Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 66339c31 authored by Kirill Tkhai's avatar Kirill Tkhai Committed by Ingo Molnar
Browse files

sched: Use dl_bw_of() under RCU read lock 



dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
Probability of use-after-free isn't zero here.

Also add lockdep assert into dl_bw_cpus().

Signed-off-by: default avatarKirill Tkhai <ktkhai@parallels.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7a96c231

kernel/sched/core.c

+10 −0
Original line number Diff line number Diff line
@@ -2021,6 +2021,8 @@ unsigned long to_ratio(u64 period, u64 runtime) 
#ifdef CONFIG_SMP

inline struct dl_bw *dl_bw_of(int i)

{

	rcu_lockdep_assert(rcu_read_lock_sched_held(),

			   "sched RCU must be held");

	return &cpu_rq(i)->rd->dl_bw;

}
@@ -2029,6 +2031,8 @@ static inline int dl_bw_cpus(int i) 
	struct root_domain *rd = cpu_rq(i)->rd;

	int cpus = 0;



	rcu_lockdep_assert(rcu_read_lock_sched_held(),

			   "sched RCU must be held");

	for_each_cpu_and(i, rd->span, cpu_active_mask)

		cpus++;
@@ -7645,6 +7649,8 @@ static int sched_dl_global_constraints(void) 
	int cpu, ret = 0;

	unsigned long flags;



	rcu_read_lock();



	/*

	 * Here we want to check the bandwidth not being set to some

	 * value smaller than the currently allocated bandwidth in
@@ -7666,6 +7672,8 @@ static int sched_dl_global_constraints(void) 
			break;

	}



	rcu_read_unlock();



	return ret;

}
@@ -7681,6 +7689,7 @@ static void sched_dl_do_global(void) 
	if (global_rt_runtime() != RUNTIME_INF)

		new_bw = to_ratio(global_rt_period(), global_rt_runtime());



	rcu_read_lock();

	/*

	 * FIXME: As above...

	 */
@@ -7691,6 +7700,7 @@ static void sched_dl_do_global(void) 
		dl_b->bw = new_bw;

		raw_spin_unlock_irqrestore(&dl_b->lock, flags);

	}

	rcu_read_unlock();

}



static int sched_rt_global_validate(void)