From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752923AbcFBIO5 (ORCPT ); Thu, 2 Jun 2016 04:14:57 -0400 Received: from mail.skyhub.de ([78.46.96.112]:50296 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbcFBIOx (ORCPT ); Thu, 2 Jun 2016 04:14:53 -0400 Date: Thu, 2 Jun 2016 10:14:39 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: Guenter Roeck , Ingo Molnar , linux-hwmon@vger.kernel.org, X86 ML , LKML , Rui Huang , Sherry Hurwitz Subject: Re: [PATCH] hwmon: (fam15h_power) Disable preemption when reading registers Message-ID: <20160602081439.GD10803@pd.tnic> References: <1464775486-23446-1-git-send-email-bp@alien8.de> <574EE1B3.9010704@roeck-us.net> <20160601134126.GB22373@pd.tnic> <20160601181509.GB10954@roeck-us.net> <20160602072619.GB10803@pd.tnic> <20160602075830.GC10803@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20160602075830.GC10803@pd.tnic> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 02, 2016 at 09:58:30AM +0200, Borislav Petkov wrote: > Ha, very nice! Let me try it. Yap, much better than opencoding on_each_cpu_mask() :-) --- From: Borislav Petkov Date: Wed, 1 Jun 2016 11:36:13 +0200 Subject: [PATCH] hwmon: (fam15h_power) Disable preemption when reading registers We need to read a bunch of registers on each compute unit and possibly on the current CPU too. Disable preemption around it. Otherwise, you get: BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/327 caller is read_registers+0x6a/0x110 [fam15h_power] CPU: 3 PID: 327 Comm: systemd-udevd Not tainted 4.7.0-rc1+ #4 Hardware name: HP HP EliteBook 745 G3/807E, BIOS N73 Ver. 01.08 01/28/2016 ... Suggested-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: Rui Huang Cc: Sherry Hurwitz Cc: Guenter Roeck Fixes: fa7943449943 ("hwmon: (fam15h_power) Add compute unit accumulated power") --- drivers/hwmon/fam15h_power.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c index eb97a9241d17..15aa49d082c4 100644 --- a/drivers/hwmon/fam15h_power.c +++ b/drivers/hwmon/fam15h_power.c @@ -172,9 +172,9 @@ static void do_read_registers_on_cu(void *_data) */ static int read_registers(struct fam15h_power_data *data) { - int this_cpu, ret, cpu; int core, this_core; cpumask_var_t mask; + int ret, cpu; ret = zalloc_cpumask_var(&mask, GFP_KERNEL); if (!ret) @@ -183,7 +183,6 @@ static int read_registers(struct fam15h_power_data *data) memset(data->cu_on, 0, sizeof(int) * MAX_CUS); get_online_cpus(); - this_cpu = smp_processor_id(); /* * Choose the first online core of each compute unit, and then @@ -205,12 +204,9 @@ static int read_registers(struct fam15h_power_data *data) cpumask_set_cpu(cpumask_any(topology_sibling_cpumask(cpu)), mask); } - if (cpumask_test_cpu(this_cpu, mask)) - do_read_registers_on_cu(data); + on_each_cpu_mask(mask, do_read_registers_on_cu, data, true); - smp_call_function_many(mask, do_read_registers_on_cu, data, true); put_online_cpus(); - free_cpumask_var(mask); return 0; -- 2.7.3 -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.