RE: [PATCH 2/2] pci-hyperv: properly handle device eject

[Long Li]

> -----Original Message-----
> From: Dexuan Cui
> Sent: Tuesday, September 13, 2016 10:45 PM
> To: Long Li <longli@xxxxxxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx>;
> Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Bjorn Helgaas
> <bhelgaas@xxxxxxxxxx>
> Cc: devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> pci@xxxxxxxxxxxxxxx
> Subject: RE: [PATCH 2/2] pci-hyperv: properly handle device eject
> 
> > From: Long Li
> > Sent: Wednesday, September 14, 2016 1:41
> >
> > I think this code is safe here. If we reach the code
> > pci_stop_and_remove_bus_device_locked, create_root_hv_pci_bus() is
> > already called.
> 
> When hv_pci_probe() -> create_root_hv_pci_bus() -> pci_scan_child_bus()
> is running on one cpu, I think nothing in the current code can prevent
> hv_eject_device_work() -> pci_stop_and_remove_bus_device_locked()
> from running on another cpu?
> 
> The race window is pretty small however.

This is a valid race condition. I'll work on a V2 patch. Thanks!

> 
> Thanks,
> -- Dexuan