Messages in this thread Patch in this message | | | From | Muchun Song <> | Subject | [PATCH v3] mm: memcg/slab: Fix return child memcg objcg for root memcg | Date | Fri, 30 Oct 2020 00:44:29 +0800 |
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Consider the following memcg hierarchy.
root / \ A B
If we failed to get the reference on objcg of memcg A, the get_obj_cgroup_from_current can return the wrong objcg for the root memcg.
Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Roman Gushchin <guro@fb.com> --- changelog in v3: 1. Fix commit grammar, thanks to Shakeel.
changelog in v2: 1. Do not use a comparison with the root_mem_cgroup
mm/memcontrol.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1337775b04f3..8c8b4c3ed5a0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2961,6 +2961,7 @@ __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) objcg = rcu_dereference(memcg->objcg); if (objcg && obj_cgroup_tryget(objcg)) break; + objcg = NULL; } rcu_read_unlock(); -- 2.20.1
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