From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753315AbdJFI5L (ORCPT ); Fri, 6 Oct 2017 04:57:11 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50010 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753305AbdJFI5I (ORCPT ); Fri, 6 Oct 2017 04:57:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Feras Daoud , Erez Shitrit , Alex Vesker , Leon Romanovsky , Doug Ledford , Sasha Levin Subject: [PATCH 4.4 16/50] IB/ipoib: Fix deadlock over vlan_mutex Date: Fri, 6 Oct 2017 10:53:04 +0200 Message-Id: <20171006083707.687232625@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171006083705.157012217@linuxfoundation.org> References: <20171006083705.157012217@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Feras Daoud [ 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 Signed-off-by: Erez Shitrit Reviewed-by: Alex Vesker Signed-off-by: Leon Romanovsky Signed-off-by: Doug Ledford Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- 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 @@ -185,7 +185,6 @@ 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; @@ -193,6 +192,11 @@ 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) {