Hello, I have run into this RTS bug recently. In short, when executing multiple consequtive forks, after 500-600 or so the process is terminated by SIGSEGV. I know this kind of thing is totally artificial, but still. The problem I have is that I can't get any meaningful backtrace in gdb. For example, for threaded RTS I get this (gdb) bt #0 0x0000000000560d63 in base_GHCziEventziThread_ensureIOManagerIsRunning1_info () Backtrace stopped: Cannot access memory at address 0x7fffff7fcea0 For non-threaded RTS I get this (gdb) bt #0 0x00000000007138c9 in stg_makeStablePtrzh () Backtrace stopped: Cannot access memory at address 0x7fffff7fc720 Build command: ghc --make -O2 -g -fforce-recomp fork.hs Add threaded if needed. I was able to reproduce this bug with both GHC 7.10.3 and todays HEAD with the code below.
import System.Exit (exitSuccess) import System.Posix.Process (forkProcess)
fork_ n | n > 0 = processPid =<< forkProcess (fork_ $! n - 1) | otherwise = putStrLn "I'm done!"
processPid pid | pid > 0 = exitSuccess | pid < 0 = putStrLn "OOOPS, forkProcess failed!" | otherwise = pure ()
main = fork_ 1000
With best regards.