From: Thomas Gleixner <tglx@linutronix.de>
To: "Charles (Chas) Williams" <ciwillia@brocade.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
x86@kernel.org, linux-kernel@vger.kernel.org,
"M. Vefa Bicakci" <m.v.b@runbox.com>
Subject: Re: [RFC PATCH] perf/x86/intel/rapl: avoid access unallocate memory
Date: Mon, 7 Nov 2016 17:19:04 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1611071717000.3709@nanos> (raw)
In-Reply-To: <24e69019-60d0-29e7-e31f-c6f00f9ed98a@brocade.com>
On Wed, 2 Nov 2016, Charles (Chas) Williams wrote:
> On 11/02/2016 08:25 AM, Sebastian Andrzej Siewior wrote:
> > I am not sure if this a race with the new hotplug code or something that was
> > always there. Both (M. Vefa Bicakc and Charles) say that the box boots
> > sometimes fine (without the patch). smp_store_boot_cpu_info() should have
> > run
> > before the notofoert and thus should have set the info properly. However I
> > got
> > the following bootlog from Charles with this patch:
>
> I don't this this is a race. Here is some debugging from the two CPU VM
> (2 sockets, 1 core per socket). In identify_cpu() we have:
>
> /* The boot/hotplug time assigment got cleared, restore it */
> c->logical_proc_id = topology_phys_to_logical_pkg(c->phys_proc_id);
>
> The values just after this:
>
> [ 0.228306] identify_cpu: c ffff88023fd0a040 logical_proc_id 65535
> c->phys_proc_id 2
>
> So what's interesting here, is the phys_proc_id of 2 for CPU1:
>
> int topology_phys_to_logical_pkg(unsigned int phys_pkg)
> {
> if (phys_pkg >= max_physical_pkg_id)
> return -1;
> return physical_to_logical_pkg[phys_pkg];
> }
>
> And we happen to know the max_physical_pkg_id is 2 in this case.
> So apparently, topology_phys_to_logical_pkg() returns -1 and it gets
> assigned to the logical_proc_id.
>
> I don't know why the CPU's phys_proc_id is 2.
max_physical_pkg_id gets initialized via:
cpus = boot_cpu_data.x86_max_cores;
max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
What's the value of boot_cpu_data.x86_max_cores and MAX_LOCAL_APIC?
Thanks,
tglx
next prev parent reply other threads:[~2016-11-07 16:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 12:25 [RFC PATCH] perf/x86/intel/rapl: avoid access unallocate memory Sebastian Andrzej Siewior
2016-11-02 22:47 ` Charles (Chas) Williams
2016-11-03 17:47 ` Sebastian Andrzej Siewior
2016-11-04 12:20 ` Charles (Chas) Williams
2016-11-04 18:03 ` Sebastian Andrzej Siewior
2016-11-04 20:42 ` Charles (Chas) Williams
2016-11-04 20:57 ` Sebastian Andrzej Siewior
2016-11-07 16:19 ` Thomas Gleixner [this message]
2016-11-07 16:59 ` Charles (Chas) Williams
2016-11-07 20:20 ` Thomas Gleixner
2016-11-08 14:20 ` Charles (Chas) Williams
2016-11-08 14:31 ` Thomas Gleixner
2016-11-08 14:57 ` Charles (Chas) Williams
2016-11-08 16:22 ` Thomas Gleixner
2016-11-09 15:35 ` [PATCH] x86/cpuid: Deal with broken firmware once more Thomas Gleixner
2016-11-09 15:37 ` Thomas Gleixner
2016-11-09 16:03 ` Peter Zijlstra
2016-11-09 16:34 ` Charles (Chas) Williams
2016-11-09 18:37 ` Thomas Gleixner
2016-11-09 18:15 ` Charles (Chas) Williams
2016-11-09 20:27 ` [tip:x86/urgent] x86/cpu: Deal with broken firmware (VMWare/XEN) tip-bot for Thomas Gleixner
2016-11-11 5:49 ` Alok Kataria
2016-11-10 3:57 ` [PATCH] x86/cpuid: Deal with broken firmware once more M. Vefa Bicakci
2016-11-10 10:50 ` Charles (Chas) Williams
2016-11-10 11:14 ` Thomas Gleixner
2016-11-12 22:05 ` M. Vefa Bicakci
2016-11-10 11:13 ` Thomas Gleixner
2016-11-10 11:39 ` Peter Zijlstra
2016-11-10 14:02 ` Boris Ostrovsky
2016-11-10 15:05 ` Charles (Chas) Williams
2016-11-10 15:31 ` Boris Ostrovsky
2016-11-10 15:54 ` Sebastian Andrzej Siewior
2016-11-10 17:15 ` Thomas Gleixner
2016-11-12 22:05 ` M. Vefa Bicakci
2016-11-13 18:04 ` Boris Ostrovsky
2016-11-13 23:42 ` M. Vefa Bicakci
2016-11-15 1:21 ` Boris Ostrovsky
2016-11-18 11:16 ` Thomas Gleixner
2016-11-18 14:22 ` Boris Ostrovsky
2016-11-10 15:12 ` Thomas Gleixner
2016-11-10 15:38 ` Boris Ostrovsky
2016-11-10 17:13 ` Thomas Gleixner
2016-11-10 18:01 ` Boris Ostrovsky
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