Re: [PATCH] block: fix a mismatched alloc free in bio_alloc_bioset

[Bart Van Assche]

On 8/18/19 3:57 AM, Pan Bian wrote:
> The function kmalloc is called to allocate memory if bs is NULL.
> However, mempool_free is used to release the memory chunk even if bs is
> NULL in the error hanlding code. This patch checks bs and use the
> correct function to release memory.
>
> Signed-off-by: Pan Bian <bianpan2016@xxxxxxx>
> ---
>   block/bio.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index 299a0e7..c5f5238 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -515,7 +515,10 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
>   	return bio;
>   
>   err_free:
> -	mempool_free(p, &bs->bio_pool);
> +	if (!bs)
> +		kfree(p);
> +	else
> +		mempool_free(p, &bs->bio_pool);
>   	return NULL;
>   }
>   EXPORT_SYMBOL(bio_alloc_bioset);

Please add "Fixes:" and "Cc: stable" tags. See also 
Documentation/process/submitting-patches.rst.

Thanks,

Bart.