无缘无故死机了？

下面是日志，最近经常出现。
> Aug 20 09:44:07 V490 /usr/dt/bin/ttsession[11648]: [ID 862433
> daemon.error] child (12607) exit
> ed due to signal 1
> Aug 20 10:26:42 V490 dtexec[17071]: [ID 579743 user.error] libtt[17071]:
> _Tt_stream_socket::ac
> cept(): t_listen(): System error: Interrupted system call
> Aug 20 11:30:27V490/usr/dt/bin/ttsession[22273]: [ID 862433
> daemon.error] child (22292) exit
> ed due to signal 1
> Aug 20 12:03:26 V490 /usr/dt/bin/ttsession[8359]: [ID 499248
> daemon.error] fork1(): Resource t
> emporarily unavailable
> Aug 20 12:11:38 V490 reboot: [ID 662345 auth.crit] rebooted by LOGIN

reboot了啊
那里死机了?