Re: [PATCH v2 15/19] md: check for failure when adding pages in alloc_behind_master_bio

[Song Liu <song@xxxxxxxxxx>]

On Thu, Mar 30, 2023 at 3:44 AM Johannes Thumshirn
<johannes.thumshirn@xxxxxxx> wrote:
>
> alloc_behind_master_bio() can possibly add multiple pages to a bio, but it
> is not checking for the return value of bio_add_page() if adding really
> succeeded.
>
> Check if the page adding succeeded and if not bail out.
>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
> Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> ---
>  drivers/md/raid1.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 68a9e2d9985b..bd7c339a84a1 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -1147,7 +1147,8 @@ static void alloc_behind_master_bio(struct r1bio *r1_bio,
>                 if (unlikely(!page))
>                         goto free_pages;
>
> -               bio_add_page(behind_bio, page, len, 0);
> +               if (!bio_add_page(behind_bio, page, len, 0))
> +                       goto free_pages;

We will leak page here, no?

Thanks,
Song