git: 86db3c735dd9 - main - stress2: Added a regression test

The branch main has been updated by pho:

URL: https://cgit.FreeBSD.org/src/commit/?id=86db3c735dd999f75eab54d848fb8402e6689c80

commit 86db3c735dd999f75eab54d848fb8402e6689c80
Author:     Peter Holm <pho@FreeBSD.org>
AuthorDate: 2025-10-17 08:04:48 +0000
Commit:     Peter Holm <pho@FreeBSD.org>
CommitDate: 2025-10-17 08:04:48 +0000

    stress2: Added a regression test
---
 tools/test/stress2/misc/unionfs20.sh | 206 +++++++++++++++++++++++++++++++++++
 1 file changed, 206 insertions(+)

diff --git a/tools/test/stress2/misc/unionfs20.sh b/tools/test/stress2/misc/unionfs20.sh
new file mode 100755
index 000000000000..0c87bc0d80aa
--- /dev/null
+++ b/tools/test/stress2/misc/unionfs20.sh
@@ -0,0 +1,206 @@
+#!/bin/sh
+
+#
+# Copyright (c) 2025 Peter Holm <pho@FreeBSD.org>
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+
+# Bug 289700 - unionfs: page fault in unionfs_find_node_status when closing a file within a socket's receive buffer
+
+# "Fatal trap 12: page fault while in kernel mode" seen:
+# https://people.freebsd.org/~pho/stress/log/log0618.txt
+
+. ../default.cfg
+
+prog=$(basename "$0" .sh)
+here=`pwd`
+log=/tmp/$prog.log
+md1=$mdstart
+md2=$((md1 + 1))
+mp1=/mnt$md1
+mp2=/mnt$md2
+
+set -eu
+mdconfig -l | grep -q md$md1 && mdconfig -d -u $md1
+mdconfig -l | grep -q md$md2 && mdconfig -d -u $md2
+
+mdconfig -s 2g -u $md1
+newfs $newfs_flags /dev/md$md1 > /dev/null
+mdconfig -s 2g -u $md2
+newfs $newfs_flags /dev/md$md2 > /dev/null
+
+mkdir -p $mp1 $mp2
+mount /dev/md$md1 $mp1
+mount /dev/md$md2 $mp2
+mount -t unionfs -o noatime $mp1 $mp2
+set +e
+
+cd /tmp
+sed '1,/^EOF/d' < $here/$0 > $prog.c
+mycc -o $prog -Wall -Wextra -O2 $prog.c
+rm -f $prog.c
+[ -d $RUNDIR ] || mkdir -p $RUNDIR
+cd $RUNDIR
+
+n=3
+for i in `jot $n`; do
+	mkdir $mp2/d$i
+done
+(cd $here/../testcases/swap; ./swap -t 3m -i 20 -l 100 -h > /dev/null) &
+sleep 2
+for i in `jot $n`; do
+	(cd $mp2/d$i; /tmp/$prog) &
+done
+while pgrep -q $prog; do sleep .5; done
+while pkill swap; do :; done
+wait
+
+cd $here
+umount $mp2 # The unionfs mount
+umount $mp2
+umount $mp1
+
+mdconfig -d -u $md1
+mdconfig -d -u $md2
+rm -f /tmp/$prog
+exit 0
+EOF
+#include <sys/param.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+
+#include <stdio.h>
+#include <errno.h>
+#include <err.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdatomic.h>
+#include <string.h>
+
+#define PARALLEL 2
+#define SYNC 0
+
+static int debug;
+static _Atomic(int) *share;
+
+int
+send_fd(int socket, int fd_to_send)
+{
+	struct cmsghdr *cmsg;
+	struct msghdr msg = {0};
+	struct iovec iov;
+	char buf[1] = {0};  // dummy data
+	char cmsgbuf[CMSG_SPACE(sizeof(fd_to_send))];
+
+	memset(cmsgbuf, 0, sizeof(cmsgbuf));
+
+	iov.iov_base = buf;
+	iov.iov_len = sizeof(buf);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	msg.msg_control = cmsgbuf;
+	msg.msg_controllen = sizeof(cmsgbuf);
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(fd_to_send));
+
+	memcpy(CMSG_DATA(cmsg), &fd_to_send, sizeof(fd_to_send));
+
+	return (sendmsg(socket, &msg, 0));
+}
+
+int
+recv_fd(int socket)
+{
+	struct cmsghdr *cmsg;
+	struct msghdr msg = {0};
+	struct iovec iov;
+	char buf[1];
+	int received_fd;
+	char cmsgbuf[CMSG_SPACE(sizeof(received_fd))];
+
+	memset(cmsgbuf, 0, sizeof(cmsgbuf));
+
+	iov.iov_base = buf;
+	iov.iov_len = sizeof(buf);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	msg.msg_control = cmsgbuf;
+	msg.msg_controllen = sizeof(cmsgbuf);
+
+	if (recvmsg(socket, &msg, 0) < 0)
+		err(1, "recvmsg()");
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	if (cmsg == NULL || cmsg->cmsg_len != CMSG_LEN(sizeof(received_fd))) {
+		fprintf(stderr, "No passed fd\n");
+		return (-1);
+	}
+
+	if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
+		fprintf(stderr, "Invalid cmsg_level or cmsg_type\n");
+		return (-1);
+	}
+
+	memcpy(&received_fd, CMSG_DATA(cmsg), sizeof(received_fd));
+	return (received_fd);
+}
+
+int
+main(void)
+{
+	pid_t pid;
+	time_t start;
+	size_t len;
+	int fd, pair[2], status;
+
+	fd  = -1;
+	len = PAGE_SIZE;
+	if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE,
+	    MAP_ANON | MAP_SHARED, -1, 0)) == MAP_FAILED)
+		err(1, "mmap");
+
+	if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, pair) == -1)
+		err(1, "socketpair");
+
+	start = time(NULL);
+	while (time(NULL) - start < 180) {
+		share[SYNC] = 0;
+		if ((pid = fork()) == -1)
+			err(1, "fork");
+		if (pid == 0) {
+			close(pair[0]);
+			atomic_fetch_add(&share[SYNC], 1);
+			while (share[SYNC] != PARALLEL)
+				usleep(1000);
+			// Not calling recv_fd() triggers the issue
+//			fd = recv_fd(pair[1]);
+			if (debug)
+				fprintf(stderr, "Received fd=%d\n", fd);
+			_exit(0);
+		}
+		fd = open("foo", O_RDWR|O_CREAT|O_TRUNC, 0666);
+		if (fd == -1)
+			err(1, "open");
+		if (debug)
+			fprintf(stderr, "Sending fd=%d\n", fd);
+		atomic_fetch_add(&share[SYNC], 1);
+		while (share[SYNC] != PARALLEL)
+			usleep(1000);
+		send_fd(pair[0], fd);
+		usleep(arc4random() % 1000);
+		wait(&status);
+		close(fd);
+		unlink("foo");
+	}
+}