It seems that this modification ignores some certain cases, for example calling
rte_mempool_create_empty directly, maybe add a new flag bit to indicate
when to put tailq entry into rte_mempool_tailq list is a better way ?
Looking forward to any suggestions.
Thanks.
Fengnan Chang.
changfengnan <changfeng...@bytedance.com> 于2022年11月14日周一 15:14写道：
>
> rte_mempool_create put tailq entry into rte_mempool_tailq list before
> populate, and pool_data set when populate. So in multi process, if
> process A create mempool, and process B can get mempool through
> rte_mempool_lookup before pool_data set, if B call rte_mempool_lookup,
> it will cause segment fault.
> Fix this by put tailq entry into rte_mempool_tailq after populate.
>
> Signed-off-by: changfengnan <changfeng...@bytedance.com>
> ---
> lib/mempool/rte_mempool.c | 40 +++++++++++++++++++--------------------
> 1 file changed, 19 insertions(+), 21 deletions(-)
>
> diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
> index 4c78071a34..b23d6138ff 100644
> --- a/lib/mempool/rte_mempool.c
> +++ b/lib/mempool/rte_mempool.c
> @@ -798,9 +798,7 @@ rte_mempool_create_empty(const char *name, unsigned n,
> unsigned elt_size,
> int socket_id, unsigned flags)
> {
> char mz_name[RTE_MEMZONE_NAMESIZE];
> - struct rte_mempool_list *mempool_list;
> struct rte_mempool *mp = NULL;
> - struct rte_tailq_entry *te = NULL;
> const struct rte_memzone *mz = NULL;
> size_t mempool_size;
> unsigned int mz_flags = RTE_MEMZONE_1GB|RTE_MEMZONE_SIZE_HINT_ONLY;
> @@ -820,8 +818,6 @@ rte_mempool_create_empty(const char *name, unsigned n,
> unsigned elt_size,
> RTE_CACHE_LINE_MASK) != 0);
> #endif
>
> - mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head,
> rte_mempool_list);
> -
> /* asked for zero items */
> if (n == 0) {
> rte_errno = EINVAL;
> @@ -866,14 +862,6 @@ rte_mempool_create_empty(const char *name, unsigned n,
> unsigned elt_size,
> private_data_size = (private_data_size +
> RTE_MEMPOOL_ALIGN_MASK) &
> (~RTE_MEMPOOL_ALIGN_MASK);
>
> -
> - /* try to allocate tailq entry */
> - te = rte_zmalloc("MEMPOOL_TAILQ_ENTRY", sizeof(*te), 0);
> - if (te == NULL) {
> - RTE_LOG(ERR, MEMPOOL, "Cannot allocate tailq entry!\n");
> - goto exit_unlock;
> - }
> -
> mempool_size = RTE_MEMPOOL_HEADER_SIZE(mp, cache_size);
> mempool_size += private_data_size;
> mempool_size = RTE_ALIGN_CEIL(mempool_size, RTE_MEMPOOL_ALIGN);
> @@ -908,7 +896,6 @@ rte_mempool_create_empty(const char *name, unsigned n,
> unsigned elt_size,
> mp->private_data_size = private_data_size;
> STAILQ_INIT(&mp->elt_list);
> STAILQ_INIT(&mp->mem_list);
> -
> /*
> * local_cache pointer is set even if cache_size is zero.
> * The local_cache points to just past the elt_pa[] array.
> @@ -922,12 +909,6 @@ rte_mempool_create_empty(const char *name, unsigned n,
> unsigned elt_size,
> mempool_cache_init(&mp->local_cache[lcore_id],
> cache_size);
> }
> -
> - te->data = mp;
> -
> - rte_mcfg_tailq_write_lock();
> - TAILQ_INSERT_TAIL(mempool_list, te, next);
> - rte_mcfg_tailq_write_unlock();
> rte_mcfg_mempool_write_unlock();
>
> rte_mempool_trace_create_empty(name, n, elt_size, cache_size,
> @@ -936,7 +917,6 @@ rte_mempool_create_empty(const char *name, unsigned n,
> unsigned elt_size,
>
> exit_unlock:
> rte_mcfg_mempool_write_unlock();
> - rte_free(te);
> rte_mempool_free(mp);
> return NULL;
> }
> @@ -951,11 +931,22 @@ rte_mempool_create(const char *name, unsigned n,
> unsigned elt_size,
> {
> int ret;
> struct rte_mempool *mp;
> + struct rte_mempool_list *mempool_list;
> + struct rte_tailq_entry *te = NULL;
> +
> + /* try to allocate tailq entry */
> + te = rte_zmalloc("MEMPOOL_TAILQ_ENTRY", sizeof(*te), 0);
> + if (te == NULL) {
> + RTE_LOG(ERR, MEMPOOL, "Cannot allocate tailq entry!\n");
> + return NULL;
> + }
>
> mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
> private_data_size, socket_id, flags);
> - if (mp == NULL)
> + if (mp == NULL) {
> + rte_free(te);
> return NULL;
> + }
>
> /*
> * Since we have 4 combinations of the SP/SC/MP/MC examine the flags
> to
> @@ -984,12 +975,19 @@ rte_mempool_create(const char *name, unsigned n,
> unsigned elt_size,
> if (obj_init)
> rte_mempool_obj_iter(mp, obj_init, obj_init_arg);
>
> + te->data = mp;
> + mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head,
> rte_mempool_list);
> + rte_mcfg_tailq_write_lock();
> + TAILQ_INSERT_TAIL(mempool_list, te, next);
> + rte_mcfg_tailq_write_unlock();
> +
> rte_mempool_trace_create(name, n, elt_size, cache_size,
> private_data_size, mp_init, mp_init_arg, obj_init,
> obj_init_arg, flags, mp);
> return mp;
>
> fail:
> + rte_free(te);
> rte_mempool_free(mp);
> return NULL;
> }
> --
> 2.37.0 (Apple Git-136)
>
