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authorAlex Williamson <alex.williamson@redhat.com>2016-05-30 07:50:10 -0600
committerAlex Williamson <alex.williamson@redhat.com>2016-05-30 07:50:10 -0600
commit956b56a984ddf10aa69b25318dc04430101beed6 (patch)
tree5d698890a0f6ab87af4c647908395f51d30e8356 /drivers/vfio
parent1a695a905c18548062509178b98bc91e67510864 (diff)
downloadlinux-956b56a984ddf10aa69b25318dc04430101beed6.tar.bz2
vfio/pci: Fix ordering of eventfd vs virqfd shutdown
Both the INTx and MSI/X disable paths do an eventfd_ctx_put() for the trigger eventfd before calling vfio_virqfd_disable() any potential mask and unmask eventfds. This opens a use-after-free race where an inopportune irqfd can reference the freed signalling eventfd. Reorder to avoid this possibility. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/pci/vfio_pci_intrs.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index e9ea3fef144a..15ecfc9c5f6c 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -228,9 +228,9 @@ static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd)
static void vfio_intx_disable(struct vfio_pci_device *vdev)
{
- vfio_intx_set_signal(vdev, -1);
vfio_virqfd_disable(&vdev->ctx[0].unmask);
vfio_virqfd_disable(&vdev->ctx[0].mask);
+ vfio_intx_set_signal(vdev, -1);
vdev->irq_type = VFIO_PCI_NUM_IRQS;
vdev->num_ctx = 0;
kfree(vdev->ctx);
@@ -401,13 +401,13 @@ static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix)
struct pci_dev *pdev = vdev->pdev;
int i;
- vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);
-
for (i = 0; i < vdev->num_ctx; i++) {
vfio_virqfd_disable(&vdev->ctx[i].unmask);
vfio_virqfd_disable(&vdev->ctx[i].mask);
}
+ vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);
+
if (msix) {
pci_disable_msix(vdev->pdev);
kfree(vdev->msix);