[PATCH 4.9 082/130] sh_eth: fix invalid context bug while calling auto-negotiation by ethtool

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>

[ Upstream commit 53a710b5044d8475faa6813000b6dd659400ef7b ]

Since commit 35b5f6b1a82b ("PHYLIB: Locking fixes for PHY I/O
potentially sleeping") phy_start_aneg() function utilizes a mutex
to serialize changes to phy state, however the helper function is
called in atomic context.

The bug can be reproduced by running "ethtool -r" command, the bug
is reported if CONFIG_DEBUG_ATOMIC_SLEEP build option is enabled.

Fixes: dc19e4e5e02f ("sh: sh_eth: Add support ethtool")
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/renesas/sh_eth.c |   10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -2079,18 +2079,10 @@ static void sh_eth_get_regs(struct net_d
 
 static int sh_eth_nway_reset(struct net_device *ndev)
 {
-	struct sh_eth_private *mdp = netdev_priv(ndev);
-	unsigned long flags;
-	int ret;
-
 	if (!ndev->phydev)
 		return -ENODEV;
 
-	spin_lock_irqsave(&mdp->lock, flags);
-	ret = phy_start_aneg(ndev->phydev);
-	spin_unlock_irqrestore(&mdp->lock, flags);
-
-	return ret;
+	return phy_start_aneg(ndev->phydev);
 }
 
 static u32 sh_eth_get_msglevel(struct net_device *ndev)