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authorLi Zefan <lizf@cn.fujitsu.com>2010-04-22 17:30:00 +0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-05-04 09:25:00 -0700
commitfae9c791703606636c1220e47f6690660042ce7f (patch)
treec4d1bf20f4b73ee438ae2c3168b9b7ead1418215
parent9a9686b634acc5cb6b7c601c171ae64af0318a24 (diff)
downloadlinux-fae9c791703606636c1220e47f6690660042ce7f.tar.bz2
cgroup: Fix an RCU warning in alloc_css_id()
With CONFIG_PROVE_RCU=y, a warning can be triggered: # mount -t cgroup -o memory xxx /mnt # mkdir /mnt/0 ... kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection! ... This is a false-positive. It's safe to directly access parent_css->id. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--kernel/cgroup.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 4ca928db890c..3a53c771e503 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4561,13 +4561,13 @@ static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent,
{
int subsys_id, i, depth = 0;
struct cgroup_subsys_state *parent_css, *child_css;
- struct css_id *child_id, *parent_id = NULL;
+ struct css_id *child_id, *parent_id;
subsys_id = ss->subsys_id;
parent_css = parent->subsys[subsys_id];
child_css = child->subsys[subsys_id];
- depth = css_depth(parent_css) + 1;
parent_id = parent_css->id;
+ depth = parent_id->depth;
child_id = get_new_cssid(ss, depth);
if (IS_ERR(child_id))