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From: torek@elf.ee.lbl.gov (Chris Torek)
Newsgroups: comp.sources.wanted
Subject: Re: Modifying a unix process table on the fly
Message-ID: <9952@dog.ee.lbl.gov>
Date: 15 Feb 91 09:48:01 GMT
References: <5962@rtech.Ingres.COM> <118873@uunet.UU.NET>
Reply-To: torek@elf.ee.lbl.gov (Chris Torek)
Organization: Lawrence Berkeley Laboratory, Berkeley
Lines: 16
X-Local-Date: Fri, 15 Feb 91 01:48:01 PST

In article <118873@uunet.UU.NET> rbj@uunet.UU.NET (Root Boy Jim) writes:
>I have always thought that setting the "Wait Channel" to the address
>of the lightning bolt (lbolt) would be a nice way to either
>(1) unwedge a process, or (2) crash the system.

Actually, chances are it would do nothing.  4BSD (at least, and
probably most others now) has a hash table of sleeping processes so
that wakeup() can avoid looking at everything.  wakeup(chan) computes
hash(chan) and runs down only that particular list of sleeping
processes.

Of course, if the hash for &lbolt were the same as that for the current
wait, you would probably get the crash. :-)
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab EE div (+1 415 486 5427)
Berkeley, CA		Domain:	torek@ee.lbl.gov