diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 98823f3..2c3df2b 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -365,7 +365,7 @@ vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
 				fp->f_ops= &badfileops;
 			return (error);
 		}
-		fp->f_flag |= FHASLOCK;
+		atomic_set_int(&fp->f_flag, FHASLOCK);
 	}
 	if (fmode & FWRITE) {
 		VOP_ADD_WRITECOUNT(vp, 1);