#3279: Segmentation fault in reactive program
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Reporter: Baughn | Owner: simonmar
Type: bug | Status: new
Priority: high | Milestone: 6.12.1
Component: Runtime System | Version: 6.11
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Os: Unknown/Multiple
Architecture: x86_64 (amd64) |
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Comment (by Baughn):
There was a bug inside Unamb.hs. I think I'd best paste the relevant
code..
race a b = block $ do
v <- newEmptyMVar
let f x = forkIO $ putCatch x v
ta <- f a
tb <- f b
- We rely on killing the threads forked here in order to limit excessive
work, but as you can see I'd forgotten to unblock exceptions first.
Switching to a corrected implementation
race a b = block $ do
v <- newEmptyMVar
let f x = forkIO $ putCatch (unblock x) v
ta <- f a
tb <- f b
removed that problem. It also removed the crash. However, I have a feeling
it may still exist in potentia, as a race condition. At any rate, that's a
place to start; exceptions thrown to blocked threads that go on to
evaluate bottoms.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3279#comment:8>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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