From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754359AbdBVHxX (ORCPT ); Wed, 22 Feb 2017 02:53:23 -0500 Received: from mail-pg0-f65.google.com ([74.125.83.65]:34305 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753762AbdBVHxP (ORCPT ); Wed, 22 Feb 2017 02:53:15 -0500 From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org Cc: Wanpeng Li , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Matt Fleming Subject: [PATCH] sched/fair: Update rq clock before changing a task's CPU affinity Date: Tue, 21 Feb 2017 23:52:55 -0800 Message-Id: <1487749975-5994-1-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li ------------[ cut here ]------------ WARNING: CPU: 6 PID: 81 at kernel/sched/sched.h:812 set_next_entity+0x11d/0x380 rq->clock_update_flags < RQCF_ACT_SKIP CPU: 6 PID: 81 Comm: torture_shuffle Not tainted 4.10.0+ #1 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0x85/0xc2 __warn+0xcb/0xf0 warn_slowpath_fmt+0x5f/0x80 set_next_entity+0x11d/0x380 set_curr_task_fair+0x2b/0x60 do_set_cpus_allowed+0x139/0x180 __set_cpus_allowed_ptr+0x113/0x260 set_cpus_allowed_ptr+0x10/0x20 torture_shuffle+0xfd/0x180 kthread+0x10f/0x150 ? torture_shutdown_init+0x60/0x60 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x31/0x40 ---[ end trace dd94d92344cea9c6 ]--- This is triggered during boot when CONFIG_SCHED_DEBUG is enabled. The task is running && !queued, so there is no rq clock update before calling set_curr_task. This patch fixes it by updating rq clock after holding rq->lock/pi_lock just as what other dequeue + put_prev + enqueue + set_curr story does. Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Matt Fleming Signed-off-by: Wanpeng Li --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 34e2291..2c51bdf 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1087,6 +1087,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, int ret = 0; rq = task_rq_lock(p, &rf); + update_rq_clock(rq); if (p->flags & PF_KTHREAD) { /* -- 2.7.4