From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758835AbaJ3KSb (ORCPT ); Thu, 30 Oct 2014 06:18:31 -0400 Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:49591 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758164AbaJ3KS2 (ORCPT ); Thu, 30 Oct 2014 06:18:28 -0400 Date: Thu, 30 Oct 2014 10:18:08 +0000 From: Russell King - ARM Linux To: Christoph Hellwig Cc: Rabin Vincent , linux-arm-kernel@lists.infradead.org, Ingo Molnar , linux-kernel@vger.kernel.org, Steven Rostedt Subject: Re: [PATCH] tracing/syscalls: ignore numbers outside NR_syscalls' range Message-ID: <20141030101808.GO27405@n2100.arm.linux.org.uk> References: <1414620418-29472-1-git-send-email-rabin@rab.in> <20141030082606.GA7945@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141030082606.GA7945@infradead.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 30, 2014 at 01:26:06AM -0700, Christoph Hellwig wrote: > On Wed, Oct 29, 2014 at 11:06:58PM +0100, Rabin Vincent wrote: > > ARM has some private syscalls (for example, set_tls(2)) which lie > > outside the range of NR_syscalls. If any of these are called while > > syscall tracing is being performed, out-of-bounds array access will > > occur in the ftrace and perf sys_{enter,exit} handlers. > > While this patch looks like good caution, having syscalls outside of > NR_syscalls seems like a receipe for a disaster. Can you try to fix > that issue as ell, please? No. We've had them since the inception of Linux on ARM. They predate this tracing crap by more than a decade. We're not changing them because that would be a massive user API breakage. -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net.