Recent commit ("Syncronize filesystems to disk when suspending.") has added int argument to sync() vfsops, but sys/tmpfs missed that change.
https://leaf.dragonflybsd.org/~tkusumi/diff/openbsd/tmpfs-sync-fix-arg.cvs.patch Index: sys/tmpfs/tmpfs_vfsops.c =================================================================== RCS file: /cvs/src/sys/tmpfs/tmpfs_vfsops.c,v retrieving revision 1.14 diff -u -p -u -r1.14 tmpfs_vfsops.c --- sys/tmpfs/tmpfs_vfsops.c 11 Dec 2017 05:27:40 -0000 1.14 +++ sys/tmpfs/tmpfs_vfsops.c 7 Mar 2018 07:23:49 -0000 @@ -65,7 +65,7 @@ int tmpfs_vget(struct mount *, ino_t, st int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); int tmpfs_vptofh(struct vnode *, struct fid *); int tmpfs_statfs(struct mount *, struct statfs *, struct proc *); -int tmpfs_sync(struct mount *, int, struct ucred *, struct proc *); +int tmpfs_sync(struct mount *, int, int, struct ucred *, struct proc *); int tmpfs_init(struct vfsconf *); int @@ -350,7 +350,8 @@ tmpfs_statfs(struct mount *mp, struct st } int -tmpfs_sync(struct mount *mp, int waitfor, struct ucred *cred, struct proc *p) +tmpfs_sync(struct mount *mp, int waitfor, int stall, struct ucred *cred, + struct proc *p) { return 0;