Messages in this thread | | | Date | Mon, 19 Apr 2010 11:45:22 +0800 | From | Lai Jiangshan <> | Subject | Re: INFO: suspicious rcu_dereference_check() usage - include/linux/cgroup.h:492 invoked rcu_dereference_check() without protection! |
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Should be [tip:core/urgent]
Acked-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Paul E. McKenney wrote: > > Looks reasonable to me! > > Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > >> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> >> --- >> kernel/sched.c | 10 ++++++++++ >> 1 files changed, 10 insertions(+), 0 deletions(-) >> >> diff --git a/kernel/sched.c b/kernel/sched.c >> index 3acf694..2e06d87 100644 >> --- a/kernel/sched.c >> +++ b/kernel/sched.c >> @@ -323,6 +323,15 @@ static inline struct task_group *task_group(struct task_struct *p) >> /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ >> static inline void set_task_rq(struct task_struct *p, unsigned int cpu) >> { >> + /* >> + * Strictly speaking this rcu_read_lock() is not needed since the >> + * task_group is tied to the cgroup, which in turn can never go away >> + * as long as there are tasks attached to it. >> + * >> + * However since task_group() uses task_subsys_state() which is an >> + * rcu_dereference() user, this quiets CONFIG_PROVE_RCU. >> + */ >> + rcu_read_lock(); >> #ifdef CONFIG_FAIR_GROUP_SCHED >> p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; >> p->se.parent = task_group(p)->se[cpu]; >> @@ -332,6 +341,7 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) >> p->rt.rt_rq = task_group(p)->rt_rq[cpu]; >> p->rt.parent = task_group(p)->rt_se[cpu]; >> #endif >> + rcu_read_unlock(); >> } >> >> #else >> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >
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