diff --git a/tools/test/stress2/misc/mmap40.sh b/tools/test/stress2/misc/mmap40.sh
index 7f4d07885e05..2314596e2f5d 100755
--- a/tools/test/stress2/misc/mmap40.sh
+++ b/tools/test/stress2/misc/mmap40.sh
@@ -1,159 +1,160 @@
 #!/bin/sh
 
 #
 # SPDX-License-Identifier: BSD-2-Clause
 #
 # Copyright (c) 2020 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.
 #
 
 # Attempt to reproduce "vm_page_assert_xbusied: page XXXX not exclusive busy"
 # No problems seen.
 
 # Test scenario idea by markj@
 
 . ../default.cfg
 [ `id -u` -ne 0 ] && echo "Must be root!" && exit 1
 [ `sysctl -n vm.swap_total` -eq 0 ] && exit 0
 
 dir=/tmp
 odir=`pwd`
 cd $dir
 sed '1,/^EOF/d' < $odir/$0 > $dir/mmap40.c
 mycc -o mmap40 -Wall -Wextra -O0 -g mmap40.c || exit 1
 rm -f mmap40.c
 cd $odir
 
 set -e
 mount | grep "on $mntpoint " | grep -q /dev/md && umount -f $mntpoint
 [ -c /dev/md$mdstart ] &&  mdconfig -d -u $mdstart
 mdconfig -a -t swap -s 2g -u $mdstart
 newfs $newfs_flags md$mdstart > /dev/null
 mount /dev/md$mdstart $mntpoint
 set +e
 
 u1=`swapinfo | tail -1 | awk '{print $3}'`
-(nice $odir/../testcases/swap/swap -t 10m -i 30 -h -l 100) &
-while [ $((`swapinfo | tail -1 | awk '{print $3}'` - $u1)) -le 100 ]; do
+(nice $odir/../testcases/swap/swap -t 10m -i 30 -h -l 100) > /dev/null &
+for i in `jot 120`; do
+	u2=`swapinfo | tail -1 | awk '{print $3}'`
+	[ $u2 -lt $u1 ] && u1=$u2
+	[ $((u2 - $u1)) -gt 100 ] && break
 	sleep 1
 done
-
-$dir/mmap40
-s=0
+/usr/bin/timeout 10m $dir/mmap40; s=$?
 while pkill swap; do :; done
 wait
 [ -f mmap40.core -a $s -eq 0 ] &&
     { ls -l mmap40.core; mv mmap40.core $dir; s=1; }
 cd $odir
 
 for i in `jot 6`; do
 	mount | grep -q "on $mntpoint " || break
 	umount $mntpoint && break || sleep 10
 	[ $i -eq 6 ] &&
 	    { echo FATAL; fstat -mf $mntpoint; exit 1; }
 done
 mdconfig -d -u $mdstart
 rm -rf $dir/mmap40
 exit $s
 
 EOF
 #include <sys/param.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
 
 #include <err.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
 
 #define PARALLEL 512
 #define RUNTIME 300
 
 void
 test(void)
 {
 	pid_t pid;
 	size_t i, len;
 	time_t start;
 	void *p;
 	char *vec;
 
 	len = 1024 * 1024;
 	if ((p = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0)) ==
 	    MAP_FAILED)
 		err(1, "mmap");
 	memset(p, 0, len); /* dirty the memory */
 	if ((vec = malloc(len / PAGE_SIZE)) == NULL)
 		err(1, "malloc");
 
 	start = time(NULL);
 	while (time(NULL) - start < RUNTIME) {
 		usleep(arc4random() % 1000);
 		if (mincore(p, len, vec) == -1)
 			err(1, "mincore");
 		for (i = 0; i < len / PAGE_SIZE; i++) {
 			if ((vec[i] & MINCORE_MODIFIED) == 0) {
 				_exit(0);
 			}
 		}
 		if ((pid = fork()) == 0) {
 			_exit(0);
 		}
 		if (waitpid(pid, NULL, 0) != pid)
 			err(1, "waitpid)");
 	}
 
 	_exit(0);
 }
 
 int
 main(void)
 {
 	pid_t pids[PARALLEL];
 	time_t start;
 	int i;
 
 	for (i = 0; i < PARALLEL; i++) {
 		if ((pids[i] = fork()) == 0)
 			test();
 	}
 
 	start = time(NULL);
 	while (time(NULL) - start < RUNTIME) {
 		for (i = 0; i < PARALLEL; i++) {
 			if (waitpid(pids[i], NULL, WNOHANG) == pids[i]) {
 				if ((pids[i] = fork()) == 0)
 					test();
 			}
 		}
 	}
 
 	for (i = 0; i < PARALLEL; i++) {
 		if (waitpid(pids[i], NULL, 0) != pids[i])
 			err(1, "waitpid");
 	}
 
 	return (0);
 }