objective c - NSManagedObjectContext performBlockAndWait causing deadlock when called from two threads -

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i have osx app i'm using parent/child nsmanagedobjectcontext setup. child moc has nsprivatequeueconcurrencytype , 1 i'm using. parent set nsmainqueueconcurrencytype

when call performblockandwait on child context background thread @ same time called main thread deadlock – semaphore_wait_trap. pausing debugger shows both threads stuck @ performblockandwait

how can around this? thought method designed situation , queue blocks on context's private queue return appropriately?

i worked around creating serial queue , doing performblock calls through make sure wouldn't mess each-other up. honestly, i'm not sure if practice did solve problem particular situation.


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