Date: Sat, 15 Apr 2000 18:02:43 -0500 From: Alan Cox <alc@cs.rice.edu> To: Brian Fundakowski Feldman <green@freebsd.org> Cc: Matthew Dillon <dillon@apollo.backplane.com>, Alfred Perlstein <bright@wintelcom.net>, Michael Reifenberger <root@nihil.plaut.de>, current@freebsd.org, alc@freebsd.org Subject: Re: panic: vm_object_shadow: source object has OBJ_ONEMAPPING set. Message-ID: <20000415180243.D3462@cs.rice.edu> In-Reply-To: <Pine.BSF.4.21.0004151810080.17351-100000@green.dyndns.org>; from Brian Fundakowski Feldman on Sat, Apr 15, 2000 at 06:12:22PM -0400 References: <200004151823.LAA79731@apollo.backplane.com> <Pine.BSF.4.21.0004151810080.17351-100000@green.dyndns.org>
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On Sat, Apr 15, 2000 at 06:12:22PM -0400, Brian Fundakowski Feldman wrote: > On Sat, 15 Apr 2000, Matthew Dillon wrote: > > > Note that the ref_count == 1 test in the vm_object_shadow optimization > > should be left intact. This optimization requires a much stricter set > > of tests because we do not want to assume sharability of an object > > if someone else (the 'else' being 'someone unknown to us') has a reference > > on it, even if OBJ_ONEMAPPING is set. > > The KASSERT is broken in another way, BTW: it has undefined (read: > panic before the test even occurs) results if source is NULL, which > vm_object_shadow otherwise handles. I don't know why it's never been > tripped on, though... > Other parts of the VM insure that we never try to create a shadow object for a non-existant backing object. Alan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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