Index: user/pho/stress2/misc/sort.sh
===================================================================
--- user/pho/stress2/misc/sort.sh	(revision 351735)
+++ user/pho/stress2/misc/sort.sh	(revision 351736)
@@ -1,49 +1,52 @@
 #!/bin/sh
 
 #
 # Copyright (c) 2017 Dell EMC Isilon
 # 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.
 #
 # $FreeBSD$
 #
 
 # VM stress.
 
+# "panic: freeing free block: ffff40, size 8, mask 1" seen in WiP code:
+# https://people.freebsd.org/~pho/stress/log/sort.txt
+
 [ `sysctl -n vm.swap_total` -eq 0 ] && exit 0
 
 for i in `jot 6`; do
 	sort /dev/zero &
 	pids="$pids $!"
 done
 start=`date '+%s'`
 while [ $((`date '+%s'` - start)) -lt 180 ]; do
 	sleep 10
 	pgrep -q sort || break
 done
 while pgrep -q sort; do
 	kill -9 $pids > /dev/null 2>&1
 	sleep 1
 done
 wait
 exit 0