linux-kernel - [PATCH 7/7] sched/rt: reschedule if stop/dl task slip in after pull operations

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  6 Apr 2015 16:53:19 +0800
From:	Wanpeng Li <wanpeng.li@...ux.intel.com>
To:	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>
Cc:	Juri Lelli <juri.lelli@....com>, linux-kernel@...r.kernel.org,
	Wanpeng Li <wanpeng.li@...ux.intel.com>
Subject: [PATCH 7/7] sched/rt: reschedule if stop/dl task slip in after pull operations

pull_rt_task() can drop (and re-acquire) rq->lock, this means a dl or stop task 
can slip in, in which case need to reschedule. This patch add the reschedule
when the scenario occurs.

Signed-off-by: Wanpeng Li <wanpeng.li@...ux.intel.com>
---
 kernel/sched/rt.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 575da76..cc973e8 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2136,7 +2136,14 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p)
 	if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
 		return;
 
-	if (pull_rt_task(rq))
+	/*
+	 * pull_rt_task() can drop (and re-acquire) rq->lock; this
+	 * means a dl or stop task can slip in, in which case we need
+	 * to reschedule.
+	 */
+	if (pull_rt_task(rq) ||
+		(unlikely((rq->stop && task_on_rq_queued(rq->stop)) ||
+			rq->dl.dl_nr_running)))
 		resched_curr(rq);
 }
 
@@ -2197,6 +2204,16 @@ prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
 		 */
 		if (oldprio < p->prio)
 			pull_rt_task(rq);
+
+		/*
+		 * pull_rt_task() can drop (and re-acquire) rq->lock; this
+		 * means a dl or stop task can slip in, in which case we need
+		 * to reschedule.
+		 */
+		if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) ||
+			rq->dl.dl_nr_running))
+			resched_curr(rq);
+
 		/*
 		 * If there's a higher priority task waiting to run
 		 * then reschedule. Note, the above pull_rt_task
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/