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| author | Vladimir Davydov <vdavydov@parallels.com> | 2014-04-08 02:39:27 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-08 03:36:12 +0400 |
| commit | 051dd46050f2a9bdfff8cc067f8987069eae1743 (patch) | |
| tree | 64ccd763fcdda9a1087063f154f0d96fc6ab573a /mm/slab_common.c | |
| parent | 794b1248be4e7e157f5535c3ee49168aa4643349 (diff) | |
| download | linux-051dd46050f2a9bdfff8cc067f8987069eae1743.tar.xz | |
memcg, slab: unregister cache from memcg before starting to destroy it
Currently, memcg_unregister_cache(), which deletes the cache being
destroyed from the memcg_slab_caches list, is called after
__kmem_cache_shutdown() (see kmem_cache_destroy()), which starts to
destroy the cache.
As a result, one can access a partially destroyed cache while traversing
a memcg_slab_caches list, which can have deadly consequences (for
instance, cache_show() called for each cache on a memcg_slab_caches list
from mem_cgroup_slabinfo_read() will dereference pointers to already
freed data).
To fix this, let's move memcg_unregister_cache() before the cache
destruction process beginning, issuing memcg_register_cache() on failure.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Glauber Costa <glommer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab_common.c')
| -rw-r--r-- | mm/slab_common.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index ccc012f00126..0c2879ff414c 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -313,9 +313,9 @@ void kmem_cache_destroy(struct kmem_cache *s) s->refcount--; if (!s->refcount) { list_del(&s->list); + memcg_unregister_cache(s); if (!__kmem_cache_shutdown(s)) { - memcg_unregister_cache(s); mutex_unlock(&slab_mutex); if (s->flags & SLAB_DESTROY_BY_RCU) rcu_barrier(); @@ -325,6 +325,7 @@ void kmem_cache_destroy(struct kmem_cache *s) kmem_cache_free(kmem_cache, s); } else { list_add(&s->list, &slab_caches); + memcg_register_cache(s); mutex_unlock(&slab_mutex); printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n", s->name); |