diff --git a/tools/test/stress2/misc/mlockall6.sh b/tools/test/stress2/misc/mlockall6.sh
index b83e033736fc..33b20ce3137a 100755
--- a/tools/test/stress2/misc/mlockall6.sh
+++ b/tools/test/stress2/misc/mlockall6.sh
@@ -1,202 +1,203 @@
 #!/bin/sh
 
 #
 # SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 #
 # Copyright (c) 2019 Dell EMC Isilon
 #
 # 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.
 #
 
 # "panic: Lock (rw) vm object not locked @ vm/vm_page.c:1013" seen:
 # https://people.freebsd.org/~pho/stress/log/mlockall6-2.txt
 
 . ../default.cfg
 
 [ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1
 [ `swapinfo | wc -l` -eq 1 ] && exit 0
 
 dir=/tmp
 odir=`pwd`
 cd $dir
 sed '1,/^EOF/d' < $odir/$0 > $dir/mlockall6.c
 mycc -o mlockall6 -Wall -Wextra -O0 -g mlockall6.c || exit 1
 rm -f mlockall6.c
 cd $odir
 
 mount | grep "on $mntpoint " | grep -q /dev/md && umount -f $mntpoint
 mdconfig -l | grep -q md$mdstart &&  mdconfig -d -u $mdstart
 mdconfig -a -t swap -s 512m -u $mdstart || exit 1
 newfs $newfs_flags -n md$mdstart > /dev/null
 mount /dev/md$mdstart $mntpoint || exit 1
 
 daemon sh -c "(cd $odir/../testcases/swap; ./swap -t 20m -i 20 -l 100)" \
     > /dev/null 2>&1
 sleep 2
 
 (cd $mntpoint; /tmp/mlockall6 || echo FAIL)
 
 while pgrep -q swap; do
 	pkill -9 swap
 done
 
 n=0
 while mount | grep "on $mntpoint " | grep -q /dev/md; do
 	umount $mntpoint || sleep 1
 	n=$((n + 1))
 	[ $n -gt 10 ] && { echo FAIL; exit 1; }
 done
 mdconfig -d -u $mdstart
 rm -rf /tmp/mlockall6
 exit 0
 
 EOF
 #include <sys/param.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
 
 #include <machine/atomic.h>
 
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 #include <unistd.h>
 
 #define LOOPS 2
 #define PARALLEL 8
 #define R0 0
 #define R1 1
 #define R2 2
 #define RUNTIME (10 * 60)
 
 static volatile u_int *share;
 static int ps;
 static char c[32 * 1024 * 1024];
 
 static void
 touch(void)
 {
 	int i;
 
 	for (i = 0; i < (int)sizeof(c); i += ps)
 		c[i] = 1;
 }
 
 static void
 test2(void)
 {
 	pid_t pid;
 	volatile u_int *share2;
 	size_t len;
 	int i, status;
 
 	len = ps;
 	if ((share2 = mmap(NULL, len, PROT_READ | PROT_WRITE,
 	    MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
 		err(1, "mmap");
 	touch();
 	usleep(arc4random() % 100000);
 	alarm(600);
 	if ((pid = fork()) == 0) {
 		alarm(600);
 		while (share2[R1] == 0)	/* Wait for parent */
 			;
 		atomic_add_int(&share2[R1], 1);
 		if (arc4random() % 100 < 50)
 			usleep(arc4random() % 1000);
 		if (mlockall(MCL_CURRENT | MCL_FUTURE) == -1)
 			err(1, "mlock");
 		touch();
 		atomic_add_int(&share2[R2], 1);
 		_exit(0);
 	}
 	atomic_add_int(&share2[R1], 1);
 	while (share2[R1] != 2)	/* Wait for child */
 		;
 
 	for (i = 0; i < 100000 && share2[R2] == 0; i++)
 		touch();	/* while child is running */
 
-	if (waitpid(pid, &status, 0) == -1)
+	if (waitpid(pid, &status, 0) != pid)
 		err(1, "wait");
 
 	if (status != 0)
 		fprintf(stderr, "Got signal %d\n", WTERMSIG(status));
 	_exit(WTERMSIG(status));
 }
 
 static void
 test(void)
 {
 	pid_t pid;
 	int i, s, status;
 
 	while (share[R0] == 0)
 		;
 	s = 0;
 	for (i = 0; i < LOOPS; i++) {
 		if ((pid = fork()) == 0)
 			test2();
 		waitpid(pid, &status, 0);
 		s = (s == 0) ? status : s;
 	}
 	_exit(s);
 }
 
 int
 main(void)
 {
-	pid_t pid;
+	pid_t pids[PARALLEL];
 	size_t len;
 	time_t start;
 	int i, s, status;
 
 	ps = getpagesize();
 	len = ps;
 	if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE,
 	    MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
 		err(1, "mmap");
 	start = time(NULL);
 	s = 0;
 	while (s == 0 && (time(NULL) - start) < RUNTIME) {
 		for (i = 0; i < PARALLEL; i++) {
-			if ((pid = fork()) == 0)
+			if ((pids[i] = fork()) == 0)
 				test();
 		}
 		atomic_add_int(&share[R0], 1);	/* Start test() runs */
 		for (i = 0; i < PARALLEL; i++) {
-			waitpid(pid, &status, 0);
+			if (waitpid(pids[i], &status, 0) != pids[i])
+				err(1, "wait");
 			if (status != 0) {
 				fprintf(stderr, "FAIL: status = %d\n",
 				    status);
 			}
 			s = (s == 0) ? status : s;
 		}
 		atomic_add_int(&share[R0], -1);
 	}
 
 	return (s);
 }