[mythtv-commits] Ticket #10771: BE deadlocks after backporting #10541

[MythTV]

#10771: BE deadlocks after backporting #10541
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 Reporter:  warpme@…                    |          Owner:  danielk
     Type:  Bug Report - Hang/Deadlock  |         Status:  infoneeded
 Priority:  major                       |      Milestone:  0.25.1
Component:  MythTV - EIT                |        Version:  0.25-fixes
 Severity:  medium                      |     Resolution:
 Keywords:  EIT                         |  Ticket locked:  0
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Comment (by Stuart Morgan <smorgan@…>):

 In [changeset:788bc510ede427e43e77e8aaf53d8cf047d89b46/mythtv]:
 {{{
 #!CommitTicketReference repository="mythtv"
 revision="788bc510ede427e43e77e8aaf53d8cf047d89b46"
 Protect the reschedule queue with a seperate lock to fix a backend
 deadlock.

 Fixes a deadlock in mythbackend caused when a reschedule request occurs
 immedately prior to a recording starting.

 The recorder thread locks the scheduler when starting a recording. The
 pending
 reschedule request handled in the event loop waits for the scheduler lock
 to be
 released blocking the event loop. The backend is now stopped from handling
 any
 further events or protocol requests, meanwhile the recorder is waiting on
 events to be processed before it will release the lock resulting in an
 irrecoverable deadlock (or hang) and the failure of the recording.

 This deadlock was more likely to be triggered for users of EIT because it
 will
 ask for a reschedule every 5 minutes in addition to any reschedules
 triggered
 through other means.

 Refs #10771
 }}}

-- 
Ticket URL: <http://code.mythtv.org/trac/ticket/10771#comment:19>
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