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From: alen@cogen.UUCP (Alen Shapiro)
Newsgroups: comp.unix.wizards
Subject: tty hangs in ^S state was (Re: Killing the printer daemon)
Message-ID: <366@cogen.UUCP>
Date: Wed, 23-Sep-87 20:25:19 EDT
Article-I.D.: cogen.366
Posted: Wed Sep 23 20:25:19 1987
Date-Received: Sat, 26-Sep-87 08:28:37 EDT
References: <2419@drivax.UUCP>
Reply-To: alen@cogen.UUCP (Alen Shapiro)
Organization: Cogensys, LaJolla, Calf.
Lines: 24

In article <2419@drivax.UUCP> braun@drivax.UUCP (Kral) writes:
>
>After rebooting and recreating the situation, I tried to kill the daemon
>manually with kill -9.  It just won't die.  So what's an admin to do?
>

I've had a similar problem before, the printer was on a serial
interface and the printer died when the line was in a ^S state.
The daemon process which was in an i/o pending state would not die
until we attached a tty and typed ^Q at it!!!!

The same problem has bitten us with a DTR race condition on modem
connections. If carrier is lost and garbage on the line causes
the tty line to enter ^S state (during a tip to the tty (cua) line)
then tip will fail to fully exit with ~. and an unkillable tip
zombie is the result. Fix here (since modem control is harder
to fudge with a spare tty) is either to reboot or find someone
capable of patching the kernel tty state!!!

Does ANYONE have a better solution please?

--alen the Lisa slayer (it's a long story)

	...seismo!esosun!cogen!alen