Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756383AbZICUMI (ORCPT ); Thu, 3 Sep 2009 16:12:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756354AbZICUMG (ORCPT ); Thu, 3 Sep 2009 16:12:06 -0400 Received: from mx1-old.redhat.com ([66.187.233.31]:32831 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756325AbZICUMC (ORCPT ); Thu, 3 Sep 2009 16:12:02 -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: Andrew Morton , Linus Torvalds , David Howells , James Morris , Tom Horsley , linux-kernel@vger.kernel.org, stable@kernel.org Subject: Re: [PATCH 1/1] exec: do not sleep in TASK_TRACED under ->cred_guard_mutex In-Reply-To: Oleg Nesterov's message of Thursday, 3 September 2009 18:05:14 +0200 <20090903160514.GA23646@redhat.com> References: <20090903160514.GA23646@redhat.com> Emacs: a learning curve that you can use as a plumb line. Message-Id: <20090903200924.E46DF47C94@magilla.sf.frob.com> Date: Thu, 3 Sep 2009 13:09:24 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 942 Lines: 22 I certainly think it's right to hold the mutex only as long as necessary. Clearly holding it when we stop is wrong. I'm a bit concerned about holding it for arbitrary periods while we block in the filesystem code. e.g., consider the scenario with a hangs-forever NFS server or suchlike. But I'm not sure there is a reasonable way around that one. The paired calls that leave the mutex locked in between should have some clear comments calling attention to their pairing. Aside from that making sure that subtlety is clear, I don't see any problems in the patch off hand. But I haven't scoured the code path lately to have full confidence. I'd like to hear David's reactions. Thanks, Roland -- 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/