IRQ/nvme_pci_complete_rq: NULL pointer dereference yet again

[keith.busch@intel.com (Keith Busch)]

On Fri, Apr 06, 2018@01:00:37PM -0600, Scott Bauer wrote:
> I think we may get into a deadlock situation if we grab the pci_lock_rescan.
> the hotplug unconfigure code will eventually call driver->remove() which I believe
> can end up in the aer_remove(), which will do a flush_work. If the aer delegated
> irq handler is waiting on the pci_lock_rescan, before it does a walk_bus, we've deadlocked
> there as the hp code is waiting on the remove() to finish, and the remove is waiting on 
> the flush work to finish and the work being flushed is waiting on the lock.

Darn. I believe your point is valid, though not through pciehp since
root ports themselves are not pcie hot pluggable components, but other
paths could get there.