[Bug libc/9893] New: LD_AUDIT - misaligned _dl_call_pltexit parameter causing crash in audit library

[Bug libc/9893] New: LD_AUDIT - misaligned _dl_call_pltexit parameter causing crash in audit library

[olsajiri at gmail dot com]

The outregs parameter (struct La_x86_64_retval pointer) of _dl_call_pltexit
function is not aligned to 16. This is causing crash in the audit library.

When the audit library touches the lrv_xmm0 (or lrv_xmm1) member of the 
La_x86_64_retval, gcc will emit 'movaps' instructions which expect a
parameter aligned to 16, otherwise it segfaults.

In email discussion H.J. Lu mentioned: "According to x86-64 psABI,
La_x86_64_retval  should be aligned at 16byte"
(http://gcc.gnu.org/ml/gcc/2009-02/msg00346.html)

The issue can be reproduced by using attached audit.c as the audit library.

Here is the gdb session record showing the issue:

> ...
> (gdb) b _dl_call_pltexit
> Function "_dl_call_pltexit" not defined.
> Make breakpoint pending on future shared library load? (y or [n]) y
> Breakpoint 1 (_dl_call_pltexit) pending.
> (gdb) r
> Starting program: /opt/crash
> symbol __libc_start_main
> symbol printf
>
> Breakpoint 1, _dl_call_pltexit (l=0x7ffff7ffd000, reloc_offset=0,
> inregs=0x7fffffffe418, outregs=0x7fffffffe3c8) at dl-runtime.c:408
> 408     {
> (gdb)

-- 
           Summary: LD_AUDIT - misaligned _dl_call_pltexit parameter causing
                    crash in audit library
           Product: glibc
           Version: 2.8
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: olsajiri at gmail dot com
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: x86_64-*-linux-gnu
  GCC host triplet: x86_64-*-linux-gnu
GCC target triplet: x86_64-*-linux-gnu


http://sourceware.org/bugzilla/show_bug.cgi?id=9893

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[Bug libc/9893] LD_AUDIT - misaligned _dl_call_pltexit parameter causing crash in audit library

[olsajiri at gmail dot com]

------- Additional Comments From olsajiri at gmail dot com  2009-02-24 20:10 -------
Created an attachment (id=3763)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=3763&action=view)
audit library to reproduce the bug


-- 


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[Bug libc/9893] LD_AUDIT - misaligned _dl_call_pltexit parameter causing crash in audit library

[hjl dot tools at gmail dot com]

------- Additional Comments From hjl dot tools at gmail dot com  2009-02-24 20:35 -------
Please provide step-by-step instructions to reproduce the bug.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl dot tools at gmail dot
                   |                            |com
             Status|NEW                         |WAITING


http://sourceware.org/bugzilla/show_bug.cgi?id=9893

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[Bug libc/9893] LD_AUDIT - misaligned _dl_call_pltexit parameter causing crash in audit library

[olsajiri at gmail dot com]

------- Additional Comments From olsajiri at gmail dot com  2009-03-10 19:39 -------
Created an attachment (id=3807)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=3807&action=view)
proposed patch, sent to libc-alpha also

proposed patch, sent to libc-alpha also

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=9893

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[Bug libc/9893] LD_AUDIT - misaligned _dl_call_pltexit parameter causing crash in audit library

[drepper at redhat dot com]

------- Additional Comments From drepper at redhat dot com  2009-03-14 23:57 -------
The patch has a number of problems.  I've fixed those and applied it.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=9893

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