Messages in this thread Patch in this message |  | | | Date | Fri, 18 Nov 2011 15:58:15 -0800 | | From | Greg KH <> | | Subject | [02/26] virtio-pci: fix use after free |
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3.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: "Michael S. Tsirkin" <mst@redhat.com>
commit 72103bd1285211440621f2c46f4fce377584de54 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/virtio/virtio_pci.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -590,11 +590,11 @@ static struct virtio_config_ops virtio_p 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 */ @@ -682,6 +682,7 @@ static void __devexit virtio_pci_remove( pci_iounmap(pci_dev, vp_dev->ioaddr); pci_release_regions(pci_dev); pci_disable_device(pci_dev); + kfree(vp_dev); } #ifdef CONFIG_PM
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