From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030196AbXBZKwU (ORCPT ); Mon, 26 Feb 2007 05:52:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030201AbXBZKwT (ORCPT ); Mon, 26 Feb 2007 05:52:19 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:59263 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030200AbXBZKwB (ORCPT ); Mon, 26 Feb 2007 05:52:01 -0500 From: "Rafael J. Wysocki" To: LKML Subject: [RFC][PATCH 3/3] Freezer: Prevent ___call_usermodehelper from missing freezing requests Date: Mon, 26 Feb 2007 11:52:17 +0100 User-Agent: KMail/1.9.5 Cc: Andrew Morton , Oleg Nesterov , Pavel Machek , Srivatsa Vaddagiri , Aneesh Kumar , "Paul E. McKenney" , Gautham R Shenoy References: <200702261139.59130.rjw@sisk.pl> In-Reply-To: <200702261139.59130.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200702261152.18379.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org NOTE: Alternatively, we can just drop flush_signals() from there, but I'm not sure that's the right thing to do. --- From: Rafael J. Wysocki Since ____call_usermodehelper() calls flush_signals(current), the task that enters it may miss a freezing request. However, if ____call_usermodehelper() clears TIF_FREEZE for the current task after flush_signals(current) returns, the freezer will generate one more freezing request for this task. Signed-off-by: Rafael J. Wysocki --- kernel/kmod.c | 2 ++ 1 file changed, 2 insertions(+) Index: linux-2.6.20-mm2/kernel/kmod.c =================================================================== --- linux-2.6.20-mm2.orig/kernel/kmod.c 2007-02-25 12:07:15.000000000 +0100 +++ linux-2.6.20-mm2/kernel/kmod.c 2007-02-25 12:49:16.000000000 +0100 @@ -34,6 +34,7 @@ #include #include #include +#include #include extern int delete_module(const char *name, unsigned int flags); @@ -258,6 +259,7 @@ static int ____call_usermodehelper(void new_session = key_get(sub_info->ring); flush_signals(current); spin_lock_irq(¤t->sighand->siglock); + do_not_freeze(current); old_session = __install_session_keyring(current, new_session); flush_signal_handlers(current, 1); sigemptyset(¤t->blocked);