On 25.07.2016 16:05, Marc-André Lureau wrote:
> Hi
>
> ----- Original Message -----
>> On 25.07.2016 15:45, Marc-André Lureau wrote:
>>> Hi
>>>
>>> ----- Original Message -----
>>>> On 21.07.2016 11:57, Marc-André Lureau wrote:
>>>>> From: Marc-André Lureau <marcandre.lur...@redhat.com>
>>>>>
>>>>> vhost_net_init() calls vhost_dev_init() and in case of failure, calls
>>>>> vhost_dev_cleanup() directly. However, the structure is already
>>>>> partially cleaned on error. Calling vhost_dev_cleanup() again will call
>>>>> vhost_virtqueue_cleanup() on already clean queues, and causing potential
>>>>> double-close. Instead, adjust dev->nvqs and simplify vhost_dev_init()
>>>>> code to not call vhost_virtqueue_cleanup() but vhost_dev_cleanup()
>>>>> instead.
>>>>>
>>>>> Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
>>>>> ---
>>>>> hw/virtio/vhost.c | 13 ++++---------
>>>>> 1 file changed, 4 insertions(+), 9 deletions(-)
>>>>>
>>>>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>>>>> index 9400b47..c61302a 100644
>>>>> --- a/hw/virtio/vhost.c
>>>>> +++ b/hw/virtio/vhost.c
>>>>> @@ -1047,7 +1047,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void
>>>>> *opaque,
>>>>> for (i = 0; i < hdev->nvqs; ++i) {
>>>>> r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index +
>>>>> i);
>>>>> if (r < 0) {
>>>>> - goto fail_vq;
>>>>> + hdev->nvqs = i;
>>>>> + goto fail;
>>>>> }
>>>>> }
>>>>>
>>>>> @@ -1104,19 +1105,13 @@ int vhost_dev_init(struct vhost_dev *hdev, void
>>>>> *opaque,
>>>>> memory_listener_register(&hdev->memory_listener,
>>>>> &address_space_memory);
>>>>> QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
>>>>> return 0;
>>>>> +
>>>>> fail_busyloop:
>>>>> while (--i >= 0) {
>>>>> vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i,
>>>>> 0);
>>>>> }
>>>>> - i = hdev->nvqs;
>>>>> -fail_vq:
>>>>> - while (--i >= 0) {
>>>>> - vhost_virtqueue_cleanup(hdev->vqs + i);
>>>>> - }
>>>>> fail:
>>>>> - r = -errno;
>>>>> - hdev->vhost_ops->vhost_backend_cleanup(hdev);
>>>>> - QLIST_REMOVE(hdev, entry);
>>>>> + vhost_dev_cleanup(hdev);
>>>>> return r;
>>>>> }
>>>>>
>>>>>
>>>>
>>>> This patch introduces closing of zero fd on backend init failure or any
>>>> other error before virtqueue_init loop because of calling
>>>> 'vhost_virtqueue_cleanup()' on not initialized virtqueues.
>>>>
>>>> I'm suggesting following fixup:
>>>>
>>>> ----------------------------------------------------------------------
>>>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>>>> index 6175d8b..d7428c5 100644
>>>> --- a/hw/virtio/vhost.c
>>>> +++ b/hw/virtio/vhost.c
>>>> @@ -1038,8 +1038,9 @@ int vhost_dev_init(struct vhost_dev *hdev, void
>>>> *opaque,
>>>> VhostBackendType backend_type, uint32_t
>>>> busyloop_timeout)
>>>> {
>>>> uint64_t features;
>>>> - int i, r;
>>>> + int i, r, n_initialized_vqs;
>>>>
>>>> + n_initialized_vqs = 0;
>>>> hdev->migration_blocker = NULL;
>>>>
>>>> r = vhost_set_backend_type(hdev, backend_type);
>>>>
>>>> @@ -1069,10 +1071,9 @@ int vhost_dev_init(struct vhost_dev *hdev, void
>>>> *opaque,
>>>> goto fail;
>>>> }
>>>>
>>>> - for (i = 0; i < hdev->nvqs; ++i) {
>>>> + for (i = 0; i < hdev->nvqs; ++i, ++n_initialized_vqs) {
>>>> r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index +
>>>> i);
>>>> if (r < 0) {
>>>> - hdev->nvqs = i;
>>>
>>> Isn't that assignment doing the same thing?
>>
>> Yes.
>> But assignment to zero (hdev->nvqs = 0) required before all previous
>> 'goto fail;' instructions. I think, it's not a clean solution.
>>
>
> Good point, I'll squash your change,
Thanks for fixing it.
> should I add your sign-off-by?
I don't mind if you want to.
Best regards, Ilya Maximets.
