[PATCH 4.19 020/116] slcan: not call free_netdev before rtnl_unlock in slcan_open

[Greg Kroah-Hartman]

From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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();