3.13.11-ckt16 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Sasha Levin <sasha.levin@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/virtio/virtio_pci.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index a516842..8a430b2 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -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
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html