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This is the program:

module Main ( main ) where

import Control.Concurrent
import Control.Monad

main :: IO ()
main = recursive 0
  where
    recursive n = do
        tid <- forkIO $ do
            replicateM_ 100 $ forkOS $ return ()
        replicateM_ (n `mod` 1000) yield
        recursive (n+1)

I was trying to investigate a potential issue with leaking StablePtrs in forkOS but that's another story.

Compile with ghc Main.hs -prof -auto-all -threaded -o Main. Run as ./Main +RTS -h (I don't know if it's absolutely necessary to turn heap profiling on but I have more trouble getting these error messages without it).

Then, stop the program with SIGINT (by pressing CTRL+C or otherwise). The program sometimes crashes and produces one of the these two error messages:

Main: internal error: RELEASE_LOCK: I do not own this lock: rts/Task.c 242
    (GHC version 7.10.1 for x86_64_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Main: newBoundTask: RTS is not initialised; call hs_init() first

Sometimes the message may be slightly garbled (notice double internal error below):

Î: internal error: Main: internal error: RELEASE_LOCK: I do not own this lock: rts/Task.c 242
    (GHC version 7.10.1 for x86_64_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Replacing forkOS with forkIO seems to stop the messages. I can't reproduce this on FreeBSD. I'm using the downloaded binaries of 7.10.1 from GHC site on Arch Linux.

I used this simple bash script to see more of these messages because it won't crash reliably:

#!/bin/bash

while true; do
    timeout -s INT 0.2 ./Main +RTS -h
done

Trac metadata

Trac field	Value
Version	7.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Runtime System
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	simonmar
Operating system
Architecture