From patchwork Wed Jan 16 15:55:53 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [153/222] bonding: fix race condition in bonding_store_slaves_active Date: Wed, 16 Jan 2013 05:55:53 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 212729 Message-Id: <1358351822-7675-154-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Nikolay Aleksandrov , Jay Vosburgh , "David S. Miller" 3.5.7.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "nikolay@redhat.com" commit e196c0e579902f42cf72414461fb034e5a1ffbf7 upstream. 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: Herton Ronaldo Krzesinski --- 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 485bedb..9ea29aa 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -1582,6 +1582,7 @@ 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) @@ -1590,6 +1591,7 @@ static ssize_t bonding_store_slaves_active(struct device *d, slave->inactive = 1; } } + read_unlock(&bond->lock); out: return ret; }