Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030271AbWLTShH (ORCPT ); Wed, 20 Dec 2006 13:37:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030270AbWLTShH (ORCPT ); Wed, 20 Dec 2006 13:37:07 -0500 Received: from ug-out-1314.google.com ([66.249.92.170]:23787 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030276AbWLTShF (ORCPT ); Wed, 20 Dec 2006 13:37:05 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:date:from:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent:sender; b=E1nMo2xN7D6GvlcmvaxUtmNkJK3JfITHZ88gXzHlOApaI6eZWW4f2iSnm9Efa8h9dIG5sB4SRtmNJs4XojI6Cu5usEGjI9Y2ZXVFp6rrqkSCIeDkzBvvuhzjCF1QHQx+CmNDibFp2Pmaco0aOOCOh8A99PfbtkhCyfh1qDNvbM4= Date: Wed, 20 Dec 2006 18:35:21 +0000 From: Frederik Deweerdt To: Jeremy Fitzhardinge Cc: Andrew Morton , "Andrew J. Barr" , linux-kernel@vger.kernel.org, Jan Beulich , Andi Kleen , "Eric W. Biederman" , walt Subject: [-mm patch] ptrace: Fix EFL_OFFSET value according to i386 pda changes (was Re: BUG on 2.6.20-rc1 when using gdb) Message-ID: <20061220183521.GA28900@slug> References: <1166406918.17143.5.camel@r51.oakcourt.dyndns.org> <20061219164214.4bc92d77.akpm@osdl.org> <45891CD1.4050506@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45891CD1.4050506@goop.org> User-Agent: mutt-ng/devel-r804 (Linux) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1499 Lines: 39 On Wed, Dec 20, 2006 at 03:21:53AM -0800, Jeremy Fitzhardinge wrote: > "walt" reported a similar problem which he bisected > down to the PDA changeset which touches ptrace > (66e10a44d724f1464b5e8b5a3eae1e2cbbc2cca6). I haven't managed to repo > the problem, but I guess there's something nasty going on in ptrace - > maybe its screwing up eflags on the stack or something. Need to > double-check all the conversions from kernel<->usermode registers. Hm, > wonder if its fixed with the %gs->%fs conversion patch applied? > Hi Jeremy, Same problems here with 2.6.20-rc1-mm1 (ie with the %gs->%fs patch). It seems to me that the problem comes from the EFL_OFFSET no longer beeing accurate. The following patch fixes the problem for me. Regards, Frederik Signed-off-by: Frederik Deweerdt diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c index 7f7d830..00d8a5a 100644 --- a/arch/i386/kernel/ptrace.c +++ b/arch/i386/kernel/ptrace.c @@ -45,7 +45,7 @@ /* * Offset of eflags on child stack.. */ -#define EFL_OFFSET ((EFL-2)*4-sizeof(struct pt_regs)) +#define EFL_OFFSET ((EFL-1)*4-sizeof(struct pt_regs)) static inline struct pt_regs *get_child_regs(struct task_struct *task) { - 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/