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 Message-ID: <Mutt.19970121212202.j@uriah.heep.sax.de> In-Reply-To: <199701211013.UAA13869@ogre.devetir.qld.gov.au>; from Stephen McKay on Jan 21, 1997 20:13:45 %2B1000 References: <199701211013.UAA13869@ogre.devetir.qld.gov.au>
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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. ;-)
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