From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752915Ab2JFHUJ (ORCPT ); Sat, 6 Oct 2012 03:20:09 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:41024 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981Ab2JFHUG (ORCPT ); Sat, 6 Oct 2012 03:20:06 -0400 Date: Sat, 6 Oct 2012 12:50:33 +0530 From: Srikar Dronamraju To: Oleg Nesterov Cc: Ingo Molnar , Peter Zijlstra , Ananth N Mavinakayanahalli , Anton Arapov , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/7] uprobes/x86: Only rep+nop can be emulated correctly Message-ID: <20121006072033.GG27781@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20120930194119.GA11278@redhat.com> <20120930194158.GA11316@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20120930194158.GA11316@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) x-cbid: 12100607-5806-0000-0000-00001A555D80 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov [2012-09-30 21:41:58]: > __skip_sstep() correctly detects the "nontrivial" nop insns, > but since it doesn't update regs->ip we can not really skip > "0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0", the probed application > is killed by SIGILL'ed handle_swbp(). > > Remove these additional checks. If we want to implement this > correctly we need to know the full insn length to update ->ip. > > rep* + nop is fine even without updating ->ip. > > Signed-off-by: Oleg Nesterov > --- Acked-by: Srikar Dronamraju