Since memcg caches are now reparented on memcg offline, a memcg cache
can outlive its cgroup. If the memcg id is then reused for a new cgroup
with the same name, we can get cache name collision, which will result
in failures while trying to add a sysfs entry for a new cgroup's cache.
Let's fix this by appending the cache address to sysfs names of all
memcg caches so that they are guaranteed to have unique names.
Signed-off-by: Vladimir Davydov <vdavy...@parallels.com>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Michal Hocko <mho...@suse.cz>
Cc: Glauber Costa <glom...@gmail.com>
Cc: Christoph Lameter <c...@linux-foundation.org>
Cc: Pekka Enberg <penb...@kernel.org>
---
mm/slub.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/mm/slub.c b/mm/slub.c
index 3ea91fb54f41..f5c74daeb46d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5236,7 +5236,18 @@ static int sysfs_slab_add(struct kmem_cache *s)
}
s->kobj.kset = cache_kset(s);
- err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
+ /*
+ * A memcg cache can outlive its cgroup. If the memcg id is then reused
+ * for a new cgroup with the same name, we can get cache name
+ * collision. To make sure all memcg caches have unique names on sysfs,
+ * we append the cache address to its name.
+ */
+ if (is_root_cache(s))
+ err = kobject_init_and_add(&s->kobj, &slab_ktype,
+ NULL, "%s", name);
+ else
+ err = kobject_init_and_add(&s->kobj, &slab_ktype,
+ NULL, "%s-%p", name, s);
if (err)
goto out_put_kobj;
--
1.7.10.4
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