Re: [PATCH] block/loop: fix use after feee

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On Wed, Aug 30, 2017 at 02:51:05PM -0700, Shaohua Li wrote:
> lo_rw_aio->call_read_iter->
> 1	aops->direct_IO
> 2	iov_iter_revert
> lo_rw_aio_complete could happen between 1 and 2, the bio and bvec could
> be freed before 2, which accesses bvec.

please ignore this one, I accidentally sent it out. The correct fix is in
another patch.
 
> This conflicts with my direcio performance improvement patches, which
> I'll resend.
> 
> Signed-off-by: Shaohua Li <shli@xxxxxx>
> ---
>  drivers/block/loop.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index ef83349..153ab3c 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -490,6 +490,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
>  	bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
>  	iov_iter_bvec(&iter, ITER_BVEC | rw, bvec,
>  		      bio_segments(bio), blk_rq_bytes(cmd->rq));
> +	bio_inc_remaining(bio);
>  	/*
>  	 * This bio may be started from the middle of the 'bvec'
>  	 * because of bio splitting, so offset from the bvec must
> @@ -507,6 +508,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
>  	else
>  		ret = call_read_iter(file, &cmd->iocb, &iter);
>  
> +	bio_endio(bio);
>  	if (ret != -EIOCBQUEUED)
>  		cmd->iocb.ki_complete(&cmd->iocb, ret, 0);
>  	return 0;
> -- 
> 2.9.5
> 



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