From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1QvJBD-0004ou-52 for user-mode-linux-devel@lists.sourceforge.net; Mon, 22 Aug 2011 01:19:55 +0000 Received: from zeniv.linux.org.uk ([195.92.253.2]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1QvJBC-0003eF-Ds for user-mode-linux-devel@lists.sourceforge.net; Mon, 22 Aug 2011 01:19:55 +0000 Date: Mon, 22 Aug 2011 02:19:39 +0100 From: Al Viro Message-ID: <20110822011939.GN2203@ZenIV.linux.org.uk> References: <4E501F51.9060905@nod.at> <20110821063443.GH2203@ZenIV.linux.org.uk> <20110821084230.GI2203@ZenIV.linux.org.uk> <20110821144352.GJ2203@ZenIV.linux.org.uk> <20110821164124.GL2203@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net Subject: Re: [uml-devel] SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) To: Linus Torvalds Cc: Andrew Lutomirski , user-mode-linux-devel@lists.sourceforge.net, Richard Weinberger , linux-kernel@vger.kernel.org, mingo@redhat.com, "H. Peter Anvin" On Sun, Aug 21, 2011 at 06:09:00PM -0700, Linus Torvalds wrote: > On Sun, Aug 21, 2011 at 5:44 PM, Andrew Lutomirski wrote: > > > > Which suggests an easy-ish fix: if sysenter is used or if syscall is > > entered from the EIP is is supposed to be entered from, then just > > change ip in the argument save to point to the int 0x80 instruction. > > Indeed. Just add an "int 0x80" instruction to the vsyscall thing, and > you'd be done. > > In fact, just replace the > > jmp .Lenter_kernel > > with > > int 0x80 > > and you'd be pretty much all done, no? In case of sysenter - almost, in case of syscall - nope... ------------------------------------------------------------------------------ uberSVN's rich system and user administration capabilities and model configuration take the hassle out of deploying and managing Subversion and the tools developers use with it. Learn more about uberSVN and get a free download at: http://p.sf.net/sfu/wandisco-dev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756434Ab1HVBTy (ORCPT ); Sun, 21 Aug 2011 21:19:54 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47529 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756253Ab1HVBTx (ORCPT ); Sun, 21 Aug 2011 21:19:53 -0400 Date: Mon, 22 Aug 2011 02:19:39 +0100 From: Al Viro To: Linus Torvalds Cc: Andrew Lutomirski , "H. Peter Anvin" , mingo@redhat.com, Richard Weinberger , user-mode-linux-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) Message-ID: <20110822011939.GN2203@ZenIV.linux.org.uk> References: <4E501F51.9060905@nod.at> <20110821063443.GH2203@ZenIV.linux.org.uk> <20110821084230.GI2203@ZenIV.linux.org.uk> <20110821144352.GJ2203@ZenIV.linux.org.uk> <20110821164124.GL2203@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 21, 2011 at 06:09:00PM -0700, Linus Torvalds wrote: > On Sun, Aug 21, 2011 at 5:44 PM, Andrew Lutomirski wrote: > > > > Which suggests an easy-ish fix: if sysenter is used or if syscall is > > entered from the EIP is is supposed to be entered from, then just > > change ip in the argument save to point to the int 0x80 instruction. > > Indeed. Just add an "int 0x80" instruction to the vsyscall thing, and > you'd be done. > > In fact, just replace the > > jmp .Lenter_kernel > > with > > int 0x80 > > and you'd be pretty much all done, no? In case of sysenter - almost, in case of syscall - nope...