sparc-unknown-linux-ld segfaults when linking non-PIC data into a .so

[Nix]

This is with HJ's 2.14.90.0.7 release.

Sometime since the 2.13 release, ld has started dying hard when asked to
link non-PIC data into a shared library on sparc-unknown-linux.

This is reproducible on every box I've tried it on given, for instance,
a non-PIC copy of inflate.o and infback.o from zlib, and the trivial
link line

/usr/bin/ld -m elf32_sparc -shared  -o foo.so.10.0.0 -soname foo.so.1 inflate.o 
infback.o

(a copy of these object files is in
<http://www.esperi.demon.co.uk/nix/downloads/ld-crash.tar.bz2>)

There's nothing wrong with failing when you try to link non-PIC data
into a shared library, but ld didn't always fail, and failure like this
is rather worse than failing with an error message. (If it had failed
with an error, I might have noticed that I was linking non-PIC data into
libz.so *before* burning half an hour debugging it. :) )


The crash happens inside libbfd, during relocation. Here's a backtrace
from an ld built with -O0:

Program received signal SIGSEGV, Segmentation fault.
0x00067858 in elf32_sparc_relocate_section (output_bfd=0x15ea88, info=0x1554f0, 
input_bfd=0x173330, input_section=0x1b9428, contents=0x341d48 "\235ã¿` 
\a¿ÀÂ\006@", 
    relocs=0x1befd8, local_syms=0x34aa90, local_sections=0x34afd8) at 
../../2.14.90.0.7/bfd/elf32-sparc.c:2483
2483                              indx = elf_section_data (osec)->dynindx;
(gdb) bt
#0  0x00067858 in elf32_sparc_relocate_section (output_bfd=0x15ea88, 
info=0x1554f0, input_bfd=0x173330, input_section=0x1b9428, contents=0x341d48 
"\235ã¿` \a¿ÀÂ\006@", 
    relocs=0x1befd8, local_syms=0x34aa90, local_sections=0x34afd8) at 
../../2.14.90.0.7/bfd/elf32-sparc.c:2483
#1  0x0007e720 in elf_link_input_bfd (finfo=0xeffff0a8, input_bfd=0x173330) at 
elflink.h:5046
#2  0x00079fa4 in bfd_elf32_bfd_final_link (abfd=0xeffff0a8, info=0x173330) at 
elflink.h:3595

The line in question reads:

 indx = elf_section_data (osec)->dynindx;

Here's osec:

(gdb) print *osec

$2 = {name = 0x142800 "*ABS*", id = 2, index = 0, next = 0x0, flags = 0,
      user_set_vma = 0, reloc_done = 0, linker_mark = 0,
      linker_has_input = 0, gc_mark = 1, segment_mark = 0,
      sec_info_type = 0, use_rela_p = 0, has_tls_reloc = 0,
      need_finalize_relax = 0, has_gp_reloc = 0, flag13 = 0,
      flag14 = 0, flag15 = 0, flag16 = 0, flag20 = 0, flag24 = 0,vma = 0,
      lma = 0, _cooked_size = 0, _raw_size = 0, output_offset = 0,
      output_section = 0x1503a0, alignment_power = 0, relocation = 0x0,
      orelocation = 0x0, reloc_count = 0, filepos = 0, rel_filepos = 0,
      line_filepos = 0, userdata = 0x0, contents = 0x0, lineno = 0x0,
      lineno_count = 0, entsize = 0, comdat = 0x0, kept_section = 0x0,
      moving_line_filepos = 0, target_index = 0, used_by_bfd = 0x0,
      constructor_chain = 0x0, owner = 0x0, symbol = 0x142850,
      symbol_ptr_ptr = 0x142898, link_order_head = 0x0,
      link_order_tail = 0x0}

used_by_bfd is NULL. This isn't going to help elf_section_data().

-- 
`...some suburbanite DSL customer who thinks kernel patches are some
 form of military insignia.' --- Bob Apthorpe