[GHC] #8316: GHCi debugger segfaults when trying force a certain variable

[GHC]

#8316: GHCi debugger segfaults when trying force a certain variable
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        Reporter:  guest             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  GHCi              |              Version:  7.6.3
      Resolution:                    |             Keywords:  debugger
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHCi crash        |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4535,
       Wiki Page:                    |  Phab:D5179
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Changes (by osa1):

 * differential:  Phab:D4535 => Phab:D4535, Phab:D5179


Comment:

 I submitted a diff. As expected, it causes a deadlock in the reproducer.

 Simon, any ideas on how to fix the deadlock? Would it be possible to
 resume the evaluator thread (by updating `breakMVar`) before entering a
 BLACKHOLE?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8316#comment:17>
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