[GHC] #12751: T5611 fails non-deterministically on OSX

[GHC]

#12751: T5611 fails non-deterministically on OSX
-------------------------------------+-------------------------------------
           Reporter:  mpickering     |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 Here is the test.

 {{{#!hs
 {-# LANGUAGE CPP,ForeignFunctionInterface #-}

 import Control.Concurrent
 import Foreign.C
 import System.IO

 #ifdef mingw32_HOST_OS
 sleep n = sleepBlock (n*1000)
 foreign import stdcall unsafe "Sleep" sleepBlock :: Int -> IO ()
 #else
 sleep n = sleepBlock n
 foreign import ccall unsafe "sleep" sleepBlock :: Int -> IO ()
 #endif

 main :: IO ()
 main = do
      hSetBuffering stdout LineBuffering

      tid <- forkIO $ do
          putStrLn "child: Sleeping"
          _ <- sleep 1

          -- The following lines should not happen after the killThread
 from the
          -- parent thread completes.  However, they do...
          -- putStrLn "child: Done sleeping"
          threadDelay 100000
          putStrLn "child: Done waiting"

      threadDelay 100000
      -- putStrLn $ "parent: Throwing exception to thread " ++ show tid
      throwTo tid $ userError "Exception delivered successfully"
      putStrLn "parent: Done throwing exception"

      threadDelay 200000
 }}}

 It occasionally fails with

 {{{
 =====> T5611(normal) 1 of 1 [0, 0, 0]
 cd "./concurrent/should_run/T5611.run" &&
 "/Users/matt/Documents/haskell/ghc/inplace/test   spaces/ghc-stage2" -o
 T5611 T5611.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-
 warn-missed-specialisations -fshow-warning-groups -dno-debug-output
 cd "./concurrent/should_run/T5611.run" && ./T5611
 Actual stderr output differs from expected:
 --- ./concurrent/should_run/T5611.run/T5611.stderr.normalised   2016-10-21
 22:08:55.000000000 +0100
 +++ ./concurrent/should_run/T5611.run/T5611.run.stderr.normalised
 2016-10-21 22:08:55.000000000 +0100
 @@ -1 +0,0 @@
 -T5611: user error (Exception delivered successfully)
 *** unexpected failure for T5611(normal)

 Unexpected results from:
 TEST="T5611"
 }}}

 I am marking it broken for now. Does anyone know why it is failing?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12751>
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