netdev - [PATCH AUTOSEL 4.19 09/23] net: mdiobus: get rid of a BUG

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Message-Id: <20210603170959.3169420-9-sashal@kernel.org>
Date:   Thu,  3 Jun 2021 13:09:45 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Dan Carpenter <dan.carpenter@...cle.com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Andrew Lunn <andrew@...n.ch>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 09/23] net: mdiobus: get rid of a BUG_ON()

From: Dan Carpenter <dan.carpenter@...cle.com>

[ Upstream commit 1dde47a66d4fb181830d6fa000e5ea86907b639e ]

We spotted a bug recently during a review where a driver was
unregistering a bus that wasn't registered, which would trigger this
BUG_ON().  Let's handle that situation more gracefully, and just print
a warning and return.

Reported-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
Reviewed-by: Andrew Lunn <andrew@...n.ch>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/phy/mdio_bus.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 5c89a310359d..08c81d4cfca8 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -446,7 +446,8 @@ void mdiobus_unregister(struct mii_bus *bus)
 	struct mdio_device *mdiodev;
 	int i;
 
-	BUG_ON(bus->state != MDIOBUS_REGISTERED);
+	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
+		return;
 	bus->state = MDIOBUS_UNREGISTERED;
 
 	for (i = 0; i < PHY_MAX_ADDR; i++) {
-- 
2.30.2