From: Roman Gushchin guro@fb.com
mainline inclusion from mainline-5.3-rc1 commit 570332978ea7fdbec86a07086a584d796a87da2c category: bugfix bugzilla: 34611 CVE: NA
------------------------------------------------- There is no point in checking the root_cache->memcg_params.dying flag on kmem_cache creation path. New allocations shouldn't be performed using a dead root kmem_cache, so no new memcg kmem_cache creation can be scheduled after the flag is set. And if it was scheduled before, flush_memcg_workqueue() will wait for it anyway.
So let's drop this check to simplify the code.
Link: http://lkml.kernel.org/r/20190611231813.3148843-7-guro@fb.com Signed-off-by: Roman Gushchin guro@fb.com Acked-by: Vladimir Davydov vdavydov.dev@gmail.com Reviewed-by: Shakeel Butt shakeelb@google.com Cc: Christoph Lameter cl@linux.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Michal Hocko mhocko@suse.com Cc: Waiman Long longman@redhat.com Cc: David Rientjes rientjes@google.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Pekka Enberg penberg@kernel.org Cc: Andrei Vagin avagin@gmail.com Cc: Qian Cai cai@lca.pw Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit 570332978ea7fdbec86a07086a584d796a87da2c) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/slab_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/slab_common.c b/mm/slab_common.c index 318d2527bc0b..9e2111ae8e16 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -622,7 +622,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg, * The memory cgroup could have been offlined while the cache * creation work was pending. */ - if (memcg->kmem_state != KMEM_ONLINE || root_cache->memcg_params.dying) + if (memcg->kmem_state != KMEM_ONLINE) goto out_unlock;
idx = memcg_cache_id(memcg);