[dm-devel] [dm- devel][PATCH] vector: return null when realloc fails in vector_alloc_slot func

[Benjamin Marzinski]

On Fri, Jul 31, 2020 at 06:41:57PM +0800, Zhiqiang Liu wrote:
> 
> In vector_alloc_slot func, if REALLOC fails, it means new slot
> allocation fails. However, it just update v->allocated and then
> return the old v->slot without new slot. So, the caller will take
> the last old slot as the new allocated slot, and use it by calling
> vector_set_slot func. Finally, the data of last slot is lost.
>

Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
 
> Here, if REALLOC or MALLOC fails, we will return NULL.
> 
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26 at huawei.com>
> Signed-off-by: lixiaokeng <lixiaokeng at huawei.com>
> ---
>  libmultipath/vector.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/libmultipath/vector.c b/libmultipath/vector.c
> index 501cf4c5..29dc9848 100644
> --- a/libmultipath/vector.c
> +++ b/libmultipath/vector.c
> @@ -49,12 +49,14 @@ vector_alloc_slot(vector v)
>  	else
>  		new_slot = (void *) MALLOC(sizeof (void *) * v->allocated);
> 
> -	if (!new_slot)
> +	/* If REALLOC or MALLOC fails, it means new slot allocation fails, so return NULL. */
> +	if (!new_slot) {
>  		v->allocated -= VECTOR_DEFAULT_SIZE;
> -	else
> -		v->slot = new_slot;
> +		return NULL;
> +	}
> 
> -	return v->slot;
> +	v->slot = new_slot;
> +	return v->slot[VECTOR_SIZE(v) - 1];
>  }
> 
>  int
> -- 
> 2.24.0.windows.2