[GHC] #12800: hs_try_putmvar003 sometimes fails

[GHC]

#12800: hs_try_putmvar003 sometimes fails
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:  simonmar
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Runtime System    |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2678
       Wiki Page:                    |
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Comment (by Simon Marlow <marlowsd@…>):

 In [changeset:"91f9e13887f49c28e4dbde4edc2c5c65de44c9e9/ghc" 91f9e13/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="91f9e13887f49c28e4dbde4edc2c5c65de44c9e9"
 Fix hs_try_putmvar003 (#12800)

 Summary:
 There was a race condition on some shared data when creating the
 callback thread.

 I couldn't repro the issue without inserting a dummy usleep(100), but
 it's definitely a bug.

 Test Plan: validate

 Reviewers: bgamari, austin, erikd

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D2678

 GHC Trac Issues: #12800
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12800#comment:3>
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