linux-kernel - Re: [PATCH] percpu: fix pcpu_page_first

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Message-ID: <20190708145002.GA17098@dennisz-mbp>
Date:   Mon, 8 Jul 2019 10:50:02 -0400
From:   Dennis Zhou <dennis@...nel.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Dennis Zhou <dennis@...nel.org>, Tejun Heo <tj@...nel.org>,
        Christoph Lameter <cl@...ux.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Peng Fan <peng.fan@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Dennis Zhou (Facebook)" <dennisszhou@...il.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] percpu: fix pcpu_page_first_chunk return code handling

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@...db.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