Re: [PATCH] virtio-balloon: fix memory leak while attach virtio-balloon device

[pannengyuan]

On 2019/12/3 13:34, Michael S. Tsirkin wrote:
> On Tue, Dec 03, 2019 at 09:44:19AM +0800, address@hidden wrote:
>> From: PanNengyuan <address@hidden>
>>
>> ivq/dvq/svq/free_page_vq is forgot to cleanup in
>> virtio_balloon_device_unrealize, the memory leak stack is as follow:
>>
>> Direct leak of 14336 byte(s) in 2 object(s) allocated from:
>>     #0 0x7f99fd9d8560 in calloc (/usr/lib64/libasan.so.3+0xc7560)
>>     #1 0x7f99fcb20015 in g_malloc0 (/usr/lib64/libglib-2.0.so.0+0x50015)
>>     #2 0x557d90638437 in virtio_add_queue 
>> /mnt/sdb/qemu-4.2.0-rc0/hw/virtio/virtio.c:2327
>>     #3 0x557d9064401d in virtio_balloon_device_realize 
>> /mnt/sdb/qemu-4.2.0-rc0/hw/virtio/virtio-balloon.c:793
>>     #4 0x557d906356f7 in virtio_device_realize 
>> /mnt/sdb/qemu-4.2.0-rc0/hw/virtio/virtio.c:3504
>>     #5 0x557d9073f081 in device_set_realized 
>> /mnt/sdb/qemu-4.2.0-rc0/hw/core/qdev.c:876
>>     #6 0x557d908b1f4d in property_set_bool 
>> /mnt/sdb/qemu-4.2.0-rc0/qom/object.c:2080
>>     #7 0x557d908b655e in object_property_set_qobject 
>> /mnt/sdb/qemu-4.2.0-rc0/qom/qom-qobject.c:26
>>
>> Reported-by: Euler Robot <address@hidden>
>> Signed-off-by: PanNengyuan <address@hidden>
>> ---
>>  hw/virtio/virtio-balloon.c | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
>> index 40b04f5..5329c65 100644
>> --- a/hw/virtio/virtio-balloon.c
>> +++ b/hw/virtio/virtio-balloon.c
>> @@ -831,6 +831,13 @@ static void virtio_balloon_device_unrealize(DeviceState 
>> *dev, Error **errp)
>>      }
>>      balloon_stats_destroy_timer(s);
>>      qemu_remove_balloon_handler(s);
>> +
>> +    virtio_del_queue(vdev, 0);
>> +    virtio_del_queue(vdev, 1);
>> +    virtio_del_queue(vdev, 2);
>> +    if (s->free_page_vq) {
>> +        virtio_del_queue(vdev, 3);
>> +    }
>>      virtio_cleanup(vdev);
>>  }
> 
> Hmm ok, but how about just doing it through a vq pointer then?
> Seems cleaner. E.g. use patch below and add your on top
> using the new virtio_delete_queue?
> 

ok, It seems more cleaner, I will send a new version later.

Thanks.

> -->
> virtio: add ability to delete vq through a pointer
> 
> Devices tend to maintain vq pointers, allow deleting them like this.
> 
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> 
> --
> 
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index c32a815303..e18756d50d 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -183,6 +183,8 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int 
> queue_size,
>  
>  void virtio_del_queue(VirtIODevice *vdev, int n);
>  
> +void virtio_delete_queue(VirtQueue *vq);
> +
>  void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
>                      unsigned int len);
>  void virtqueue_flush(VirtQueue *vq, unsigned int count);
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 04716b5f6c..31dd140990 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -2330,17 +2330,22 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int 
> queue_size,
>      return &vdev->vq[i];
>  }
>  
> +void virtio_delete_queue(VirtQueue *vq)
> +{
> +    vq->vring.num = 0;
> +    vq->vring.num_default = 0;
> +    vq->handle_output = NULL;
> +    vq->handle_aio_output = NULL;
> +    g_free(vq->used_elems);
> +}
> +
>  void virtio_del_queue(VirtIODevice *vdev, int n)
>  {
>      if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
>          abort();
>      }
>  
> -    vdev->vq[n].vring.num = 0;
> -    vdev->vq[n].vring.num_default = 0;
> -    vdev->vq[n].handle_output = NULL;
> -    vdev->vq[n].handle_aio_output = NULL;
> -    g_free(vdev->vq[n].used_elems);
> +    virtio_delete_queue(&vdev->vq[n]);
>  }
>  
>  static void virtio_set_isr(VirtIODevice *vdev, int value)
> 
> 
> .
>