Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270234AbTG3Kd3 (ORCPT ); Wed, 30 Jul 2003 06:33:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270327AbTG3Kd3 (ORCPT ); Wed, 30 Jul 2003 06:33:29 -0400 Received: from mx1.elte.hu ([157.181.1.137]:59873 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S270234AbTG3Kd2 (ORCPT ); Wed, 30 Jul 2003 06:33:28 -0400 Date: Wed, 30 Jul 2003 12:31:23 +0200 (CEST) From: Ingo Molnar Reply-To: Ingo Molnar To: Andrea Arcangeli Cc: Andrew Morton , , Subject: Re: PATCH: Race in 2.6.0-test2 timer code In-Reply-To: <20030730082848.GC23835@dualathlon.random> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 800 Lines: 26 On Wed, 30 Jul 2003, Andrea Arcangeli wrote: > > cpu0 cpu1 > ------------ -------------------- > > do_setitimer > it_real_fn > del_timer_sync add_timer -> crash would you mind to elaborate the precise race? I cannot see how the above sequence could crash on current 2.6: del_timer_sync() takes the base pointer in timer->base and locks it, then checks whether the timer has this base or not and repeats the sequence if not. add_timer() locks the current CPU's base, then installs the timer and sets timer->base. Where's the race? Ingo - 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/