[GHC] #10629: threadWaitRead throws BlockedIndefinitelyOnMVar

[GHC]

#10629: threadWaitRead throws BlockedIndefinitelyOnMVar
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        Reporter:                    |                   Owner:  simonmar
  facundo.dominguez                  |                  Status:  new
            Type:  bug               |               Milestone:
        Priority:  normal            |                 Version:  7.10.1
       Component:  Runtime System    |                Keywords:
      Resolution:                    |  concurrency sockets
Operating System:  Linux             |            Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by simonmar):

 `BlockedIndefinitelyOnMVar` is thrown when the thread is blocked on an
 `MVar` that isn't reachable from anywhere else, which means that it will
 never be woken up.

 There are two possibilities:
  - the exception is being thrown erroneously (unlikely, I'd guess)
  - the IO manager has somehow lost the `MVar` that the thread is waiting
 on.

 You could proceed by instrumenting code below `GHC.Event` to find out what
 happens to the `MVar` the thread is waiting on.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10629#comment:9>
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