Re: [PATCH v2] platform/x86/intel-uncore-freq: Fix missing uncore sysfs during CPU hotplug

[liu shouye]

srinivas pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> 于2025年4月17日周四 04:40写道：
>
> On Wed, 2025-04-16 at 11:38 +0800, shouyeliu wrote:
> > From: Shouye Liu <shouyeliu@xxxxxxxxxxx>
> >
> > In certain situations, the sysfs for uncore may not be present when
> > all
> > CPUs in a package are offlined and then brought back online after
> > boot.
> >
> > This issue can occur if there is an error in adding the sysfs entry
> > due
> > to a memory allocation failure. Retrying to bring the CPUs online
> > will
> > not resolve the issue, as the uncore_cpu_mask is already set for the
> > package before the failure condition occurs.
> >
> > This issue does not occur if the failure happens during module
> > initialization, as the module will fail to load in the event of any
> > error.
> >
> > To address this, ensure that the uncore_cpu_mask is not set until the
> > successful return of uncore_freq_add_entry().
> >
> Fixes: dbce412a7733 ("platform/x86/intel-uncore-freq: Split common and
> enumeration part")
>
> > Signed-off-by: Shouye Liu <shouyeliu@xxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
>
> Thanks,
> Srinivas

Got it, I will update it in v3 version
Thanks,
Shouye

>
> > ---
> >  .../x86/intel/uncore-frequency/uncore-frequency.c   | 13 +++++++++--
> > --
> >  1 file changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-
> > frequency.c b/drivers/platform/x86/intel/uncore-frequency/uncore-
> > frequency.c
> > index 40bbf8e45fa4..bdee5d00f30b 100644
> > --- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency.c
> > +++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency.c
> > @@ -146,15 +146,13 @@ static int uncore_event_cpu_online(unsigned int
> > cpu)
> >  {
> >       struct uncore_data *data;
> >       int target;
> > +     int ret;
> >
> >       /* Check if there is an online cpu in the package for uncore
> > MSR */
> >       target = cpumask_any_and(&uncore_cpu_mask,
> > topology_die_cpumask(cpu));
> >       if (target < nr_cpu_ids)
> >               return 0;
> >
> > -     /* Use this CPU on this die as a control CPU */
> > -     cpumask_set_cpu(cpu, &uncore_cpu_mask);
> > -
> >       data = uncore_get_instance(cpu);
> >       if (!data)
> >               return 0;
> > @@ -163,7 +161,14 @@ static int uncore_event_cpu_online(unsigned int
> > cpu)
> >       data->die_id = topology_die_id(cpu);
> >       data->domain_id = UNCORE_DOMAIN_ID_INVALID;
> >
> > -     return uncore_freq_add_entry(data, cpu);
> > +     ret = uncore_freq_add_entry(data, cpu);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Use this CPU on this die as a control CPU */
> > +     cpumask_set_cpu(cpu, &uncore_cpu_mask);
> > +
> > +     return 0;
> >  }
> >
> >  static int uncore_event_cpu_offline(unsigned int cpu)
>