Messages in this thread Patch in this message | | | Date | Thu, 21 Mar 2013 09:22:21 +0800 | From | Li Zefan <> | Subject | [PATCH] memcg: fix memcg_cache_name() to use cgroup_name() |
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As cgroup supports rename, it's unsafe to dereference dentry->d_name without proper vfs locks. Fix this by using cgroup_name().
Signed-off-by: Li Zefan <lizefan@huawei.com> ---
This patch depends on "cgroup: fix cgroup_path() vs rename() race", which has been queued for 3.10.
--- mm/memcontrol.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 53b8201..72be5c9 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3217,17 +3217,16 @@ void mem_cgroup_destroy_cache(struct kmem_cache *cachep) static char *memcg_cache_name(struct mem_cgroup *memcg, struct kmem_cache *s) { char *name; - struct dentry *dentry; + + name = (char *)__get_free_page(GFP_TEMPORARY); + if (!name) + return NULL; rcu_read_lock(); - dentry = rcu_dereference(memcg->css.cgroup->dentry); + snprintf(name, PAGE_SIZE, "%s(%d:%s)", s->name, memcg_cache_id(memcg), + cgroup_name(memcg->css.cgroup)); rcu_read_unlock(); - BUG_ON(dentry == NULL); - - name = kasprintf(GFP_KERNEL, "%s(%d:%s)", s->name, - memcg_cache_id(memcg), dentry->d_name.name); - return name; } @@ -3247,7 +3246,7 @@ static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg, if (new) new->allocflags |= __GFP_KMEMCG; - kfree(name); + free_page((unsigned long)name); return new; } -- 1.8.0.2
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