From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755846AbaIKMje (ORCPT ); Thu, 11 Sep 2014 08:39:34 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51683 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755455AbaIKMeJ (ORCPT ); Thu, 11 Sep 2014 08:34:09 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David Vrabel" , "Boris Ostrovsky" Date: Thu, 11 Sep 2014 13:32:13 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 060/131] x86/xen: resume timer irqs early In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: David Vrabel commit 8d5999df35314607c38fbd6bdd709e25c3a4eeab upstream. If the timer irqs are resumed during device resume it is possible in certain circumstances for the resume to hang early on, before device interrupts are resumed. For an Ubuntu 14.04 PVHVM guest this would occur in ~0.5% of resume attempts. It is not entirely clear what is occuring the point of the hang but I think a task necessary for the resume calls schedule_timeout(), waiting for a timer interrupt (which never arrives). This failure may require specific tasks to be running on the other VCPUs to trigger (processes are not frozen during a suspend/resume if PREEMPT is disabled). Add IRQF_EARLY_RESUME to the timer interrupts so they are resumed in syscore_resume(). Signed-off-by: David Vrabel Reviewed-by: Boris Ostrovsky [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- arch/x86/xen/time.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -397,7 +397,7 @@ void xen_setup_timer(int cpu) irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt, IRQF_DISABLED|IRQF_PERCPU| IRQF_NOBALANCING|IRQF_TIMER| - IRQF_FORCE_RESUME, + IRQF_FORCE_RESUME|IRQF_EARLY_RESUME, name, NULL); evt = &per_cpu(xen_clock_events, cpu);