[Mesa-dev] [PATCH] mesa: fix deleting the dummy ATI_fs

[Marek Olšák]

Pushed, thanks!

Marek

On Fri, Nov 3, 2017 at 2:01 AM, Miklós Máté <mtmkls at gmail.com> wrote:
> The DummyShader is used by GenFragmentShadersATI() as a placeholder to
> mark IDs as allocated. Context cleanup wants to delete everything in
> ctx->Shared->ATIShaders, and crashes on these placeholders with this
> backtrace:
> ==15060== Invalid free() / delete / delete[] / realloc()
> ==15060==    at 0x482F478: free (vg_replace_malloc.c:530)
> ==15060==    by 0x57694F4: _mesa_delete_ati_fragment_shader (atifragshader.c:68)
> ==15060==    by 0x58B33AB: delete_fragshader_cb (shared.c:208)
> ==15060==    by 0x5838836: _mesa_HashDeleteAll (hash.c:295)
> ==15060==    by 0x58B365F: free_shared_state (shared.c:377)
> ==15060==    by 0x58B3BC2: _mesa_reference_shared_state (shared.c:469)
> ==15060==    by 0x578687F: _mesa_free_context_data (context.c:1366)
> ==15060==    by 0x595E9EC: st_destroy_context (st_context.c:642)
> ==15060==    by 0x5987057: st_context_destroy (st_manager.c:772)
> ==15060==    by 0x5B018B6: dri_destroy_context (dri_context.c:217)
> ==15060==    by 0x5B006D3: driDestroyContext (dri_util.c:511)
> ==15060==    by 0x4A1CBE6: dri3_destroy_context (dri3_glx.c:170)
> ==15060==  Address 0x7b5dae0 is 0 bytes inside data symbol "DummyShader"
>
> Also, DeleteFragmentShadersATI() should not assert on DummyShader, just
> remove the hash entry.
>
> Normally one would define a shader after GenFragmentShadersATI(), and
> BindFragmentShaderATI() replaces the placeholder with a real object.
> However, the specification doesn't say that one has to define a shader
> for each allocated ID.
>
> Signed-off-by: Miklós Máté <mtmkls at gmail.com>
> ---
>  src/mesa/main/atifragshader.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/main/atifragshader.c b/src/mesa/main/atifragshader.c
> index 27d8b86477..49ddb6e5af 100644
> --- a/src/mesa/main/atifragshader.c
> +++ b/src/mesa/main/atifragshader.c
> @@ -60,6 +60,10 @@ void
>  _mesa_delete_ati_fragment_shader(struct gl_context *ctx, struct ati_fragment_shader *s)
>  {
>     GLuint i;
> +
> +   if (s == &DummyShader)
> +      return;
> +
>     for (i = 0; i < MAX_NUM_PASSES_ATI; i++) {
>        free(s->Instructions[i]);
>        free(s->SetupInst[i]);
> @@ -295,7 +299,6 @@ _mesa_DeleteFragmentShaderATI(GLuint id)
>        if (prog) {
>          prog->RefCount--;
>          if (prog->RefCount <= 0) {
> -           assert(prog != &DummyShader);
>              _mesa_delete_ati_fragment_shader(ctx, prog);
>          }
>        }
> --
> 2.15.0.rc0
>
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