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| author | Kirill Tkhai <ktkhai@virtuozzo.com> | 2018-08-02 15:36:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-02 16:03:40 -0700 |
| commit | 7e97de0b033bcac4fa9a35cef72e0c06e6a22c67 (patch) | |
| tree | 7c0d969f5f2e12e34e4f53a94f42bcba82a4ceed /mm/memcontrol.c | |
| parent | e30cb13c5a09ff5f043a6570c32e49b063bea6a1 (diff) | |
| download | lwn-7e97de0b033bcac4fa9a35cef72e0c06e6a22c67.tar.gz lwn-7e97de0b033bcac4fa9a35cef72e0c06e6a22c67.zip | |
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>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 15 |
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); } |