[GHC] #15892: Segmentation fault with ByteString and -O

[GHC]

#15892: Segmentation fault with ByteString and -O
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        Reporter:  akio           |                Owner:  (none)
            Type:  bug            |               Status:  new
        Priority:  normal         |            Milestone:  8.6.3
       Component:  Compiler       |              Version:  8.6.2
      Resolution:                 |             Keywords:
Operating System:  Linux          |         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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Changes (by osa1):

 * cc: osa1, simonmar (added)


Comment:

 This seems to be related with the GC. I realized two things:

 - If I run with debug runtime I get this error:

     {{{
     segfault: internal error: Evaluated a CAF (0x851768) that was GC'd!
         (GHC version 8.7.20181113 for x86_64_unknown_linux)
         Please report this as a GHC bug:
 http://www.haskell.org/ghc/reportabug
     zsh: abort (core dumped)  ./segfault +RTS > /dev/null
     }}}

 - If I play around with GC params sometimes this programs can run for much
 longer. E.g. on my system `+RTS -A1G` or `+RTS -G5` seem to make the
 problem disappear.

 Could this be related with the recent SRT work? CCing simonmar.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15892#comment:2>
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