[GHC] #10199: Sending SIGINT to a program that uses forkOS may crash with various errors

27 Mar 2015

      #10199: Sending SIGINT to a program that uses forkOS may crash with various errors
-------------------------------------+-------------------------------------
              Reporter:  adeon       |             Owner:  simonmar
                  Type:  bug         |            Status:  new
              Priority:  low         |         Milestone:
             Component:  Runtime     |           Version:  7.10.1
  System                             |  Operating System:  Linux
              Keywords:              |   Type of failure:  Runtime crash
          Architecture:  x86_64      |        Blocked By:
  (amd64)                            |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
 This is the program:

 {{{#!hs
 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:

 {{{#!bash
 #!/bin/bash

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

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10199
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler