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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 24C82C433F5 for ; Wed, 15 Sep 2021 14:13:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EEC2611C1 for ; Wed, 15 Sep 2021 14:13:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237230AbhIOOOz (ORCPT ); Wed, 15 Sep 2021 10:14:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:60490 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233782AbhIOOOz (ORCPT ); Wed, 15 Sep 2021 10:14:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B207B6112E; Wed, 15 Sep 2021 14:13:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631715216; bh=VLTqeW2ksxe3x1aS5RB4OgaBwOKelZsEoGRpdh4+PiM=; h=Subject:To:Cc:From:Date:From; b=ZzASi/sxOjsZR3Lgsm3sum23GJRarvfHTjVfnkJwjOU93lPRV96RF24TMR0YPI4N9 fv/RTrcy8dfc3kgGXwQFQrUlfJPu81AxWjbrNiwt4S70DzhDHg184vSyW+CxnH4WFQ WHEafyzAFGi8ARKvOnJiVCINhkVw0OHzRI/qqG8s= Subject: FAILED: patch "[PATCH] sched: Prevent balance_push() on remote runqueues" failed to apply to 5.13-stable tree To: tglx@linutronix.de, bigeasy@linutronix.de, peterz@infradead.org Cc: From: Date: Wed, 15 Sep 2021 16:13:33 +0200 Message-ID: <1631715213238253@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.13-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 868ad33bfa3bf39960982682ad3a0f8ebda1656e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 28 Aug 2021 15:55:52 +0200 Subject: [PATCH] sched: Prevent balance_push() on remote runqueues sched_setscheduler() and rt_mutex_setprio() invoke the run-queue balance callback after changing priorities or the scheduling class of a task. The run-queue for which the callback is invoked can be local or remote. That's not a problem for the regular rq::push_work which is serialized with a busy flag in the run-queue struct, but for the balance_push() work which is only valid to be invoked on the outgoing CPU that's wrong. It not only triggers the debug warning, but also leaves the per CPU variable push_work unprotected, which can result in double enqueues on the stop machine list. Remove the warning and validate that the function is invoked on the outgoing CPU. Fixes: ae7927023243 ("sched: Optimize finish_lock_switch()") Reported-by: Sebastian Siewior Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/87zgt1hdw7.ffs@tglx diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f3b27c6c5153..b21a1857b75a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8523,7 +8523,6 @@ static void balance_push(struct rq *rq) struct task_struct *push_task = rq->curr; lockdep_assert_rq_held(rq); - SCHED_WARN_ON(rq->cpu != smp_processor_id()); /* * Ensure the thing is persistent until balance_push_set(.on = false); @@ -8531,9 +8530,10 @@ static void balance_push(struct rq *rq) rq->balance_callback = &balance_push_callback; /* - * Only active while going offline. + * Only active while going offline and when invoked on the outgoing + * CPU. */ - if (!cpu_dying(rq->cpu)) + if (!cpu_dying(rq->cpu) || rq != this_rq()) return; /*