From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx> commit e852c2c251ed9c23ae6e3efebc5ec49adb504207 upstream. It's not needed to set driver to NULL in mei_cl_device_remove() which is bus_type remove() handler as this is done anyway in __device_release_driver(). Actually this is causing an endless loop in driver_detach() on ubuntu patched kernel, while removing (rmmod) the mei_hdcp module. The reason list_empty(&drv->p->klist_devices.k_list) is always not-empty. as the check is always true in __device_release_driver() if (dev->driver != drv) return; The non upstream patch is causing this behavior, titled: 'vfio -- release device lock before userspace requests' Nevertheless the fix is correct also for the upstream. Link: https://patchwork.ozlabs.org/project/ubuntu-kernel/patch/20180912085046.3401-2-apw@xxxxxxxxxxxxx/ Cc: <stable@xxxxxxxxxxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx> Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx> Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx> Link: https://lore.kernel.org/r/20200628225359.2185929-1-tomas.winkler@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/misc/mei/bus.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/misc/mei/bus.c +++ b/drivers/misc/mei/bus.c @@ -722,9 +722,8 @@ static int mei_cl_device_remove(struct d mei_cldev_unregister_callbacks(cldev); module_put(THIS_MODULE); - dev->driver = NULL; - return ret; + return ret; } static ssize_t name_show(struct device *dev, struct device_attribute *a,
