Re: [PATCH] pci: iov: use device lock to protect IOV sysfs accesses

[Jakub Kicinski]

On Fri, 26 May 2017 18:47:26 -0500, Bjorn Helgaas wrote:
> On Mon, May 22, 2017 at 03:50:23PM -0700, Jakub Kicinski wrote:
> > PCI core sets the driver pointer before calling ->probe() and only
> > clears it after ->remove().  This means driver's ->sriov_configure()
> > callback will happily race with probe() and remove(), most likely
> > leading to BUGs, since drivers don't expect this.  
> 
> I guess you're referring to the pci_dev->driver pointer set by
> local_pci_probe(), and this is important because sriov_numvfs_store()
> checks that pointer, right?

Yes, exactly.  I initially thought this is how the safety of sriov
callback may have been ensured, but since the order of
local_pci_probe() and the assignment is what it is, it can't.