From 83285fa94ee4fb151358313fc944f2dde2c479cb Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Fri, 17 Sep 2021 14:36:31 +0100
Subject: [PATCH] net: phylink: don't call netif_carrier_off() with NULL netdev
Git-commit: cbcca2e3961eac736566ac13ef0d0bf6f0b764ec
Patch-mainline: v5.16-rc1
References: stable-5.14.19

[ 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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/phy/phylink.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 0d3d9c3ee83c..6e96d7b7ee44 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1332,7 +1332,10 @@ 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.
-- 
2.26.2