sna/dri: Add a bunch of assertions for hunting a use-after-free

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

2 files changed, 8 insertions, 0 deletions

diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index 36122e2b..a0129e40 100644
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -2495,6 +2495,7 @@ sna_page_flip(struct sna *sna,
 	int count;
 
 	DBG(("%s: handle %d attached\n", __FUNCTION__, bo->handle));
+	assert(bo->refcnt);
 
 	kgem_submit(&sna->kgem);
 
diff --git a/src/sna/sna_dri.c b/src/sna/sna_dri.c
index ff6b5871..de0f84da 100644
--- a/src/sna/sna_dri.c
+++ b/src/sna/sna_dri.c
@@ -115,6 +115,7 @@ get_private(DRI2Buffer2Ptr buffer)
 
 static inline struct kgem_bo *ref(struct kgem_bo *bo)
 {
+	assert(bo->refcnt);
 	bo->refcnt++;
 	return bo;
 }
@@ -877,6 +878,8 @@ sna_dri_remove_frame_event(WindowPtr win,
 
 	while (chain->chain != info)
 		chain = chain->chain;
+	assert(chain != info);
+	assert(info->chain != chain);
 	chain->chain = info->chain;
 }
 
@@ -912,8 +915,11 @@ sna_dri_add_frame_event(DrawablePtr draw, struct sna_dri_frame_event *info)
 		return;
 	}
 
+	assert(chain != info);
 	while (chain->chain != NULL)
 		chain = chain->chain;
+
+	assert(chain != info);
 	chain->chain = info;
 }
 
@@ -2031,6 +2037,7 @@ blit:
 				    CREATE_SCANOUT | CREATE_EXACT);
 		name = kgem_bo_flink(&sna->kgem, bo);
 	}
+	assert(bo->refcnt);
 	get_private(info->back)->bo = bo;
 	info->back->name = name;