Re: [dpdk-dev] [PATCH] lpm: fix freeing of rules_tbl in rte_lpm_free_v20

[Thomas Monjalon <thomas.monjalon@6wind.com>]

> > Back then when we fixed the missing free lpm I was to quickly to say yes
> > if it applies not only to the lpm6 but also to all of the lpm code.
> >
> > It turned out to not apply to all of them. In rte_lpm_create_v20 there
> > is an unexpected fused allocation:
> > mem_size = sizeof(*lpm) + (sizeof(lpm->rules_tbl[0]) * max_rules);
> > [...]
> > lpm = (struct rte_lpm_v20 *)rte_zmalloc_socket(mem_name,mem_size,
> >                 RTE_CACHE_LINE_SIZE, socket_id);
> >
> > That causes lpm->rules_tbl not to have an own struct malloc_elem that
> > can be derived via RTE_PTR_SUB(data, MALLOC_ELEM_HEADER_LEN) in
> > malloc_elem_from_data.
> > Due to that the rte_lpm_free_v20 accidentially misderives the elem and
> > assumes it is ELEM_FREE triggering in malloc_elem_free
> > if (!malloc_elem_cookies_ok(elem) || elem->state !=
> >          return -1;
> >
> > While it seems counter-intuitive the way to properly remove rules_tbl in
> > the old fused allocation style of rte_lpm_free_v20 is to not remove it.
> >
> > The newer rte_lpm_free_v1604 is safe because in rte_lpm_create_v1604
> > rules_tbl is a separate allocation.
> >
> > Fixes: d4c18f0a1d5d ("lpm: fix missing free")
> >
> > Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>
> 
> Thanks, I missed it too during the review.

Applied, thanks