Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756042AbYFPPeE (ORCPT ); Mon, 16 Jun 2008 11:34:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752102AbYFPPdv (ORCPT ); Mon, 16 Jun 2008 11:33:51 -0400 Received: from saeurebad.de ([85.214.36.134]:56919 "EHLO saeurebad.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754559AbYFPPdU (ORCPT ); Mon, 16 Jun 2008 11:33:20 -0400 From: Johannes Weiner To: Alan Cox Cc: "Rafael J. Wysocki" , Linux Kernel Mailing List Subject: Re: [Bug 10741] bug in `tty: BKL pushdown'? References: <873andbst2.fsf@saeurebad.de> <20080616113313.2f932f8d@lxorguk.ukuu.org.uk> <20080616124602.54910afd@lxorguk.ukuu.org.uk> Date: Mon, 16 Jun 2008 17:33:14 +0200 In-Reply-To: <20080616124602.54910afd@lxorguk.ukuu.org.uk> (Alan Cox's message of "Mon, 16 Jun 2008 12:46:02 +0100") Message-ID: <87ve099yyt.fsf@saeurebad.de> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 996 Lines: 39 Hi, Alan Cox writes: > On Mon, 16 Jun 2008 11:33:13 +0100 > Alan Cox wrote: > >> > The bug still exists, however, a bisect on another machine with the same >> > userland leads to different commit >> > (47f86834bbd4193139d61d659bebf9ab9d691e37 "redo locking of tty->pgrp"), >> > so it is not all that clear and stable. >> >> Now that would actually make a lot more sense as a root cause. > > Experiment time. In _proc_set_tty() in tty_io.c move the > > tty->session = get_pid(task_session(tsk)); > > back inside the lock just before > > tty->pgrp = get_pid(task_pgrp(tsk)); Like this:? spin_lock() put_pid() put_pid() tty->session = tty->pgrp = spin_unlock() That does not fix it. Hannes -- 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/