[GHC] #8209: Race condition in setNumCapabilities

[GHC]

#8209: Race condition in setNumCapabilities
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        Reporter:  akio              |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Runtime System    |          Version:  7.7
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash     |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by parcs):

 Perhaps related, I am getting a rare deadlock with this test case:

 === Test.hs
 {{{
 import GHC.Conc

 main :: IO ()
 main = do
     setNumCapabilities 2
     setNumCapabilities 3
 }}}

 === Command Line
 {{{
 $ ghc-stage2 -threaded Test.hs
 [1 of 1] Compiling Main             ( Test.hs, Test.o )
 Linking Test ...
 $ while true; do ./B; echo -n .; done
 .............................................<eventually stops>
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8209#comment:1>
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