[GHC] #7762: when using lots of memory: internal error: evacuate(static): strange closure type 4

[GHC]

#7762: when using lots of memory: internal error: evacuate(static): strange
closure type 4
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        Reporter:  rthiemann       |            Owner:  simonmar
            Type:  bug             |           Status:  new
        Priority:  highest         |        Milestone:  7.8.1
       Component:  Runtime System  |          Version:  7.0.4
      Resolution:                  |         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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Comment (by Simon Marlow <marlowsd@…>):

 In [changeset:"36b042fbf60210ab6859d96e5b4b5e121085816d/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="36b042fbf60210ab6859d96e5b4b5e121085816d"
 Make integer overflow less likely to happen (#7762)

 The particular problematic code in #7762 was this:

             nat newSize = size - n;
             char *freeAddr = MBLOCK_ROUND_DOWN(bd->start);
             freeAddr += newSize * MBLOCK_SIZE;
                         ^^^^^^^^^^^^^^^^^^^^^^  OVERFLOW!!!

 For good measure, I'm going to fix the bug twice.  This patch fixes
 the class of bugs of this kind, by making sure that any expressions
 involving BLOCK_SIZE or MBLOCK_SIZE are promoted to unsigned long.  In
 a separate patch, I'll fix a bunch of individual instances (including
 the one above).
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7762#comment:8>
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