Errors when shutting down the event manager loop

As explained in this thread on the GHC list I use the GHC event manager in my usb library. I create my own EventManager and start a thread which runs the event manager loop. When the library is finalized I automatically shutdown the loop. However this causes error messages from the RTS to be printed.

The following program shows the problem in isolation:

import Control.Concurrent
import GHC.Event

main = do
 em <- new
 tid <- forkIO $ loop em
 threadDelay 2000000
 shutdown em  -- Note that 'killThread tid' has the same effect.
 threadDelay 2000000

Make sure to build it with -threaded enabled:

$ ghc -threaded --make eventManagerBug.hs

Running it gives the following errors:

$ ./eventManagerBug
example: ioManagerWakeup: write: Bad file descriptor
example: ioManagerDie: write: Bad file descriptor

Note that these errors are printed in the ioManagerWakeup function in rts/posix/Signals.c.

Trac metadata

Trac field	Value
Version	7.2.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	bos@mailrank.com, johan.tibell@gmail.com
Operating system
Architecture