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0795b05a59
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: bc66fa87d4 ("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>
Linux kernel
============
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