[GHC] #10298: Infinite loop when shared libraries are unavailable

14 Apr 2015

      #10298: Infinite loop when shared libraries are unavailable
-------------------------------------+-------------------------------------
              Reporter:  snoyberg    |             Owner:  simonmar
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Runtime     |           Version:  7.10.1
  System                             |  Operating System:  Linux
              Keywords:              |   Type of failure:  Runtime crash
          Architecture:  x86_64      |        Blocked By:
  (amd64)                            |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
 Originally discussed at: https://groups.google.com/d/msg/haskell-
 cafe/5ZTv5mCG_HI/hBJ-VkdpxdoJ. Note that this was originally discussed as
 a static linking and Docker issue, but in fact affects dynamically linked
 executables without any containerization.

 I've put together the following script that reproduces my problem:

 {{{
 cat > hello.hs <<EOF
 main :: IO ()
 main = putStrLn "Hello World"
 EOF
 ghc hello.hs

 rm -rf tmp
 mkdir tmp

 cp hello tmp

 mkdir -p tmp/usr/lib/x86_64-linux-gnu
 cp /usr/lib/x86_64-linux-gnu/libgmp.so.10 tmp/usr/lib/x86_64-linux-gnu

 mkdir -p tmp/lib/x86_64-linux-gnu
 cp \
     /lib/x86_64-linux-gnu/libm.so.6 \
     /lib/x86_64-linux-gnu/librt.so.1 \
     /lib/x86_64-linux-gnu/libdl.so.2 \
     /lib/x86_64-linux-gnu/libc.so.6 \
     /lib/x86_64-linux-gnu/libpthread.so.0 \
     tmp/lib/x86_64-linux-gnu

 mkdir -p tmp/lib64
 cp /lib64/ld-linux-x86-64.so.2 tmp/lib64

 #mkdir -p tmp/usr/lib/x86_64-linux-gnu/gconv/
 #cp \
 #    /usr/lib/x86_64-linux-gnu/gconv/UTF-32.so \
 #    /usr/lib/x86_64-linux-gnu/gconv/gconv-modules \
 #    tmp/usr/lib/x86_64-linux-gnu/gconv

 sudo chroot tmp /hello
 }}}

 If I uncomment the block that copies the gconv files, the program runs as
 expected. However, without those files copied, the program burns CPU and
 consumes memory until killed by the OS. I ran strace on a similar
 executable, and got the results at:

 https://gist.github.com/snoyberg/095efb17e36acc1d6360

 Note that this problem also occurs with statically linked executables when
 some of the other dynamically linked libraries are not available in the
 chroot environment.

 Expected behavior: ideal would be not to require the gconv files and other
 shared libraries be present, especially when statically linked. Barring
 that, it would be much better if the RTS could produce a meaningful error
 message about the missing file. Note that strace does demonstrate that a
 open system call is failing, e.g.:

 open("/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = -1
 ENOENT (No such file or directory)

 Reproduced on GHC 7.8.4 and 7.10.1, on Ubuntu 14.04 64-bit.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10298>
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