[PATCH 4.9 014/175] net: stmmac: delete the eee_ctrl_timer after napi disabled

[Greg Kroah-Hartman]

From: Fugang Duan <fugang.duan@xxxxxxx>

[ Upstream commit 5f58591323bf3f342920179f24515935c4b5fd60 ]

There have chance to re-enable the eee_ctrl_timer and fire the timer
in napi callback after delete the timer in .stmmac_release(), which
introduces to access eee registers in the timer function after clocks
are disabled then causes system hang. Found this issue when do
suspend/resume and reboot stress test.

It is safe to delete the timer after napi disabled and disable lpi mode.

Fixes: d765955d2ae0b ("stmmac: add the Energy Efficient Ethernet support")
Signed-off-by: Fugang Duan <fugang.duan@xxxxxxx>
Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1901,9 +1901,6 @@ static int stmmac_release(struct net_dev
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 
-	if (priv->eee_enabled)
-		del_timer_sync(&priv->eee_ctrl_timer);
-
 	/* Stop and disconnect the PHY */
 	if (priv->phydev) {
 		phy_stop(priv->phydev);
@@ -1924,6 +1921,11 @@ static int stmmac_release(struct net_dev
 	if (priv->lpi_irq > 0)
 		free_irq(priv->lpi_irq, dev);
 
+	if (priv->eee_enabled) {
+		priv->tx_path_in_lpi_mode = false;
+		del_timer_sync(&priv->eee_ctrl_timer);
+	}
+
 	/* Stop TX/RX DMA and clear the descriptors */
 	priv->hw->dma->stop_tx(priv->ioaddr);
 	priv->hw->dma->stop_rx(priv->ioaddr);
@@ -3503,6 +3505,11 @@ int stmmac_suspend(struct device *dev)
 
 	napi_disable(&priv->napi);
 
+	if (priv->eee_enabled) {
+		priv->tx_path_in_lpi_mode = false;
+		del_timer_sync(&priv->eee_ctrl_timer);
+	}
+
 	/* Stop TX/RX DMA */
 	priv->hw->dma->stop_tx(priv->ioaddr);
 	priv->hw->dma->stop_rx(priv->ioaddr);