Re: [PATCH 1/1] acpi: Fix warning: 'num_cpus' may be used uninitialized in this function

[Jean Sacren <sakiwit@gmail.com>]

On Sat, Sep 11, 2010 at 01:40:37PM -0300, Henrique de Moraes Holschuh wrote:
> On Sat, 11 Sep 2010, Jean Sacren wrote:
> > warning: 'num_cpus' may be used uninitialized in this function
> > 
> > Initialize 'num_cpus' variable to zero so that gcc doesn't complain.
> 
> acpi_pad_pur() is referenced only once, so it should end up inlined, at
> which point gcc really has no excuse to not determine with perfect
> confidence whether num_cpus is being used unitialized or not.
>
If acpi_pad_pur() is called and returns with non-zero value,
acpi_pad_handle_notify() happily returns, but num_cpus is referenced by
address without being initialized, so gcc gives the warning.
> 
> Looking at the code, it realy does look like a false positive.
>
Unfortunately it is _not_ a false positive. Here gcc does what it's
supposed to do. Therefore, the patch is correct.

-- 
Jean Sacren
Bring LAMP To People