aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorKirill Tkhai <ktkhai@virtuozzo.com>2018-08-02 15:36:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-02 16:03:40 -0700
commit7e97de0b033bcac4fa9a35cef72e0c06e6a22c67 (patch)
tree7c0d969f5f2e12e34e4f53a94f42bcba82a4ceed
parente30cb13c5a09ff5f043a6570c32e49b063bea6a1 (diff)
download96b-common-7e97de0b033bcac4fa9a35cef72e0c06e6a22c67.tar.gz
memcg: remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure
In case of memcg_online_kmem() failure, memcg_cgroup::id remains hashed in mem_cgroup_idr even after memcg memory is freed. This leads to leak of ID in mem_cgroup_idr. This patch adds removal into mem_cgroup_css_alloc(), which fixes the problem. For better readability, it adds a generic helper which is used in mem_cgroup_alloc() and mem_cgroup_id_put_many() as well. Link: http://lkml.kernel.org/r/152354470916.22460.14397070748001974638.stgit@localhost.localdomain Fixes 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs") Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8c0280b3143e..b2173f7e5164 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4037,6 +4037,14 @@ static struct cftype mem_cgroup_legacy_files[] = {
static DEFINE_IDR(mem_cgroup_idr);
+static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
+{
+ if (memcg->id.id > 0) {
+ idr_remove(&mem_cgroup_idr, memcg->id.id);
+ memcg->id.id = 0;
+ }
+}
+
static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
{
VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
@@ -4047,8 +4055,7 @@ 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;
+ mem_cgroup_id_remove(memcg);
/* Memcg ID pins CSS */
css_put(&memcg->css);
@@ -4185,8 +4192,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
return memcg;
fail:
- if (memcg->id.id > 0)
- idr_remove(&mem_cgroup_idr, memcg->id.id);
+ mem_cgroup_id_remove(memcg);
__mem_cgroup_free(memcg);
return NULL;
}
@@ -4245,6 +4251,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
return &memcg->css;
fail:
+ mem_cgroup_id_remove(memcg);
mem_cgroup_free(memcg);
return ERR_PTR(-ENOMEM);
}