From 1c3098cdb05207e740715857df7b0998e372f527 Mon Sep 17 00:00:00 2001 From: Feras Daoud Date: Wed, 28 Dec 2016 14:47:22 +0200 Subject: [PATCH] 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: cbbe1efa4972 ("IPoIB: Fix deadlock between ipoib_open() and child interface create") Signed-off-by: Feras Daoud Signed-off-by: Erez Shitrit Reviewed-by: Alex Vesker Signed-off-by: Leon Romanovsky Signed-off-by: Doug Ledford --- drivers/infiniband/ulp/ipoib/ipoib_vlan.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c index fd811115af49..96821838c352 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c @@ -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) { -- 2.20.1