From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754656Ab2L1Ttq (ORCPT ); Fri, 28 Dec 2012 14:49:46 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55110 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754587Ab2L1TRr (ORCPT ); Fri, 28 Dec 2012 14:17:47 -0500 Message-Id: <20121228190400.145063929@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 28 Dec 2012 20:06:02 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "nikolay@redhat.com" , Jay Vosburgh , "David S. Miller" Subject: [ 152/173] bonding: fix race condition in bonding_store_slaves_active In-Reply-To: <20121228190330.025298996@decadent.org.uk> X-SA-Exim-Connect-IP: 151.217.219.220 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "nikolay@redhat.com" [ Upstream commit e196c0e579902f42cf72414461fb034e5a1ffbf7 ] Race between bonding_store_slaves_active() and slave manipulation functions. The bond_for_each_slave use in bonding_store_slaves_active() is not protected by any synchronization mechanism. NULL pointer dereference is easy to reach. Fixed by acquiring the bond->lock for the slave walk. v2: Make description text < 75 columns Signed-off-by: Nikolay Aleksandrov Signed-off-by: Jay Vosburgh Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/bonding/bond_sysfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c index 4ef7e2f..a03fde9 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -1579,6 +1579,7 @@ static ssize_t bonding_store_slaves_active(struct device *d, goto out; } + read_lock(&bond->lock); bond_for_each_slave(bond, slave, i) { if (!bond_is_active_slave(slave)) { if (new_value) @@ -1587,6 +1588,7 @@ static ssize_t bonding_store_slaves_active(struct device *d, slave->inactive = 1; } } + read_unlock(&bond->lock); out: return ret; }