From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Thu, 8 Jan 2009 02:07:38 +0000 (-0800)
Subject: cgroups: use task_lock() for access tsk->cgroups safe in cgroup_clone()
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=104cbd55377029e70fc2cee01089e84b9c36e5dc;p=openwrt%2Fstaging%2Fblogic.git

cgroups: use task_lock() for access tsk->cgroups safe in cgroup_clone()

Use task_lock() protect tsk->cgroups and get_css_set(tsk->cgroups).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a288da176e46..00d5136d38c2 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2903,6 +2903,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
 		mutex_unlock(&cgroup_mutex);
 		return 0;
 	}
+	task_lock(tsk);
 	cg = tsk->cgroups;
 	parent = task_cgroup(tsk, subsys->subsys_id);
 
@@ -2915,6 +2916,7 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
 
 	/* Keep the cgroup alive */
 	get_css_set(cg);
+	task_unlock(tsk);
 	mutex_unlock(&cgroup_mutex);
 
 	/* Now do the VFS work to create a cgroup */