Date: Mon, 5 Mar 2001 11:17:51 +0900 (JST) From: =?euc-kr?q?jaewoo=20Kim?= <unixmast@yahoo.co.kr> To: freebsd-questions@FreeBSD.ORG Subject: Ghost process with broken Telnet connection. Message-ID: <20010305021751.23037.qmail@web11908.mail.yahoo.com>
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I have 2 FreeBSD 4.2 system, one for telnet service
and
the orther for application development.
I have find out some strange things concernning with
telnet connections, especially in broken telnet
connections.
Hereinafter, my experiences;
AA. Tested Software
FreeBSD 4.2 Release
FreeBSD 4 Stable 2001.02.18 snap.kr.install.iso
FreeBSD 4.11 Release
BB. Tested Telnet Client
NetTerm 4.2
Telnet.exe included in Win98
telnet included in FreeBSD and Linux
CC. Tested Hardware
Intel Server 800MHz with 256MB RAM, 8GB Segate
SCSI HDD, 100MBPS Intel NIC
Pentium 150MHz with 64MB RAM, 30GB IBM HDD,
10MBPS 3C900 NIC
DD. Procedures
aa. Open two telnet clients window at Win98 or
orther clients
bb. Run infinite loop program ( ex. top ) at
each telnet terminal after successfully login to BSD.
cc. Disconnect one telnet client connection
without normal procedure.
This means break the telnet connection in
force, killing telnet client window is a example.
dd. Then watch the orther telnet client's
window, the top process says the idle CPU time is
almost zero(0) per cent.
And you will find out the infinite loop
process( another top which ran from broken telnet
session in this case )
remains and occupy every CPU time.
My guess is the process belongs to broken
telnet session does not realize that session was
broken and
retry to create a new process tediously,
but nothing is clear.
ee. A shell script which read user input from
keyboard in a loop makes same result.
ff. After a couple of test, system's reply is
slow down in significant.
Especially lots of I/O, ls -lRa /* in
example.
One day my telnet server had 450 more
processes without any logged in user, most of them are
the ghost process described above.
Is there anyone who knows solutions or suggestions for
this problem, who experienced same thing ?
Thanks
unixmast@yahoo.co.kr KIM Jaewoo
=====
Kim Jaewoo
unixmast@yahoo.co.kr
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