[PATCH 3.16.y-ckt 028/129] virtio_pci: fix use after free on release

From: Luis Henriques
Date: Fri Feb 26 2016 - 06:03:35 EST

3.16.7-ckt25 -stable review patch. If anyone has any objections, please let me know.


From: "Michael S. Tsirkin" <mst@xxxxxxxxxx>

commit 2989be09a8a9d62a785137586ad941f916e08f83 upstream.

KASan detected a use-after-free error in virtio-pci remove code. In
virtio_pci_remove(), vp_dev is still used after being freed in
unregister_virtio_device() (in virtio_pci_release_dev() more

To fix, keep a reference until cleanup is done.

Fixes: 63bd62a08ca4 ("virtio_pci: defer kfree until release callback")
Reported-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Tested-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
[ luis: backported to 3.16:
- file rename: virtio_pci_legacy.c -> virtio_pci.c ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/virtio/virtio_pci.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index c09527df161c..3eecbbad6cb4 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -756,6 +756,7 @@ out:
static void virtio_pci_remove(struct pci_dev *pci_dev)
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+ struct device *dev = get_device(&vp_dev->vdev.dev);


@@ -763,6 +764,7 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
pci_iounmap(pci_dev, vp_dev->ioaddr);
+ put_device(dev);