Re: [PATCH V2] block/bio-integrity: fix mismatched alloc free

From: Ming Lei <ming.lei@redhat.com>
To: Pan Bian <bianpan2016@163.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH V2] block/bio-integrity: fix mismatched alloc free
Date: Mon, 19 Aug 2019 11:56:14 +0800	[thread overview]
Message-ID: <20190819035613.GC3086@ming.t460p> (raw)
In-Reply-To: <1566176353-20157-1-git-send-email-bianpan2016@163.com>

On Mon, Aug 19, 2019 at 08:59:13AM +0800, Pan Bian wrote:
> The function kmalloc rather than mempool_alloc is called to allocate
> memory when the memory pool is unavailable. However, mempool_alloc is
> used to release the memory chunck in both cases when error occurs. This
> patch fixes the bug.
> 
> Fixes: 9f060e2231c ("block: Convert integrity to bvec_alloc_bs()")
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> Cc: stable@vger.kernel.org
> ---
> V2: add Fixes and CC tags
> ---
>  block/bio-integrity.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/block/bio-integrity.c b/block/bio-integrity.c
> index fb95dbb..011dfc8 100644
> --- a/block/bio-integrity.c
> +++ b/block/bio-integrity.c
> @@ -75,7 +75,10 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
>  
>  	return bip;
>  err:
> -	mempool_free(bip, &bs->bio_integrity_pool);
> +	if (!bs || !mempool_initialized(&bs->bio_integrity_pool))
> +		kfree(bip);
> +	else
> +		mempool_free(bip, &bs->bio_integrity_pool);
>  	return ERR_PTR(-ENOMEM);
>  }
>  EXPORT_SYMBOL(bio_integrity_alloc);

'err' is still reached in case that 'bs' is valid, so fix nothing.

Thanks,
Ming