6.12-stable review patch. If anyone has any objections, please let me know.
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From: Wei Fang wei.fang@nxp.com
[ Upstream commit 0795b05a59b1371b18ffbf09d385296b12e9f5d5 ]
There is a potential crash issue when disabling and re-enabling the network port. When disabling the network port, phy_detach() calls device_link_del() to remove the device link, but it does not clear phydev->devlink, so phydev->devlink is not a NULL pointer. Then the network port is re-enabled, but if phy_attach_direct() fails before calling device_link_add(), the code jumps to the "error" label and calls phy_detach(). Since phydev->devlink retains the old value from the previous attach/detach cycle, device_link_del() uses the old value, which accesses a NULL pointer and causes a crash. The simplified crash log is as follows.
[ 24.702421] Call trace: [ 24.704856] device_link_put_kref+0x20/0x120 [ 24.709124] device_link_del+0x30/0x48 [ 24.712864] phy_detach+0x24/0x168 [ 24.716261] phy_attach_direct+0x168/0x3a4 [ 24.720352] phylink_fwnode_phy_connect+0xc8/0x14c [ 24.725140] phylink_of_phy_connect+0x1c/0x34
Therefore, phydev->devlink needs to be cleared when the device link is deleted.
Fixes: bc66fa87d4fd ("net: phy: Add link between phy dev and mac dev") Signed-off-by: Wei Fang wei.fang@nxp.com Reviewed-by: Andrew Lunn andrew@lunn.ch Reviewed-by: Florian Fainelli florian.fainelli@broadcom.com Link: https://patch.msgid.link/20250523083759.3741168-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/phy/phy_device.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 8af44224480f1..13dea33d86ffa 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -2010,8 +2010,10 @@ void phy_detach(struct phy_device *phydev) struct module *ndev_owner = NULL; struct mii_bus *bus;
- if (phydev->devlink) + if (phydev->devlink) { device_link_del(phydev->devlink); + phydev->devlink = NULL; + }
if (phydev->sysfs_links) { if (dev)