linux-kernel - [net PATCH 1/2] net: phy: Remove LED entry from LEDs list on unregister

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Message-ID: <20241003221006.4568-1-ansuelsmth@gmail.com>
Date: Fri,  4 Oct 2024 00:10:04 +0200
From: Christian Marangi <ansuelsmth@...il.com>
To: Andrew Lunn <andrew@...n.ch>,
	Heiner Kallweit <hkallweit1@...il.com>,
	Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Florian Fainelli <f.fainelli@...il.com>,
	Christian Marangi <ansuelsmth@...il.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Daniel Golle <daniel@...rotopia.org>,
	stable@...r.kernel.org
Subject: [net PATCH 1/2] net: phy: Remove LED entry from LEDs list on unregister

Commit c938ab4da0eb ("net: phy: Manual remove LEDs to ensure correct
ordering") correctly fixed a problem with using devm_ but missed
removing the LED entry from the LEDs list.

This cause kernel panic on specific scenario where the port for the PHY
is torn down and up and the kmod for the PHY is removed.

On setting the port down the first time, the assosiacted LEDs are
correctly unregistered. The associated kmod for the PHY is now removed.
The kmod is now added again and the port is now put up, the associated LED
are registered again.
On putting the port down again for the second time after these step, the
LED list now have 4 elements. With the first 2 already unregistered
previously and the 2 new one registered again.

This cause a kernel panic as the first 2 element should have been
removed.

Fix this by correctly removing the element when LED is unregistered.

Reported-by: Daniel Golle <daniel@...rotopia.org>
Tested-by: Daniel Golle <daniel@...rotopia.org>
Cc: stable@...r.kernel.org
Fixes: c938ab4da0eb ("net: phy: Manual remove LEDs to ensure correct ordering")
Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
---
 drivers/net/phy/phy_device.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 560e338b307a..499797646580 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -3326,10 +3326,11 @@ static __maybe_unused int phy_led_hw_is_supported(struct led_classdev *led_cdev,

 static void phy_leds_unregister(struct phy_device *phydev)
 {
-	struct phy_led *phyled;
+	struct phy_led *phyled, *tmp;

-	list_for_each_entry(phyled, &phydev->leds, list) {
+	list_for_each_entry_safe(phyled, tmp, &phydev->leds, list) {
 		led_classdev_unregister(&phyled->led_cdev);
+		list_del(&phyled->list);
 	}
 }

-- 
2.45.2