2 * Copyright (c) 2008 Robert N. M. Watson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * Reproduce a race in which:
30 * - Process (a) is blocked in read on a socket waiting on data.
31 * - Process (b) is blocked in shutdown() on a socket waiting on (a).
32 * - Process (c) delivers a signal to (b) interrupting its wait.
34 * This race is premised on shutdown() not interrupting (a) properly, and the
35 * signal to (b) causing problems in the kernel.
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/socket.h>
50 receive_and_exit(int s)
55 ssize = recv(s, &ch, sizeof(ch), 0);
57 err(-1, "receive_and_exit: recv");
62 shutdown_and_exit(int s)
65 if (shutdown(s, SHUT_RD) < 0)
66 err(-1, "shutdown_and_exit: shutdown");
76 if (socketpair(PF_LOCAL, SOCK_STREAM, 0, sv) < 0)
77 err(-1, "socketpair");
83 receive_and_exit(sv[1]);
88 (void)kill(pida, SIGKILL);
92 shutdown_and_exit(sv[1]);
94 if (kill(pidb, SIGKILL) < 0)
97 printf("ok 1 - unix_sorflush\n");