Re: 2.6.16-rc6-mm2 uninitialized online_policy_cpus.bits[0]

[Venkatesh Pallipadi]

On Sat, Mar 18, 2006 at 05:35:12PM -0800, Andrew Morton wrote:
> Con Kolivas <kernel@xxxxxxxxxxx> wrote:
> >
> > Wonder if this is related to rc6's oops?
> >  gcc 4.0.3
> > 
> >    CC [M]  arch/i386/kernel/cpu/cpufreq/speedstep-centrino.o
> >  arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c: In function 
> >  'centrino_target':
> >  include/linux/bitmap.h:170: warning: 'online_policy_cpus.bits[0]' is used 
> >  uninitialized in this function
> >    CC [M]  arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.o
> >  arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c: In function 
> >  'acpi_cpufreq_target':
> >  include/linux/bitmap.h:170: warning: 'online_policy_cpus.bits[0]' is used 
> >  uninitialized in this function
> 
> Well conceivably.  That warning is a consequence of my quick hack to make
> the ACPI tree compile on uniprocessor.
> 
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.16-rc6/2.6.16-rc6-mm2/broken-out/git-acpi-up-fix.patch
> 
> My patch is, as the compiler points out, wrong.
> 
> I've sent that patch two or three times to the APCI maintainers, to the
> ACPI mailing list and to the author of the original buggy patch.  The
> response thus far has been dead silence.
> 
> IOW, despite my efforts, the ACPI tree has been in a non-compiling state on
> uniprocessor since February 11.
> 
> This is pathetic.  People are trying to get things done here and ACPI is
> getting in the way.  


Oops. Sorry. It is me who dropped the ball here. I somehow assumed that
your original patch fixed the issue and didn't look at the actual code.

Here is the patch against mm.

Thanks,
Venki



Fix the UP build breakage in acpi-cpufreq and speedstep-centrino due to
previous p-state software coordination patch.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>

diff -purN linux-2.6.15/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c linux-2.6.15-new/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
--- linux-2.6.15/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c	2006-03-18 19:41:25.000000000 -0800
+++ linux-2.6.15-new/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c	2006-03-18 19:48:10.000000000 -0800
@@ -225,9 +225,11 @@ acpi_cpufreq_target (
 	freqs.old = data->freq_table[cur_state].frequency;
 	freqs.new = data->freq_table[next_state].frequency;
 
-#ifdef CONFIG_SMP
+#ifdef CONFIG_HOTPLUG_CPU
 	/* cpufreq holds the hotplug lock, so we are safe from here on */
 	cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
+#else
+	online_policy_cpus = policy->cpus;
 #endif
 
 	for_each_cpu_mask(j, online_policy_cpus) {
diff -purN linux-2.6.15/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c linux-2.6.15-new/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
--- linux-2.6.15/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c	2006-03-18 19:41:25.000000000 -0800
+++ linux-2.6.15-new/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c	2006-03-18 19:47:46.000000000 -0800
@@ -652,9 +652,11 @@ static int centrino_target (struct cpufr
 		return -EINVAL;
 	}
 
-#ifdef CONFIG_SMP
+#ifdef CONFIG_HOTPLUG_CPU
 	/* cpufreq holds the hotplug lock, so we are safe from here on */
 	cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
+#else
+	online_policy_cpus = policy->cpus;
 #endif
 
 	saved_mask = current->cpus_allowed;
-
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