diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2020-12-14 19:06:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 12:13:39 -0800 |
| commit | 2f7659a314736b32b66273dbf91c19874a052fde (patch) | |
| tree | 29c4d92b3052ea1d5187ad38ac5fba91c5bb4413 | |
| parent | 378876b0e3782daacb7848db03679d6f76c82265 (diff) | |
| download | linux-2f7659a314736b32b66273dbf91c19874a052fde.tar.gz linux-2f7659a314736b32b66273dbf91c19874a052fde.tar.bz2 linux-2f7659a314736b32b66273dbf91c19874a052fde.zip | |
mm: memcg/slab: fix return of child memcg objcg for root memcg
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.
Link: https://lkml.kernel.org/r/20201029164429.58703-1-songmuchun@bytedance.com
Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eugene Syromiatnikov <esyr@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Adrian Reber <areber@redhat.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/memcontrol.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2e13c0a419fc..4ac4d5edada4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2975,6 +2975,7 @@ __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(); |