Index: head/lib/libc/sys/open.2
===================================================================
--- head/lib/libc/sys/open.2
+++ head/lib/libc/sys/open.2
@@ -28,7 +28,7 @@
 .\"     @(#)open.2	8.2 (Berkeley) 11/16/93
 .\" $FreeBSD$
 .\"
-.Dd June 14, 2019
+.Dd September 17, 2019
 .Dt OPEN 2
 .Os
 .Sh NAME
@@ -419,6 +419,11 @@
 .It Bq Er EISDIR
 The named file is a directory, and the arguments specify
 it is to be modified.
+.It Bq Er EISDIR
+The named file is a directory, and the flags specified
+.Dv O_CREAT
+without
+.Dv O_DIRECTORY .
 .It Bq Er EROFS
 The named file resides on a read-only file system,
 and the file is to be modified.
Index: head/sys/kern/vfs_vnops.c
===================================================================
--- head/sys/kern/vfs_vnops.c
+++ head/sys/kern/vfs_vnops.c
@@ -264,6 +264,10 @@
 				error = EEXIST;
 				goto bad;
 			}
+			if (vp->v_type == VDIR) {
+				error = EISDIR;
+				goto bad;
+			}
 			fmode &= ~O_CREAT;
 		}
 	} else {