> -----Original Message-----
> From: Yunjian Wang <wangyunj...@huawei.com>
> Sent: Monday, April 17, 2023 8:12 AM
> To: dev@dpdk.org
> Cc: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>;
> konstantin.v.anan...@yandex.ru; luyi...@huawei.com; Yunjian Wang
> <wangyunj...@huawei.com>; sta...@dpdk.org
> Subject: [dpdk-dev] [PATCH] ring: fix use after free in ring release
>
> When using the ring to find out tailq entry, however it had been freed by
> rte_memzone_free function. This change prevents that from happening.
I am unable to follow the problem you are describing.
After the memzone for the ring is released, the contents of the memzone are not
being used. I understand that the variable 'r' is being used, but that should
not cause any issues.
>
> Fixes: 4e32101f9b01 ("ring: support freeing")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Yunjian Wang <wangyunj...@huawei.com>
> ---
> lib/ring/rte_ring.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c index
> 8ed455043d..17d2d7f8a8 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -333,11 +333,6 @@ rte_ring_free(struct rte_ring *r)
> return;
> }
>
> - if (rte_memzone_free(r->memzone) != 0) {
> - RTE_LOG(ERR, RING, "Cannot free memory\n");
> - return;
> - }
Why do we need to free the memzone later?
> -
> ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
> rte_mcfg_tailq_write_lock();
>
> @@ -349,7 +344,7 @@ rte_ring_free(struct rte_ring *r)
>
> if (te == NULL) {
> rte_mcfg_tailq_write_unlock();
> - return;
> + goto free_memzone;
> }
>
> TAILQ_REMOVE(ring_list, te, next);
> @@ -357,6 +352,10 @@ rte_ring_free(struct rte_ring *r)
> rte_mcfg_tailq_write_unlock();
>
> rte_free(te);
> +
> +free_memzone:
> + if (rte_memzone_free(r->memzone) != 0)
> + RTE_LOG(ERR, RING, "Cannot free memory\n");
> }
>
> /* dump the status of the ring on the console */
> --
> 2.33.0
