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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, yangerkun <yangerkun@huawei.com>,
        Oliver Hartkopp <socketcan@hartkopp.net>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.4 39/91] slcan: not call free_netdev before rtnl_unlock in slcan_open
Date:   Wed,  1 Apr 2020 18:17:35 +0200
Message-Id: <20200401161527.443991002@linuxfoundation.org>
In-Reply-To: <20200401161512.917494101@linuxfoundation.org>
References: <20200401161512.917494101@linuxfoundation.org>
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From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit 2091a3d42b4f339eaeed11228e0cbe9d4f92f558 ]

As the description before netdev_run_todo, we cannot call free_netdev
before rtnl_unlock, fix it by reorder the code.

This patch is a 1:1 copy of upstream slip.c commit f596c87005f7
("slip: not call free_netdev before rtnl_unlock in slip_open").

Reported-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/can/slcan.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -621,7 +621,10 @@ err_free_chan:
 	tty->disc_data = NULL;
 	clear_bit(SLF_INUSE, &sl->flags);
 	slc_free_netdev(sl->dev);
+	/* do not call free_netdev before rtnl_unlock */
+	rtnl_unlock();
 	free_netdev(sl->dev);
+	return err;
 
 err_exit:
 	rtnl_unlock();