diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 1d6a81d10c..f1564ee443 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -2943,7 +2943,7 @@ FlushOneBuffer(Buffer buffer)
 
 	bufHdr = GetBufferDescriptor(buffer - 1);
 
-	LWLockHeldByMe(bufHdr->content_lock);
+	Assert(LWLockHeldByMe(bufHdr->content_lock));
 
 	FlushBuffer(bufHdr, NULL);
 }