Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751558AbaBLJtn (ORCPT ); Wed, 12 Feb 2014 04:49:43 -0500 Received: from merlin.infradead.org ([205.233.59.134]:58984 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbaBLJtl (ORCPT ); Wed, 12 Feb 2014 04:49:41 -0500 Date: Wed, 12 Feb 2014 10:49:30 +0100 From: Peter Zijlstra To: Dan Carpenter Cc: kbuild@01.org, Ingo Molnar , linux-kernel@vger.kernel.org Subject: [PATCH] sched: Fix rt/dl hotplug condition Message-ID: <20140212094930.GB3545@laptop.programming.kicks-ass.net> References: <20140212090222.GK26776@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140212090222.GK26776@mwanda> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dan Carpenter reported: > kernel/sched/rt.c:1347 pick_next_task_rt() warn: variable dereferenced before check 'prev' (see line 1338) > kernel/sched/deadline.c:1011 pick_next_task_dl() warn: variable dereferenced before check 'prev' (see line 1005) Cc: Steven Rostedt Cc: Juri Lelli Fixes: 38033c37faab ("sched: Push down pre_schedule() and idle_balance()") Reported-by: Dan Carpenter Signed-off-by: Peter Zijlstra --- kernel/sched/deadline.c | 2 +- kernel/sched/rt.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index ed31ef66ab9d..d60008e4bce9 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1001,7 +1001,7 @@ struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev) dl_rq = &rq->dl; #ifdef CONFIG_SMP - if (dl_task(prev)) + if (prev && dl_task(prev)) pull_dl_task(rq); #endif diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 72f9ec759972..7294b498b2c1 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1334,7 +1334,7 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev) #ifdef CONFIG_SMP /* Try to pull RT tasks here if we lower this rq's prio */ - if (rq->rt.highest_prio.curr > prev->prio) + if (prev && (rq->rt.highest_prio.curr > prev->prio)) pull_rt_task(rq); #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/