commit dd9cb842fa9d90653a9b48aba52f89c069f3bc50 upstream. If no driver is attached to a device or the driver does not provide the path_event function, an FCES path-event on this device could end up in a kernel-panic. Verify the driver availability before the path_event function call. Fixes: 32ef938815c1 ("s390/cio: Add support for FCES status notification") Cc: stable@vger.kernel.org Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com> Suggested-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>