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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 2E3C4C433EF for ; Mon, 13 Sep 2021 14:21:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19DFC60249 for ; Mon, 13 Sep 2021 14:21:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241388AbhIMOWT (ORCPT ); Mon, 13 Sep 2021 10:22:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:41588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344199AbhIMOSu (ORCPT ); Mon, 13 Sep 2021 10:18:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7915C61506; Mon, 13 Sep 2021 13:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631540729; bh=37IGAPbcpOnofpDuEk7W4e8n+wX30U18HFbXwwutDKQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d+jWWrfnQwEv2qIfDlt+36c5eBL6jAJUD7eMOrWrMVt63rlvCyLy9e9+c7M3ooppD IZoqpXCt2OVgc+Sdb5P7vn16SyR4JJLYTPhqi2jhDEJ+APyVQneXSCPmxI8LfiTIPm hHedvbxU4eaOWscnblpfD9zEBKsyiMARAu7kkcmE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Frederic Weisbecker , Thomas Gleixner , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 5.14 011/334] posix-cpu-timers: Force next expiration recalc after itimer reset Date: Mon, 13 Sep 2021 15:11:05 +0200 Message-Id: <20210913131113.781633675@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Frederic Weisbecker [ Upstream commit 406dd42bd1ba0c01babf9cde169bb319e52f6147 ] When an itimer deactivates a previously armed expiration, it simply doesn't do anything. As a result the process wide cputime counter keeps running and the tick dependency stays set until it reaches the old ghost expiration value. This can be reproduced with the following snippet: void trigger_process_counter(void) { struct itimerval n = {}; n.it_value.tv_sec = 100; setitimer(ITIMER_VIRTUAL, &n, NULL); n.it_value.tv_sec = 0; setitimer(ITIMER_VIRTUAL, &n, NULL); } Fix this with resetting the relevant base expiration. This is similar to disarming a timer. Signed-off-by: Frederic Weisbecker Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210726125513.271824-4-frederic@kernel.org Signed-off-by: Sasha Levin --- kernel/time/posix-cpu-timers.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 517be7fd175e..a002685f688d 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -1346,8 +1346,6 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid, } } - if (!*newval) - return; *newval += now; } -- 2.30.2