Re: 2.6.12-rc2-mm3

Borislav Petkov
2005-04-11T21:59:21Z

On Monday 11 April 2005 11:43, Andrew Morton wrote:
> (Please do reply-to-all)
>
> "J.A. Magallon" <jamagallon@able.es> wrote:
> > On 04.11, Andrew Morton wrote:
> > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-r
> > >c2/2.6.12-rc2-mm3/
> >
> > Is this not needed anymore ?
> >
> > --- 25/arch/i386/kernel/entry.S~nmi_stack_correct-fix 2005-04-05
> > 00:02:48.000000000 -0700 +++ 25-akpm/arch/i386/kernel/entry.S 2005-04-05
> > 00:02:48.000000000 -0700
>
> Hopefully not. fix-crash-in-entrys-restore_all.patch works around the
> problem. -

Hello Andrew,
I don't know whether you remember the mysterious crashes I was telling you
about last week and me rookiesh-ly trying to debug them with kgdb over the
serial console. Well, today I tried for the n-th time again and after rc2-mm3
blocked again while loading, here's what I did:

<snip>
[ 12.335438] NET: Registered protocol family 17
[ 12.362483] Testing NMI watchdog ... OK.
[ 12.416195] Starting balanced_irq
[ 12.443099] VFS: Mounted root (ext2 filesystem) readonly.
[ 12.472490] Freeing unused kernel memory: 196k freed
[ 12.521004] logips2pp: Detected unknown logitech mouse model 1
[ 12.572581] Warning: unable to open an initial console.
[ 12.972518] input: PS/2 Logitech Mouse on isa0060/serio1

Program received signal SIGTRAP, Trace/breakpoint trap.
0xc0102ee7 in resume_kernelX () at atomic.h:175 <--- this one is wrong for a
mysterious reason
175 {
(gdb) p $eip
$1 = (void *) 0xc0102ee7

(gdb) disas 0xc0102ee7
Dump of assembler code for function resume_kernelX:
0xc0102ee7 <resume_kernelX+0>: mov 0x30(%esp),%eax
0xc0102eeb <resume_kernelX+4>: mov 0x38(%esp),%ah
0xc0102eef <resume_kernelX+8>: mov 0x2c(%esp),%al
0xc0102ef3 <resume_kernelX+12>: and $0x20403,%eax
0xc0102ef8 <resume_kernelX+17>: cmp $0x403,%eax
0xc0102efd <resume_kernelX+22>: je 0xc0102f0c <ldt_ss>
End of assembler dump.
(gdb)

And as we see, we're at the "mov 0x30(%esp),%eax" which accesses above the
bottom of the stack. After applying nmi_stack_correct-fix.patch, rc2-mm3
booted just fine, so I IMHO think that we might still be needing this, after
all.

Regards,
Boris.