On 18.08.2014 20:36, Milan Broz wrote:
> The commit
>    298a9fa08a1577211d42a75e8fc073baef61e0d9
>    dm crypt: use per-bio data
> causes OOPS on 32bit i686 architecture
>
>    BUG: unable to handle kernel paging request at 20000000
>    IP: [<e0fe2433>] clone_endio+0x13/0xe0 [dm_mod]
>    ...
>
>   [<c1257b61>] bio_endio+0x61/0x90
>   [<e142476c>] crypt_dec_pending+0x8c/0xd0 [dm_crypt]
>   [<e142666f>] kcryptd_crypt+0x4bf/0x4f0 [dm_crypt]
>
> This patch fixes the issue by aligning per-bio alocated structure size.
>
> Reported-by: Krzysztof Kolasa <kkolasa@winsoft.pl>
> Signed-off-by: Milan Broz <gmazyland@gmail.com>
> ---
>   drivers/md/dm-crypt.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
> index 2785007..33f26a2 100644
> --- a/drivers/md/dm-crypt.c
> +++ b/drivers/md/dm-crypt.c
> @@ -1735,9 +1735,10 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
>   		goto bad;
>   	}
>   
> -	cc->per_bio_data_size = ti->per_bio_data_size =
> -				sizeof(struct dm_crypt_io) + cc->dmreq_start +
> -				sizeof(struct dm_crypt_request) + cc->iv_size;
> +	cc->per_bio_data_size = ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start +
> +				      sizeof(struct dm_crypt_request) + cc->iv_size,
> +				      ARCH_KMALLOC_MINALIGN);
> +	ti->per_bio_data_size = cc->per_bio_data_size;
>   
>   	cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
>   	if (!cc->page_pool) {

patch tested positive for x86 ( no oops ) and x86_64  ( continues to 
work OK ).

thanks