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authorKirill Tkhai <ktkhai@parallels.com>2014-09-30 12:23:37 +0400
committerIngo Molnar <mingo@kernel.org>2014-10-03 05:46:58 +0200
commitf10e00f4bf360c36edbe6bf18a6c75b171cbe012 (patch)
tree0733366372b97784b82acafa6d0fc0a57f62e27b /kernel
parent10a12983b3d437a6998b3845870e52c1c752c101 (diff)
downloadop-kernel-dev-f10e00f4bf360c36edbe6bf18a6c75b171cbe012.zip
op-kernel-dev-f10e00f4bf360c36edbe6bf18a6c75b171cbe012.tar.gz
sched/dl: Use dl_bw_of() under rcu_read_lock_sched()
rq->rd is freed using call_rcu_sched(), so rcu_read_lock() to access it is not enough. We should use either rcu_read_lock_sched() or preempt_disable(). Reported-by: Sasha Levin <sasha.levin@oracle.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kirill Tkhai <ktkhai@parallels.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Fixes: 66339c31bc39 "sched: Use dl_bw_of() under RCU read lock" Link: http://lkml.kernel.org/r/1412065417.20287.24.camel@tkhai Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c25
1 files changed, 16 insertions, 9 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b5349fe..c84bdc0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5264,6 +5264,7 @@ static int sched_cpu_inactive(struct notifier_block *nfb,
{
unsigned long flags;
long cpu = (long)hcpu;
+ struct dl_bw *dl_b;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_PREPARE:
@@ -5271,15 +5272,19 @@ static int sched_cpu_inactive(struct notifier_block *nfb,
/* explicitly allow suspend */
if (!(action & CPU_TASKS_FROZEN)) {
- struct dl_bw *dl_b = dl_bw_of(cpu);
bool overflow;
int cpus;
+ rcu_read_lock_sched();
+ dl_b = dl_bw_of(cpu);
+
raw_spin_lock_irqsave(&dl_b->lock, flags);
cpus = dl_bw_cpus(cpu);
overflow = __dl_overflow(dl_b, cpus, 0, 0);
raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+ rcu_read_unlock_sched();
+
if (overflow)
return notifier_from_errno(-EBUSY);
}
@@ -7647,11 +7652,10 @@ static int sched_dl_global_constraints(void)
u64 runtime = global_rt_runtime();
u64 period = global_rt_period();
u64 new_bw = to_ratio(period, runtime);
+ struct dl_bw *dl_b;
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
@@ -7662,25 +7666,27 @@ static int sched_dl_global_constraints(void)
* solutions is welcome!
*/
for_each_possible_cpu(cpu) {
- struct dl_bw *dl_b = dl_bw_of(cpu);
+ rcu_read_lock_sched();
+ dl_b = dl_bw_of(cpu);
raw_spin_lock_irqsave(&dl_b->lock, flags);
if (new_bw < dl_b->total_bw)
ret = -EBUSY;
raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+ rcu_read_unlock_sched();
+
if (ret)
break;
}
- rcu_read_unlock();
-
return ret;
}
static void sched_dl_do_global(void)
{
u64 new_bw = -1;
+ struct dl_bw *dl_b;
int cpu;
unsigned long flags;
@@ -7690,18 +7696,19 @@ 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...
*/
for_each_possible_cpu(cpu) {
- struct dl_bw *dl_b = dl_bw_of(cpu);
+ rcu_read_lock_sched();
+ dl_b = dl_bw_of(cpu);
raw_spin_lock_irqsave(&dl_b->lock, flags);
dl_b->bw = new_bw;
raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+
+ rcu_read_unlock_sched();
}
- rcu_read_unlock();
}
static int sched_rt_global_validate(void)
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