uwb: properly check kthread_run return value
commit
bbf26183b7a6236ba602f4d6a2f7cade35bba043 upstream.
uwbd_start() calls kthread_run() and checks that the return value is
not NULL. But the return value is not NULL in case kthread_run() fails,
it takes the form of ERR_PTR(-EINTR).
Use IS_ERR() instead.
Also add a check to uwbd_stop().
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>