vfio: Move PCI INTx eventfd setting earlier

We need to be ready to recieve an interrupt as soon as we call
request_irq, so our eventfd context setting needs to be moved
earlier.  Without this, an interrupt from our device or one
sharing the interrupt line can pass a NULL into eventfd_signal
and oops.

Cc: stable@vger.kernel.org
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index d8dedc7..c8139a5 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -400,19 +400,20 @@ static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd)
                return PTR_ERR(trigger);
        }
 
+       vdev->ctx[0].trigger = trigger;
+
        if (!vdev->pci_2_3)
                irqflags = 0;
 
        ret = request_irq(pdev->irq, vfio_intx_handler,
                          irqflags, vdev->ctx[0].name, vdev);
        if (ret) {
+               vdev->ctx[0].trigger = NULL;
                kfree(vdev->ctx[0].name);
                eventfd_ctx_put(trigger);
                return ret;
        }
 
-       vdev->ctx[0].trigger = trigger;
-
        /*
         * INTx disable will stick across the new irq setup,
         * disable_irq won't.