[PATCH 4.9 084/130] ravb: fix invalid context bug while calling auto-negotiation by ethtool

From: Greg Kroah-Hartman
Date: Thu Aug 23 2018 - 04:10:25 EST

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


From: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>

[ Upstream commit 0973a4dd79fe56a3beecfcff675ba4c01df0b0c1 ]

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: c156633f1353 ("Renesas Ethernet AVB driver proper")
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/ravb_main.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)

--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1122,15 +1122,10 @@ error_exit:

static int ravb_nway_reset(struct net_device *ndev)
- struct ravb_private *priv = netdev_priv(ndev);
int error = -ENODEV;
- unsigned long flags;

- if (ndev->phydev) {
- spin_lock_irqsave(&priv->lock, flags);
+ if (ndev->phydev)
error = phy_start_aneg(ndev->phydev);
- spin_unlock_irqrestore(&priv->lock, flags);
- }

return error;