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From: akbloom@aplcen.apl.jhu.edu (Keith Bloom)
Newsgroups: comp.unix.programmer
Subject: Re: Writing a program that cannot be killed except by reboot
Message-ID: <1991Apr14.200931.17551@aplcen.apl.jhu.edu>
Date: 14 Apr 91 20:09:31 GMT
References: <444@wrdis01.af.mil>
Distribution: na
Organization: The Johns Hopkins University
Lines: 19

mcgough@wrdis01.af.mil (Jeffrey B. McGough) writes:

>Is there anyway to block ALL signals to a program so that it
>may not be killed by kill???

>I know the manual says that sig 9 may not be caught or blocked
>but I was wondering if there might be a funny (strange, interesting)
>hack to get around this...

I've seen situations in which the program is trying to write to some
device like a network socket or parallel or serial port, and there's
something wrong with the connection.  In this case, it frequently
happens that even kill -9 won't work; rebooting is the only thing *I*
can think of to do when this happens.  I suppose a program could do this
deliberately.

By the way, is there any *legitimate* reason for a device driver to
simply "hang" forever?  In other words, is this ever *not* a bug in
the device driver?