From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753464Ab2HCLCz (ORCPT ); Fri, 3 Aug 2012 07:02:55 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:34851 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753375Ab2HCLCw (ORCPT ); Fri, 3 Aug 2012 07:02:52 -0400 Date: Fri, 3 Aug 2012 15:02:47 +0400 From: Cyrill Gorcunov To: richard -rw- weinberger , Pavel Emelyanov Cc: "Eric W. Biederman" , Kees Cook , Thomas Gleixner , linux-kernel@vger.kernel.org, Randy Dunlap , Darren Hart , Peter Zijlstra , Andrew Morton , Jiri Kosina , David Howells , "Serge E. Hallyn" , linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, spender@grsecurity.net Subject: Re: [PATCH v2] futex: mark get_robust_list as deprecated Message-ID: <20120803110247.GB11952@moon> References: <20120323190855.GA27213@www.outflux.net> <87pq7935w2.fsf@xmission.com> 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 Fri, Aug 03, 2012 at 12:17:43PM +0200, richard -rw- weinberger wrote: > On Thu, Aug 2, 2012 at 1:11 PM, Eric W. Biederman wrote: > > richard -rw- weinberger writes: > > > >> On Fri, Mar 23, 2012 at 8:08 PM, Kees Cook wrote: > >>> Notify get_robust_list users that the syscall is going away. > >>> > >>> Suggested-by: Thomas Gleixner > >>> Signed-off-by: Kees Cook > >>> --- > >> > >> I'm using this system call in an application and noticed that's marked > >> as deprecated now. > >> My application collects all kind of information from crashing programs. > >> It's installed in /proc/sys/kernel/core_pattern. > >> > >> If program X is crashing it executes get_robust_list(X) to get the > >> address of the robust list > >> and reads the list from /proc/X/mem. > >> > >> Is there another way to get the robust list from another program (by it's pid)? > > > > The folks doing checkpoint/restart claim to not need this, so there > > might be a way either that or they just haven't hit this problem yet. > > > > What you are doing sounds like a reasonable use of get_robust_list to me. > > > > CRIU folks, how do you deal with futex robust lists? Well, I believe we were over-optimistic in claiming that we don't need this syscall (to be fair I think we simply yet not faced the problem Eric points). So we need some way to fetch this address and set it back. If get_robust_list get deprecated maybe we could print it out in /proc/pid/stat or something? Cyrill From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com Sender: Cyrill Gorcunov Date: Fri, 3 Aug 2012 15:02:47 +0400 From: Cyrill Gorcunov Message-ID: <20120803110247.GB11952@moon> References: <20120323190855.GA27213@www.outflux.net> <87pq7935w2.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: [kernel-hardening] Re: [PATCH v2] futex: mark get_robust_list as deprecated To: richard -rw- weinberger , Pavel Emelyanov Cc: "Eric W. Biederman" , Kees Cook , Thomas Gleixner , linux-kernel@vger.kernel.org, Randy Dunlap , Darren Hart , Peter Zijlstra , Andrew Morton , Jiri Kosina , David Howells , "Serge E. Hallyn" , linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, spender@grsecurity.net List-ID: On Fri, Aug 03, 2012 at 12:17:43PM +0200, richard -rw- weinberger wrote: > On Thu, Aug 2, 2012 at 1:11 PM, Eric W. Biederman wrote: > > richard -rw- weinberger writes: > > > >> On Fri, Mar 23, 2012 at 8:08 PM, Kees Cook wrote: > >>> Notify get_robust_list users that the syscall is going away. > >>> > >>> Suggested-by: Thomas Gleixner > >>> Signed-off-by: Kees Cook > >>> --- > >> > >> I'm using this system call in an application and noticed that's marked > >> as deprecated now. > >> My application collects all kind of information from crashing programs. > >> It's installed in /proc/sys/kernel/core_pattern. > >> > >> If program X is crashing it executes get_robust_list(X) to get the > >> address of the robust list > >> and reads the list from /proc/X/mem. > >> > >> Is there another way to get the robust list from another program (by it's pid)? > > > > The folks doing checkpoint/restart claim to not need this, so there > > might be a way either that or they just haven't hit this problem yet. > > > > What you are doing sounds like a reasonable use of get_robust_list to me. > > > > CRIU folks, how do you deal with futex robust lists? Well, I believe we were over-optimistic in claiming that we don't need this syscall (to be fair I think we simply yet not faced the problem Eric points). So we need some way to fetch this address and set it back. If get_robust_list get deprecated maybe we could print it out in /proc/pid/stat or something? Cyrill