Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754894Ab0F2SFm (ORCPT ); Tue, 29 Jun 2010 14:05:42 -0400 Received: from www.tglx.de ([62.245.132.106]:45800 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754557Ab0F2SFk (ORCPT ); Tue, 29 Jun 2010 14:05:40 -0400 Date: Tue, 29 Jun 2010 20:03:54 +0200 (CEST) From: Thomas Gleixner To: Darren Hart cc: Linus Torvalds , Michal Hocko , Ingo Molnar , LKML , Nick Piggin , Alexey Kuznetsov , Peter Zijlstra , Jakub Jelinek Subject: Re: [PATCH] futex: futex_find_get_task make credentials check conditional In-Reply-To: <4C2A2627.3080408@us.ibm.com> Message-ID: References: <20100623091307.GA11072@tiehlicka.suse.cz> <4C2417AA.4030306@us.ibm.com> <20100625082711.GA32765@tiehlicka.suse.cz> <4C24ED34.9040808@us.ibm.com> <4C253D32.6040304@us.ibm.com> <20100628144246.GA14201@tiehlicka.suse.cz> <20100628153214.GA24127@tiehlicka.suse.cz> <20100628155845.GC24127@tiehlicka.suse.cz> <20100628163952.GD24127@tiehlicka.suse.cz> <1277743748.3561.139.camel@laptop> <20100629084230.GE6215@tiehlicka.suse.cz> <4C2A2627.3080408@us.ibm.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1314 Lines: 34 On Tue, 29 Jun 2010, Darren Hart wrote: > On 06/29/2010 09:41 AM, Linus Torvalds wrote: > > > > The other thing I'd like to see is to move the whole cred checking up > > a level. There's no reason to check the credentials in > > futex_find_get_task() that I can see - why not do it in the caller > > instead? IOW, I think futex_find_get_task() should just look something > > like this instead: > > > /me beats head on desk, duh. Still, I'm hoping this isn't necessary and we can > lose the credentials checking entirely. I did some archaeology in my mail and code archives. The only hint I found from the early days of the PI futex code is a mail which mutters something about pid reuse. The euid/uid check surfaced in the code archive right after that, but to be honest I fail to see how it should be related. I rather believe that the whole thing resulted out of being overly paranoid about the PI usage. Jakub, any idea why this check got there ? Today I cannot see a real reason to keep that check, it just adds a restriction for no benefit. Thanks, tglx -- 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/