From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Ido Schimmel <idosch@idosch.org>
Cc: x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
Len Brown <len.brown@intel.com>,
Linux PM <linux-pm@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Laura Abbott <labbott@fedoraproject.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Simon Schricker <sschricker@suse.de>,
Borislav Petkov <bp@suse.de>, Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH 2/2] PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS sysfs interface
Date: Thu, 09 May 2019 19:18:28 +0200 [thread overview]
Message-ID: <1627338.1fd8ofggM8@kreacher> (raw)
In-Reply-To: <20190509102315.GA31824@splinter>
On Thursday, May 9, 2019 12:23:15 PM CEST Ido Schimmel wrote:
> On Thu, Mar 21, 2019 at 11:20:17PM +0100, Rafael J. Wysocki wrote:
> > +static struct attribute *intel_epb_attrs[] = {
> > + &dev_attr_energy_perf_bias.attr,
> > + NULL
> > +};
> > +
> > +static const struct attribute_group intel_epb_attr_group = {
> > + .name = power_group_name,
> > + .attrs = intel_epb_attrs
> > +};
> > +
> > static int intel_epb_online(unsigned int cpu)
> > {
> > + struct device *cpu_dev = get_cpu_device(cpu);
> > +
> > intel_epb_restore();
> > + if (!cpuhp_tasks_frozen)
> > + sysfs_merge_group(&cpu_dev->kobj, &intel_epb_attr_group);
> > +
> > return 0;
> > }
> >
> > static int intel_epb_offline(unsigned int cpu)
> > {
> > - return intel_epb_save();
> > + struct device *cpu_dev = get_cpu_device(cpu);
> > +
> > + if (!cpuhp_tasks_frozen)
> > + sysfs_unmerge_group(&cpu_dev->kobj, &intel_epb_attr_group);
> > +
> > + intel_epb_save();
> > + return 0;
> > }
>
> Hi,
>
> I just booted net-next and got the following NULL pointer dereference
> [1] during boot. I believe it is caused by this patch.
I think you're right, sorry about this.
> CONFIG_PM is disabled in my config which means 'power_group_name' is
> defined as NULL. When I enable CONFIG_PM the issue is not reproduced.
So does the patch below fix it for you?
---
arch/x86/kernel/cpu/intel_epb.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
Index: linux-pm/arch/x86/kernel/cpu/intel_epb.c
===================================================================
--- linux-pm.orig/arch/x86/kernel/cpu/intel_epb.c
+++ linux-pm/arch/x86/kernel/cpu/intel_epb.c
@@ -97,6 +97,7 @@ static void intel_epb_restore(void)
wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, (epb & ~EPB_MASK) | val);
}
+#ifdef CONFIG_PM
static struct syscore_ops intel_epb_syscore_ops = {
.suspend = intel_epb_save,
.resume = intel_epb_restore,
@@ -193,6 +194,25 @@ static int intel_epb_offline(unsigned in
return 0;
}
+static inline void register_intel_ebp_syscore_ops(void)
+{
+ register_syscore_ops(&intel_epb_syscore_ops);
+}
+#else /* !CONFIG_PM */
+static int intel_epb_online(unsigned int cpu)
+{
+ intel_epb_restore();
+ return 0;
+}
+
+static int intel_epb_offline(unsigned int cpu)
+{
+ return intel_epb_save();
+}
+
+static inline void register_intel_ebp_syscore_ops(void) {}
+#endif
+
static __init int intel_epb_init(void)
{
int ret;
@@ -206,7 +226,7 @@ static __init int intel_epb_init(void)
if (ret < 0)
goto err_out_online;
- register_syscore_ops(&intel_epb_syscore_ops);
+ register_intel_ebp_syscore_ops();
return 0;
err_out_online:
next prev parent reply other threads:[~2019-05-09 17:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 22:12 [PATCH 0/2] PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS handling fixes and sysfs i/f Rafael J. Wysocki
2019-03-21 22:18 ` [PATCH 1/2] PM / arch: x86: Rework the MSR_IA32_ENERGY_PERF_BIAS handling Rafael J. Wysocki
2019-03-22 9:03 ` Hannes Reinecke
2019-03-22 14:28 ` Borislav Petkov
2019-03-22 14:31 ` Thomas Gleixner
2019-03-22 14:35 ` Borislav Petkov
2019-03-22 16:12 ` Thomas Gleixner
2019-03-22 16:52 ` Joe Perches
2019-03-25 10:06 ` Rafael J. Wysocki
2019-03-22 16:27 ` Thomas Renninger
2019-03-22 16:43 ` Borislav Petkov
2019-03-25 11:31 ` Borislav Petkov
2019-03-21 22:20 ` [PATCH 2/2] PM / arch: x86: MSR_IA32_ENERGY_PERF_BIAS sysfs interface Rafael J. Wysocki
2019-03-22 9:03 ` Hannes Reinecke
2019-03-22 14:46 ` Borislav Petkov
2019-03-25 10:01 ` Rafael J. Wysocki
2019-03-22 15:00 ` Peter Zijlstra
2019-03-25 9:56 ` Rafael J. Wysocki
2019-03-25 11:32 ` Borislav Petkov
2019-05-09 10:23 ` Ido Schimmel
2019-05-09 17:18 ` Rafael J. Wysocki [this message]
2019-05-09 17:43 ` Ido Schimmel
2019-05-09 21:28 ` [PATCH] x86: intel_epb: Take CONFIG_PM into account Rafael J. Wysocki
2019-05-10 6:01 ` Ingo Molnar
2019-05-27 10:56 ` [PATCH] x86: intel_epb: Do not build when CONFIG_PM is unset Rafael J. Wysocki
2019-05-30 7:47 ` Ingo Molnar
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