From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753453AbbANODl (ORCPT ); Wed, 14 Jan 2015 09:03:41 -0500 Received: from terminus.zytor.com ([198.137.202.10]:36898 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753388AbbANODg (ORCPT ); Wed, 14 Jan 2015 09:03:36 -0500 Date: Wed, 14 Jan 2015 06:03:07 -0800 From: tip-bot for Peter Zijlstra Message-ID: Cc: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, hpa@zytor.com Reply-To: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com, mingo@kernel.org In-Reply-To: <20150105103554.361872747@infradead.org> References: <20150105103554.361872747@infradead.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/core: Validate rq_clock*() serialization Git-Commit-ID: cebde6d681aa45f96111cfcffc1544cf2a0454ff X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: cebde6d681aa45f96111cfcffc1544cf2a0454ff Gitweb: http://git.kernel.org/tip/cebde6d681aa45f96111cfcffc1544cf2a0454ff Author: Peter Zijlstra AuthorDate: Mon, 5 Jan 2015 11:18:10 +0100 Committer: Ingo Molnar CommitDate: Wed, 14 Jan 2015 13:34:19 +0100 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) Link: http://lkml.kernel.org/r/20150105103554.361872747@infradead.org Cc: Linus Torvalds Cc: umgwanakikbuti@gmail.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- kernel/sched/sched.h | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2a0b302..50ff902 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 9a2a45c..bd23732 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; }