[ Upstream commit d1408f6b4d ]
Commit 2c9d6c2b87 ("usbnet: run unbind() before unregister_netdev()")
sought to fix a use-after-free on disconnect of USB Ethernet adapters.
It turns out that a different fix is necessary to address the issue:
https://lore.kernel.org/netdev/18b3541e5372bc9b9fc733d422f4e698c089077c.1650177997.git.lukas@wunner.de/
So the commit was not necessary.
The commit made binding and unbinding of USB Ethernet asymmetrical:
Before, usbnet_probe() first invoked the ->bind() callback and then
register_netdev(). usbnet_disconnect() mirrored that by first invoking
unregister_netdev() and then ->unbind().
Since the commit, the order in usbnet_disconnect() is reversed and no
longer mirrors usbnet_probe().
One consequence is that a PHY disconnected (and stopped) in ->unbind()
is afterwards stopped once more by unregister_netdev() as it closes the
netdev before unregistering. That necessitates a contortion in ->stop()
because the PHY may only be stopped if it hasn't already been
disconnected.
Reverting the commit allows making the call to phy_stop() unconditional
in ->stop().
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de> # LAN9514/9512/9500
Tested-by: Ferry Toth <fntoth@gmail.com> # LAN9514
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Cc: Martyn Welch <martyn.welch@collabora.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fbda837107