diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 6f32bebd8a9b6d74deb4b52bf2c6a65f357ee715..cc9632c7149ed3bc5f2c195d598f4a3d5678a906 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1432,6 +1432,8 @@ void of_detach_node(const struct device_node *np)
 	write_lock(&devtree_lock);
 
 	parent = np->parent;
+	if (!parent)
+		goto out_unlock;
 
 	if (allnodes == np)
 		allnodes = np->allnext;
@@ -1455,6 +1457,7 @@ void of_detach_node(const struct device_node *np)
 		prevsib->sibling = np->sibling;
 	}
 
+out_unlock:
 	write_unlock(&devtree_lock);
 }