Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!mailrus!ncar!asuvax!mcdphx!xroads!jerry
From: jerry@xroads.UUCP (Jerry M. Denman)
Newsgroups: comp.unix.wizards
Subject: Re: when does kill -9 pid not work?
Message-ID: <790@xroads.UUCP>
Date: 7 Aug 89 06:58:59 GMT
References: <20495@adm.BRL.MIL> <9748@alice.UUCP>
Reply-To: jerry@xroads.UUCP (Jerry M. Denman)
Organization: Crossroads, Phoenix, AZ 85046
Lines: 21


In article <9748@alice.UUCP> debra@alice.UUCP () writes:
>In article <20495@adm.BRL.MIL> Leisner.Henr@xerox.com (Marty) writes:
>}I had an infinite loop in my boot loader, and I couldn't kill the DOS task
>}via a
>}kill -9 pid
>
>kill -9 pid (executed as the owner of the process or as root) is
>guaranteed to work.
>

I would have to differ in opinion on that answer.  According to Bach, 
if a process gets "hung" while in kernal mode, there is no way to kill
it.  This is to prevent corruption of the kernal tables.  If a process is
in any other mode besides kernal, then a kill -9 will terminate it.  The 
most common example of this is if you hang a device driver.  They spend
a greater share of the time executing kernal level tasks and do tend to 
drop off into never never land without notice.  Many times when this happens
a reboot is the only way to clear the process from the table.

Of course, I have been know to be wrong.