From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753118AbdEJOad (ORCPT ); Wed, 10 May 2017 10:30:33 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:45402 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799AbdEJOac (ORCPT ); Wed, 10 May 2017 10:30:32 -0400 Date: Wed, 10 May 2017 16:30:12 +0200 (CEST) From: Thomas Gleixner To: Tommi Rantala cc: Guenter Roeck , LKML , Fenghua Yu , Jean Delvare , linux-hwmon@vger.kernel.org, Sebastian Siewior , Peter Zijlstra , x86@kernel.org Subject: [PATCH] hwmon: (coretemp) Handle frozen hotplug state correctly Message-ID: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The recent conversion to the hotplug state machine missed that the original hotplug notifiers did not execute in the frozen state, which is used on suspend on resume. This does not matter on single socket machines, but on multi socket systems this breaks when the device for a non-boot socket is removed when the last CPU of that socket is brought offline. The device removal locks up the machine hard w/o any debug output. Prevent executing the hotplug callbacks when cpuhp_tasks_frozen is true. Thanks to Tommi for providing debug information patiently while I failed to spot the obvious. Fixes: e00ca5df37ad ("hwmon: (coretemp) Convert to hotplug state machine") Reported-by: Tommi Rantala Signed-off-by: Thomas Gleixner --- drivers/hwmon/coretemp.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/drivers/hwmon/coretemp.c +++ b/drivers/hwmon/coretemp.c @@ -605,6 +605,13 @@ static int coretemp_cpu_online(unsigned struct platform_data *pdata; /* + * Don't execute this on resume as the offline callback did + * not get executed on suspend. + */ + if (cpuhp_tasks_frozen) + return 0; + + /* * CPUID.06H.EAX[0] indicates whether the CPU has thermal * sensors. We check this bit only, all the early CPUs * without thermal sensors will be filtered out. @@ -654,6 +661,13 @@ static int coretemp_cpu_offline(unsigned struct temp_data *tdata; int indx, target; + /* + * Don't execute this on suspend as the device remove locks + * up the machine. + */ + if (cpuhp_tasks_frozen) + return 0; + /* If the physical CPU device does not exist, just return */ if (!pdev) return 0;