From owner-freebsd-current@FreeBSD.ORG Wed Sep 12 11:35:35 2007 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8EF7C16A41A for ; Wed, 12 Sep 2007 11:35:35 +0000 (UTC) (envelope-from andrew@fubar.geek.nz) Received: from mta02.xtra.co.nz (mta02.xtra.co.nz [210.54.141.253]) by mx1.freebsd.org (Postfix) with ESMTP id 17A4E13C45D for ; Wed, 12 Sep 2007 11:35:34 +0000 (UTC) (envelope-from andrew@fubar.geek.nz) Received: from fep03.xtra.co.nz ([172.23.12.31]) by mta02.xtra.co.nz with ESMTP id <20070912113529.QSYB2671.mta02.xtra.co.nz@fep03.xtra.co.nz> for ; Wed, 12 Sep 2007 23:35:29 +1200 Received: from serv.int.fubar.geek.nz ([219.89.91.5]) by fep03.xtra.co.nz with ESMTP id <20070912113528.YSMD27104.fep03.xtra.co.nz@serv.int.fubar.geek.nz> for ; Wed, 12 Sep 2007 23:35:28 +1200 Date: Wed, 12 Sep 2007 23:35:27 +1200 From: Andrew Turner To: freebsd-current@freebsd.org Message-ID: <20070912233527.63f97084@hermies.int.fubar.geek.nz> X-Mailer: Claws Mail 2.10.0 (GTK+ 2.10.14; i386-portbld-freebsd6.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Tracking down problems with vm X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Sep 2007 11:35:35 -0000 I'm working on tracking down the problems I've found running FreeBSD on XEN's full virtualization. I'm looking at fixing a page fault in kernel when INVARIANTS is enabled. The problem is in uma_dbg_alloc slab->us_data is NULL. This means freei is set to a value that is too large for the slabref->us_freelist array. I've placed extra debugging code in the uma functions to try to find where us_data is set to NULL. The point I found is in the call to uma_dbg_getslab from uma_dbg_alloc. I've not managed to track down where it was set to NULL however. Can anyone give me a hint as to where to look to track down why the us_data is NULL? Andrew -- Andrew Turner http://fubar.geek.nz/blog/