MSG_SMB_UNLOCK should be send to smbd that are waiting on blocked byte-range-locks when a lock holder died. In smbd_cleanupd_unlock() we do this twice: once via a broadcast and then again via brl_revalidate() to processes that are actually recorded in brlock.tdb. As brl_revalidate() should already take care of signaling anyone who would be interested in the message, there's no need to broadcast.
Created attachment 14179 [details] git-am fix for 4.8.next. Cherry-picked from master. I think 4.7.x also suffers from this bug, but it isn't as critical there (brl_revalidate() is idempotent).
Reassigning to Karolin for inclusion in 4.8.
(In reply to Ralph Böhme from comment #2) Pushed to autobuild-v4-8-test.
(In reply to Karolin Seeger from comment #3) Pushed to v4-8-test. Closing out bug report. Thanks!