On 13/06/2010 07:26, austin seipp wrote:

Hello,

I am running GHC on x86_64 debian linux, and recently I have discovered that the executables generated by my GHC segfault when the linking step is not dynamic. I discovered this while attempting to install haskell-src-exts, which requires a linked version of Setup.hs when cabal builds it (and which would fail inexplicably until I did further investigation.)

Example:

link ~/t » cat hi.hs main :: IO () main = putStrLn "hi" link ~/t » ghc -dynamic hi.hs link ~/t » file ./a.out ./a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped link ~/t » ldd ./a.out linux-vdso.so.1 => (0x00007fffbadff000) libHShaskell98-1.0.1.1-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/haskell98-1.0.1.1/libHShaskell98-1.0.1.1-ghc6.12.3.so (0x00007fab3a4c4000) libHSrandom-1.0.0.2-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/random-1.0.0.2/libHSrandom-1.0.0.2-ghc6.12.3.so (0x00007fab3a2af000) libHStime-1.1.4-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/time-1.1.4/libHStime-1.1.4-ghc6.12.3.so (0x00007fab39fad000) libHSprocess-1.0.1.3-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/process-1.0.1.3/libHSprocess-1.0.1.3-ghc6.12.3.so (0x00007fab39d93000) libHSdirectory-1.0.1.1-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/directory-1.0.1.1/libHSdirectory-1.0.1.1-ghc6.12.3.so (0x00007fab39b77000) libHSunix-2.4.0.2-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/unix-2.4.0.2/libHSunix-2.4.0.2-ghc6.12.3.so (0x00007fab398c6000) librt.so.1 => /lib/librt.so.1 (0x00007fab396a2000) libutil.so.1 => /lib/libutil.so.1 (0x00007fab3949f000) libdl.so.2 => /lib/libdl.so.2 (0x00007fab3929b000) libHSold-time-1.0.0.5-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/old-time-1.0.0.5/libHSold-time-1.0.0.5-ghc6.12.3.so (0x00007fab3903c000) libHSold-locale-1.0.0.2-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/old-locale-1.0.0.2/libHSold-locale-1.0.0.2-ghc6.12.3.so (0x00007fab38e28000) libHSfilepath-1.1.0.4-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/filepath-1.1.0.4/libHSfilepath-1.1.0.4-ghc6.12.3.so (0x00007fab38c07000) libHSarray-0.3.0.1-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/array-0.3.0.1/libHSarray-0.3.0.1-ghc6.12.3.so (0x00007fab38992000) libHSbase-4.2.0.2-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/base-4.2.0.2/libHSbase-4.2.0.2-ghc6.12.3.so (0x00007fab381f2000) libHSinteger-gmp-0.2.0.1-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/integer-gmp-0.2.0.1/libHSinteger-gmp-0.2.0.1-ghc6.12.3.so (0x00007fab37fe1000) libgmp.so.3 => /usr/lib/libgmp.so.3 (0x00007fab37da1000) libHSghc-prim-0.2.0.0-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/ghc-prim-0.2.0.0/libHSghc-prim-0.2.0.0-ghc6.12.3.so (0x00007fab37b1c000) libHSrts-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/libHSrts-ghc6.12.3.so (0x00007fab378ba000) libm.so.6 => /lib/libm.so.6 (0x00007fab37637000) libHSffi-ghc6.12.3.so => /usr/local/lib/ghc-6.12.3/libHSffi-ghc6.12.3.so (0x00007fab3742a000) libc.so.6 => /lib/libc.so.6 (0x00007fab370c9000) libpthread.so.0 => /lib/libpthread.so.0 (0x00007fab36eac000) /lib64/ld-linux-x86-64.so.2 (0x00007fab3a6cb000) link ~/t » ./a.out hi link ~/t » rm ./a.out *.hi *.o link ~/t » ghc hi.hs link ~/t » file ./a.out ./a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped link ~/t » ldd ./a.out linux-vdso.so.1 => (0x00007fffaafff000) librt.so.1 => /lib/librt.so.1 (0x00007fdf83d77000) libutil.so.1 => /lib/libutil.so.1 (0x00007fdf83b74000) libdl.so.2 => /lib/libdl.so.2 (0x00007fdf8396f000) libgmp.so.3 => /usr/lib/libgmp.so.3 (0x00007fdf83730000) libm.so.6 => /lib/libm.so.6 (0x00007fdf834ae000) libc.so.6 => /lib/libc.so.6 (0x00007fdf8314c000) libpthread.so.0 => /lib/libpthread.so.0 (0x00007fdf82f30000) /lib64/ld-linux-x86-64.so.2 (0x00007fdf83f9c000) link ~/t » ./a.out [1] 7850 segmentation fault ./a.out link ~/t » gdb7.0 ./a.out

139 ↵ GNU gdb (GDB) 7.0 Copyright (C) 2009 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or laterhttp://gnu.org/licenses/gpl.html This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-unknown-linux-gnu". For bug reporting instructions, please see: http://www.gnu.org/software/gdb/bugs/... Reading symbols from /home/a/t/a.out...done. (gdb) r Starting program: /home/a/t/a.out [Thread debugging using libthread_db enabled]

Program received signal SIGSEGV, Segmentation fault. 0x000000000067b3c0 in strlen@@GLIBC_2.2.5 () (gdb) bt #0 0x000000000067b3c0 in strlen@@GLIBC_2.2.5 () #1 0x0000000000432dd7 in setFullProgArgv () #2 0x000000000043464d in hs_init () #3 0x000000000043478d in startupHaskell () #4 0x0000000000433d59 in real_main () #5 0x0000000000433e87 in hs_main () #6 0x00007ffff6fccc4d in __libc_start_main () from /lib/libc.so.6 #7 0x0000000000402d49 in _start () (gdb)

What's interesting is that this occurs with all versions of GHC on my machine, which include: * GHC 6.12.1 * GHC 6.12.3 * GHC 6.13.20100426

Executables that were statically linked with GHC before this strange behavior started occurring appear to still work, i.e. xmonad& xmobar. I recently did an update of my machine with aptitude, but I would not think this would interfere with GHC.

Strange - I suspect there is some ABI change in glibc that means the static libraries are no longer compatible with the new version. You'll get more information out of gdb if you compile with -debug, then try stepping through from setFullProgArgv to see what goes wrong. If there is an ABI change, and it's going to appear in all the major Linux distros at some point, this could give us some difficulties with binary distributions. Cheers, Simon