From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53288C282CE for ; Mon, 8 Apr 2019 19:15:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17DE620879 for ; Mon, 8 Apr 2019 19:15:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554750911; bh=MFnEtxT55xkq6IhxM5qEsLQ9KT+PDNss+AmRB4KhUm4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=ZAy6Jbb1N/WTZdINn4np7mUYq0/hk3rgBuUV2a3FeV7K0JT59Z/DmyNk1YFmNK9Gm mfNVIszy3Ysb8iM6KtPFb6tZPPsh/NKNJKZC/LZ+4U+5o+ZE+wAB9mXYByrkl7otvd X+6qCD/q3mRsVoD7qPp+z7hAkmVizSXwSlFFApQE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728826AbfDHTOi (ORCPT ); Mon, 8 Apr 2019 15:14:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:45446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727629AbfDHTOf (ORCPT ); Mon, 8 Apr 2019 15:14:35 -0400 Received: from tzanussi-mobl.hsd1.il.comcast.net (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2643B21905; Mon, 8 Apr 2019 19:14:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554750875; bh=MFnEtxT55xkq6IhxM5qEsLQ9KT+PDNss+AmRB4KhUm4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=PE67saR9TKDkkJ2MKsJDWs9U7vrLvdusTW0vjuRExOLoEuiwtH4WCGgJHEdnAJCre uY44kbnQViQoppMUtEfEy0vcSIF3QyFyoX3EuD8BtTnTCLasByW3OJ8KAz3YyHPE63 8u84qZ4suxIcufYnGqg72se+j2bordRm0ED3h9yY= From: Tom Zanussi To: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Cc: rostedt@goodmis.org, tglx@linutronix.de, C.Emde@osadl.org, jkacur@redhat.com, bigeasy@linutronix.de, daniel.wagner@siemens.com, julia@ni.com, amartin@nvidia.com Subject: [PATCH 10/13] hrtimer: cpu_chill(): save task state in ->saved_state() Date: Mon, 8 Apr 2019 14:14:12 -0500 Message-Id: <0f9545ca84d4d0ec5bedd2b36a4fda0871fad244.1554737688.git.tom.zanussi@linux.intel.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14.109-rt58-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior [ Upstream commit d70f218ee02d6fc3832274653aa6c6e98dd9aa43 ] In the previous change I saved the current task state on stack. This was bad because while the task is scheduled-out it might receive a wake-up. The wake up changes the task state and we must not destroy it. Save the task-state in ->saved_state under a PI-lock to unsure that state changes during are not missed while the task temporary scheduled out. Reported-by: Mike Galbraith Tested-by: Mike Galbraith Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Tom Zanussi --- kernel/time/hrtimer.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 6da6b5dded3c..9990b567b089 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1864,20 +1864,28 @@ COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp, */ void cpu_chill(void) { - ktime_t chill_time; unsigned int freeze_flag = current->flags & PF_NOFREEZE; - long saved_state; + struct task_struct *self = current; + ktime_t chill_time; - saved_state = current->state; - chill_time = ktime_set(0, NSEC_PER_MSEC); + raw_spin_lock_irq(&self->pi_lock); + self->saved_state = self->state; __set_current_state_no_track(TASK_UNINTERRUPTIBLE); + raw_spin_unlock_irq(&self->pi_lock); + + chill_time = ktime_set(0, NSEC_PER_MSEC); + current->flags |= PF_NOFREEZE; sleeping_lock_inc(); schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD); sleeping_lock_dec(); if (!freeze_flag) current->flags &= ~PF_NOFREEZE; - __set_current_state_no_track(saved_state); + + raw_spin_lock_irq(&self->pi_lock); + __set_current_state_no_track(self->saved_state); + self->saved_state = TASK_RUNNING; + raw_spin_unlock_irq(&self->pi_lock); } EXPORT_SYMBOL(cpu_chill); #endif -- 2.14.1