Messages in this thread | | | Date | Mon, 29 Mar 2010 15:43:43 -0700 | Subject | Re: [PATCH tip/core/urgent] rcu: protect fork-time cgroup access | From | Paul Menage <> |
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On Mon, Mar 29, 2010 at 2:15 PM, Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote: > Add an rcu_read_lock() / rcu_read_unlock() pair to protect a fork-time > cgroup access. This seems likely to be a false positive. > > Located by: Alessio Igor Bogani <abogani@texware.it> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > --- > > sched.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/sched.c b/kernel/sched.c > index 9ab3cd7..d4bb5e0 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -2621,7 +2621,9 @@ void sched_fork(struct task_struct *p, int clone_flags) > if (p->sched_class->task_fork) > p->sched_class->task_fork(p); > > + rcu_read_lock(); > set_task_cpu(p, cpu); > + rcu_read_unlock();
I think you're right that this is a false positive - it would only be a problem if it were possible for the task to be moved to a different cgroup, and I think that shouldn't be the case at this point in the fork path since the new process isn't visible on the tasklist yet, right?
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