On Fri, Jan 02, 2015 at 02:47:40PM -0500, Sasha Levin wrote:
> 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() even if that was the device's last reference.
>
> Instead, free the memory only once we know the device is gone in the release
> callback.
>
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Isn't this an old bug: do we need to copy stable on a fix?
What is the behaviour without this patch?
Is there a way to make this cause a crash?
> ---
> drivers/virtio/virtio_pci_common.c | 9 ++++-----
> drivers/virtio/virtio_pci_legacy.c | 1 -
> 2 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index 59d3685..caa483d 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -423,11 +423,10 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
>
> 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);
> }
>
> #ifdef CONFIG_PM_SLEEP
> diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> index 913ca23..15e6e6d 100644
> --- a/drivers/virtio/virtio_pci_legacy.c
> +++ b/drivers/virtio/virtio_pci_legacy.c
> @@ -301,5 +301,4 @@ void virtio_pci_legacy_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);
> }
It seems inelegant to free a structure allocated in another file:
I think we should move this function to virtio_pci_legacy.
Will send a patch in a minute.
> --
> 1.7.10.4
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