我有默认的 CentOS7 服务器，除了 WildFly10 之外没有任何其他软件，而且我是那里唯一的用户。
我使用命令运行 WildFlyscreen并从服务器注销，直到它在成功上线约 20 天后变得不可用。
WildFly 的日志没有任何异常，但ps aux显示不再有screen进程，并且/var/log/messages对我来说有几行不清楚的内容：
Jan 22 13:06:01 p000000 systemd: Starting Session c386 of user root.
Jan 22 13:06:01 p000000 systemd: Started Session c386 of user root.
Jan 22 13:09:01 p000000 systemd: Starting Unmount All Filesystems.
Jan 22 13:09:01 p000000 systemd: Reached target Unmount All Filesystems.
Jan 22 13:09:01 p000000 systemd: Stopping Session c137 of user root.
Jan 22 13:09:01 p000000 systemd: Stopped Session c137 of user root.
Jan 22 13:09:01 p000000 systemd: Stopping user-0.slice.
Jan 22 13:09:01 p000000 systemd: Removed slice user-0.slice.
Jan 22 13:09:01 p000000 systemd: Stopping Dump dmesg to /var/log/dmesg...
Jan 22 13:09:01 p000000 systemd: Stopped Dump dmesg to /var/log/dmesg.
Jan 22 13:09:01 p000000 systemd: Stopping Graphical Interface.
Jan 22 13:09:01 p000000 systemd: Stopped target Graphical Interface.
Jan 22 13:09:01 p000000 systemd: Stopping Multi-User System.
Jan 22 13:09:01 p000000 systemd: Stopped target Multi-User System.
Jan 22 13:09:01 p000000 systemd: Stopping OpenSSH server daemon...
Jan 22 13:09:01 p000000 systemd: Stopping SASL authentication daemon....
Jan 22 13:09:01 p000000 systemd: Stopping Xinetd A Powerful Replacement For Inetd...
Jan 22 13:09:01 p000000 rsyslogd: [origin software="rsyslogd" swVersion="7.4.7" x-pid="107" x-info="http://www.rsyslog.com"] exiting on signal 15.
Jan 22 13:09:19 p000000 rsyslogd: [origin software="rsyslogd" swVersion="7.4.7" x-pid="106" x-info="http://www.rsyslog.com"] start
发生了什么事？为什么screen进程意外停止了？