diff --git a/mm/vma.c b/mm/vma.c
index 9df9e3b78604..dc92f3dd8514 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -67,18 +67,13 @@ struct mmap_state {
 		.state = VMA_MERGE_START,				\
 	}
 
-/*
- * If, at any point, the VMA had unCoW'd mappings from parents, it will maintain
- * more than one anon_vma_chain connecting it to more than one anon_vma. A merge
- * would mean a wider range of folios sharing the root anon_vma lock, and thus
- * potential lock contention, we do not wish to encourage merging such that this
- * scales to a problem.
- */
-static bool vma_had_uncowed_parents(struct vm_area_struct *vma)
+/* Was this VMA ever forked from a parent, i.e. maybe contains CoW mappings? */
+static bool vma_is_fork_child(struct vm_area_struct *vma)
 {
 	/*
 	 * The list_is_singular() test is to avoid merging VMA cloned from
-	 * parents. This can improve scalability caused by anon_vma lock.
+	 * parents. This can improve scalability caused by the anon_vma root
+	 * lock.
 	 */
 	return vma && vma->anon_vma && !list_is_singular(&vma->anon_vma_chain);
 }
@@ -115,11 +110,19 @@ static bool is_mergeable_anon_vma(struct vma_merge_struct *vmg, bool merge_next)
 	VM_WARN_ON(src && src_anon != src->anon_vma);
 
 	/* Case 1 - we will dup_anon_vma() from src into tgt. */
-	if (!tgt_anon && src_anon)
-		return !vma_had_uncowed_parents(src);
+	if (!tgt_anon && src_anon) {
+		struct vm_area_struct *copied_from = vmg->copied_from;
+
+		if (vma_is_fork_child(src))
+			return false;
+		if (vma_is_fork_child(copied_from))
+			return false;
+
+		return true;
+	}
 	/* Case 2 - we will simply use tgt's anon_vma. */
 	if (tgt_anon && !src_anon)
-		return !vma_had_uncowed_parents(tgt);
+		return !vma_is_fork_child(tgt);
 	/* Case 3 - the anon_vma's are already shared. */
 	return src_anon == tgt_anon;
 }