Re: [PATCH] libsas: flush pending destruct work in sas_unregister_domain_devices()

[Cong Wang]

On Thu, Dec 7, 2017 at 5:37 AM, John Garry <john.garry@xxxxxxxxxx> wrote:
> On 28/11/2017 17:04, Cong Wang wrote:
>>
>> I don't understand, the only caller of sas_unregister_domain_devices()
>> is sas_deform_port().
>>
>
> And sas_deform_port() may be called from another worker on the same queue,
> right? As in sas_phye_loss_of_signal()->sas_deform_port()

Oh, good catch! I didn't notice this subtle call path.

Do you have any better idea to fix this? We saw this on 4.9 too.

>
> The device destruct takes place in a separate worker from which
> sas_deform_port() is called, but the same queue. So we have this queued
> destruct happen after the port is fully deformed -> hence the WARN.
>
> I guess you only tested your patch on disks attached through an expander.

I have very limited scsi hardware, so my testing is limited too.