From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030241AbXCLOoZ (ORCPT ); Mon, 12 Mar 2007 10:44:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030220AbXCLOoY (ORCPT ); Mon, 12 Mar 2007 10:44:24 -0400 Received: from mx1.redhat.com ([66.187.233.31]:56022 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030241AbXCLOoX (ORCPT ); Mon, 12 Mar 2007 10:44:23 -0400 Message-ID: <45F56730.2050604@redhat.com> Date: Mon, 12 Mar 2007 10:44:00 -0400 From: Chuck Ebbert Organization: Red Hat User-Agent: Thunderbird 1.5.0.9 (X11/20070212) MIME-Version: 1.0 To: Ingo Molnar CC: Andrew Morton , Linus Torvalds , Thomas Gleixner , linux-kernel@vger.kernel.org, Theodore Tso Subject: Re: [patch] futex: PI state locking fix References: <20070312091342.GA27425@elte.hu> In-Reply-To: <20070312091342.GA27425@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > Subject: [patch] futex: PI state locking fix > From: Ingo Molnar > > testing of -rt by IBM uncovered a locking bug in wake_futex_pi(): the PI > state needs to be locked before we access it. > > this patch has been tested in -rt. Must-have for v2.6.21. > Does that fix this: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=224262 [] rt_mutex_next_owner+0x2f/0x40 kernel/rt_mutex_common.c:rt_mutex_top_waiter():74: BUG_ON(w->lock != lock); [] do_futex+0x94d/0xbe3 inlined: futex_unlock_pi() inlined: wake_futex_pi() kernel/futex.c:wake_futex_pi():569: new_owner = rt_mutex_next_owner(&pi_state->pi_mutex); [] sys_futex+0x11d/0x130 [] syscall_call+0x7/0xb