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| author | Johannes Weiner <hannes@cmpxchg.org> | 2016-07-27 01:26:58 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-27 02:19:19 +0300 |
| commit | 1fe4d021acbc356723818a633fe0a10c59c2a4c1 (patch) | |
| tree | ee83530151ecf806ff619a1043fb4c035fc6d7cb | |
| parent | 25843c2b21d675c68e512daa4a2b50a18f7a840d (diff) | |
| download | linux-1fe4d021acbc356723818a633fe0a10c59c2a4c1.tar.xz | |
cgroup: fix idr leak for the first cgroup root
The valid cgroup hierarchy ID range includes 0, so we can't filter for
positive numbers when freeing it, or it'll leak the first ID. No big
deal, just disruptive when reading the code.
The ID is freed during error handling and when the reference count hits
zero, so the double-free test is not necessary; remove it.
Link: http://lkml.kernel.org/r/20160617162359.GB19084@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/cgroup.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 75c0ff00aca6..3108150e47b1 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1160,18 +1160,12 @@ static void cgroup_exit_root_id(struct cgroup_root *root) { lockdep_assert_held(&cgroup_mutex); - if (root->hierarchy_id) { - idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id); - root->hierarchy_id = 0; - } + idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id); } static void cgroup_free_root(struct cgroup_root *root) { if (root) { - /* hierarchy ID should already have been released */ - WARN_ON_ONCE(root->hierarchy_id); - idr_destroy(&root->cgroup_idr); kfree(root); } |