1#!/bin/sh 2 3# 4# Copyright (c) 2014 EMC Corp. 5# All rights reserved. 6# 7# Redistribution and use in source and binary forms, with or without 8# modification, are permitted provided that the following conditions 9# are met: 10# 1. Redistributions of source code must retain the above copyright 11# notice, this list of conditions and the following disclaimer. 12# 2. Redistributions in binary form must reproduce the above copyright 13# notice, this list of conditions and the following disclaimer in the 14# documentation and/or other materials provided with the distribution. 15# 16# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26# SUCH DAMAGE. 27# 28 29[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1 30 31# Demonstrate starvation: Thread stuck in "ufs" for minutes. 32# Only seen with >= 16 CPUs. 33# Not a problem with 4BSD. 34# http://people.freebsd.org/~pho/stress/log/spin.txt 35# Fixed by r273966. 36 37. ../default.cfg 38 39timeout=1200 40 41here=`pwd` 42cd /tmp 43sed '1,/^EOF/d' < $here/$0 > spin.c 44mycc -o spin -Wall -Wextra -O0 spin.c || exit 1 45rm -f spin.c 46cd $here 47 48mount | grep $mntpoint | grep -q /dev/md && umount -f $mntpoint 49mdconfig -l | grep -q md$mdstart && mdconfig -d -u $mdstart 50 51mdconfig -a -t swap -s 1g -u $mdstart || exit 1 52newfs $newfs_flags -n md$mdstart > /dev/null 53mount /dev/md$mdstart $mntpoint 54 55cpus=`sysctl hw.ncpu | sed 's/.*: //'` 56(cd $mntpoint; /tmp/spin $((cpus + 1))) & 57error=0 58n=0 59while kill -0 $! 2>/dev/null; do 60 sleep 1 61 if [ $((n += 1)) -gt $timeout ]; then 62 echo FAIL 63 ps -l | grep -v sed | sed -n '1p;/ufs/p' 64 pkill spin 65 error=1 66 fi 67done 68wait 69 70while mount | grep $mntpoint | grep -q /dev/md; do 71 umount $mntpoint || sleep 1 72done 73mdconfig -d -u $mdstart 74rm -f /tmp/spin 75exit $error 76EOF 77#include <sys/param.h> 78#include <sys/wait.h> 79 80#include <err.h> 81#include <fcntl.h> 82#include <stdio.h> 83#include <stdlib.h> 84#include <unistd.h> 85 86void 87work(void) 88{ 89 90 while (access("rendezvous", R_OK) != 0) 91 ; 92 93 _exit(0); 94} 95 96int 97main(int argc, char **argv) 98{ 99 int fd, i, parallel; 100 101 if (argc == 2) 102 parallel = atoi(argv[1]); 103 else 104 errx(1, "Usage: %s <cpus>", argv[0]); 105 106 for (i = 0; i < parallel; i++) { 107 if (fork() == 0) 108 work(); 109 } 110 111 /* open(2) blocked on "ufs" for minutes */ 112 if ((fd = open("rendezvous", O_CREAT, 0644)) == -1) 113 err(1, "open()"); 114 close(fd); 115 116 for (i = 0; i < parallel; i++) 117 wait(NULL); 118 119 if (unlink("rendezvous") == -1) 120 err(1, "unlink()"); 121 122 return (0); 123} 124