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| author | Wenwei Tao <ww.tao0320@gmail.com> | 2016-05-13 22:59:20 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2016-05-26 15:09:23 -0400 |
| commit | b00c52dae6d9ee8d0f2407118ef6544ae5524781 (patch) | |
| tree | 458e49e47efd51634d11c09d00e10f147e47f1e1 /kernel/cgroup.c | |
| parent | ea8ea737c46cffa5d0ee74309f81e55a7e5e9c2a (diff) | |
| download | linux-b00c52dae6d9ee8d0f2407118ef6544ae5524781.tar.gz linux-b00c52dae6d9ee8d0f2407118ef6544ae5524781.tar.bz2 linux-b00c52dae6d9ee8d0f2407118ef6544ae5524781.zip | |
cgroup: remove redundant cleanup in css_create
When create css failed, before call css_free_rcu_fn, we remove the css
id and exit the percpu_ref, but we will do these again in
css_free_work_fn, so they are redundant. Especially the css id, that
would cause problem if we remove it twice, since it may be assigned to
another css after the first remove.
tj: This was broken by two commits updating the free path without
synchronizing the creation failure path. This can be easily
triggered by trying to create more than 64k memory cgroups.
Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Fixes: 9a1049da9bd2 ("percpu-refcount: require percpu_ref to be exited explicitly")
Fixes: 01e586598b22 ("cgroup: release css->id after css_free")
Cc: stable@vger.kernel.org # v3.17+
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 86cb5c6e8932..789b84f973c9 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5150,7 +5150,7 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp, err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_KERNEL); if (err < 0) - goto err_free_percpu_ref; + goto err_free_css; css->id = err; /* @css is ready to be brought online now, make it visible */ @@ -5174,9 +5174,6 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp, err_list_del: list_del_rcu(&css->sibling); - cgroup_idr_remove(&ss->css_idr, css->id); -err_free_percpu_ref: - percpu_ref_exit(&css->refcnt); err_free_css: call_rcu(&css->rcu_head, css_free_rcu_fn); return ERR_PTR(err); |