nv50: avoid segfault with enabled but unbound vertex attrib

Before validating vertex arrays we need to check if a VBO is present.
Checking if vb->buffer is not NULL fixes the issue.

Fixes the following piglit test:
  gl-3.1-vao-broken-attrib

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>

diff --git a/src/gallium/drivers/nouveau/nv50/nv50_vbo.c b/src/gallium/drivers/nouveau/nv50/nv50_vbo.c
index 1fd33b8aa5934ea8a0f82053732e5723012bca12..3d200bd65e88a80ec4a477381113add14fe7ddf5 100644 (file)
--- a/src/gallium/drivers/nouveau/nv50/nv50_vbo.c
+++ b/src/gallium/drivers/nouveau/nv50/nv50_vbo.c
@@ -382,6 +382,11 @@ nv50_vertex_arrays_validate(struct nv50_context *nv50)
       if (nv50->vbo_user & (1 << b)) {
          address = addrs[b] + ve->pipe.src_offset;
          limit = addrs[b] + limits[b];
+      } else
+      if (!vb->buffer) {
+         BEGIN_NV04(push, NV50_3D(VERTEX_ARRAY_FETCH(i)), 1);
+         PUSH_DATA (push, 0);
+         continue;
       } else {
          struct nv04_resource *buf = nv04_resource(vb->buffer);
          if (!(refd & (1 << b))) {