From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753710AbdJSOan (ORCPT ); Thu, 19 Oct 2017 10:30:43 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45980 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498AbdJSNt7 (ORCPT ); Thu, 19 Oct 2017 09:49:59 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wanpeng Li , "Peter Zijlstra (Intel)" , Matt Fleming , Linus Torvalds , Mike Galbraith , Thomas Gleixner , Ingo Molnar , Sasha Levin Subject: [PATCH 4.9 17/51] sched/fair: Update rq clock before changing a tasks CPU affinity Date: Thu, 19 Oct 2017 15:48:38 +0200 Message-Id: <20171019134842.367975188@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171019134841.383925150@linuxfoundation.org> References: <20171019134841.383925150@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wanpeng Li [ Upstream commit a499c3ead88ccf147fc50689e85a530ad923ce36 ] This is triggered during boot when CONFIG_SCHED_DEBUG is enabled: ------------[ 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 ]--- 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. Signed-off-by: Wanpeng Li Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Matt Fleming Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1487749975-5994-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1141,6 +1141,7 @@ static int __set_cpus_allowed_ptr(struct int ret = 0; rq = task_rq_lock(p, &rf); + update_rq_clock(rq); if (p->flags & PF_KTHREAD) { /*