[GHC] #9666: runtime crashing with +RTS -w -h

[GHC]

#9666: runtime crashing with +RTS -w -h
-------------------------------------+-------------------------------------
       Reporter:  lspitzner          |                   Owner:  simonmar
           Type:  bug                |                  Status:  new
       Priority:  low                |               Milestone:
      Component:  Runtime System     |                 Version:  7.8.3
       Keywords:                     |        Operating System:  Linux
   Architecture:  x86_64 (amd64)     |         Type of failure:  Runtime
     Difficulty:  Unknown            |  crash
     Blocked By:                     |               Test Case:  (see
Related Tickets:                     |  description)
                                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 A combination of the RTS flags -w and -h makes executables generated with
 ghc crash at runtime. Does not happen always; my current guess is that a
 gc run triggers the bug.

 Reproducible with the following input:

 '''Main.hs'''


 {{{#!hs
 module Main where

 import qualified Data.Map.Strict as M

 main = print $ M.lookup 10 $ M.fromList [ (i,i)
                                         | i<-[1..10000000] ]
 }}}


 {{{
 > ghc -rtsopts Main.hs && ./Main +RTS -w -h
 [1 of 1] Compiling Main             ( Main.hs, Main.o )
 Linking Main ...
 Main: internal error: heapCensus, unknown object: 4093
     (GHC version 7.8.3 for x86_64_unknown_linux)
 }}}


 optimization level did not change the outcome.


 I am aware that -w is marked experimental, and I don't need it. Just
 noticed the crashing.


 @simon: you get added to Cc (one more time) every time I press "preview",
 it seems. Doubt that is intentional.. I'll leave you in Cc just so you get
 this message. (hmm.. where is the bug-tracker bug-tracker..)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9666>
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