Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262880AbVEHPPq (ORCPT ); Sun, 8 May 2005 11:15:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262882AbVEHPPq (ORCPT ); Sun, 8 May 2005 11:15:46 -0400 Received: from one.firstfloor.org ([213.235.205.2]:25065 "EHLO one.firstfloor.org") by vger.kernel.org with ESMTP id S262880AbVEHPPk (ORCPT ); Sun, 8 May 2005 11:15:40 -0400 To: Antoine Martin Cc: linux-kernel@vger.kernel.org, jdike@addtoit.com Subject: Re: 2.6.11.8 + UML/x86_64 (2.6.12-rc3+) = oops References: <20050504191828.620C812EE7@sc8-sf-spam2.sourceforge.net> <1115248927.12088.52.camel@cobra> <1115392141.12197.3.camel@cobra> <1115483506.12131.33.camel@cobra> <1115570102.10373.23.camel@cobra> From: Andi Kleen Date: Sun, 08 May 2005 17:15:36 +0200 In-Reply-To: <1115570102.10373.23.camel@cobra> (Antoine Martin's message of "Sun, 08 May 2005 17:35:02 +0100") Message-ID: User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1420 Lines: 35 Antoine Martin writes: >> (..) >> That is a wrmsr to 0x00000000c0000102 (KERNEL_GS_BASE), the code >> is trying to write 0x0000c8e816000002 into it. That is a non canonical >> address, which causes the GPF. >> >> The strange thing is that the kernel should have rejected it in >> the first place. The code to allow user space to set kernel gs >> checks for the address being > TASK_SIZE and TASK_SIZE is 0x800000000000. >> It should have rejected it in the first place. >> >> Are you sure you did not apply any strange UML related patches >> to the host kernel? Maybe those are buggy. > The only extra patch applied on top of what is on the web page (as per > Jeff's instructions) is the mconsole-exec patch, and AFAIK it wouldn't > affect the code above. > > Alexander Nyberg is also experiencing crashes, aren't you? Ok, the bug is found now. It is a kernel bug that it allows to set non canonical addresses in 64bit segment registers through ptrace. But even if I fixed that then it will not help you run UML, because UML needs to set correct addresses of course, not illegal ones. I will submit a patch later for the crash problem. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/