From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f47.google.com (mail-pb0-f47.google.com [209.85.160.47]) by kanga.kvack.org (Postfix) with ESMTP id 55B1C6B0035 for ; Thu, 30 Jan 2014 17:39:54 -0500 (EST) Received: by mail-pb0-f47.google.com with SMTP id rp16so3699190pbb.20 for ; Thu, 30 Jan 2014 14:39:53 -0800 (PST) Received: from mail-pa0-x22b.google.com (mail-pa0-x22b.google.com [2607:f8b0:400e:c03::22b]) by mx.google.com with ESMTPS id g5si8093045pav.114.2014.01.30.14.39.53 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 30 Jan 2014 14:39:53 -0800 (PST) Received: by mail-pa0-f43.google.com with SMTP id rd3so3688230pab.16 for ; Thu, 30 Jan 2014 14:39:53 -0800 (PST) Date: Thu, 30 Jan 2014 14:39:51 -0800 (PST) From: David Rientjes Subject: Re: [PATCH] memcg: fix mutex not unlocked on memcg_create_kmem_cache fail path In-Reply-To: <20140130141538.a9e3977b5e7b76bdcf59a15f@linux-foundation.org> Message-ID: References: <1391097693-31401-1-git-send-email-vdavydov@parallels.com> <20140130130129.6f8bd7fd9da55d17a9338443@linux-foundation.org> <20140130132939.96a25a37016a12f9a0093a90@linux-foundation.org> <20140130135002.22ce1c12b7136f75e5985df6@linux-foundation.org> <20140130140902.93d35d866f9ea1c697811f6e@linux-foundation.org> <20140130141538.a9e3977b5e7b76bdcf59a15f@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Vladimir Davydov , mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, 30 Jan 2014, Andrew Morton wrote: > > It always was. > > eh? kmem_cache_create_memcg()'s kstrdup() will allocate the minimum > needed amount of memory. > Ah, good point. We could this incrementally on my patch: diff --git a/mm/memcontrol.c b/mm/memcontrol.c --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -637,6 +637,9 @@ int memcg_limited_groups_array_size; * better kept as an internal representation in cgroup.c. In any case, the * cgrp_id space is not getting any smaller, and we don't have to necessarily * increase ours as well if it increases. + * + * Updates to MAX_SIZE should update the space for the memcg name in + * memcg_create_kmem_cache(). */ #define MEMCG_CACHES_MIN_SIZE 4 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX @@ -3400,8 +3403,10 @@ void mem_cgroup_destroy_cache(struct kmem_cache *cachep) static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, struct kmem_cache *s) { - char *name = NULL; struct kmem_cache *new; + const char *cgrp_name; + char *name = NULL; + size_t len; BUG_ON(!memcg_can_account_kmem(memcg)); @@ -3409,9 +3414,22 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, if (unlikely(!name)) return NULL; + /* + * Format of a memcg's kmem cache name: + * (:) + */ + len = strlen(s->name); + /* Space for parentheses, colon, terminator */ + len += 4; + /* MEMCG_CACHES_MAX_SIZE is USHRT_MAX */ + len += 5; + BUILD_BUG_ON(MEMCG_CACHES_MAX_SIZE > USHRT_MAX); + rcu_read_lock(); - snprintf(name, PATH_MAX, "%s(%d:%s)", s->name, memcg_cache_id(memcg), - cgroup_name(memcg->css.cgroup)); + cgrp_name = cgroup_name(memcg->css.cgroup); + len += strlen(cgrp_name); + snprintf(name, len, "%s(%d:%s)", s->name, memcg_cache_id(memcg), + cgrp_name); rcu_read_unlock(); new = kmem_cache_create_memcg(memcg, name, s->object_size, s->align, -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org