Bogus objdump output from kernel object files?

From: Chuck Ebbert <76306.1226@compuserve.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Roland McGrath <roland@redhat.com>,
	Ulrich Drepper <drepper@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Bogus objdump output from kernel object files?
Date: Tue, 14 Feb 2006 04:54:14 -0500	[thread overview]
Message-ID: <200602140458_MC3-1-B85E-D2BA@compuserve.com> (raw)

On Sun, 12 Feb 2006 at 01:40:46 -0800, Andrew Morton wrote:

> btw, is something up with `make foo.lst'?  It hasn't worked for me for
some
> time.
> 
> bix:/usr/src/25> make mm/vmscan.lst
>   MKLST   mm/vmscan.lst

Just doing 'objdump -d -r -l -j .text mm/vmscan.o' gives:

mm/vmscan.o:     file format elf32-i386

Disassembly of section .text:

00000000 <shrink_slab>:
kswapd_init():
^^^^^^^^^^^^^^
This is actually at offset 0 in .init.text

mm/vmscan.c:176
       0:       55                      push   %ebp
shrink_slab():
^^^^^^^^^^^^^^
OK, back to the right location.

       1:       89 e5                   mov    %esp,%ebp
       3:       57                      push   %edi
kswapd_init():
mm/vmscan.c:1801
^^^^^^^^^^^^^^^^
Now back to kswapd_init() again?!?!

       4:       56                      push   %esi
       5:       89 c6                   mov    %eax,%esi
include/asm/processor.h:710
       7:       53                      push   %ebx
       8:       83 ec 24                sub    $0x24,%esp
mm/vmscan.c:180
^^^^^^^^^^^^^^^

       b:       85 c0                   test   %eax,%eax
include/asm/processor.h:710
       d:       b8 20 00 00 00          mov    $0x20,%eax
mm/vmscan.c:176
      12:       89 55 e4                mov    %edx,0xffffffe4(%ebp)
mm/vmscan.c:180
      15:       0f 44 f0                cmove  %eax,%esi
include/asm/rwsem.h:126
      18:       a1 0c 00 00 00          mov    0xc,%eax
                        19: R_386_32    .data
      1d:       89 c2                   mov    %eax,%edx
      1f:       83 c2 01                add    $0x1,%edx
mm/vmscan.c:1803
^^^^^^^^^^^^^^^^

      22:       7e 09                   jle    2d <shrink_slab+0x2d>
      24:       0f b1 15 0c 00 00 00    cmpxchg %edx,0xc
                        27: R_386_32    .data
      2b:       75 f0                   jne    1d <shrink_slab+0x1d>
mm/vmscan.c:183
      2d:       85 c0                   test   %eax,%eax
      2f:       c7 45 e8 01 00 00 00    movl   $0x1,0xffffffe8(%ebp)
      36:       0f 88 2c 01 00 00       js     168 <shrink_slab+0x168>

So it is confused somehow.  This is with debug info generated by gcc 4.0.2
from
Fedora Core 4 (Red Hat 4.0.2-8) and locally-compiled objdump 2.16.1 (there
seems to be no binutils update for FC4 available.)
-- 
Chuck
"Equations are the Devil's sentences."  --Stephen Colbert