diff --git a/tools/test/stress2/misc/open2.sh b/tools/test/stress2/misc/open2.sh
new file mode 100755
index 000000000000..7c0994bfd4e4
--- /dev/null
+++ b/tools/test/stress2/misc/open2.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2021 Peter Holm <pho@FreeBSD.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+# open(2) and openat(2) syscall fuzz test
+
+# umount(8) returns busy
+# https://people.freebsd.org/~pho/stress/log/log0111.txt
+# Fixed by: cef8a95acbae
+
+[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1
+
+snums=`grep -Ew 'SYS_open|SYS_openat' /usr/include/sys/syscall.h 2>/dev/null |
+    awk '{print $NF}'`
+    [ -z "$snums" ] && exit 0
+for i in $snums; do
+	./syscall4.sh $i; s=$?
+	[ $s -ne 0 ] && break
+done
+exit $s
diff --git a/tools/test/stress2/misc/rename2.sh b/tools/test/stress2/misc/rename2.sh
index 2c9781602d2c..085a424a98f2 100755
--- a/tools/test/stress2/misc/rename2.sh
+++ b/tools/test/stress2/misc/rename2.sh
@@ -1,103 +1,103 @@
 #!/bin/sh
 
 #
 # Copyright (c) 2009 Peter Holm <pho@FreeBSD.org>
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 1. Redistributions of source code must retain the above copyright
 #    notice, this list of conditions and the following disclaimer.
 # 2. Redistributions in binary form must reproduce the above copyright
 #    notice, this list of conditions and the following disclaimer in the
 #    documentation and/or other materials provided with the distribution.
 #
 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 # ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 # SUCH DAMAGE.
 #
 
 # With lookup_shared=1 rename() will fail from time to time with ENOENT and
 # the following stat() will succeed. (Variation of rename.sh)
 
 . ../default.cfg
 
 here=`pwd`
 cd /tmp
 sed '1,/^EOF/d' < $here/$0 > rename2.c
 mycc -o rename2 -Wall rename2.c || exit 1
 rm -f rename2.c
 cd $here
 
 rm -rf /tmp/rename.dir.*
 start=`date +%s`
-while [ $((`date +%s` - start -lt 300 ]; do
+while [ $((`date +%s` - start)) -lt 300 ]; do
 	for j in `jot 10`; do
 		/tmp/rename2 &
 	done
 	wait
 done
 rm -rf /tmp/rename.dir.* /tmp/rename2
 exit 0
 EOF
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <err.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
 
 static char dir1[128];
 static char dir2[128];
 
 int
 main(int argc, char **argv)
 {
 	struct stat sb;
 	time_t start;
 
 	sprintf(dir1, "/tmp/rename.dir.%d", getpid());
 	sprintf(dir2, "/tmp/rename.dir.2.%d", getpid());
 	if (mkdir(dir1, 0700) == -1)
 		err(1, "mkdir(%s)", dir1);
 
 	if (chdir(dir1) == -1)
 		err(1, "chdir(%s)", dir1);
 	if (chdir("..") == -1)
 		err(1, "chdir(%s)", "..");
 
 	start = time(NULL);
 	while ((time(NULL) - start) < 120) {
 		if (rename(dir1, dir2) == -1) {
 			warn("rename(%s, %s)", dir1, dir2);
 			if (stat(dir1, &sb) == -1)
 				err(1, "stat(%s)", dir1);
 			else
 				errx(1, "stat(%s) succeeded!", dir1);
 		}
 		if (rename(dir2, dir1) == -1) {
 			warn("rename(%s, %s)", dir2, dir1);
 			if (stat(dir2, &sb) == -1)
 				err(1, "stat(%s)", dir2);
 			else
 				errx(1, "stat(%s) succeeded!", dir2);
 		}
 	}
 
 	if (rmdir(dir1) == -1)
 		err(1, "rmdir(%s)", dir1);
 
 	return (0);
 }