This is a note to let you know that I've just added the patch titled
macvtap: Fix race between device delete and open.
to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
macvtap-fix-race-between-device-delete-and-open.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Sun Oct 12 20:11:55 CEST 2014
From: Vlad Yasevich <vyasevich@xxxxxxxxx>
Date: Mon, 22 Sep 2014 16:34:17 -0400
Subject: macvtap: Fix race between device delete and open.
From: Vlad Yasevich <vyasevich@xxxxxxxxx>
[ Upstream commit 40b8fe45d1f094e3babe7b2dc2b71557ab71401d ]
In macvtap device delete and open calls can race and
this causes a list curruption of the vlan queue_list.
The race intself is triggered by the idr accessors
that located the vlan device. The device is stored
into and removed from the idr under both an rtnl and
a mutex. However, when attempting to locate the device
in idr, only a mutex is taken. As a result, once cpu
perfoming a delete may take an rtnl and wait for the mutex,
while another cput doing an open() will take the idr
mutex first to fetch the device pointer and later take
an rtnl to add a queue for the device which may have
just gotten deleted.
With this patch, we now hold the rtnl for the duration
of the macvtap_open() call thus making sure that
open will not race with delete.
CC: Michael S. Tsirkin <mst@xxxxxxxxxx>
CC: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Vladislav Yasevich <vyasevic@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/macvtap.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -112,17 +112,15 @@ out:
return err;
}
+/* Requires RTNL */
static int macvtap_set_queue(struct net_device *dev, struct file *file,
struct macvtap_queue *q)
{
struct macvlan_dev *vlan = netdev_priv(dev);
- int err = -EBUSY;
- rtnl_lock();
if (vlan->numqueues == MAX_MACVTAP_QUEUES)
- goto out;
+ return -EBUSY;
- err = 0;
rcu_assign_pointer(q->vlan, vlan);
rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
sock_hold(&q->sk);
@@ -136,9 +134,7 @@ static int macvtap_set_queue(struct net_
vlan->numvtaps++;
vlan->numqueues++;
-out:
- rtnl_unlock();
- return err;
+ return 0;
}
static int macvtap_disable_queue(struct macvtap_queue *q)
@@ -454,11 +450,12 @@ static void macvtap_sock_destruct(struct
static int macvtap_open(struct inode *inode, struct file *file)
{
struct net *net = current->nsproxy->net_ns;
- struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode));
+ struct net_device *dev;
struct macvtap_queue *q;
- int err;
+ int err = -ENODEV;
- err = -ENODEV;
+ rtnl_lock();
+ dev = dev_get_by_macvtap_minor(iminor(inode));
if (!dev)
goto out;
@@ -498,6 +495,7 @@ out:
if (dev)
dev_put(dev);
+ rtnl_unlock();
return err;
}
Patches currently in stable-queue which might be from vyasevich@xxxxxxxxx are
queue-3.16/ipv6-remove-rt6i_genid.patch
queue-3.16/macvtap-fix-race-between-device-delete-and-open.patch
queue-3.16/bridge-fix-br_should_learn-to-check-vlan_enabled.patch
queue-3.16/tg3-work-around-hw-fw-limitations-with-vlan-encapsulated-frames.patch
queue-3.16/bridge-check-if-vlan-filtering-is-enabled-only-once.patch
queue-3.16/tg3-allow-for-recieve-of-full-size-8021ad-frames.patch
queue-3.16/sctp-handle-association-restarts-when-the-socket-is-closed.patch
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