From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] tproxy: nf_tproxy_assign_sock() can handle tw sockets Date: Sun, 11 Jul 2010 08:19:21 +0300 Message-ID: <4C395459.6080407@redhat.com> References: <1278626921.2435.73.camel@edumazet-laptop> <1278695580.2696.55.camel@edumazet-laptop> <1278742649.2538.17.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Felipe W Damasio , David Miller , Patrick McHardy , linux-kernel@vger.kernel.org, netdev To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44941 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750873Ab0GKFTb (ORCPT ); Sun, 11 Jul 2010 01:19:31 -0400 In-Reply-To: <1278742649.2538.17.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: On 07/10/2010 09:17 AM, Eric Dumazet wrote: > > Strange thing with your crash report is CR2 value, with unexpected value > of 000000000b388000 while RAX value is dce8dce85d415d41 > > Faulting instruction is : > > 48 83 b8 b0 00 00 00 00 cmpq $0x0,0xb0(%rax) > > So I would have expected CR2 being RAX+0xb0, but its not. > Nothing strange about it. You only get page faults and valid cr2 for canonical addresses (17 high order bits all equal). In this case rax+0xb0 is not a canonical address, so you got a general protection fault instead, with cr2 unchanged. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.