Hello I am having problems with the threaded rts (6.5.20050207) dying with 'schedule: re-entered unsafely'. The same code seems to work with 6.2.2 with threaded rts. The exact error message is: "foo: schedule: re-entered unsafely. Perhaps a 'foreign import unsafe' should be 'safe'?" I originally notices the problem with networking code which didn't use any of Network (nor threadWaitX). However the error appeared even with the standard libraries tipping in the direction of a bug in the rts. The code works most of the time, but has a small probability of failing when load is high. The test case implements a dummy web server which can be tried with e.g. apache benchmark (ab), /usr/sbin/ab2 -c 1000 -n 5000 127.0.0.1:8080/foo usually crashes the code when run a few times. The code should be compiled and run as ghc --make -threaded foo.hs -o foo && ./foo 8080 import Network import Control.Concurrent import qualified Control.Exception as E import System import System.IO main = do [port] <- getArgs server port server port = do s <- listenOn $ PortNumber $ fromIntegral $ read port acceptLoop s acceptLoop sock = do (csock,_,_) <- accept sock forkIO (handle csock `E.catch` print) acceptLoop sock handle sock = do hPutStr sock "HTTP/1.0 200 OK\r\nContent-Type: text/plain\r\n\r\n" hPutStr sock ("This is the body for the request to\n"++"hope you like this.\n\nnow garbage:\n") hClose sock - Einar Karttunen