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From: veench@ark.UUCP
Newsgroups: comp.os.minix
Subject: How to crash MINIX in a nice way, and the bugfix
Message-ID: <917@ark.cs.vu.nl>
Date: Fri, 27-Feb-87 08:40:13 EST
Article-I.D.: ark.917
Posted: Fri Feb 27 08:40:13 1987
Date-Received: Mon, 2-Mar-87 21:45:56 EST
Reply-To: veench@cs.vu.nl (Veen van Dick)
Distribution: world
Organization: VU Informatica, Amsterdam
Lines: 20
Keywords: bug with reviving readers on a pipe


How to create the crash:
	cat 2>&1 | cat
	type <del>

This causes a do_close on every filedescriptor of the first cat,
and twice a release and on the second cat.
So the variable reviving has the value 2,
and in get_work there will only one proces be found to be revived.
The fix is simple,

On page 644 of the book in file fs/pipe.c on line 10549 is found:
if (rfp->fp_suspended == NOT_SUSPENDED) return;

This should be:

if (rfp->fp_suspended == NOT_SUSPENDED || rfp->fp_revived == REVIVING) return;
					  ---------------------------

					Dick van Veen