Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753853AbdGYUAB (ORCPT ); Tue, 25 Jul 2017 16:00:01 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35788 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753561AbdGYTYE (ORCPT ); Tue, 25 Jul 2017 15:24:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Juergen Gross , Boris Ostrovsky Subject: [PATCH 4.12 058/196] xen/x86: fix cpu hotplug Date: Tue, 25 Jul 2017 12:20:57 -0700 Message-Id: <20170725192049.414771355@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170725192046.422343510@linuxfoundation.org> References: <20170725192046.422343510@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1428 Lines: 47 4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Juergen Gross commit c185ddec54657c145a0c2055e4b87918da24974f upstream. 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(). Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/smp_pv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -417,7 +418,7 @@ static void xen_pv_play_dead(void) /* us */ tick_nohz_idle_enter(); - cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); + cpuhp_online_idle(CPUHP_AP_ONLINE_IDLE); } #else /* !CONFIG_HOTPLUG_CPU */