The patch titled
Subject: cgroup: fix idr leak for the first cgroup root
has been added to the -mm tree. Its filename is
cgroup-fix-idr-leak-for-the-first-cgroup-root.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/cgroup-fix-idr-leak-for-the-first-cgroup-root.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/cgroup-fix-idr-leak-for-the-first-cgroup-root.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: 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@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Nikolay Borisov <kernel@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff -puN kernel/cgroup.c~cgroup-fix-idr-leak-for-the-first-cgroup-root kernel/cgroup.c
--- a/kernel/cgroup.c~cgroup-fix-idr-leak-for-the-first-cgroup-root
+++ a/kernel/cgroup.c
@@ -1158,18 +1158,12 @@ static void cgroup_exit_root_id(struct c
{
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);
}
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
cgroup-fix-idr-leak-for-the-first-cgroup-root.patch
cgroup-remove-unnecessary-0-check-from-css_from_id.patch
mm-memcontrol-fix-cgroup-creation-failure-after-many-small-jobs.patch
mm-memcontrol-fix-cgroup-creation-failure-after-many-small-jobs-fix.patch
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