From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752054AbdITFBI (ORCPT ); Wed, 20 Sep 2017 01:01:08 -0400 Received: from omzsmtpe01.verizonbusiness.com ([199.249.25.210]:63874 "EHLO omzsmtpe01.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751686AbdITEp5 (ORCPT ); Wed, 20 Sep 2017 00:45:57 -0400 From: "Levin, Alexander (Sasha Levin)" Cc: Feras Daoud , Erez Shitrit , Leon Romanovsky , Doug Ledford , "Levin, Alexander (Sasha Levin)" X-Host: ranger.odc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH review for 4.4 18/47] IB/ipoib: Fix deadlock over vlan_mutex Thread-Topic: [PATCH review for 4.4 18/47] IB/ipoib: Fix deadlock over vlan_mutex Thread-Index: AQHTMcs5hIAl+tR3ik6QIqg1HT9NrA== Date: Wed, 20 Sep 2017 04:45:04 +0000 Message-ID: <20170920044445.7392-18-alexander.levin@verizon.com> References: <20170920044445.7392-1-alexander.levin@verizon.com> In-Reply-To: <20170920044445.7392-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8K51C5K025257 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 --- 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 57a34f87dedf..3a647fd50f09 100644 --- 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 *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; @@ -193,6 +192,11 @@ 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) { -- 2.11.0