Date: Thu, 4 Feb 1999 09:49:50 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Stephen McKay <syssgm@detir.qld.gov.au>, freebsd-current@FreeBSD.ORG, syssgm@detir.qld.gov.au Subject: Re: panic: vm_object_qcollapse(): object mismatch Message-ID: <199902041749.JAA89484@apollo.backplane.com> References: <199902041300.XAA10590@nymph.detir.qld.gov.au> <199902041726.JAA88650@apollo.backplane.com>
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I introduced this bug in 1.139 when I added the KASSERT(). Bleh. However, the code still needs to be protected at splbio(). And so I've committed. -Matt : Hmmm. This looks like an out-an-out bug to me. The assertion is wrong. : It's scanning the backing_object and asserting that the pages in the : backing object are associated with object rather then backing_object. : : This section of code only runs when paging is in progress on a : collapseable object AND there are also idle pages in that object. : The collapse condition is probably due to an exiting process ( typical : in a buildworld ). : : ( from vm/vm_object.c ) : /* : * busy the page and move it from the backing store to the : * parent object. : */ : : vm_page_busy(p); : : KASSERT(p->object == object, ("vm_object_qcollapse(): object mismatch")); : ^^^^^^^^^^ : should be 'backing_object' : : There is also an interrupt race. Since paging can be in progress, : pages in the object can be ripped out from under it so we have to : run at splbio() in the loop. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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