Re: [GHC] #15595: Stack overflow in withArgs leads to infinite memory-consuming loop

3 Sep 2018

      #15595: Stack overflow in withArgs leads to infinite memory-consuming loop
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        Reporter:  NeilMitchell   |                Owner:  (none)
            Type:  bug            |               Status:  new
        Priority:  normal         |            Milestone:  8.6.1
       Component:  Compiler       |              Version:  8.5
      Resolution:                 |             Keywords:
Operating System:  Windows        |         Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash  |            Test Case:
      Blocked By:                 |             Blocking:
 Related Tickets:                 |  Differential Rev(s):
       Wiki Page:                 |
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Comment (by osa1):

 Right, so this is because the thread is in masked state and stack overflow
 exception is not actually raised because of this. If I change the program
 above to this:

 {{{#!haskell
 {-# LANGUAGE ForeignFunctionInterface #-}

 import Foreign.C
 import Foreign.Ptr
 import GHC.Foreign (withCStringsLen)
 import GHC.IO.Encoding (utf8)
 import Control.Exception (mask_)

 foreign import ccall unsafe "setProgArgv"
   c_setProgArgv  :: CInt -> Ptr CString -> IO ()

 main :: IO ()
 main = do
     putStrLn "Starting"
     mask_ $
       withCStringsLen utf8 (replicate 1000 "") $ \len css -> do
         c_setProgArgv (fromIntegral len) css
     putStrLn "Done"
 }}}

 (only difference is that I added a `mask_`) this also loops.

 Not sure about what's the right thing to do here ...

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15595#comment:2
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