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Date: Fri, 1 Mar 2024 20:01:36 +0300
From: Dan Carpenter <dan.carpenter@linaro.org>
To: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Tudor Ambarus <tudor.ambarus@linaro.org>,
	Pratyush Yadav <pratyush@kernel.org>,
	Michael Walle <mwalle@kernel.org>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Takahiro Kuwano <Takahiro.Kuwano@infineon.com>,
	kernel@collabora.com, kernel-janitors@vger.kernel.org,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: spi-nor: core: correct type of i to be signed
Message-ID: <c7db3fa0-d5a2-43aa-8038-0a722f2b8f26@moroto.mountain>
References: <20240301144517.2811370-1-usama.anjum@collabora.com>
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In-Reply-To: <20240301144517.2811370-1-usama.anjum@collabora.com>

On Fri, Mar 01, 2024 at 07:45:16PM +0500, Muhammad Usama Anjum wrote:
> The i should be signed to find out the end of the loop. Otherwise,
> i >= 0 is always true and loop becomes infinite.
> 
> Fixes: 6a9eda34418f ("mtd: spi-nor: core: set mtd->eraseregions for non-uniform erase map")
> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
> ---
>  drivers/mtd/spi-nor/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 65b32ea59afc6..46bc45b80883f 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -3373,7 +3373,7 @@ static u32
>  spi_nor_get_region_erasesize(const struct spi_nor_erase_region *region,
>  			     const struct spi_nor_erase_type *erase_type)
>  {
> -	u8 i;
> +	s8 i;

I have a patch in my output which also addresses this bug but you beat
me to the punch.  Declaring iterators as "u8 i;" is a canonical bug.

https://staticthinking.wordpress.com/2022/06/01/unsigned-int-i-is-stupid/

regards,
dan carpenter