RE: [PATCH net-next v12 5/5] net: wangxun: add pcie error handler

["Jiawen Wu" <jiawenwu@trustnetic.com>]

> > Simon says: I think the issue below can be looked at in the context
> >             of possible follow-up.
> 
> I'll consider handling this in another patch.
> 
> >
> > [Severity: High]
> > This is a pre-existing issue, but does failing to open the device in
> > txgbe_open() lead to a NULL pointer dereference on subsequent open attempts?
> >
> > If txgbe_open() encounters an error, the error path calls
> > wx_reset_interrupt_capability(), which frees wx->msix_q_entries and sets
> > it to NULL.
> >
> > If a user subsequently attempts to bring the interface up again,
> > txgbe_request_queue_irqs() is called, which dereferences the NULL
> > wx->msix_q_entries array.
> >
> > >  	wx_ptp_stop(wx);
> > >  	txgbe_down(wx);
> >

After checking the code closely, I think Sashiko is overstated here.

wx_reset_interrupt_capability() called pci_free_irq_vectors() which set
pdev->msix_enabled = 0. And this would prevent wx->msix_q_entries from being
used in txgbe_request_queue_irqs().