Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751544AbdGRPEH (ORCPT ); Tue, 18 Jul 2017 11:04:07 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:46028 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408AbdGRPEF (ORCPT ); Tue, 18 Jul 2017 11:04:05 -0400 Subject: Re: [PATCH] xen/x86: fix cpu hotplug To: Juergen Gross , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20170705140520.4948-1-jgross@suse.com> Cc: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, stable@vger.kernel.org From: Boris Ostrovsky Message-ID: <2b982ef6-aefd-7e52-80c1-3bd87e10a78d@oracle.com> Date: Tue, 18 Jul 2017 11:05:18 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170705140520.4948-1-jgross@suse.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 685 Lines: 17 On 07/05/2017 10:05 AM, Juergen Gross wrote: > Commit dc6416f1d711eb4c1726e845d653235dcaae12e1 ("xen/x86: Call > cpu_startup_entry(CPUHP_AP_ONLINE_IDLE) from xen_play_dead()") > introduced an error leading to a stack overflow of the idle task when > a cpu was brought offline/online many times: by calling > cpu_startup_entry() instead of returning at the end of xen_play_dead() > do_idle() would be entered again and again. > > Don't use cpu_startup_entry(), but cpuhp_online_idle() instead allowing > to return from xen_play_dead(). > > Cc: # 4.12 > Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky