From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755617Ab2GaQYZ (ORCPT ); Tue, 31 Jul 2012 12:24:25 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:49634 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755540Ab2GaQYY (ORCPT ); Tue, 31 Jul 2012 12:24:24 -0400 Date: Tue, 31 Jul 2012 12:15:15 -0400 From: Konrad Rzeszutek Wilk To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, Ian.Campbell@citrix.com, x86@kernel.org Subject: Re: [PATCH] extend_brk and fixes to users of extend_brk (v1). Message-ID: <20120731161515.GQ4789@phenom.dumpdata.com> References: <1343731376-20658-1-git-send-email-konrad.wilk@oracle.com> <5017FE81.3080903@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5017FE81.3080903@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 31, 2012 at 08:49:21AM -0700, H. Peter Anvin wrote: > On 07/31/2012 03:42 AM, Konrad Rzeszutek Wilk wrote: > > > > [PATCH 3/3] x86: Let extend_brk return a NULL pointer instead of > > > >makes extend_brk not do BUG_ON and instead just return NULL. This allows > >us to handle the bootup issues more gracefully. > > > > NAK. The whole point of the brk allocator is that users specify the > upper limit on what they may need and stick to it. Hence it is a > fatal code bug if that is ever exceeded. We want to catch those > errors, not "handle" them. OK, thanks for pointing that out. > > This means you're either abusing the brk allocator to do something > it is not meant to do... which may mean you can a failure in *other* > code, or you have a bug in your code that you haven't fixed. Its the latter - and of one of the patches in this patchset fixes that. Will drop the one that alter extend_brk. Thanks!