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IPoIB: Fix use-after-free of multicast object

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commit bea1e22df4 upstream.

Fix a crash in ipoib_mcast_join_task().  (with help from Or Gerlitz)

Commit c8c2afe360 ("IPoIB: Use rtnl lock/unlock when changing device
flags") added a call to rtnl_lock() in ipoib_mcast_join_task(), which
is run from the ipoib_workqueue, and hence the workqueue can't be
flushed from the context of ipoib_stop().

In the current code, ipoib_stop() (which doesn't flush the workqueue)
calls ipoib_mcast_dev_flush(), which goes and deletes all the
multicast entries.  This takes place without any synchronization with
a possible running instance of ipoib_mcast_join_task() for the same
ipoib device, leading to a crash due to NULL pointer dereference.

Fix this by making sure that the workqueue is flushed before
ipoib_mcast_dev_flush() is called.  To make that possible, we move the
RTNL-lock wrapped code to ipoib_mcast_join_finish().

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Patrick McHardy
2012-08-30 07:01:30 +00:00
committed by Greg Kroah-Hartman
parent d125a7eba6
commit 0a442076e4
2 changed files with 11 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/infiniband/ulp/ipoib/ipoib_main.c
View File

@@ -148,7 +148,7 @@ static int ipoib_stop(struct net_device *dev)
netif_stop_queue(dev);
ipoib_ib_dev_down(dev, 0);
ipoib_ib_dev_down(dev, 1);
ipoib_ib_dev_stop(dev, 0);
if (!test_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags)) {

19
drivers/infiniband/ulp/ipoib/ipoib_multicast.c
View File

@@ -189,7 +189,9 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
mcast->mcmember = *mcmember;
/* Set the cached Q_Key before we attach if it's the broadcast group */
/* Set the multicast MTU and cached Q_Key before we attach if it's
* the broadcast group.
*/
if (!memcmp(mcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
sizeof (union ib_gid))) {
spin_lock_irq(&priv->lock);
@@ -197,10 +199,17 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
spin_unlock_irq(&priv->lock);
return -EAGAIN;
}
priv->mcast_mtu = IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));
priv->qkey = be32_to_cpu(priv->broadcast->mcmember.qkey);
spin_unlock_irq(&priv->lock);
priv->tx_wr.wr.ud.remote_qkey = priv->qkey;
set_qkey = 1;
if (!ipoib_cm_admin_enabled(dev)) {
rtnl_lock();
dev_set_mtu(dev, min(priv->mcast_mtu, priv->admin_mtu));
rtnl_unlock();
}
}
if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
@@ -586,14 +595,6 @@ void ipoib_mcast_join_task(struct work_struct *work)
return;
}
priv->mcast_mtu = IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));
if (!ipoib_cm_admin_enabled(dev)) {
rtnl_lock();
dev_set_mtu(dev, min(priv->mcast_mtu, priv->admin_mtu));
rtnl_unlock();
}
ipoib_dbg_mcast(priv, "successfully joined all multicast groups\n");
clear_bit(IPOIB_MCAST_RUN, &priv->flags);