From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Tue, 23 Jun 2020 17:47:23 +0100
Subject: net: phylink: fix ethtool -A with attached PHYs
Patch-mainline: v5.8-rc3
Git-commit: c718af2d00a37587b09e5958d142da7569f3d55b
References: bsc#1176447
Fix a phylink's ethtool set_pauseparam support deadlock caused by phylib
interacting with phylink: we must not hold the state lock while calling
phylib functions that may call into phylink_phy_change().
Fixes: f904f15ea9b5 ("net: phylink: allow ethtool -A to change flow control advertisement")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/phy/phylink.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1437,20 +1437,23 @@ int phylink_ethtool_set_pauseparam(struc
linkmode_set_pause(config->advertising, pause->tx_pause,
pause->rx_pause);
- /* If we have a PHY, phylib will call our link state function if the
- * mode has changed, which will trigger a resolve and update the MAC
- * configuration.
- */
- if (pl->phydev) {
- phy_set_asym_pause(pl->phydev, pause->rx_pause,
- pause->tx_pause);
- } else if (!test_bit(PHYLINK_DISABLE_STOPPED,
- &pl->phylink_disable_state)) {
+ if (!pl->phydev && !test_bit(PHYLINK_DISABLE_STOPPED,
+ &pl->phylink_disable_state)) {
phylink_mac_config(pl, &pl->link_config);
phylink_mac_an_restart(pl);
}
+
mutex_unlock(&pl->state_mutex);
+ /* If we have a PHY, a change of the pause frame advertisement will
+ * cause phylib to renegotiate (if AN is enabled) which will in turn
+ * call our phylink_phy_change() and trigger a resolve. Note that
+ * we can't hold our state mutex while calling phy_set_asym_pause().
+ */
+ if (pl->phydev)
+ phy_set_asym_pause(pl->phydev, pause->rx_pause,
+ pause->tx_pause);
+
return 0;
}
EXPORT_SYMBOL_GPL(phylink_ethtool_set_pauseparam);