From: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx Signed-off-by: Vineeth Vijayan <vneethv@xxxxxxxxxxxxx> Suggested-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx> Reviewed-by: Jan Hoeppner <hoeppner@xxxxxxxxxxxxx> Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx> Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/s390/cio/device.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -1194,7 +1194,7 @@ static int io_subchannel_chp_event(struc else path_event[chpid] = PE_NONE; } - if (cdev) + if (cdev && cdev->drv && cdev->drv->path_event) cdev->drv->path_event(cdev, path_event); break; } Patches currently in stable-queue which might be from vneethv@xxxxxxxxxxxxx are queue-5.15/s390-cio-verify-the-driver-availability-for-path_event-call.patch