Commit 1c3098cd authored Dec 28, 2016 by Feras Daoud Committed by Doug Ledford Jan 12, 2017

IB/ipoib: Fix deadlock over vlan_mutex



This patch fixes Deadlock while executing ipoib_vlan_delete.

The function takes the vlan_rwsem semaphore and calls
unregister_netdevice. The later function calls
ipoib_mcast_stop_thread that cause workqueue flush.

When the queue has one of the ipoib_ib_dev_flush_xxx events,
a deadlock occur because these events also tries to catch the
same vlan_rwsem semaphore.

To fix, unregister_netdevice should be called after releasing
the semaphore.

Fixes: cbbe1efa ("IPoIB: Fix deadlock between ipoib_open() and child interface create")
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

parent 80b5b35a

drivers/infiniband/ulp/ipoib/ipoib_vlan.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -196,7 +196,6 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
		list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) {
		if (priv->pkey == pkey &&
		priv->child_type == IPOIB_LEGACY_CHILD) {
		unregister_netdevice(priv->dev);
		list_del(&priv->list);
		dev = priv->dev;
		break;
		@@ -204,6 +203,11 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
		}
		up_write(&ppriv->vlan_rwsem);

		if (dev) {
		ipoib_dbg(ppriv, "delete child vlan %s\n", dev->name);
		unregister_netdevice(dev);
		}

		rtnl_unlock();

		if (dev) {