memcg: remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure
authorKirill Tkhai <ktkhai@virtuozzo.com>
Thu, 2 Aug 2018 22:36:01 +0000 (15:36 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 5 Sep 2018 07:20:04 +0000 (09:20 +0200)
commitf108e46efaac72dedc96204c9f235d6aa31c80fd
treeecb32171e59832b8865170d55fa50a36dc6776c3
parenta6c6516eee1591bc09cf3dd839f71e023dae5ddf
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>
mm/memcontrol.c