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authorSasha Levin <sasha.levin@oracle.com>2015-01-02 14:47:40 -0500
committerMichael S. Tsirkin <mst@redhat.com>2015-01-06 16:35:36 +0200
commit63bd62a08ca45a0c804c3c89777edc7f76a2d6da (patch)
tree4e7c1e3590d1ca21715a00930c1554c4a5eac8cf
parent945399a8c78ac225cdbaece0f94c0d8741b4e1d8 (diff)
virtio_pci: defer kfree until release callback
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. Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
-rw-r--r--drivers/virtio/virtio_pci_legacy.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index 08d191527020..4beaee384906 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -213,11 +213,10 @@ 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 */
@@ -311,5 +310,4 @@ 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);
}