[GHC] #11978: running a profiled build of shake test suite with rts args +RTS -hb -N10 triggers SIGSEGV

[GHC]

#11978: running a profiled build of shake test suite with rts args  +RTS -hb -N10
triggers SIGSEGV
---------------------------------+----------------------------------------
        Reporter:  carter        |                Owner:
            Type:  bug           |               Status:  new
        Priority:  highest       |            Milestone:
       Component:  Compiler      |              Version:  8.0.1
      Resolution:                |             Keywords:
Operating System:  MacOS X       |         Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown  |            Test Case:
      Blocked By:                |             Blocking:
 Related Tickets:  #4820         |  Differential Rev(s):
       Wiki Page:                |
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Comment (by erikd):

 My friend `printf` tells me that when the value of `size` is less than
 `sizeofW(StgThunkHeader)` when the closure type is `WHITEHOLE` which seems
 legitimate. Since everything seems legitimate, the solution to this may
 simply be to add a check:

 {{{
     if (size > sizeofW(StgThunkHeader)) {
         for (i = 0; i < size - sizeofW(StgThunkHeader); i++) {
             ((StgThunk *)(p))->payload[i] = 0;
         }
     }
 }}}

 @simonmar does this seem right?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11978#comment:11>
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