Re: [PATCH] mtd: nftl/inftl: check mtd_erase() return value

[Boris Brezillon <boris.brezillon@bootlin.com>]

On Thu, 25 Jan 2018 00:24:34 +0100
Miquel Raynal <miquel.raynal@free-electrons.com> wrote:

> Since the creation of mtd_erase(), the function can return a negative
> error code without updating the instr->state flag. This happens for
> instance when ->_erase() is not implemented or ->erasesize has an invalid
> value. The calling function should error out in this case.
> 
> Functions in nftlmount/inftlmount call mtd_erase() without checking the
> return code. The instr->state flag is checked but might not have been
> updated depending on the error path.
> 
> Add checks on the returned value of mtd_erase().
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
> ---
>  drivers/mtd/inftlmount.c | 7 +++++--
>  drivers/mtd/nftlmount.c  | 3 ++-
>  2 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/inftlmount.c b/drivers/mtd/inftlmount.c
> index 8d6bb189ea8e..cab4a0b9f881 100644
> --- a/drivers/mtd/inftlmount.c
> +++ b/drivers/mtd/inftlmount.c
> @@ -219,7 +219,9 @@ static int find_boot_record(struct INFTLrecord *inftl)
>  				 */
>  				instr->addr = ip->Reserved0 * inftl->EraseSize;
>  				instr->len = inftl->EraseSize;
> -				mtd_erase(mtd, instr);
> +				ret = mtd_erase(mtd, instr);
> +				if (ret < 0)
> +					return ret;
>  			}
>  			if ((ip->lastUnit - ip->firstUnit + 1) < ip->virtualUnits) {
>  				printk(KERN_WARNING "INFTL: Media Header "
> @@ -393,7 +395,8 @@ int INFTL_formatblock(struct INFTLrecord *inftl, int block)
>  	   mark only the failed block in the bbt. */
>  	for (physblock = 0; physblock < inftl->EraseSize;
>  	     physblock += instr->len, instr->addr += instr->len) {
> -		mtd_erase(inftl->mbd.mtd, instr);
> +		if (mtd_erase(inftl->mbd.mtd, instr < 0))

		    ^ mtd_erase(inftl->mbd.mtd, instr) < 0

which means you did not even compile test your patch :P.

> +			goto fail;
>  
>  		if (instr->state == MTD_ERASE_FAILED) {
>  			printk(KERN_WARNING "INFTL: error while formatting block %d\n",
> diff --git a/drivers/mtd/nftlmount.c b/drivers/mtd/nftlmount.c
> index 184c8fbfe465..8dbc40ab7d73 100644
> --- a/drivers/mtd/nftlmount.c
> +++ b/drivers/mtd/nftlmount.c
> @@ -331,7 +331,8 @@ int NFTL_formatblock(struct NFTLrecord *nftl, int block)
>  	instr->mtd = nftl->mbd.mtd;
>  	instr->addr = block * nftl->EraseSize;
>  	instr->len = nftl->EraseSize;
> -	mtd_erase(mtd, instr);
> +	if (mtd_erase(mtd, instr) < 0)
> +		goto fail;
>  
>  	if (instr->state == MTD_ERASE_FAILED) {
>  		printk("Error while formatting block %d\n", block);



-- 
Boris Brezillon, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com