Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752432AbdFAQdL (ORCPT ); Thu, 1 Jun 2017 12:33:11 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33119 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751929AbdFAPom (ORCPT ); Thu, 1 Jun 2017 11:44:42 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Erez Shitrit" , "Alex Vesker" , "Doug Ledford" , "Feras Daoud" , "Leon Romanovsky" Date: Thu, 01 Jun 2017 16:43:15 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 034/212] IB/ipoib: Fix deadlock over vlan_mutex In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1776 Lines: 54 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Feras Daoud commit 1c3098cdb05207e740715857df7b0998e372f527 upstream. 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 Signed-off-by: Ben Hutchings --- 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 @@ -196,7 +196,6 @@ 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; @@ -204,6 +203,11 @@ 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) {