Index: lib/libc/gen/tree.c
===================================================================
RCS file: /cvs/src/lib/libc/gen/tree.c,v
retrieving revision 1.1
diff -u -p -r1.1 tree.c
--- lib/libc/gen/tree.c	19 Jun 2017 03:06:26 -0000	1.1
+++ lib/libc/gen/tree.c	9 Oct 2018 02:48:18 -0000
@@ -346,7 +346,7 @@ rbe_remove(const struct rb_type *t, stru
 			else
 				RBE_RIGHT(tmp) = rbe;
 
-			rbe_if_augment(t, parent);
+			rbe_if_augment(t, tmp);
 		} else
 			RBH_ROOT(rbt) = rbe;
 
Index: sys/kern/subr_tree.c
===================================================================
RCS file: /cvs/src/sys/kern/subr_tree.c,v
retrieving revision 1.9
diff -u -p -r1.9 subr_tree.c
--- sys/kern/subr_tree.c	8 Jun 2017 03:30:52 -0000	1.9
+++ sys/kern/subr_tree.c	9 Oct 2018 02:48:18 -0000
@@ -346,7 +346,7 @@ rbe_remove(const struct rb_type *t, stru
 			else
 				RBE_RIGHT(tmp) = rbe;
 
-			rbe_if_augment(t, parent);
+			rbe_if_augment(t, tmp);
 		} else
 			RBH_ROOT(rbt) = rbe;