diff --git a/tools/regression/sockets/unix_sorflush/Makefile b/tools/regression/sockets/unix_sorflush/Makefile
new file mode 100644
index 000000000000..7f0b9f1a85a3
--- /dev/null
+++ b/tools/regression/sockets/unix_sorflush/Makefile
@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+PROG=	unix_sorflush
+NO_MAN=
+WARNS=	3
+
+.include <bsd.prog.mk>
diff --git a/tools/regression/sockets/unix_sorflush/unix_sorflush.c b/tools/regression/sockets/unix_sorflush/unix_sorflush.c
new file mode 100644
index 000000000000..126de2f28714
--- /dev/null
+++ b/tools/regression/sockets/unix_sorflush/unix_sorflush.c
@@ -0,0 +1,99 @@
+/*-
+ * Copyright (c) 2008 Robert N. M. Watson
+ * 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.
+ */
+
+/*
+ * Reproduce a race in which:
+ *
+ * - Process (a) is blocked in read on a socket waiting on data.
+ * - Process (b) is blocked in shutdown() on a socket waiting on (a).
+ * - Process (c) delivers a signal to (b) interrupting its wait.
+ *
+ * This race is premised on shutdown() not interrupting (a) properly, and the
+ * signal to (b) causing problems in the kernel.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/socket.h>
+
+#include <err.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static void
+receive_and_exit(int s)
+{
+	ssize_t ssize;
+	char ch;
+
+	ssize = recv(s, &ch, sizeof(ch), 0);
+	if (ssize < 0)
+		err(-1, "receive_and_exit: recv");
+	exit(0);
+}
+
+static void
+shutdown_and_exit(int s)
+{
+
+	if (shutdown(s, SHUT_RD) < 0)
+		err(-1, "shutdown_and_exit: shutdown");
+	exit(0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	pid_t pida, pidb;
+	int sv[2];
+
+	if (socketpair(PF_LOCAL, SOCK_STREAM, 0, sv) < 0)
+		err(-1, "socketpair");
+
+	pida = fork();
+	if (pida < 0)
+		err(-1, "fork");
+	if (pida == 0)
+		receive_and_exit(sv[1]);
+	sleep(1);
+	pidb = fork();
+	if (pidb < 0) {
+		warn("fork");
+		(void)kill(pida, SIGKILL);
+		exit(-1);
+	}
+	if (pidb == 0)
+		shutdown_and_exit(sv[1]);
+	sleep(1);
+	if (kill(pidb, SIGKILL) < 0)
+		err(-1, "kill");
+	sleep(1);
+	printf("ok 1 - unix_sorflush\n");
+	exit(0);
+}