@@ -670,11 +670,10 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
static void virtio_pci_release_dev(struct device *_d)
{
- /*
- * 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.
- */
+ struct virtio_device *vdev = dev_to_virtio(_d);
+ struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+ kfree(vp_dev);
}
/* the PCI probing function */
@@ -764,7 +763,6 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
pci_iounmap(pci_dev, vp_dev->ioaddr);
pci_release_regions(pci_dev);
pci_disable_device(pci_dev);
- kfree(vp_dev);
}
#ifdef CONFIG_PM_SLEEP
This is a note to let you know that I have just added a patch titled virtio_pci: defer kfree until release callback to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11-ckt16. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 625358bfc3edfff83a34b8855807b535798b41fe Mon Sep 17 00:00:00 2001 From: Sasha Levin <sasha.levin@oracle.com> Date: Fri, 2 Jan 2015 14:47:40 -0500 Subject: virtio_pci: defer kfree until release callback commit 63bd62a08ca45a0c804c3c89777edc7f76a2d6da upstream. A struct device which has just been unregistered can live on past the point at which a driver decides to drop it's initial reference to the kobject gained on allocation. This implies that when releasing a virtio device, we can't free a struct virtio_device until the underlying struct device has been released, which might not happen immediately on device_unregister(). Unfortunately, this is exactly what virtio pci does: it has an empty release callback, and frees memory immediately after unregistering the device. This causes an easy to reproduce crash if CONFIG_DEBUG_KOBJECT_RELEASE it enabled. To fix, free the memory only once we know the device is gone in the release callback. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/virtio/virtio_pci.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) -- 1.9.1