PM / hibernate: Fix restore hang in freeze_processes()
During restore, pm_notifier chain are called with
PM_RESTORE_PREPARE. The firmware_class driver handler
fw_pm_notify does not have a handler for this. As a result,
it keeps a reader on the kmod.c umhelper_sem. During
freeze_processes, the call to __usermodehelper_disable tries to
take a write lock on this semaphore and hangs waiting.
Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org> Acked-by: Ming Lei <ming.lei@canonical.com> Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>