From: Peter Zijlstra Date: Wed, 15 Oct 2008 18:37:23 +0000 (+0200) Subject: sched: only update rq->clock while holding rq->lock X-Git-Tag: v2.6.28-rc1~43^2~9 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=8cd162ce230b154e564a1285bb5f89fcf73f0dce;p=linux-2.6-omap-h63xx.git sched: only update rq->clock while holding rq->lock Vatsa noticed rq->clock going funny and tracked it down to an update_rq_clock() outside a rq->lock section. This is a problem because things like double_rq_lock() update the rq->clock value for both rqs. Therefore disabling interrupts isn't strong enough. Reported-by: Srivatsa Vaddagiri Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched.c b/kernel/sched.c index 6f230596bd0..c530b84c7f8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4441,12 +4441,8 @@ need_resched_nonpreemptible: if (sched_feat(HRTICK)) hrtick_clear(rq); - /* - * Do the rq-clock update outside the rq lock: - */ - local_irq_disable(); + spin_lock_irq(&rq->lock); update_rq_clock(rq); - spin_lock(&rq->lock); clear_tsk_need_resched(prev); if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {