sfp_i2c_mdiobus_create() allocates the I2C MDIO bus with mdio_i2c_alloc(),
a plain (non-devm) allocation, and registers it. sfp_i2c_mdiobus_destroy()
only unregisters the bus and clears sfp->i2c_mii without calling
mdiobus_free(). As the only reference to the bus is then cleared, the
struct mii_bus is leaked.

This is hit whenever a copper/RollBall SFP module that instantiated an MDIO
bus is removed: sfp_sm_main() takes the global teardown path and calls
sfp_i2c_mdiobus_destroy(). sfp_cleanup(), on driver unbind, frees
sfp->i2c_mii directly, which is why the leak only triggered on module
hot-removal and not on unbind.

Free the bus in sfp_i2c_mdiobus_destroy() to match the allocation done in
sfp_i2c_mdiobus_create().

Fixes: e85b1347ace6 ("net: sfp: create/destroy I2C mdiobus before PHY probe/after PHY release")
Signed-off-by: Petr Wozniak <redacted>
---
 drivers/net/phy/sfp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 03bfd8640db9..c4d274ab651e 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c

@@ -963,6 +963,7 @@ static int sfp_i2c_mdiobus_create(struct sfp *sfp)
 static void sfp_i2c_mdiobus_destroy(struct sfp *sfp)
 {
 	mdiobus_unregister(sfp->i2c_mii);
+	mdiobus_free(sfp->i2c_mii);
 	sfp->i2c_mii = NULL;
 }
 

-- 
2.51.0