[GHC] #8453: segfault/assertion failure with multi-threaded profiling

17 Oct 2013

      #8453: segfault/assertion failure with multi-threaded profiling
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       Reporter:  akio            |             Owner:
           Type:  bug             |            Status:  new
       Priority:  normal          |         Milestone:
      Component:  Profiling       |           Version:  7.7
       Keywords:                  |  Operating System:  Linux
   Architecture:  x86_64 (amd64)  |   Type of failure:  Runtime crash
     Difficulty:  Unknown         |         Test Case:
     Blocked By:                  |          Blocking:
Related Tickets:                  |
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 Steps to reproduce:

 {{{
 ghc-stage2 selector_thunks.hs -rtsopts -fforce-recomp -prof -threaded
 -debug -O2
 ./selector_thunk +RTS -N4
 }}}

 In a few seconds, it either segfaults or dies with the following error
 message:

 {{{
 selector_thunks: internal error: ASSERTION FAILED: file
 rts/dist/build/sm/Evac_thr.c, line 778

     (GHC version 7.7.20131002 for x86_64_unknown_linux)
     Please report this as a GHC bug:
 http://www.haskell.org/ghc/reportabug
 }}}

 selector_thunks.hs:

 {{{
 import Control.Monad
 import Control.Concurrent
 import Data.IORef

 main = do
   gref <- newIORef [return ()]
   forM_ [0::Int ..10] $ \_ -> forkIO $ do
     ref <- newIORef [return ()]
     forever $ do
       list <- readIORef gref
       writeIORef ref $! reverse list
       acts <- readIORef ref
       last acts
   forM_ [1..100000099] $ \i ->
     writeIORef gref $! reverse $
       concatMap (replicate 10) $
       mapfst $ foldr (\x y -> seq x (x : y)) [] $
       map f [1..10+ (div i 1000000)]

 mapfst :: [(a, b)] -> [a]
 mapfst [] = []
 mapfst (x:xs) = (case x of (a, _) -> a) : mapfst xs

 f :: Int -> (IO (), Int)
 f x = (x `seq` return (), x)
 }}}

 I only tested the code with a recent HEAD, but I have seen a similar
 assertion failure with GHC 7.6.3, in a non-contrived application program.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8453
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