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

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

[Stephen Rothwell]

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Hi all,

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 ...

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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

[Stephen Rothwell]

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On Fri, 3 Sep 2010 12:10:23 +1000 Stephen Rothwell <sfr@canb.auug.org.au> 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").

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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

[Wu Fengguang]

On Fri, Sep 03, 2010 at 10:12:01AM +0800, Stephen Rothwell wrote:
> On Fri, 3 Sep 2010 12:10:23 +1000 Stephen Rothwell <sfr@canb.auug.org.au> 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 <haicheng.li@linux.intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
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;
 
 	for (; start < end; start = next) {
 		pgd_t *pgd = pgd_offset_k(start);

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

[Haicheng Li]

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 <sfr@canb.auug.org.au> 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 <haicheng.li@linux.intel.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> ---
> 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 <haicheng.li@linux.intel.com>

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

[tip:x86/mm] x86, mm: fix uninitialized addr in kernel_physical_mapping_init()

[tip-bot for Wu Fengguang]

Commit-ID:  1c5f50ee347daea013671f718b70cd6bf497bef9
Gitweb:     http://git.kernel.org/tip/1c5f50ee347daea013671f718b70cd6bf497bef9
Author:     Wu Fengguang <fengguang.wu@intel.com>
AuthorDate: Fri, 3 Sep 2010 17:04:07 +0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 3 Sep 2010 11:40:11 +0200

x86, mm: fix uninitialized addr in kernel_physical_mapping_init()

This re-adds the lost chunk in commit 9b861528a80.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Haicheng Li <haicheng.li@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <20100903090407.GA19771@localhost>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/mm/init_64.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

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