[PATCH v2] lib/ring: do not allow zero size ring

[Wathsala Vithanage]

On 11/10/25 17:15, Isaac Boukris wrote:
> this might happen when for instance the ring size is read from
> config, and would cause runtime crash.
>
> Signed-off-by: Isaac Boukris <iboukris at gmail.com>
> ---
>
> v2:
> * move the fix to the POWEROF2 macro itself.
> * fixed style in the test code.
>
>   app/test/test_ring.c | 7 +++++++
>   lib/ring/rte_ring.c  | 2 +-
>   2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/app/test/test_ring.c b/app/test/test_ring.c
> index ba1fec1de3..3078348b2f 100644
> --- a/app/test/test_ring.c
> +++ b/app/test/test_ring.c
> @@ -505,6 +505,13 @@ test_ring_negative_tests(void)
>   	struct rte_ring *rt = NULL;
>   	unsigned int i;
>   
> +	/* Test zero size ring */
> +	rp = test_ring_create("test_zero_size_ring", -1, 0, SOCKET_ID_ANY, 0);
> +	if (rp != NULL) {
> +		printf("Test failed to detect zero size ring\n");
> +		goto test_fail;
> +	}
> +
>   	/* Test with esize not a multiple of 4 */
>   	rp = test_ring_create("test_bad_element_size", 23,
>   				RING_SIZE + 1, SOCKET_ID_ANY, 0);
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index edd63aa535..0a9fc31530 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -47,7 +47,7 @@ EAL_REGISTER_TAILQ(rte_ring_tailq)
>   		     RING_F_MP_HTS_ENQ | RING_F_MC_HTS_DEQ)
>   
>   /* true if x is a power of 2 */
> -#define POWEROF2(x) ((((x)-1) & (x)) == 0)
> +#define POWEROF2(x) ((x != 0) && (((x)-1) & (x)) == 0)
>   
>   /* by default set head/tail distance as 1/8 of ring capacity */
>   #define HTD_MAX_DEF	8

Acked-by: Wathsala Vithanage <wathsala.vithanage at arm.com>