From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751475Ab0IJJkv (ORCPT ); Fri, 10 Sep 2010 05:40:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10889 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871Ab0IJJkt (ORCPT ); Fri, 10 Sep 2010 05:40:49 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Oleg Nesterov X-Fcc: ~/Mail/linus Cc: KOSAKI Motohiro , Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, oss-security@lists.openwall.com, Solar Designer , Kees Cook , Al Viro , Neil Horman , linux-fsdevel@vger.kernel.org, pageexec@freemail.hu, Brad Spengler , Eugene Teo , KAMEZAWA Hiroyuki Subject: Re: [PATCH 1/2] oom: don't ignore rss in nascent mm In-Reply-To: Oleg Nesterov's message of Friday, 10 September 2010 00:05:04 +0200 <20100909220504.GA6273@redhat.com> References: <20100908023417.8B055401AF@magilla.sf.frob.com> <20100909134842.C93F.A69D9226@jp.fujitsu.com> <20100909140219.C942.A69D9226@jp.fujitsu.com> <20100909220504.GA6273@redhat.com> X-Windows: putting new limits on productivity. Message-Id: <20100910093958.143B5405D5@magilla.sf.frob.com> Date: Fri, 10 Sep 2010 02:39:58 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I wonder if it makes sense to move ->cred_guard_mutex from task_struct > to signal_struct and thus make multiple-threads-inside-exec impossible. > Only one thread can win anyway. That probably makes sense. Note that cred_guard_mutex is also overloaded for ptrace_attach, so this would add some more serialization of attaches to threads in the same group. But as long as actual attachment serializes on tasklist_lock anyway, it doesn't make a material difference. (Even without that, it would presumably be the same debugger attaching serially to threads in the same group, so it wouldn't degrade anything in practice.) Thanks, Roland From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland McGrath Subject: Re: [PATCH 1/2] oom: don't ignore rss in nascent mm Date: Fri, 10 Sep 2010 02:39:58 -0700 (PDT) Message-ID: <20100910093958.143B5405D5@magilla.sf.frob.com> References: <20100908023417.8B055401AF@magilla.sf.frob.com> <20100909134842.C93F.A69D9226@jp.fujitsu.com> <20100909140219.C942.A69D9226@jp.fujitsu.com> <20100909220504.GA6273@redhat.com> Reply-To: oss-security-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: KOSAKI Motohiro , Linus Torvalds , Andrew Morton , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, oss-security-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org, Solar Designer , Kees Cook , Al Viro , Neil Horman , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, pageexec-Y8qEzhMunLyT9ig0jae3mg@public.gmane.org, Brad Spengler , Eugene Teo , KAMEZAWA Hiroyuki To: Oleg Nesterov Return-path: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: Oleg Nesterov's message of Friday, 10 September 2010 00:05:04 +0200 <20100909220504.GA6273-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Id: linux-fsdevel.vger.kernel.org > I wonder if it makes sense to move ->cred_guard_mutex from task_struct > to signal_struct and thus make multiple-threads-inside-exec impossible. > Only one thread can win anyway. That probably makes sense. Note that cred_guard_mutex is also overloaded for ptrace_attach, so this would add some more serialization of attaches to threads in the same group. But as long as actual attachment serializes on tasklist_lock anyway, it doesn't make a material difference. (Even without that, it would presumably be the same debugger attaching serially to threads in the same group, so it wouldn't degrade anything in practice.) Thanks, Roland