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

[Miklós Máté]

This fixes a crash upon context destruction when
glGenFragmentShadersATI() was used. 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"

This hasn't been an issue yet, because the only thing that calls
glGenFragmentShadersATI() is my WIP piglit test. SWKOTOR and Doom3
use hard-coded shader names.

The patch also fixes this:
name=glGenFragmentShadersATI(1);
glDeleteFragmentShaderATI(name);

Signed-off-by: Miklós Máté <mtmkls at gmail.com>
---
 src/mesa/main/atifragshader.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/mesa/main/atifragshader.c b/src/mesa/main/atifragshader.c
index 27d8b86477..fdfaea0528 100644
--- a/src/mesa/main/atifragshader.c
+++ b/src/mesa/main/atifragshader.c
@@ -60,6 +60,9 @@ 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 +298,6 @@ _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