virtio-pci: fix use after free
Commit 31a3ddda166cda86d2b5111e09ba4bda5239fae6 introduced
a use after free in virtio-pci. The main issue is
that the release method signals removal of the virtio device,
while remove signals removal of the pci device.
For example, on driver removal or hot-unplug,
virtio_pci_release_dev is called before virtio_pci_remove.
We then might get a crash as virtio_pci_remove tries to use the
device freed by virtio_pci_release_dev.
We allocate/free all resources together with the
pci device, so we can leave the release method empty.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 79a31e5..3d1bf41 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -594,11 +594,11 @@
static void virtio_pci_release_dev(struct device *_d)
{
- struct virtio_device *dev = container_of(_d, struct virtio_device,
- dev);
- struct virtio_pci_device *vp_dev = to_vp_device(dev);
-
- kfree(vp_dev);
+ /*
+ * No need for a release method as we allocate/free
+ * all devices together with the pci devices.
+ * Provide an empty one to avoid getting a warning from core.
+ */
}
/* the PCI probing function */
@@ -686,6 +686,7 @@
pci_iounmap(pci_dev, vp_dev->ioaddr);
pci_release_regions(pci_dev);
pci_disable_device(pci_dev);
+ kfree(vp_dev);
}
#ifdef CONFIG_PM
