Messages in this thread | | | Date | Tue, 2 Aug 2016 18:01:04 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH v2 3/3] mm: memcontrol: add sanity checks for memcg->id.ref on get/put |
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On Tue 02-08-16 18:00:50, Vladimir Davydov wrote: > Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
> --- > mm/memcontrol.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 67109d556a4a..32b2f33865f9 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4033,6 +4033,7 @@ static DEFINE_IDR(mem_cgroup_idr); > > static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) > { > + VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0); > atomic_add(n, &memcg->id.ref); > } > > @@ -4056,6 +4057,7 @@ static struct mem_cgroup *mem_cgroup_id_get_active(struct mem_cgroup *memcg) > > static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) > { > + VM_BUG_ON(atomic_read(&memcg->id.ref) < n); > if (atomic_sub_and_test(n, &memcg->id.ref)) { > idr_remove(&mem_cgroup_idr, memcg->id.id); > memcg->id.id = 0; > @@ -4176,6 +4178,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void) > INIT_LIST_HEAD(&memcg->cgwb_list); > #endif > idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); > + atomic_set(&memcg->id.ref, 1); > return memcg; > fail: > if (memcg->id.id > 0) > @@ -4245,7 +4248,6 @@ fail: > static int mem_cgroup_css_online(struct cgroup_subsys_state *css) > { > /* Online state pins memcg ID, memcg ID pins CSS */ > - mem_cgroup_id_get(mem_cgroup_from_css(css)); > css_get(css); > return 0; > } > -- > 2.1.4
-- Michal Hocko SUSE Labs
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