Re: [PATCH] block: bio-integrity: fix memory leak in bio_integrity_map_user()

[Christoph Hellwig <hch@lst.de>]

On Wed, May 13, 2026 at 10:05:15AM +0300, Dmitry Antipov wrote:
> Since 'iov_iter_extract_pages()' may allocate new array of pages
> even when it returns non-zero error value, matching cleanup with
> 'vfree()' should be performed on all return paths afterwards. So
> adjust 'bio_integrity_map_user()' to ensure that both 'pages' and
> 'bvec' arrays are always freed on return.
> 
> Fixes: 8582792cf23b ("block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()")
> Fixes: 492c5d455969 ("block: bio-integrity: directly map user buffers")
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>

The change looks fine:

Reviewed-by: Christoph Hellwig <hch@lst.de>

We'd still be much better off converting it to iov_iter_extract_bvecs
to share common code, and make it more efficient by no needing the
separate pages allocation.

> ---
>  block/bio-integrity.c | 21 ++++++---------------
>  1 file changed, 6 insertions(+), 15 deletions(-)
> 
> diff --git a/block/bio-integrity.c b/block/bio-integrity.c
> index e796de1a749e..53fb04adb09b 100644
> --- a/block/bio-integrity.c
> +++ b/block/bio-integrity.c
> @@ -400,7 +400,7 @@ int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
>  	ret = iov_iter_extract_pages(iter, &pages, bytes, nr_vecs,
>  					extraction_flags, &offset);
>  	if (unlikely(ret < 0))
> -		goto free_bvec;
> +		goto out_free;
>  
>  	/*
>  	 * Handle partial pinning. This can happen when pin_user_pages_fast()
> @@ -414,16 +414,12 @@ int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
>  			for (i = 0; i < npinned; i++)
>  				unpin_user_page(pages[i]);
>  		}
> -		if (pages != stack_pages)
> -			kvfree(pages);
>  		ret = -EFAULT;
> -		goto free_bvec;
> +		goto out_free;
>  	}
>  
>  	nr_bvecs = bvec_from_pages(bvec, pages, nr_vecs, bytes, offset,
>  				   &is_p2p);
> -	if (pages != stack_pages)
> -		kvfree(pages);
>  	if (nr_bvecs > queue_max_integrity_segments(q))
>  		copy = true;
>  	if (is_p2p)
> @@ -434,15 +430,10 @@ int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter)
>  	else
>  		ret = bio_integrity_init_user(bio, bvec, nr_bvecs, bytes);
>  	if (ret)
> -		goto release_pages;
> -	if (bvec != stack_vec)
> -		kfree(bvec);
> -
> -	return 0;
> -
> -release_pages:
> -	bio_integrity_unpin_bvec(bvec, nr_bvecs);
> -free_bvec:
> +		bio_integrity_unpin_bvec(bvec, nr_bvecs);
> +out_free:
> +	if (pages != stack_pages)
> +		kvfree(pages);
>  	if (bvec != stack_vec)
>  		kfree(bvec);
>  	return ret;
> -- 
> 2.54.0
---end quoted text---