1#!/bin/sh 2 3# 4# Copyright (c) 2008 Peter Holm <pho@FreeBSD.org> 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# panic: spin lock held too long 30 31# Test program and scenario by Peter Wemm <peter@FreeBSD.org> 32 33. ../default.cfg 34 35odir=`pwd` 36 37cd /tmp 38sed '1,/^EOF/d' < $odir/$0 > pth.c 39mycc -o pth -Wall pth.c -pthread 40rm -f pth.c 41cd $odir 42 43for i in `jot 2000`; do 44 /tmp/pth 2>/dev/null 45done 46 47rm -f /tmp/pth 48exit 49EOF 50#include <pthread.h> 51 52#include <sys/types.h> 53#include <stdlib.h> 54#include <unistd.h> 55#include <string.h> 56#include <stdio.h> 57 58static pthread_t worker1_thr; 59static pthread_t worker2_thr; 60 61static pthread_mutex_t worker_mtx; 62static pthread_cond_t worker_go; 63static pthread_cond_t worker_done; 64 65struct workitem { 66 struct workitem *next; 67 int a, b; 68}; 69 70struct workitem *head; 71 72static void * 73worker(void *arg) 74{ 75 struct workitem *w; 76 77 pthread_detach(pthread_self()); 78 fprintf(stderr, "WORKER: started %p\n", arg); fflush(stderr); 79 80 for (;;) { 81 pthread_mutex_lock(&worker_mtx); 82 while (head == NULL) { 83 pthread_cond_wait(&worker_go, &worker_mtx); 84 } 85 w = head; 86 head = w->next; 87 pthread_mutex_unlock(&worker_mtx); 88 89 fprintf(stderr, "WORKER(%p): got work a=%d b=%d\n", arg, w->a, w->b); fflush(stderr); 90 free(w); 91 pthread_cond_signal(&worker_done); 92 } 93} 94 95void 96work_add(int a, int b) 97{ 98 struct workitem *w; 99 int dowake = 0; 100 101 w = calloc(sizeof(*w), 1); 102 w->a = a; 103 w->b = b; 104 pthread_mutex_lock(&worker_mtx); 105 if (head == 0) 106 dowake = 1; 107 w->next = head; 108 head = w; 109 pthread_mutex_unlock(&worker_mtx); 110 if (dowake) 111 pthread_cond_signal(&worker_go); 112} 113 114int 115main() 116{ 117 pthread_mutex_init(&worker_mtx, NULL); 118 pthread_cond_init(&worker_go, NULL); 119 pthread_cond_init(&worker_done, NULL); 120 121 fprintf(stderr, "pthread create\n"); fflush(stderr); 122 pthread_create(&worker1_thr, NULL, worker, (void *)1); 123 pthread_create(&worker2_thr, NULL, worker, (void *)2); 124 125 work_add(10, 15); 126 work_add(11, 22); 127 work_add(314, 159); 128 129 pthread_mutex_lock(&worker_mtx); 130 while (head != NULL) { 131 pthread_cond_wait(&worker_done, &worker_mtx); 132 } 133 pthread_mutex_unlock(&worker_mtx); 134 135 fprintf(stderr, "job complete\n"); fflush(stderr); 136 exit(0); 137} 138