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authorPeter Zijlstra <peterz@infradead.org>2015-01-05 11:18:10 +0100
committerIngo Molnar <mingo@kernel.org>2015-01-14 13:34:19 +0100
commitcebde6d681aa45f96111cfcffc1544cf2a0454ff (patch)
tree87cfce57adc5dde39b37ee7bc2e665d572f8117a /kernel/sched
parent1b537c7d1e58c761212a193085f9049b58f672e6 (diff)
sched/core: Validate rq_clock*() serialization
rq->clock{,_task} are serialized by rq->lock, verify this. One immediate fail is the usage in scale_rt_capability, so 'annotate' that for now, there's more 'funny' there. Maybe change rq->lock into a raw_seqlock_t? (Only 32-bit is affected) Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/20150105103554.361872747@infradead.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: umgwanakikbuti@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/fair.c2
-rw-r--r--kernel/sched/sched.h7
2 files changed, 8 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2a0b302e51de..50ff90289293 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5948,8 +5948,8 @@ static unsigned long scale_rt_capacity(int cpu)
*/
age_stamp = ACCESS_ONCE(rq->age_stamp);
avg = ACCESS_ONCE(rq->rt_avg);
+ delta = __rq_clock_broken(rq) - age_stamp;
- delta = rq_clock(rq) - age_stamp;
if (unlikely(delta < 0))
delta = 0;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 9a2a45c970e7..bd2373273a9e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -687,13 +687,20 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
#define raw_rq() raw_cpu_ptr(&runqueues)
+static inline u64 __rq_clock_broken(struct rq *rq)
+{
+ return ACCESS_ONCE(rq->clock);
+}
+
static inline u64 rq_clock(struct rq *rq)
{
+ lockdep_assert_held(&rq->lock);
return rq->clock;
}
static inline u64 rq_clock_task(struct rq *rq)
{
+ lockdep_assert_held(&rq->lock);
return rq->clock_task;
}