cgroup: Fix an RCU warning in alloc_css_id()
authorLi Zefan <lizf@cn.fujitsu.com>
Thu, 22 Apr 2010 09:30:00 +0000 (17:30 +0800)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tue, 4 May 2010 16:25:00 +0000 (09:25 -0700)
commitfae9c791703606636c1220e47f6690660042ce7f
treec4d1bf20f4b73ee438ae2c3168b9b7ead1418215
parent9a9686b634acc5cb6b7c601c171ae64af0318a24
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>
kernel/cgroup.c