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.
