[PATCH] percpu: fix pcpu_page_first_chunk return code handling

[PATCH] percpu: fix pcpu_page_first_chunk return code handling

[Arnd Bergmann]

gcc complains that pcpu_page_first_chunk() might return an uninitialized
error code when the loop is never entered:

mm/percpu.c: In function 'pcpu_page_first_chunk':
mm/percpu.c:2929:9: error: 'rc' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Make it return zero like before the cleanup.

Fixes: a13e0ad81216 ("percpu: Make pcpu_setup_first_chunk() void function")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/percpu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/percpu.c b/mm/percpu.c
index 5a918a4b1da0..5b65f753c575 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2917,6 +2917,7 @@ int __init pcpu_page_first_chunk(size_t reserved_size,
 		ai->reserved_size, ai->dyn_size);
 
 	pcpu_setup_first_chunk(ai, vm.addr);
+	rc = 0;
 	goto out_free_ar;
 
 enomem:
-- 
2.20.0

Re: [PATCH] percpu: fix pcpu_page_first_chunk return code handling

[Dennis Zhou]

On Mon, Jul 08, 2019 at 02:52:09PM +0200, Arnd Bergmann wrote:
> gcc complains that pcpu_page_first_chunk() might return an uninitialized
> error code when the loop is never entered:
> 
> mm/percpu.c: In function 'pcpu_page_first_chunk':
> mm/percpu.c:2929:9: error: 'rc' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> Make it return zero like before the cleanup.
> 
> Fixes: a13e0ad81216 ("percpu: Make pcpu_setup_first_chunk() void function")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  mm/percpu.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/percpu.c b/mm/percpu.c
> index 5a918a4b1da0..5b65f753c575 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -2917,6 +2917,7 @@ int __init pcpu_page_first_chunk(size_t reserved_size,
>  		ai->reserved_size, ai->dyn_size);
>  
>  	pcpu_setup_first_chunk(ai, vm.addr);
> +	rc = 0;
>  	goto out_free_ar;
>  
>  enomem:
> -- 
> 2.20.0
> 

Hi Arnd,

I got the report for the kbuild bot. I have the fix in my tree already.

Thanks,
Dennis