[Bug 914448] Re: libc6-dbg puts ld-2.X.so into wrong location

[Ppluzhnikov-google]

GDB bug:
http://sourceware.org/bugzilla/show_bug.cgi?id=9538

** Bug watch added: Sourceware.org Bugzilla #9538
   http://sourceware.org/bugzilla/show_bug.cgi?id=9538

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https://bugs.launchpad.net/bugs/914448

Title:
  libc6-dbg puts ld-2.X.so into wrong location

Status in “eglibc” package in Ubuntu:
  New

Bug description:
  Using libc6_2.13-24ubuntu2_amd64.deb with
  libc6-dbg_2.13-24ubuntu2_amd64.deb,

  gdb -q /bin/date
  Reading symbols from /bin/date...done.

  (gdb) set stop-on-solib-events 1
  (gdb) run
  Starting program: /bin/date 
  Stopped due to shared library event
  (gdb) bt
  #0  0x00007ffff7deb300 in _dl_debug_state () from /lib64/ld-linux-x86-64.so.2
  #1  0x00007ffff7ddf386 in ?? () from /lib64/ld-linux-x86-64.so.2
  #2  0x00007ffff7df1014 in ?? () from /lib64/ld-linux-x86-64.so.2
  #3  0x00007ffff7de118f in ?? () from /lib64/ld-linux-x86-64.so.2
  #4  0x00007ffff7ddd5b8 in ?? () from /lib64/ld-linux-x86-64.so.2
  #5  0x0000000000000001 in ?? ()
  #6  0x00007fffffffe7bc in ?? ()
  #7  0x0000000000000000 in ?? ()
  (gdb) quit

  Note lack of debug symbols for /lib64/ld-linux-x86-64.so.2

  The problem is that /lib64/ld-linux-x86-64.so.2 has .gnu_debuglink of
  "ld-2.13.so".

  This means that GDB will look for /usr/lib/debug/lib64/ld-2.13.so (not present)
  and will not look for /usr/lib/debug/lib/x86_64-linux-gnu/ld-2.13.so (which is present).

  strace confirms that:

  grep 'ld-2.13.so"' /tmp/strace.out 
  open("/lib64/ld-2.13.so", O_RDONLY)     = -1 ENOENT (No such file or directory)
  open("/lib64/.debug/ld-2.13.so", O_RDONLY) = -1 ENOENT (No such file or directory)
  open("/usr/lib/debug//lib64/ld-2.13.so", O_RDONLY) = -1 ENOENT (No such file or directory)
  open("/usr/lib/debug/lib64/ld-2.13.so", O_RDONLY) = -1 ENOENT (No such file or directory)
  readlink("/lib64/ld-linux-x86-64.so.2", "/lib/x86_64-linux-gnu/ld-2.13.so"..., 4095) = 32
  lstat("/lib/x86_64-linux-gnu/ld-2.13.so", {st_mode=S_IFREG|0755, st_size=141088, ...}) = 0

  
  Arguably, GDB should do readlink("/lib64/ld-linux-x86-64.so.2"), and look for
  the real path name as well. If GDB did that, it would have worked.

  But for now, libc6-dbg should probably provide a symlink from
  /usr/lib/debug/lib64/ld-2.13.so to /usr/lib/debug/lib/x86_64-linux-gnu/ld-2.13.so

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