917c07ca1d
Let fall down in the hard path (thus handling shared waiters wakeup correctly) for the shared waiters also in the rwlock held in shared mode as well, fixing possible deadlocks. Please note that this is a special condition as we want this fix in before RC2 as we assume it is critical and so it has been handled as an instant-merge. For the STABLE_7 branch, 1 week before the MFC is assumed. Approved by: re (kib)