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IB/ipoib: Fix deadlock over vlan_mutex

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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: cbbe1efa4972 ("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>
This commit is contained in:
Feras Daoud 2016-12-28 14:47:22 +02:00 committed by Doug Ledford
parent 80b5b35aba
commit 1c3098cdb0
1 changed files with 5 additions and 1 deletions
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6
drivers/infiniband/ulp/ipoib/ipoib_vlan.c
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@ -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) {