From owner-freebsd-current@FreeBSD.ORG Thu Jun 18 11:43:11 2009 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 123D6106568A; Thu, 18 Jun 2009 11:43:11 +0000 (UTC) (envelope-from serenity@exscape.org) Received: from ch-smtp01.sth.basefarm.net (ch-smtp01.sth.basefarm.net [80.76.149.212]) by mx1.freebsd.org (Postfix) with ESMTP id 8FA738FC16; Thu, 18 Jun 2009 11:43:10 +0000 (UTC) (envelope-from serenity@exscape.org) Received: from c83-253-252-234.bredband.comhem.se ([83.253.252.234]:57231 helo=mx.exscape.org) by ch-smtp01.sth.basefarm.net with esmtp (Exim 4.69) (envelope-from ) id 1MHG1E-0007vM-65; Thu, 18 Jun 2009 13:43:02 +0200 Received: from [192.168.1.5] (macbookpro [192.168.1.5]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by mx.exscape.org (Postfix) with ESMTPSA id 790466B162; Thu, 18 Jun 2009 13:42:56 +0200 (CEST) Message-Id: From: Thomas Backman To: Andriy Gapon In-Reply-To: <4A3A1D27.4010802@icyb.net.ua> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v935.3) Date: Thu, 18 Jun 2009 13:42:55 +0200 References: <949B5884-5303-4EFF-AC7D-293640FFA012@exscape.org> <0C235698-3ED2-4AE9-A7D1-5DC56D8324A4@exscape.org> <200905212129.47892.mel.flynn+fbsd.current@mailing.thruhere.net> <44F486FA-E798-448D-BE31-F7A51EF1F612@exscape.org> <60173AF0-7E54-4BDD-8927-0DADA9DAD1B4@exscape.org> <20090522200306.GE2630@atarininja.org> <20090617225849.GB28509@atarininja.org> <4A3A1D27.4010802@icyb.net.ua> X-Mailer: Apple Mail (2.935.3) X-Originating-IP: 83.253.252.234 X-Scan-Result: No virus found in message 1MHG1E-0007vM-65. X-Scan-Signature: ch-smtp01.sth.basefarm.net 1MHG1E-0007vM-65 5c90402651a87bf0de3a7dc1e9d4d6bc Cc: Wesley Shields , freebsd-current@FreeBSD.org Subject: Re: DTrace panic while probing syscall::open (and possibly many others) 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: Thu, 18 Jun 2009 11:43:11 -0000 On Jun 18, 2009, at 12:55 PM, Andriy Gapon wrote: > on 18/06/2009 12:43 Thomas Backman said the following: >> >> at dtrace_isa.c:527 >> #14 0xffffffff816b31fc in dtrace_copyinstr (uaddr=34365163021, >> kaddr=18446743524025463312, size=256, flags=0xffffffff8146e0c0) >> at dtrace_isa.c:558 > > kaddr=18446743524025463312 == FFFFFF8004467210 > I think kernelbase on amd64 is 0xFFFFFFFF80000000. > FFFFFF8004467210 kaddr > is smaller than > FFFFFFFF80000000 kernelbase > > The numbers do look suspiciously similar, so I am not sure if you > are seeing a > race or a real bug somewhere. > -- > Andriy Gapon Hmmm... Looking around a bit for these numbers, I found, in /sys/amd64/include/ vmparam.h: /* * Virtual addresses of things. Derived from the page directory and * page table indexes from pmap.h for precision. * * 0x0000000000000000 - 0x00007fffffffffff user map * 0x0000800000000000 - 0xffff7fffffffffff does not exist (hole) * 0xffff800000000000 - 0xffff804020100fff recursive page table (512GB slot) * 0xffff804020101000 - 0xfffffeffffffffff unused * 0xffffff0000000000 - 0xffffff7fffffffff 512GB direct map mappings * 0xffffff8000000000 - 0xffffffffffffffff 512GB kernel map * * Within the kernel map: * * 0xffffffff80000000 KERNBASE */ So, kaddr is inside the "kernel map", but not KERNBASE. What this means, I have no clue whatsoever. (I'm not a kernel developer and I don't know too much about (virtual) memory either!) Regards, Thomas