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=-13.6 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 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 47D11C433DB for ; Mon, 1 Mar 2021 11:31:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 087DF64E07 for ; Mon, 1 Mar 2021 11:31:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233463AbhCALbI (ORCPT ); Mon, 1 Mar 2021 06:31:08 -0500 Received: from forward1-smtp.messagingengine.com ([66.111.4.223]:43601 "EHLO forward1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233677AbhCALbA (ORCPT ); Mon, 1 Mar 2021 06:31:00 -0500 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailforward.nyi.internal (Postfix) with ESMTP id 0524C194147D; Mon, 1 Mar 2021 06:29:35 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Mon, 01 Mar 2021 06:29:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=NhOsrl IGKRI62w447MXum4xO4tVtVnjIIkw7gvjr9C4=; b=Sa9pm4r8k6UgdAXC5cIKRn Iza+W+m45FvYX211NIx1ZvOIDpakiHzTWAwy5ulfcHPZh67zu9ttKhyTQrmSZiRe o9fh8NPn9wmiXKOVqAwmiNiVrQ0XQ7dW5V+W7NKC6IBtImx7HQTGV3HPJ7uwgGU6 +KNg22A1YSS7nZztdw1wOCeQji9VrIljepIkLI2OPYhog2q/OFtV28Sl2zpS0Azj anWN3lZut5TLcxPBDO0vYmar/ElkHtp2KoYVOeLNr/SnEhiih9exAwNI99CQ0Oex 9xrthGoOXaF9GlNlkT2wyCzs6ngzTI1iXVOFVY6/CDPSDYrcOUzQyf1ZPSUqeFmg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrleekgddvjecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucggtffrrghtthgvrhhnpeelleelvdegfeelledtteegudegfffghfduffduudekge efleegieegkeejhfelveenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeek fedrkeeirdejgedrieegnecuvehluhhsthgvrhfuihiivgepuddunecurfgrrhgrmhepmh grihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA id E4215240057; Mon, 1 Mar 2021 06:29:33 -0500 (EST) Subject: FAILED: patch "[PATCH] entry: Explicitly flush pending rcuog wakeup before last" failed to apply to 4.4-stable tree To: frederic@kernel.org, mingo@kernel.org, peterz@infradead.org Cc: From: Date: Mon, 01 Mar 2021 12:29:32 +0100 Message-ID: <161459817215177@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 4.4-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 47b8ff194c1fd73d58dc339b597d466fe48c8958 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 1 Feb 2021 00:05:47 +0100 Subject: [PATCH] entry: Explicitly flush pending rcuog wakeup before last rescheduling point Following the idle loop model, cleanly check for pending rcuog wakeup before the last rescheduling point on resuming to user mode. This way we can avoid to do it from rcu_user_enter() with the last resort self-IPI hack that enforces rescheduling. Signed-off-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-5-frederic@kernel.org diff --git a/kernel/entry/common.c b/kernel/entry/common.c index f09cae37ddd5..8442e5c9cfa2 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -184,6 +184,10 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, * enabled above. */ local_irq_disable_exit_to_user(); + + /* Check if any of the above work has queued a deferred wakeup */ + rcu_nocb_flush_deferred_wakeup(); + ti_work = READ_ONCE(current_thread_info()->flags); } @@ -197,6 +201,9 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs) lockdep_assert_irqs_disabled(); + /* Flush pending rcuog wakeup before the last need_resched() check */ + rcu_nocb_flush_deferred_wakeup(); + if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK)) ti_work = exit_to_user_mode_loop(regs, ti_work); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 4b1e5bd16492..2ebc211fffcb 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -707,13 +707,15 @@ noinstr void rcu_user_enter(void) lockdep_assert_irqs_disabled(); /* - * We may be past the last rescheduling opportunity in the entry code. - * Trigger a self IPI that will fire and reschedule once we resume to - * user/guest mode. + * Other than generic entry implementation, we may be past the last + * rescheduling opportunity in the entry code. Trigger a self IPI + * that will fire and reschedule once we resume in user/guest mode. */ instrumentation_begin(); - if (do_nocb_deferred_wakeup(rdp) && need_resched()) - irq_work_queue(this_cpu_ptr(&late_wakeup_work)); + if (!IS_ENABLED(CONFIG_GENERIC_ENTRY) || (current->flags & PF_VCPU)) { + if (do_nocb_deferred_wakeup(rdp) && need_resched()) + irq_work_queue(this_cpu_ptr(&late_wakeup_work)); + } instrumentation_end(); rcu_eqs_enter(true);