From: Pavel Skripkin <paskripkin@xxxxxxxxx> commit 10eff1f5788b6ffac212c254e2f3666219576889 upstream. This reverts commit ab609f25d19858513919369ff3d9a63c02cd9e2e. This patch is correct in the sense that we _should_ call device_put() in case of device_register() failure, but the problem in this code is more vast. We need to set bus->state to UNMDIOBUS_REGISTERED before calling device_register() to correctly release the device in mdiobus_free(). This patch prevents us from doing it, since in case of device_register() failure put_device() will be called 2 times and it will cause UAF or something else. Also, Reported-by: tag in revered commit was wrong, since syzbot reported different leak in same function. Link: https://lore.kernel.org/netdev/20210928092657.GI2048@kadam/ Acked-by: Yanfei Xu <yanfei.xu@xxxxxxxxxxxxx> Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> Link: https://lore.kernel.org/r/f12fb1faa4eccf0f355788225335eb4309ff2599.1633024062.git.paskripkin@xxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/phy/mdio_bus.c | 1 - 1 file changed, 1 deletion(-) --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -544,7 +544,6 @@ int __mdiobus_register(struct mii_bus *b err = device_register(&bus->dev); if (err) { pr_err("mii_bus %s failed to register\n", bus->id); - put_device(&bus->dev); return -EINVAL; }
