Kernel Bugzilla #2682: arch/sparc/kernel/sun4m_smp.c: [OPERA] potential error detected by an analysi

Kernel Bugzilla #2682: arch/sparc/kernel/sun4m_smp.c: [OPERA] potential error detected by an analysi

[Adrian Bunk]

Kernel Bugzilla #2682 [1] contains the following report by
Zhenmin <lzmhome@yahoo.com>:

<--  snip  -->

The potential error is detected by a static analysis tool in
/arch/sparc/kernel/sun4m_smp.c:227-228

225  if(cpu_callin_map[i]) {
226    /* Another "Red Snapper". */
227    __cpu_number_map[i] = i;
228    __cpu_logical_map[i] = i;
229  } else {

Lines 227-228 may be changed to:

227    __cpu_number_map[i] = cpucount;
228    __cpu_logical_map[cpucount] = i;

Can anyone confirm whether it is a bug or not?

<--  snip  -->

(the line numbers are wrong by a few lines in recent kernels, but
 "Red Snapper" is easy to find in the file.

AFAIR SMP is not working on sparc32 in kernel 2.6, but could you anyways 
comment on this issue?

TIA
Adrian

[1] http://bugzilla.kernel.org/show_bug.cgi?id&82

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: Kernel Bugzilla #2682: arch/sparc/kernel/sun4m_smp.c: [OPERA] potential error detected by an ana

[William Lee Irwin III]

On Sun, Jan 22, 2006 at 06:53:56PM +0100, Adrian Bunk wrote:
> Kernel Bugzilla #2682 [1] contains the following report by
> Zhenmin <lzmhome@yahoo.com>:
> <--  snip  -->
> The potential error is detected by a static analysis tool in
> /arch/sparc/kernel/sun4m_smp.c:227-228
> 225  if(cpu_callin_map[i]) {
> 226    /* Another "Red Snapper". */
> 227    __cpu_number_map[i] = i;
> 228    __cpu_logical_map[i] = i;
> 229  } else {
> Lines 227-228 may be changed to:
> 227    __cpu_number_map[i] = cpucount;
> 228    __cpu_logical_map[cpucount] = i;
> Can anyone confirm whether it is a bug or not?
> <--  snip  -->
> (the line numbers are wrong by a few lines in recent kernels, but
>  "Red Snapper" is easy to find in the file.
> AFAIR SMP is not working on sparc32 in kernel 2.6, but could you anyways 
> comment on this issue?

Bob Breuer's SMP patch does a drastic rearrangement that eliminates
that line along with many others surrounding it. It is a better idea to
take Bob's patch than to fiddle with things piecemeal.

It's not so much a bug as nonsensical.


-- wli

Re: Kernel Bugzilla #2682: arch/sparc/kernel/sun4m_smp.c: [OPERA]

[David S. Miller]

From: William Lee Irwin III <wli@holomorphy.com>
Date: Sun, 22 Jan 2006 13:34:17 -0800

> Bob Breuer's SMP patch does a drastic rearrangement that eliminates
> that line along with many others surrounding it. It is a better idea to
> take Bob's patch than to fiddle with things piecemeal.
> 
> It's not so much a bug as nonsensical.

I'd like to see Bob's patch formally submitted then.

Re: Kernel Bugzilla #2682: arch/sparc/kernel/sun4m_smp.c: [OPERA] potential error detected by an ana

[William Lee Irwin III]

From: William Lee Irwin III <wli@holomorphy.com>
Date: Sun, 22 Jan 2006 13:34:17 -0800
>> Bob Breuer's SMP patch does a drastic rearrangement that eliminates
>> that line along with many others surrounding it. It is a better idea to
>> take Bob's patch than to fiddle with things piecemeal.
>> It's not so much a bug as nonsensical.

On Tue, Jan 24, 2006 at 01:09:50PM -0800, David S. Miller wrote:
> I'd like to see Bob's patch formally submitted then.

I've been a bit too far beyond lax in my duties to offer a coherent
excuse. Bob, it looks like I need to get my act together and merge your
stuff ASAP. It might be a good idea to resend your last patch so Dave
can get a look at it, too. In the meantime I can testboot it on a bunch
of different boxen.

I'll follow up in private with realtime communication info..


-- wli