Re: [PATCH v2 1/2] dm verity: init fec io before cleaning it

[Mikulas Patocka <mpatocka@redhat.com>]

On Tue, 21 Nov 2023, Wu Bo wrote:

> If BIO error, it may goto verity_finish_io() before
> verity_fec_init_io(). Therefor, the fec_io->rs is not initialized and
> may crash when doing memory freeing in verity_fec_finish_io().
> 
> Crash call stack:
>  die+0x90/0x2b8
>  __do_kernel_fault+0x260/0x298
>  do_bad_area+0x2c/0xdc
>  do_translation_fault+0x3c/0x54
>  do_mem_abort+0x54/0x118
>  el1_abort+0x38/0x5c
>  el1h_64_sync_handler+0x50/0x90
>  el1h_64_sync+0x64/0x6c
>  free_rs+0x18/0xac
>  fec_rs_free+0x10/0x24
>  mempool_free+0x58/0x148
>  verity_fec_finish_io+0x4c/0xb0
>  verity_end_io+0xb8/0x150
> 
> Cc: stable@vger.kernel.org      # v6.0+
> Fixes: 5721d4e5a9cd ("dm verity: Add optional "try_verify_in_tasklet" feature")
> Signed-off-by: Wu Bo <bo.wu@vivo.com>
> ---
>  drivers/md/dm-verity-target.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
> index e115fcfe723c..beec14b6b044 100644
> --- a/drivers/md/dm-verity-target.c
> +++ b/drivers/md/dm-verity-target.c
> @@ -642,7 +642,6 @@ static void verity_work(struct work_struct *w)
>  
>  	io->in_tasklet = false;
>  
> -	verity_fec_init_io(io);
>  	verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
>  }
>  
> @@ -792,6 +791,8 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
>  	bio->bi_private = io;
>  	io->iter = bio->bi_iter;
>  
> +	verity_fec_init_io(io);
> +
>  	verity_submit_prefetch(v, io);
>  
>  	submit_bio_noacct(bio);
> -- 
> 2.25.1

Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>