I actually have no idea if this is a haskell bug or not, but since the earlier reported symptoms are similar, and the "pandoc" program is compiled with GHC, I thought I would report it here as well.

This situation sounds exactly like this bug reported 17 months ago.

Symptoms are 'pandoc --version' hangs and consumes memory until the process eventually dies with an OOM error. This seems to only happen when LC_ALL is set in the environment, and only when running the statically linked pandoc.

$ uname -a
Linux server 3.5.0-43-generic #66~precise1-Ubuntu SMP Thu Oct 24 14:52:23 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

$ wget https://s3.amazonaws.com/rstudio-buildtools/pandoc-1.12.3.zip

$ unzip pandoc-1.12.3.zip

$ file pandoc-1.12.3/linux/debian/x86_64/pandoc
pandoc-1.12.3/linux/debian/x86_64/pandoc: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.15, BuildID[sha1]=0x9bc69f51b7c213cf58e9f8692f4b46f9f05fb723, not stripped

$ LC_ALL=C strace -e trace=open,close  pandoc-1.12.3/linux/debian/x86_64/pandoc --version
open("/usr/lib/gconv/gconv-modules.cache", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/gconv/gconv-modules", O_RDONLY) = -1 ENOENT (No such file or directory)
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
^C--- SIGINT (Interrupt) @ 0 (0) ---

Note this problem does not occur if I run an older dynamically linked pandoc under the same circumstances.

$ /usr/bin/pandoc --version
pandoc 1.9.1.1
Compiled with citeproc-hs 0.3.4, texmath 0.6.0.3, highlighting-kate 0.5.0.5.
Syntax highlighting is supported for the following languages:
    Actionscript, Ada, Alert, Alert_indent, Apache, Asn1, Asp, Awk, Bash,
    Bibtex, Boo, C, Changelog, Clojure, Cmake, Coffeescript, Coldfusion,
    Commonlisp, Cpp, Cs, Css, D, Diff, Djangotemplate, Doxygen, Dtd, Eiffel, ...