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-rw-r--r--mm/slab_common.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 8afa188f6e20..f0ab6d4ceb4c 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -904,6 +904,18 @@ static void flush_memcg_workqueue(struct kmem_cache *s)
* previous workitems on workqueue are processed.
*/
flush_workqueue(memcg_kmem_cache_wq);
+
+ /*
+ * If we're racing with children kmem_cache deactivation, it might
+ * take another rcu grace period to complete their destruction.
+ * At this moment the corresponding percpu_ref_kill() call should be
+ * done, but it might take another rcu grace period to complete
+ * switching to the atomic mode.
+ * Please, note that we check without grabbing the slab_mutex. It's safe
+ * because at this moment the children list can't grow.
+ */
+ if (!list_empty(&s->memcg_params.children))
+ rcu_barrier();
}
#else
static inline int shutdown_memcg_caches(struct kmem_cache *s)