( struct st_context *st )
>
>     st_destroy_program_variants(st);
>
>     _mesa_free_context_data(ctx);
>
>     /* This will free the st_context too, so 'st' must not be accessed
>      * afterwards. */
>     st_destroy_context_priv(st);
>     st = NULL;
>
> -   pipe->destroy( pipe );
> -
>     free(ctx);
>  }
>
>  static void
>  st_emit_string_marker(struct gl_context *ctx, const GLchar *string, GLsizei len)
>  {
>     struct st_context *st = ctx->st;
>     st->pipe->emit_string_marker(st->pipe, string, len);
>  }
>
>