Re: [Mesa-dev] Fix a crash in update_texture_state() when requesting a fallback for external texture target

[Brian Paul]

On 10/12/2012 02:42 AM, Abdiel Janulgue wrote:

On Wednesday, October 10, 2012 08:33:08 AM Brian Paul wrote:

On 10/10/2012 05:42 AM, Abdiel Janulgue wrote:

I found a crash where updating the texture unit states ends up requesting
a
fallback texture for a  GL_TEXTURE_EXTERNAL_OES target and sets a null
current texture object for the current unit.

This is a fix by supporting  TEXTURE_EXTERNAL_INDEX target in
_mesa_get_fallback_texture() and making sure the texture unit is not
really
used should an invalid  fallback be returned.

Cheers,
-abdiel

diff --git a/src/mesa/main/texobj.c b/src/mesa/main/texobj.c
index e0494c9..7e2b6b5 100644
--- a/src/mesa/main/texobj.c
+++ b/src/mesa/main/texobj.c
@@ -771,6 +771,9 @@ _mesa_get_fallback_texture(struct gl_context *ctx,
gl_texture_index tex)

            target = GL_TEXTURE_BUFFER;
            break;

         case TEXTURE_EXTERNAL_INDEX:
+         dims = 2;
+         target = GL_TEXTURE_EXTERNAL_OES;
+         break;

         default:
            /* no-op */
            return NULL;

diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index 8ca9092..009b077 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -600,6 +600,11 @@ update_texture_state( struct gl_context *ctx )

               texTarget = (gl_texture_index) (ffs(enabledTargets) - 1);
               texObj = _mesa_get_fallback_texture(ctx, texTarget);

+
+            if (!texObj)
+               /* invalid fallback texture: make sure to disable texture
unit */
+               continue;

So texObj should only be null here if _mesa_get_fallback_texture()
fails because of a bad/unsupported texture target or we run out of
memory for a 1-texel texture (pretty unlikely).

So I think I'd like to see an assert(texObj) there followed by the
if/continue so that we get the assertion with debug builds but don't
crash with release builds.

Looks OK otherwise.

Thanks Brian. I've pushed the improved changes with your feedback to
g...@gitorious.org:mesa3d/mesa.git master branch

Thanks.  I'm going to tweak the comments and will commit it in a bit.

-Brian

_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev