sna/gen3+: Clear the render.vbo when replacing it for vertex upload

As we may trigger a flush and a retire when searching for a vertex
buffer for the new vertices, we need to be careful to decouple the
destroyed vbo in order to avoid a use-after-free when inspecting the
state.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/sna/gen5_render.c b/src/sna/gen5_render.c
index 54d7c86b..0e3aec67 100644
--- a/src/sna/gen5_render.c
+++ b/src/sna/gen5_render.c
@@ -274,6 +274,7 @@ static int gen5_vertex_finish(struct sna *sna)
 		sna->render.nvertex_reloc = 0;
 		sna->render.vertex_used = 0;
 		sna->render.vertex_index = 0;
+		sna->render.vbo = NULL;
 		sna->render_state.gen5.vb_id = 0;
 
 		kgem_bo_destroy(&sna->kgem, bo);