Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751941Ab0FCEkn (ORCPT ); Thu, 3 Jun 2010 00:40:43 -0400 Received: from SMTP.ANDREW.CMU.EDU ([128.2.11.61]:46797 "EHLO smtp.andrew.cmu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751827Ab0FCEkl (ORCPT ); Thu, 3 Jun 2010 00:40:41 -0400 Date: Thu, 3 Jun 2010 00:40:02 -0400 From: Ben Blum To: Oleg Nesterov Cc: Paul Menage , Ben Blum , linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, akpm@linux-foundation.org, ebiederm@xmission.com, lizf@cn.fujitsu.com, matthltc@us.ibm.com Subject: Re: [RFC] [PATCH 2/2] cgroups: make procs file writable Message-ID: <20100603044001.GA21006@ghc02.ghc.andrew.cmu.edu> References: <20100530013002.GA762@ghc01.ghc.andrew.cmu.edu> <20100530013303.GC762@ghc01.ghc.andrew.cmu.edu> <20100531175242.GA14691@redhat.com> <20100531180446.GA16249@redhat.com> <20100602140659.GA5324@redhat.com> <20100602202048.GB28663@redhat.com> <20100602205855.GA30039@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100602205855.GA30039@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-PMX-Version: 5.5.9.388399, Antispam-Engine: 2.7.2.376379, Antispam-Data: 2010.6.3.42715 X-SMTP-Spam-Clean: 8% ( BODYTEXTP_SIZE_3000_LESS 0, BODY_SIZE_1000_LESS 0, BODY_SIZE_2000_LESS 0, BODY_SIZE_400_499 0, BODY_SIZE_5000_LESS 0, BODY_SIZE_7000_LESS 0, __BOUNCE_CHALLENGE_SUBJ 0, __BOUNCE_NDR_SUBJ_EXEMPT 0, __CD 0, __CT 0, __CT_TEXT_PLAIN 0, __HAS_MSGID 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __SANE_MSGID 0, __TO_MALFORMED_2 0, __USER_AGENT 0) X-SMTP-Spam-Score: 8% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 636 Lines: 18 On Wed, Jun 02, 2010 at 10:58:55PM +0200, Oleg Nesterov wrote: > Hmm. The usage of ->thread_group in ->can_attach() methods doesn't > look safe to me... but currently bool threadgroup is always false. > > Oleg. > > I recall putting a rcu_read_lock() around that part and being assured that made it safe. But I don't remember the details. Maybe taking tasklist_lock is necessary? -- Ben -- 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/