[563] in linux-net channel archive
Pty problems
daemon@ATHENA.MIT.EDU (Marcus Nilsson)
Fri Jun 23 00:54:23 1995
Date: Thu, 22 Jun 1995 17:09:57 +0200 (MET DST)
From: Marcus Nilsson <marcus@kuai.se>
To: linux-net@vger.rutgers.edu
In-Reply-To: <Pine.SCO.3.91.950622123330.7654A-100000@silmaril.paradigm.co.za>
We have a considerable amount of rlogin on our server, due to the face
that we are an Internet Access Provider. Now, it seems that sometimes the
pty "hangs". All ptys don't hang, just one. Say that ttyp4 hangs, then
when the fifth user logs in it says(when using telnet, rlogin just stops):
Linux (tao.kuai.se) (ttyp4)
Then it stops. I have recompiled both telnetd and rlogind to put some
debug info there. And in rlogind, I have traced down that it hangs
at the first write to the pty. In telnetd, the above line obviously is
written my the "protocol" function, which suggests a ptyhang. Also, as
soon as one user has logged out, leaving a pty free, then you can telnet
or rlogin in on that pty, then it hangs again on the same pty(in this
case ttyp4). All this suggests that one pty hangs.
Now, of course this is no good for us as an Internet Provider. Can
someone _please_ look at this. I know this is a hard problem to fix,
because of the fact it cannot be reproduced, but _please_....
I'm not 100% sure that it's the first write that causes the deadlock, it
could be the first read, or whatever.
Any tips, pointers, whatever is appreciated.
/Marcus Nilsson
