#4533: IO manager can leak MVars if threads are killed
---------------------------------+------------------------------------------
Reporter: bos | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.0.1 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: Incorrect result at runtime
---------------------------------+------------------------------------------
If a thread is killed in {{{threadWaitRead}}} and no data ever comes in on
the file descriptor it was waiting on, the IO manager will not remove the
{{{FdData}}} structure from its queue of waited-for events. This causes
the queue to slowly grow in size.
Test case:
{{{
-- Compile with: ghc -threaded --make
import Control.Monad
import Control.Concurrent
main = do
forM_ [0..10000] $ \i -> do
when (i`mod`100==0) $ print i
t <- forkIO $ threadWaitRead 0
threadDelay 5000
killThread t
}}}
This is not hugely likely to affect real programs, but could lead to a
(perhaps accidental) denial of service against a long-running application.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4533>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
_______________________________________________
Glasgow-haskell-bugs mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
