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Subject: Re: False positive "do_IRQ: #.55 No irq handler for vector" messages
 on AMD ryzen based laptops
To:     "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
        Thomas Gleixner <tglx@linutronix.de>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Borislav Petkov <bp@alien8.de>
References: <95e76875-f6b2-cbea-cd74-dc14ee77b2f8@redhat.com>
 <alpine.DEB.2.21.1902192144390.1644@nanos.tec.linutronix.de>
 <13dbe818-a364-4cd4-3ac4-78bd7e8d28e3@amd.com>
From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <9f17f1aa-f258-fb18-0736-04a5c03cf40e@redhat.com>
Date:   Thu, 21 Feb 2019 13:30:16 +0100
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Hi,

On 19-02-19 22:47, Lendacky, Thomas wrote:
> On 2/19/19 3:01 PM, Thomas Gleixner wrote:
>> Hans,
>>
>> On Tue, 19 Feb 2019, Hans de Goede wrote:
>>
>> Cc+: ACPI/AMD folks
>>
>>> Various people are reporting false positive "do_IRQ: #.55 No irq handler for
>>> vector"
>>> messages on AMD ryzen based laptops, see e.g.:
>>>
>>> https://bugzilla.redhat.com/show_bug.cgi?id=1551605
>>>
>>> Which contains this dmesg snippet:
>>>
>>> Feb 07 20:14:29 localhost.localdomain kernel: smp: Bringing up secondary CPUs
>>> ...
>>> Feb 07 20:14:29 localhost.localdomain kernel: x86: Booting SMP configuration:
>>> Feb 07 20:14:29 localhost.localdomain kernel: .... node  #0, CPUs:      #1
>>> Feb 07 20:14:29 localhost.localdomain kernel: do_IRQ: 1.55 No irq handler for
>>> vector
>>> Feb 07 20:14:29 localhost.localdomain kernel:  #2
>>> Feb 07 20:14:29 localhost.localdomain kernel: do_IRQ: 2.55 No irq handler for
>>> vector
>>> Feb 07 20:14:29 localhost.localdomain kernel:  #3
>>> Feb 07 20:14:29 localhost.localdomain kernel: do_IRQ: 3.55 No irq handler for
>>> vector
>>> Feb 07 20:14:29 localhost.localdomain kernel: smp: Brought up 1 node, 4 CPUs
>>> Feb 07 20:14:29 localhost.localdomain kernel: smpboot: Max logical packages: 1
>>> Feb 07 20:14:29 localhost.localdomain kernel: smpboot: Total of 4 processors
>>> activated (15968.49 BogoMIPS)
>>>
>>> It seems that we get an IRQ for each CPU as we bring it online,
>>> which feels to me like it is some sorta false-positive.
>>
>> Sigh, that looks like BIOS value add again.
>>
>> It's not a false positive. Something _IS_ sending a vector 55 to these CPUs
>> for whatever reason.
>>
> 
> I remember seeing something like this in the past and it turned out to be
> a BIOS issue.  BIOS was enabling the APs to interact with the legacy 8259
> interrupt controller when only the BSP should. During POST the APs were
> exposed to ExtINT/INTR events as a result of the mis-configuration
> (probably due to a UEFI timer-tick using the 8259) and this left a pending
> ExtINT/INTR interrupt latched on the APs.
> 
> When the APs were started by the OS, the latched ExtINT/INTR interrupt is
> processed shortly after the OS enables interrupts. The AP then queries the
> 8259 to identify the vector number (which is the value of the 8259's ICW2
> register + the IRQ level). The master 8259's ICW2 was set to 0x30 and,
> since no interrupts are actually pending, the 8259 will respond with IRQ7
> (spurious interrupt) yielding a vector of 0x37 or 55.
> 
> The OS was not expecting vector 55 and printed the message.
> 
>  From the Intel Developer's Manual: Vol 3a, Section 10.5.1:
> "Only one processor in the system should have an LVT entry configured to
> use the ExtINT delivery mode."
> 
> Not saying this is the problem, but very well could be.

That sounds like a likely candidate, esp. also since this only happens
once per CPU when we first only the CPU.

Can you provide me with a patch with some printk-s / pr_debugs to
test for this, then I can build a kernel with that patch added and
we can see if your hypothesis is right.

Regards,

Hans


> 
> Thanks,
> Tom
> 
>>> I temporarily have access to a loaner laptop for a couple of weeks which shows
>>> the same errors and I would like to fix this, but I don't really know how to
>>> fix this.
>>
>> Can you please enable CONFIG_GENERIC_IRQ_DEBUGFS and dig in the files there
>> whether vector 55 is used on CPU0 and which device is associated to that.
>>
>> I bet its a legacy IRQ and as that space starts at 48 (IRQ0) this should be
>> IRQ9 which is usually - DRUMROLL - the ACPI interrupt.
>>
>> The kernel clearly sets that up to be delivered to CPU 0 only, but I've
>> seen that before that the BIOS value add thinks that this setup is not
>> relevant.
>>
>> /me goes off and sings LALALA
>>
>>> Note if you want I can set up root ssh-access to the laptop.
>>
>> As a least resort. root ssh - SHUDDER - Ooops now I spilled my preferred
>> password for that :)
>>
>> Thanks,
>>
>> 	tglx
>>