[PATCH v2 net 1/1] net: stmmac: Use rtnl_lock/unlock on netif_set_real_num_rx_queues() call

[Wong Vee Khee]

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.roull...@st.com>
Tested-by: Christophe ROULLIER <christophe.roull...@st.com>
Cc: Alexandre TORGUE <alexandre.tor...@st.com>
Reviewed-by: Ong Boon Leong <boon.leong....@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.w...@intel.com>
---
v2 changelog:
- Move rtnl_lock() before priv->lock and release it after to avoid a
  possible ABBA deadlock scenario.
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index ba855465a2db..c8770e9668a1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5272,6 +5272,7 @@ int stmmac_resume(struct device *dev)
                        return ret;
        }
 
+       rtnl_lock();
        mutex_lock(&priv->lock);
 
        stmmac_reset_queues_param(priv);
@@ -5287,6 +5288,7 @@ 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();
-- 
2.17.0