linux-kernel - [PATCH 3.10 133/139] IB/ipoib: rtnl_unlock can not come after free

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Message-Id: <1509571624-5001-34-git-send-email-w@1wt.eu>
Date:   Wed,  1 Nov 2017 22:26:58 +0100
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux@...ck-us.net
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>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 133/139] IB/ipoib: rtnl_unlock can not come after free_netdev

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

commit 89a3987ab7a923c047c6dec008e60ad6f41fac22 upstream.

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: Willy Tarreau <w@....eu>
---
 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 8292554..7604ae5 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
@@ -165,11 +165,11 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
 out:
 	mutex_unlock(&ppriv->vlan_mutex);
 
+	rtnl_unlock();
+
 	if (result)
 		free_netdev(priv->dev);
 
-	rtnl_unlock();
-
 	return result;
 }
 
-- 
2.8.0.rc2.1.gbe9624a