From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Paul Menage <menage@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>
Subject: [PATCH] cpuset: rcu_read_lock() to protect task_cs() even we don't dereference to task_cs()'s return value
Date: Fri, 21 Nov 2008 16:49:40 +0800 [thread overview]
Message-ID: <49267624.70305@cn.fujitsu.com> (raw)
task_cs() calls cgroup_subsys_state().
we must use rcu_read_lock() to protect cgroup_subsys_state().
in current_cpuset_is_being_rebound(), we don't dereference to task_cs()'s
return value, but task_cs() accesses css_set, this css_set maybe freed
when task_cs() called.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3e00526..e0e087e 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1141,7 +1136,11 @@ done:
int current_cpuset_is_being_rebound(void)
{
- return task_cs(current) == cpuset_being_rebound;
+ struct cpuset *cs;
+ rcu_read_lock();
+ cs = task_cs(current);
+ rcu_read_unlock();
+ return cs == cpuset_being_rebound;
}
static int update_relax_domain_level(struct cpuset *cs, s64 val)
next reply other threads:[~2008-11-21 8:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-21 8:49 Lai Jiangshan [this message]
2008-11-21 19:05 ` [PATCH] cpuset: rcu_read_lock() to protect task_cs() even we don't dereference to task_cs()'s return value Paul Menage
2008-11-21 19:07 ` Paul Menage
2008-11-22 3:01 ` Lai Jiangshan
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