diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index 68f1cbcf9c2..506f2902986 100644
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -1181,6 +1181,10 @@ MemoryContextCreate(MemoryContext node,
 	/* Creating new memory contexts is not allowed in a critical section */
 	Assert(CritSectionCount == 0);
 
+	/* Validate parent, to help prevent crazy context linkages */
+	Assert(parent == NULL || MemoryContextIsValid(parent));
+	Assert(node != parent);
+
 	/* Initialize all standard fields of memory context header */
 	node->type = tag;
 	node->isReset = true;