panic! 'impossible' happened, thread blocked indefinitely
GHCi, version 6.4.1, crashed with the following error:
ghc-6.4.1: panic! (the `impossible' happened, GHC
version 6.4.1):
thread blocked indefinitely
Please report it as a compiler bug to
glasgow-haskell-bugs@haskell.org,
or http://sourceforge.net/projects/ghc/.
I was calling a test function which was forking a
Thread which was blocking in an 'atomically' waiting
on a TChan.
If I ran the test function a second time, while the
Thread from the first run is presumably still hanging
around, I would receive the above error/crash.
If I reloaded the source in GHCi after running the
test function a single time GHCi would give an error
message (but not crash):
*** Exception: thread blocked indefinitely
Most of the time after the error message there would
be no modules loaded. I could load again, and repeat
the fun.
_Very_ occasionaly the modules would remain loaded and
I could repeat the cycle without having to reload the
modules.
Since fixing my test function so the forked Thread
dies at the desired time (ie now it won't be hanging
around blocked on the TChan) I haven't observed the
failure.
My email: kgrapone@gmail.com
Edited by Simon Marlow