From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753274AbaJTJDa (ORCPT ); Mon, 20 Oct 2014 05:03:30 -0400 Received: from relay.parallels.com ([195.214.232.42]:36118 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753217AbaJTJD2 (ORCPT ); Mon, 20 Oct 2014 05:03:28 -0400 Message-ID: <1413795794.19914.20.camel@tkhai> Subject: Re: [PATCH] sched/numa: fix unsafe get_task_struct() in task_numa_assign() From: Kirill Tkhai To: Oleg Nesterov CC: Kirill Tkhai , Peter Zijlstra , "linux-kernel@vger.kernel.org" , Ingo Molnar , Vladimir Davydov Date: Mon, 20 Oct 2014 13:03:14 +0400 In-Reply-To: <20141019194314.GA3434@redhat.com> References: <1413376300.24793.55.camel@tkhai> <20141017213641.GB32576@redhat.com> <4323181413620101@web21o.yandex.ru> <20141018205614.GA15934@redhat.com> <33631413674011@web7o.yandex.ru> <20141019192437.GA842@redhat.com> <20141019193744.GA3097@redhat.com> <20141019194314.GA3434@redhat.com> Organization: Parallels Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.8.5-2+b3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Originating-IP: [10.30.26.172] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org В Вс, 19/10/2014 в 21:43 +0200, Oleg Nesterov пишет: > On 10/19, Oleg Nesterov wrote: > > > > Forgot to mention... Or we can make task_struct_cachep SLAB_DESTROY_BY_RCU, > > in this case ->curr (or any other "task_struct *" ponter) can not go away > > under rcu_read_lock(). task_numa_compare() still needs the PF_EXITING check, > > but we do not need to recheck ->curr or probe_kernel_read(). > > Damn, please ignore ;) we still need to recheck ->curr. Yeah, this bug like "collect puzzle" :)