From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v3 07/11] x86/intel_pstate: changes in cpufreq_del_cpu for CPU offline Date: Thu, 11 Jun 2015 10:04:50 -0400 Message-ID: <55799582.5060905@citrix.com> References: <1434011290-17415-1-git-send-email-wei.w.wang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1434011290-17415-1-git-send-email-wei.w.wang@intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Wang , xen-devel@lists.xen.org, jbeulich@suse.com Cc: andrew.cooper3@citrix.com List-Id: xen-devel@lists.xenproject.org Hi, On 11/06/2015 04:28, Wei Wang wrote: > cpufreq_cpu_policy is used in intel_pstate_set_pstate(), so we change > to NULL it after the call of cpufreq_driver->exit. Otherwise, a > calltrace will show up on your screen due to the reference of a NULL > pointer when you power down the system. > > Signed-off-by: Wei Wang > --- > xen/drivers/cpufreq/cpufreq.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/xen/drivers/cpufreq/cpufreq.c b/xen/drivers/cpufreq/cpufreq.c > index 6003a8c..a8772e8 100644 > --- a/xen/drivers/cpufreq/cpufreq.c > +++ b/xen/drivers/cpufreq/cpufreq.c > @@ -335,12 +335,11 @@ int cpufreq_del_cpu(unsigned int cpu) > > /* for HW_ALL, stop gov for each core of the _PSD domain */ > /* for SW_ALL & SW_ANY, stop gov for the 1st core of the _PSD domain */ > - if (hw_all || (cpumask_weight(cpufreq_dom->map) == > - perf->domain_info.num_processors)) > + if (!policy->policy && (hw_all || (cpumask_weight(cpufreq_dom->map) == > + perf->domain_info.num_processors))) Based on your patch #6, the field policy contains value which is defined per-cpufreq driver (because you defined internal value). How can you be sure that a driver will never use 0 as a valid value? Regards, -- Julien Grall