[GHC] #8134: ghc enters a loop while building 7.6.3 for powerpc64 platform.

[GHC]

#8134: ghc enters a loop while building 7.6.3 for powerpc64 platform.
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        Reporter:  k0da              |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:  7.6.3
       Component:  Compiler          |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  powerpc64
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by juhpetersen):

 The problem also happens on s390x.

 You can find some more details in the Fedora bug tracking this:
 https://bugzilla.redhat.com/show_bug.cgi?id=989593

 Basically it looks like some kind of process lockup or race condition
 which seems to happen randomly during the above big "ghc -M -dep-makefile"
 invocation above.  A subprocess has completed but somehow ghc is still
 hanging on it.

 {{{
 15692 pts/3    Ssl+   3:37               /usr/lib64/ghc-7.6.3/ghc
 -B/usr/lib64/ghc-7.6.3 -optc-I/usr/include -v1 -M -dep-m
 16531 pts/3    Z+     0:00                \_ [gcc] <defunct>
 }}}

 There seems to be no systematic pattern - I didn't count the number of
 source files being
 preprocessed but it seems to happen each time quite some way into the
 processing of the files for me.

 gdb shows ghc is hung on

 {{{
 #0  0x00000080c6c31ad0 in .pthread_cond_wait () from
 /lib64/libpthread.so.0
 }}}

 Still not completely sure if this is a ghc or glibc issue or some conflict
 between them.
 Apparently the pthread handling on non-intel glibc is different from intel
 platforms.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8134#comment:7>
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