linux-kernel - [PATCH review for 4.4 19/47] IB/ipoib: rtnl_unlock can not come after free

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Message-ID: <20170920044445.7392-19-alexander.levin@verizon.com>
Date:   Wed, 20 Sep 2017 04:45:04 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Feras Daoud <ferasda@...lanox.com>,
        Or Gerlitz <ogerlitz@...lanox.com>,
        Erez Shitrit <erezsh@...lanox.com>,
        Leon Romanovsky <leon@...nel.org>,
        "Doug Ledford" <dledford@...hat.com>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
Subject: [PATCH review for 4.4 19/47] IB/ipoib: rtnl_unlock can not come after
 free_netdev

From: Feras Daoud <ferasda@...lanox.com>

[ Upstream commit 89a3987ab7a923c047c6dec008e60ad6f41fac22 ]

The ipoib_vlan_add function calls rtnl_unlock after free_netdev,
rtnl_unlock not only releases the lock, but also calls netdev_run_todo.
The latter function browses the net_todo_list array and completes the
unregistration of all its net_device instances. If we call free_netdev
before rtnl_unlock, then netdev_run_todo call over the freed device causes
panic.
To fix, move rtnl_unlock call before free_netdev call.

Fixes: 9baa0b036410 ("IB/ipoib: Add rtnl_link_ops support")
Cc: Or Gerlitz <ogerlitz@...lanox.com>
Signed-off-by: Feras Daoud <ferasda@...lanox.com>
Signed-off-by: Erez Shitrit <erezsh@...lanox.com>
Reviewed-by: Yuval Shaia <yuval.shaia@...cle.com>
Signed-off-by: Leon Romanovsky <leon@...nel.org>
Signed-off-by: Doug Ledford <dledford@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_vlan.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
index 3a647fd50f09..9b47a437d6c9 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
@@ -160,11 +160,11 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
 out:
 	up_write(&ppriv->vlan_rwsem);
 
+	rtnl_unlock();
+
 	if (result)
 		free_netdev(priv->dev);
 
-	rtnl_unlock();
-
 	return result;
 }
 
-- 
2.11.0