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| author | Sasha Levin <sasha.levin@oracle.com> | 2015-01-02 14:47:40 -0500 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2015-01-06 16:35:36 +0200 |
| commit | 63bd62a08ca45a0c804c3c89777edc7f76a2d6da (patch) | |
| tree | 4e7c1e3590d1ca21715a00930c1554c4a5eac8cf /drivers | |
| parent | 945399a8c78ac225cdbaece0f94c0d8741b4e1d8 (diff) | |
| download | linux-63bd62a08ca45a0c804c3c89777edc7f76a2d6da.tar.bz2 | |
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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/virtio/virtio_pci_legacy.c | 10 |
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); } |