[GHC] #13707: xmobar crashes with segmentation faults?

[GHC]

#13707: xmobar crashes with segmentation faults?
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Rufflewind):

 The crash is quite rare and sporadic.  I've had it run for 1-3 days
 without crashing.

 GDB:

 {{{
     0x7ffff55ffcdd <evacuate+93>    or     rdx,rcx
   > 0x7ffff55ffce0 <evacuate+96>    movzx  ecx,WORD PTR [rdx+0x2e]
     0x7ffff55ffce4 <evacuate+100>   test   cx,0x20b

 > print/x $rdx  # variable "bd"
 0x6300000000

 > backtrace
 #0  evacuate (p=p at entry=0x4200266b98) at rts/sm/Evac.c:583
 #1  0x00007ffff55ff155 in scavenge_block (bd=0x4200201980) at
 rts/sm/Scav.c:548
 #2  0x00007ffff561495e in scavenge_find_work () at rts/sm/Scav.c:2132
 #3  scavenge_loop () at rts/sm/Scav.c:2195
 #4  0x00007ffff561b08f in scavenge_until_all_done () at rts/sm/GC.c:1020
 #5  GarbageCollect (collect_gen=collect_gen at entry=1,
     do_heap_census=do_heap_census at entry=false, gc_type=gc_type at entry=0,
     cap=cap at entry=0x7ffff5648a00 <MainCapability>,
 idle_cap=idle_cap at entry=0x0)
     at rts/sm/GC.c:406
 #6  0x00007ffff560da3d in scheduleDoGC (pcap=pcap at entry=0x7fffffffdba8,
     task=task at entry=0x5c28d0, force_major=force_major at entry=false)
     at rts/Schedule.c:1822
 #7  0x00007ffff560e6fb in schedule (task=0x5c28d0,
 initialCapability=<optimized out>)
     at rts/Schedule.c:558
 #8  scheduleWaitThread (tso=<optimized out>, ret=ret at entry=0x0,
     pcap=pcap at entry=0x7fffffffdc08) at rts/Schedule.c:2551
 #9  0x00007ffff560fed8 in rts_evalLazyIO (cap=cap at entry=0x7fffffffdc08,
     p=p at entry=0x5ad4a0, ret=ret at entry=0x0) at rts/RtsAPI.c:530
 #10 0x00007ffff561086e in hs_main (argc=1, argv=0x7fffffffddd8,
     main_closure=0x5ad4a0, rts_config=...) at rts/RtsMain.c:64
 #11 0x0000000000578fe1 in main ()
 }}}

 Built using GHC from
 https://downloads.haskell.org/~ghc/8.2.1/ghc-8.2.1-x86_64-deb8-linux.tar.xz
 installed on Arch Linux with ncurses5-compat-libs.  xmobar was built with:

 {{{
 cabal install --disable-executable-stripping --with-
 ghc=/opt/ghc-8.2.1/bin/ghc \
     -f 'with_utf8 with_xft with_iwlib with_xpm with_inotify'

 constraints: HTTP ==4000.3.7,
              X11 ==1.8,
              array ==0.5.2.0,
              base ==4.10.0.0,
              binary ==0.8.5.1,
              bytestring ==0.10.8.2,
              containers ==0.5.10.2,
              data-default ==0.7.1.1,
              data-default-class ==0.1.2.0,
              data-default-instances-containers ==0.0.1,
              data-default-instances-dlist ==0.0.1,
              data-default-instances-old-locale ==0.0.1,
              deepseq ==1.4.3.0,
              directory ==1.3.0.2,
              dlist ==0.8.0.3,
              filepath ==1.4.1.2,
              ghc-prim ==0.5.1.0,
              integer-gmp ==1.0.1.0,
              mtl ==2.2.1,
              network ==2.6.3.2,
              network-uri ==2.6.1.0,
              old-locale ==1.0.0.7,
              parsec ==3.1.11,
              process ==1.6.1.0,
              regex-base ==0.93.2,
              regex-compat ==0.95.1,
              regex-posix ==0.95.2,
              rts ==1.0,
              stm ==2.4.4.1,
              text ==1.2.2.2,
              time ==1.8.0.2,
              transformers ==0.5.2.0,
              unix ==2.7.2.2,
              utf8-string ==1.0.1.1
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13707#comment:18>
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