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authorKirill Tkhai <ktkhai@virtuozzo.com>2018-08-02 15:36:01 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-05 09:20:04 +0200
commitf108e46efaac72dedc96204c9f235d6aa31c80fd (patch)
treeecb32171e59832b8865170d55fa50a36dc6776c3 /mm
parenta6c6516eee1591bc09cf3dd839f71e023dae5ddf (diff)
memcg: remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure
[ Upstream commit 7e97de0b033bcac4fa9a35cef72e0c06e6a22c67 ] 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> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 349f4a8e3c4f..86a6b331b964 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4072,6 +4072,14 @@ 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);
@@ -4082,8 +4090,7 @@ 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);
@@ -4208,8 +4215,7 @@ 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;
}
@@ -4268,6 +4274,7 @@ 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);
}