Re: WARNING and PANIC in irq_matrix_free

[Song Liu]

Hi,

We are seeing something probably related.

We run ethtool on a system with Broadcom NIC to increase number of
combined queues.


    [root@ ~]# ethtool -l eth0
    Channel parameters for eth0:
    Pre-set maximums:
    RX:             9
    TX:             8
    Other:          0
    Combined:       17
    Current hardware settings:
    RX:             0
    TX:             0
    Other:          0
    Combined:       8

    [root@ ~]# ethtool -L eth0 combined 16

The last command PANIC the kernel easily (5 out of 5 in my tests).

I haven't got luck to catch much console output, the only line I got is:

    [ 504.727865] WARNING: CPU: 10 PID: 0 at kernel/irq/matrix.c:371
irq_matrix_free+0x32/0xd0

The NIC we have is

    Broadcom Limited BCM57302 NetXtreme-C 10Gb/25Gb Ethernet Controller

Thanks,
Song

On Wed, May 23, 2018 at 1:49 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Wed, 23 May 2018, Tariq Toukan wrote:
>> On 19/05/2018 2:20 PM, Thomas Gleixner wrote:
>> > On Fri, 18 May 2018, Dmitry Safonov wrote:
>> > > I'm not entirely sure that it's the same fault, but at least backtrace
>> > > looks resembling.
>> >
>> > Yes, it's similar, but not the same issue. I'll stare are the code ...
>> >
>> > Thanks,
>> >
>> >     tglx
>> >
>>
>> We still see the issue in our daily regression runs.
>> I have your patch merged into my internal branch, it prints the following:
>>
>> [ 4898.226258] Trying to clear prev_vector: 0
>> [ 4898.226439] Trying to clear prev_vector: 0
>>
>> i.e. vector(0) is lower than FIRST_EXTERNAL_VECTOR.
>
> Could you please enable the vector and irq matrix trace points and capture
> the trace when this happens?
>
> Thanks,
>
>         tglx
>