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| author | Al Viro <viro@zeniv.linux.org.uk> | 2012-08-17 21:29:06 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-08-22 10:26:13 -0400 |
| commit | 90b1253e4139776e8257914ae9e2292d0de2fecc (patch) | |
| tree | 47ed9f35d8f58d42f6e3c8614d355b1edc86f51b /drivers/vfio | |
| parent | 6d2cd3ce815b302e885b44ca1bdbe3c7db321c7a (diff) | |
| download | lwn-90b1253e4139776e8257914ae9e2292d0de2fecc.tar.gz lwn-90b1253e4139776e8257914ae9e2292d0de2fecc.zip | |
vfio: get rid of vfio_device_put()/vfio_group_get_device* races
we really need to make sure that dropping the last reference happens
under the group->device_lock; otherwise a loop (under device_lock)
might find vfio_device instance that is being freed right now, has
already dropped the last reference and waits on device_lock to exclude
the sucker from the list.
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'drivers/vfio')
| -rw-r--r-- | drivers/vfio/vfio.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 92b85676e6be..887ae43276bb 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -396,7 +396,6 @@ static void vfio_device_release(struct kref *kref) struct vfio_device, kref); struct vfio_group *group = device->group; - mutex_lock(&group->device_lock); list_del(&device->group_next); mutex_unlock(&group->device_lock); @@ -412,7 +411,7 @@ static void vfio_device_release(struct kref *kref) static void vfio_device_put(struct vfio_device *device) { struct vfio_group *group = device->group; - kref_put(&device->kref, vfio_device_release); + kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock); vfio_group_put(group); } |