Subject: Re: linux-next: build warning after merge of the tip tree

From: Haicheng Li <[email-masked]>
Date: Fri, 03 Sep 2010 18:07:55 +0800

Wu Fengguang wrote:
> On Fri, Sep 03, 2010 at 10:12:01AM +0800, Stephen Rothwell wrote:
>> On Fri, 3 Sep 2010 12:10:23 +1000 Stephen Rothwell <[email-masked]> wrote:
>>> After merging the tip tree, today's linux-next build (x86_64 allmodconfig)
>>> produced this warning:
>>>
>>> arch/x86/mm/init_64.c: In function 'kernel_physical_mapping_init':
>>> arch/x86/mm/init_64.c:601: warning: 'addr' may be used uninitialized in this function
>>>
>>> The code does look suspicious ... 'addr' gets declared and then passed to
>>> a function, but is not set anywhere ...
>> Forgot to say:
>>
>> Introduced by commit 9b861528a8012e7bc4d1f7bae07395b225331477 ("x86-64,
>> mem: Update all PGDs for direct mapping and vmemmap mapping changes").
> 
> 
> The original patch has the following line, however get lost some time
> later:
> 
>         http://www.spinics.net/lists/linux-mm/msg08152.html
> 
> ===
> x86, mm: fix uninitialized addr in kernel_physical_mapping_init()
> 
> This re-adds the lost chunk in commit 9b861528a80.
> 
> CC: Haicheng Li <[email-masked]>
> Reported-by: Stephen Rothwell <[email-masked]>
> Signed-off-by: Wu Fengguang <[email-masked]>
> ---
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 64e7bc2..74f0f35 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -570,6 +570,7 @@ kernel_physical_mapping_init(unsigned long start,
>  
>  	start = (unsigned long)__va(start);
>  	end = (unsigned long)__va(end);
> +	addr = start;

weird, this line was in my original patch: http://lkml.org/lkml/2010/8/20/166

Acked-by: Haicheng Li <[email-masked]>

>  	for (; start < end; start = next) {
>  		pgd_t *pgd = pgd_offset_k(start);
>