Re: [PATCH 2/2] mtd: spi-nor: spansion: make sure local struct does not contain garbage

[Tudor Ambarus <tudor.ambarus@linaro.org>]

On 5/9/23 20:25, Tudor Ambarus wrote:
> Following error was seen with um-x86_64-gcc12/um-allyesconfig:
> + /kisskb/src/drivers/mtd/spi-nor/spansion.c: error: 'op' is used uninitialized [-Werror=uninitialized]:  => 495:27, 364:27
> 
> Set the spi_mem_op fields at the time of declaration so that all
> uninitialized members be initialized to default value.
> 
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Fixes: 6afcc84080c41 ("mtd: spi-nor: spansion: Add support for Infineon S25FS256T")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
> ---
>  drivers/mtd/spi-nor/spansion.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
> index d44ffaac1dba..257d05ed4146 100644
> --- a/drivers/mtd/spi-nor/spansion.c
> +++ b/drivers/mtd/spi-nor/spansion.c
> @@ -492,7 +492,10 @@ s25fs256t_post_bfpt_fixup(struct spi_nor *nor,
>  			  const struct sfdp_parameter_header *bfpt_header,
>  			  const struct sfdp_bfpt *bfpt)
>  {
> -	struct spi_mem_op op;
> +	struct spi_mem_op op =
> +		CYPRESS_NOR_RD_ANY_REG_OP(nor->params->addr_mode_nbytes,
> +					  SPINOR_REG_CYPRESS_ARCFN, 1,
> +					  nor->bouncebuf);
>  	int ret;
>  

oops, this is wrong as addr_mode_nbytes is updated just below in
cypress_nor_set_addr_mode_nbytes(), so the fix is to init op with {} at
declaration, as in the previous patch.

>  	ret = cypress_nor_set_addr_mode_nbytes(nor);
> @@ -500,10 +503,6 @@ s25fs256t_post_bfpt_fixup(struct spi_nor *nor,
>  		return ret;
>  
>  	/* Read Architecture Configuration Register (ARCFN) */
> -	op = (struct spi_mem_op)
> -		CYPRESS_NOR_RD_ANY_REG_OP(nor->params->addr_mode_nbytes,
> -					  SPINOR_REG_CYPRESS_ARCFN, 1,
> -					  nor->bouncebuf);
>  	ret = spi_nor_read_any_reg(nor, &op, nor->reg_proto);
>  	if (ret)
>  		return ret;