1#!/bin/sh 2 3# 4# SPDX-License-Identifier: BSD-2-Clause-FreeBSD 5# 6# Copyright (c) 2020 Peter Holm 7# 8# Redistribution and use in source and binary forms, with or without 9# modification, are permitted provided that the following conditions 10# are met: 11# 1. Redistributions of source code must retain the above copyright 12# notice, this list of conditions and the following disclaimer. 13# 2. Redistributions in binary form must reproduce the above copyright 14# notice, this list of conditions and the following disclaimer in the 15# documentation and/or other materials provided with the distribution. 16# 17# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27# SUCH DAMAGE. 28# 29 30# 20200224 13:05:04 all (1/1): systrace.sh 31# [ thread pid 64171 tid 100708 ] 32# Stopped at sdt_modevent+0x1c1: int $3 33# db> 34 35# markj@ wrote: 36# I think I see the problem now. It should happen if you: 37# 1. load systrace.ko 38# 2. enable some system call probes, and disable them again 39# 3. unload systrace.ko 40# 4. load some unrelated module 41# 5. goto 1 42# 43# In particular, if systrace.ko is loaded at different addresses each 44# time, we'll end up calling a stale function pointer. 45 46# https://people.freebsd.org/~pho/stress/log/mark137.txt 47 48[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1 49. ../default.cfg 50 51dtrace -n 'dtrace:::BEGIN { exit(0); }' > /dev/null 2>&1 || exit 0 52for i in `jot 2`; do 53 sleep 4 & pid=$! 54 dtrace -w -n 'syscall::*read:entry,syscall::*write:entry {\ 55 @rw[execname,probefunc] = count(); }' -p $pid > /dev/null 2>&1 56 wait $pid 57 kldstat | grep -q dtraceall.ko && kldunload dtraceall.ko 58 59 mount -t tmpfs dummy $mntpoint && umount $mntpoint 60done 61kldstat | grep -q tmpfs && kldunload tmpfs.ko 62exit 0 63