From owner-freebsd-current Tue Jan 21 12:57:59 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id MAA12508 for current-outgoing; Tue, 21 Jan 1997 12:57:59 -0800 (PST) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by freefall.freebsd.org (8.8.4/8.8.4) with SMTP id MAA12284 for ; Tue, 21 Jan 1997 12:55:49 -0800 (PST) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id VAA17124; Tue, 21 Jan 1997 21:50:32 +0100 Received: (from j@localhost) by uriah.heep.sax.de (8.8.4/8.6.9) id VAA23164; Tue, 21 Jan 1997 21:22:02 +0100 (MET) Message-ID: Date: Tue, 21 Jan 1997 21:22:02 +0100 From: j@uriah.heep.sax.de (J Wunsch) To: syssgm@devetir.qld.gov.au (Stephen McKay) Cc: mark@grondar.za (Mark Murray), freebsd-current@freebsd.org Subject: Re: VM bogon? Was: Re: NIS breakage References: <199701211013.UAA13869@ogre.devetir.qld.gov.au> X-Mailer: Mutt 0.55-PL10 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: <199701211013.UAA13869@ogre.devetir.qld.gov.au>; from Stephen McKay on Jan 21, 1997 20:13:45 +1000 Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk As Stephen McKay wrote: > >Hmm. I've just been looking at copyout(). If the target pages are not > >present, then their page table page might not be present either. In this > >case, won't the attempt to check the target pages' writability cause a > >fault? This fault would then be translated to EFAULT (Bad address) by > >copyout_fault. > > In fact, I'm now so keen on my hypothesis that I've written some code. > Unfortunately, I have no -current box to test it on. Thus, if Mr Murry > wishes to risk all, the following patch may help. Too bad :-(, it doesn't fix it. I've just rebuilt my scratch box's system (a 386/40 that can netboot -current), and i can still easily trigger the bug. Just start vi with some file, and then start a large compilation in another session so the vi becomes paged out. Hit a key, splash!, Bad address. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)