[PATCH 5.9 033/252] net: stmmac: Use rtnl_lock/unlock on netif_set_real_num_rx_queues() call

[Greg Kroah-Hartman]

From: Wong Vee Khee <vee.khee.wong@xxxxxxxxx>

[ Upstream commit 8e5debed39017836a850c6c7bfacc93299d19bad ]

Fix an issue where dump stack is printed on suspend resume flow due to
netif_set_real_num_rx_queues() is not called with rtnl_lock held().

Fixes: 686cff3d7022 ("net: stmmac: Fix incorrect location to set real_num_rx|tx_queues")
Reported-by: Christophe ROULLIER <christophe.roullier@xxxxxx>
Tested-by: Christophe ROULLIER <christophe.roullier@xxxxxx>
Cc: Alexandre TORGUE <alexandre.torgue@xxxxxx>
Reviewed-by: Ong Boon Leong <boon.leong.ong@xxxxxxxxx>
Signed-off-by: Wong Vee Khee <vee.khee.wong@xxxxxxxxx>
Link: https://lore.kernel.org/r/20201115074210.23605-1-vee.khee.wong@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5170,6 +5170,7 @@ int stmmac_resume(struct device *dev)
 			return ret;
 	}
 
+	rtnl_lock();
 	mutex_lock(&priv->lock);
 
 	stmmac_reset_queues_param(priv);
@@ -5185,6 +5186,7 @@ int stmmac_resume(struct device *dev)
 	stmmac_enable_all_queues(priv);
 
 	mutex_unlock(&priv->lock);
+	rtnl_unlock();
 
 	if (!device_may_wakeup(priv->device) || !priv->plat->pmt) {
 		rtnl_lock();