| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 034/104] IB/ipoib: Fix deadlock over vlan_mutex | Date | Fri, 6 Oct 2017 10:51:12 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Feras Daoud <ferasda@mellanox.com>
[ Upstream commit 1c3098cdb05207e740715857df7b0998e372f527 ]
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> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/infiniband/ulp/ipoib/ipoib_vlan.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c @@ -193,7 +193,6 @@ int ipoib_vlan_delete(struct net_device 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; @@ -201,6 +200,11 @@ int ipoib_vlan_delete(struct net_device } up_write(&ppriv->vlan_rwsem); + if (dev) { + ipoib_dbg(ppriv, "delete child vlan %s\n", dev->name); + unregister_netdevice(dev); + } + rtnl_unlock(); if (dev) {
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