Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] ARM: NOMMU: work around maybe-uninitialized warning
To:     Arnd Bergmann <arnd@arndb.de>, Russell King <linux@armlinux.org.uk>
Cc:     Nicolas Pitre <nicolas.pitre@linaro.org>,
        afzal mohammed <afzal.mohd.ma@gmail.com>,
        Laura Abbott <labbott@redhat.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20171102092155.737712-1-arnd@arndb.de>
From:   Vladimir Murzin <vladimir.murzin@arm.com>
Message-ID: <681a1757-ddbe-c9a7-6945-fa72600cf172@arm.com>
Date:   Thu, 2 Nov 2017 12:25:47 +0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.2.1
MIME-Version: 1.0
In-Reply-To: <20171102092155.737712-1-arnd@arndb.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-GB
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 02/11/17 09:21, Arnd Bergmann wrote:
> The reworked MPU code produces a new warning in some configurations,
> presumably starting with the code move after the compiler now makes
> different inlining decisions:
> 
> arch/arm/mm/pmsa-v7.c: In function 'adjust_lowmem_bounds_mpu':
> arch/arm/mm/pmsa-v7.c:310:5: error: 'specified_mem_size' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> This appears to be harmless, as we know that there is always at
> least one memblock, and the only way this could get triggered is
> if the for_each_memblock() loop was never entered.
> 
> I could not come up with a better workaround than initializing
> the specified_mem_size to zero, but at least that is the value
> that the variable would have in the hypothetical case of no
> memblocks.
> 
> Fixes: 877ec119dbbf ("ARM: 8706/1: NOMMU: Move out MPU setup in separate module")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> Vladimir, if this looks good to you, can you forward it to Russell's
> patch tracker, or otherwise suggest a different fix?

Accepted as patch 8719/1. Not sure if Russell will pick it up or not... anyway,
thanks for the patch!

Vladimir

> ---
>  arch/arm/mm/pmsa-v7.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mm/pmsa-v7.c b/arch/arm/mm/pmsa-v7.c
> index 106ae1c435a3..976df60ac426 100644
> --- a/arch/arm/mm/pmsa-v7.c
> +++ b/arch/arm/mm/pmsa-v7.c
> @@ -234,7 +234,7 @@ static int __init allocate_region(phys_addr_t base, phys_addr_t size,
>  /* MPU initialisation functions */
>  void __init adjust_lowmem_bounds_mpu(void)
>  {
> -	phys_addr_t  specified_mem_size, total_mem_size = 0;
> +	phys_addr_t  specified_mem_size = 0, total_mem_size = 0;
>  	struct memblock_region *reg;
>  	bool first = true;
>  	phys_addr_t mem_start;
> 


From 1582945654361281415@xxx Thu Nov 02 09:23:34 +0000 2017
X-GM-THRID: 1582945654361281415
X-Gmail-Labels: Inbox,Category Forums,HistoricalUnread