From: Muchun Song <songmuchun@bytedance.com>
To: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
akpm@linux-foundation.org, shakeelb@google.com, guro@fb.com,
iamjoonsoo.kim@lge.com, laoar.shao@gmail.com,
chris@chrisdown.name, christian.brauner@ubuntu.com,
peterz@infradead.org, mingo@kernel.org, keescook@chromium.org,
tglx@linutronix.de, esyr@redhat.com, surenb@google.com,
areber@redhat.com, elver@google.com
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH 1/5] mm: memcg/slab: Fix return child memcg objcg for root memcg
Date: Tue, 27 Oct 2020 16:02:52 +0800 [thread overview]
Message-ID: <20201027080256.76497-2-songmuchun@bytedance.com> (raw)
In-Reply-To: <20201027080256.76497-1-songmuchun@bytedance.com>
Consider the following memcg hierarchy.
root
/ \
A B
If we get the objcg of memcg A failed, 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>
---
mm/memcontrol.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1337775b04f3..fcbd79c5023e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2945,7 +2945,7 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
{
- struct obj_cgroup *objcg = NULL;
+ struct obj_cgroup *objcg;
struct mem_cgroup *memcg;
if (memcg_kmem_bypass())
@@ -2964,6 +2964,9 @@ __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
}
rcu_read_unlock();
+ if (memcg == root_mem_cgroup)
+ return NULL;
+
return objcg;
}
--
2.20.1
next prev parent reply other threads:[~2020-10-27 8:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 8:02 [PATCH 0/5] Fix some bugs in memcg/slab Muchun Song
2020-10-27 8:02 ` Muchun Song [this message]
2020-10-27 17:42 ` [PATCH 1/5] mm: memcg/slab: Fix return child memcg objcg for root memcg Roman Gushchin
2020-10-27 19:05 ` Roman Gushchin
2020-10-27 8:02 ` [PATCH 2/5] mm: memcg/slab: Fix use after free in obj_cgroup_charge Muchun Song
2020-10-27 18:31 ` Roman Gushchin
2020-10-27 8:02 ` [PATCH 3/5] mm: memcg/slab: Rename *_lruvec_slab_state to *_lruvec_kmem_state Muchun Song
2020-10-27 18:37 ` Roman Gushchin
2020-10-27 8:02 ` [PATCH 4/5] mm: memcg/slab: Fix root memcg vmstats Muchun Song
2020-10-27 18:48 ` Roman Gushchin
2020-10-28 2:56 ` [External] " Muchun Song
2020-10-28 3:47 ` Muchun Song
2020-10-29 0:14 ` Roman Gushchin
2020-10-29 6:15 ` Muchun Song
2020-11-10 1:32 ` Roman Gushchin
2020-11-10 2:57 ` Muchun Song
2020-10-27 8:02 ` [PATCH 5/5] mm: memcontrol: Simplify the mem_cgroup_page_lruvec Muchun Song
2020-10-27 13:36 ` Michal Hocko
2020-10-27 14:15 ` [External] " Muchun Song
2020-10-27 14:31 ` Michal Hocko
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