net: phylink: don't call netif_carrier_off() with NULL netdev

[ Upstream commit cbcca2e3961eac736566ac13ef0d0bf6f0b764ec ]

Dan Carpenter points out that we have a code path that permits a NULL
netdev pointer to be passed to netif_carrier_off(), which will cause
a kernel oops. In any case, we need to set pl->old_link_state to false
to have the desired effect when there is no netdev present.

Fixes: f97493657c63 ("net: phylink: add suspend/resume support")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 0a0abe8..5a58c77 100644 (file)
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1333,7 +1333,10 @@ void phylink_suspend(struct phylink *pl, bool mac_wol)
                 * but one would hope all packets have been sent. This
                 * also means phylink_resolve() will do nothing.
                 */
-               netif_carrier_off(pl->netdev);
+               if (pl->netdev)
+                       netif_carrier_off(pl->netdev);
+               else
+                       pl->old_link_state = false;
 
                /* We do not call mac_link_down() here as we want the
                 * link to remain up to receive the WoL packets.