From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752487AbYIJEG6 (ORCPT ); Wed, 10 Sep 2008 00:06:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750788AbYIJEGu (ORCPT ); Wed, 10 Sep 2008 00:06:50 -0400 Received: from mx2.redhat.com ([66.187.237.31]:40464 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1749667AbYIJEGt (ORCPT ); Wed, 10 Sep 2008 00:06:49 -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: Ingo Molnar , Frank Mayhar , linux-kernel@vger.kernel.org, Thomas Gleixner , Alexey Dobriyan , Andrew Morton Subject: Re: [PATCH 2.6.27-rc5] Fix itimer/many thread hang. In-Reply-To: Oleg Nesterov's message of Tuesday, 9 September 2008 20:01:52 +0400 <20080909160152.GA714@tv-sign.ru> References: <1220906643.31846.21.camel@bobble.smo.corp.google.com> <20080909070329.GD2086@elte.hu> <20080909160152.GA714@tv-sign.ru> X-Shopping-List: (1) Luminescent honey scenarios (2) Abrupt perspiration rectractors (3) Chimerical suspicion excitements (4) Muscular perilous capture detergents Message-Id: <20080910040404.245301541FE@magilla.localdomain> Date: Tue, 9 Sep 2008 21:04:04 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > As for this particular function, it seems to me that ->signal == NULL > is not possible, no? The concern is to make sure that the timer tick path is always safe for a tick that hits during release_task(current) in exit_notify(). A timer tick there can come with current->signal == NULL. We just need to make sure one way or another that this is safe. Thanks, Roland