Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!hp-pcd!hpcvmb!carlj
From: carlj@hpcvmb.HP (Carl Johnson)
Newsgroups: comp.unix.microport
Subject: Re: Trouble killing processes in SysV/AT
Message-ID: <7680001@hpcvmb.HP>
Date: 2 May 88 14:25:54 GMT
References: <3951@killer.UUCP>
Organization: HP Corvallis, Oregon.
Lines: 32


>In article <3951@killer.UUCP> wnp@killer.UUCP (Wolf Paul) writes:
>>Can anyone enlighten me as to what causes a process to become "immortal"
>>in System VR2,  or Microport UNIX System V/AT, to be more specific?
>>
>>I have encountered this a number of times, where it would be impossible
>>even for root to kill a process; if the parent process of the "immortal"
>>process is killed, the child attaches itself to init, PID 1.

>The only processes (I can think of) that cannot be killed, even with
>signal 9, are *DEFUNCT* processes and processes suspended waiting on I/O.
>Since the above case is evidently not a DEFUNCT, I would suspect an I/O
>problem.  Since there was no mention of what the process is doing, its
>tough to determine.  Is the process a hung getty?  How about a little more
>info.
>
>Ken Keirnan - Pacific Bell - {att,bellcore,sun,ames,pyramid}!pacbell!pbhyf!kjk
>  San Ramon, California	                    kjk@pbhyf.PacBell.COM

Since I have seen what sounds like the same problem, I'll mention what I've
seen.  Every time I have seen it it has been when I have been using more
(or less or pg) as a filter when listing some output.  Since the process
has always been on the output of a pipe, I have always assumed it was
a problem with pipes.  In every case the virtual console will accept and
echo input, but it doesn't respond to it.  The only solution has been to
switch to another virtual console and kill the parent of the process (which
I think has always been a login shell).  This then allows me to switch
back and log in again, and leaves the offending process in the background
with a PPID of 1.  I doubt this is a common problem with other systems,
since without virtual consoles I don't see any way to get control back
short of re-booting.

Carl Johnson - Hewlett-Packard Co. - ...!hplabs!hp-pcd!carlj