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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,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 08CC3C43381 for ; Mon, 1 Apr 2019 17:43:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF50820830 for ; Mon, 1 Apr 2019 17:43:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140615; bh=sEcKuufavJxOnZcjjVjDWN2lkLleBMaAr17XnbTnOtA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VwdEocsO2B1xS/IKbCjArV7ou4twWxxZWgd3zMRIjEt4e906GdyzXaYZteGFNqpLQ 7h9IsZBCFS3GKuetBc+ANYCGzAP8JzNZ+FLQjPKueXdfJCk5kHMINUg0k3GkEFVEBm ukZky1i+rUc7O323581WI8igoBp/+aRqR9g2oOC0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387970AbfDARgC (ORCPT ); Mon, 1 Apr 2019 13:36:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:47202 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729666AbfDARf7 (ORCPT ); Mon, 1 Apr 2019 13:35:59 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ADE6520896; Mon, 1 Apr 2019 17:35:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140159; bh=sEcKuufavJxOnZcjjVjDWN2lkLleBMaAr17XnbTnOtA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tLB8t6AixRyNf3Kp6io+fhzFDfKit0VuPozFxgNR0i+gEGcrAK024o4fFHCF4VuB9 GqCHa3VyEB+WUe1rI3GGmKFZdw/hsMJuCL2dGsZBBnbZs0n/hITI2tnvbNrf8Dzvph c7H14D4cg32/ox+1rswlkzTPirKVpA2d4QHRPuMA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lianwei Wang , peterz@infradead.org, linux-pm@vger.kernel.org, oleg@redhat.com, Thomas Gleixner , Sasha Levin Subject: [PATCH 4.4 084/131] cpu/hotplug: Handle unbalanced hotplug enable/disable Date: Mon, 1 Apr 2019 19:02:34 +0200 Message-Id: <20190401170059.116218209@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170051.645954551@linuxfoundation.org> References: <20190401170051.645954551@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 01b41159066531cc8d664362ff0cd89dd137bbfa ] When cpu_hotplug_enable() is called unbalanced w/o a preceeding cpu_hotplug_disable() the code emits a warning, but happily decrements the disabled counter. This causes the next operations to malfunction. Prevent the decrement and just emit a warning. Signed-off-by: Lianwei Wang Cc: peterz@infradead.org Cc: linux-pm@vger.kernel.org Cc: oleg@redhat.com Link: http://lkml.kernel.org/r/1465541008-12476-1-git-send-email-lianwei.wang@gmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Sasha Levin --- kernel/cpu.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 40d20bf5de28..42ce0b0ae5c5 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -183,10 +183,17 @@ void cpu_hotplug_disable(void) } EXPORT_SYMBOL_GPL(cpu_hotplug_disable); +static void __cpu_hotplug_enable(void) +{ + if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) + return; + cpu_hotplug_disabled--; +} + void cpu_hotplug_enable(void) { cpu_maps_update_begin(); - WARN_ON(--cpu_hotplug_disabled < 0); + __cpu_hotplug_enable(); cpu_maps_update_done(); } EXPORT_SYMBOL_GPL(cpu_hotplug_enable); @@ -626,7 +633,7 @@ void enable_nonboot_cpus(void) /* Allow everyone to use the CPU hotplug again */ cpu_maps_update_begin(); - WARN_ON(--cpu_hotplug_disabled < 0); + __cpu_hotplug_enable(); if (cpumask_empty(frozen_cpus)) goto out; -- 2.19.1