diff options
| author | Sasha Levin <sasha.levin@oracle.com> | 2015-01-02 14:47:40 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2015-02-20 00:49:34 +0000 |
| commit | 119d5897cc5f9f73e352a1c647d21b9d506b8c0a (patch) | |
| tree | e0592cfc58b11b686574140316d718cfad230eb6 /drivers | |
| parent | ddabe0f7922dc94249030ce3f3f7cae9ef34dbe3 (diff) | |
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>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/virtio/virtio_pci.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 03d1984bd363..65c907dc354e 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -612,11 +612,10 @@ static 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 */ @@ -704,7 +703,6 @@ static void __devexit 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 |