From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [patch 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic Date: Thu, 13 Apr 2017 08:20:57 +0530 Message-ID: <20170413025057.GL5910@vireshk-i7> References: <20170412200726.941336635@linutronix.de> <20170412201043.129216383@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pg0-f41.google.com ([74.125.83.41]:36138 "EHLO mail-pg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755817AbdDMCvB (ORCPT ); Wed, 12 Apr 2017 22:51:01 -0400 Received: by mail-pg0-f41.google.com with SMTP id g2so23431191pge.3 for ; Wed, 12 Apr 2017 19:51:00 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20170412201043.129216383@linutronix.de> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Thomas Gleixner Cc: LKML , Peter Zijlstra , Ingo Molnar , Sebastian Siewior , Benjamin Herrenschmidt , "David S. Miller" , Fenghua Yu , Herbert Xu , Lai Jiangshan , Len Brown , Michael Ellerman , "Rafael J. Wysocki" , Tejun Heo , Tony Luck , linux-pm@vger.kernel.org On 12-04-17, 22:07, Thomas Gleixner wrote: > The access to the HBIRD_ESTAR_MODE register in the cpu frequency control > functions must happen on the target CPU. This is achieved by temporarily > setting the affinity of the calling user space thread to the requested CPU > and reset it to the original affinity afterwards. > > That's racy vs. CPU hotplug and concurrent affinity settings for that > thread resulting in code executing on the wrong CPU and overwriting the > new affinity setting. > > Replace it by a straight forward smp function call. > > Signed-off-by: Thomas Gleixner > Cc: "David S. Miller" > Cc: "Rafael J. Wysocki" > Cc: Viresh Kumar > Cc: linux-pm@vger.kernel.org > --- > drivers/cpufreq/sparc-us2e-cpufreq.c | 45 ++++++++++++++++------------------- > 1 file changed, 21 insertions(+), 24 deletions(-) Acked-by: Viresh Kumar -- viresh