Re: [PATCH] s390: vfio-ap: disable IRQ in remove callback results in kernel OOPS

Pierre Morel
2019-10-30T14:00:18Z

On 10/30/19 8:44 AM, Harald Freudenberger wrote:
> On 29.10.19 23:09, Tony Krowiak wrote:
>> From: aekrowia <akrowiak@linux.ibm.com>
>>
>> When an AP adapter card is configured off via the SE or the SCLP
>> Deconfigure Adjunct Processor command and the AP bus subsequently detects
>> that the adapter card is no longer in the AP configuration, the card
>> device representing the adapter card as well as each of its associated
>> AP queue devices will be removed by the AP bus. If one or more of the
>> affected queue devices is bound to the VFIO AP device driver, its remove
>> callback will be invoked for each queue to be removed. The remove callback
>> resets the queue and disables IRQ processing. If interrupt processing was
>> never enabled for the queue, disabling IRQ processing will fail resulting
>> in a kernel OOPS.
>>
>> This patch verifies IRQ processing is enabled before attempting to disable
>> interrupts for the queue.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> Signed-off-by: aekrowia <akrowiak@linux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
>> index be2520cc010b..42d8308fd3a1 100644
>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
>> apid = AP_QID_CARD(q->apqn);
>> apqi = AP_QID_QUEUE(q->apqn);
>> vfio_ap_mdev_reset_queue(apid, apqi, 1);
>> - vfio_ap_irq_disable(q);
>> + if (q->saved_isc != VFIO_AP_ISC_INVALID)
>> + vfio_ap_irq_disable(q);
>> kfree(q);
>> mutex_unlock(&matrix_dev->lock);
>> }
> Reset of an APQN does also clear IRQ processing. I don't say that the
> resources associated with IRQ handling for the APQN are also cleared.
> But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
> it is superfluous. However, there should not appear any kernel OOPS.
> So can you please give me more details about this kernel oops - maybe
> I need to add exception handler code to the inline ap_aqic() function.
>
> regards, Harald Freudenberger
>

Hi Tony,

wasn't it already solved by the patch 5c4c2126  from Christian ?

Can you send the trace to me please?

Thanks,

Pierre

--
Pierre Morel
IBM Lab Boeblingen