Messages in this thread | | | Date | Tue, 09 Apr 2013 11:51:39 +0900 | From | Kamezawa Hiroyuki <> | Subject | Re: [PATCH 04/12] memcg, kmem: fix reference count handling on the error path |
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(2013/04/08 15:33), Li Zefan wrote: > From: Michal Hocko <mhocko@suse.cz> > > mem_cgroup_css_online calls mem_cgroup_put if memcg_init_kmem > fails. This is not correct because only memcg_propagate_kmem takes an > additional reference while mem_cgroup_sockets_init is allowed to fail as > well (although no current implementation fails) but it doesn't take any > reference. This all suggests that it should be memcg_propagate_kmem that > should clean up after itself so this patch moves mem_cgroup_put over > there. > > Unfortunately this is not that easy (as pointed out by Li Zefan) because > memcg_kmem_mark_dead marks the group dead (KMEM_ACCOUNTED_DEAD) if it > is marked active (KMEM_ACCOUNTED_ACTIVE) which is the case even if > memcg_propagate_kmem fails so the additional reference is dropped in > that case in kmem_cgroup_destroy which means that the reference would be > dropped two times. > > The easiest way then would be to simply remove mem_cgrroup_put from > mem_cgroup_css_online and rely on kmem_cgroup_destroy doing the right > thing. > > Signed-off-by: Li Zefan <lizefan@huawei.com> > Signed-off-by: Michal Hocko <mhocko@suse.cz> > Cc: <stable@vger.kernel.org> # 3.8.x
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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