[dpdk-stable] [dpdk-dev] [PATCH v2] vhost: fix vid allocation race

[Maxime Coquelin]

On 2/1/21 9:48 AM, Peng He wrote:
> vhost_new_device might be called in different threads at the same time.
> thread 1(config thread)
>             rte_vhost_driver_start
>                ->vhost_user_start_client
>                    ->vhost_user_add_connection
>                      -> vhost_new_device
> 
> thread 2(vhost-events)
> 	vhost_user_read_cb
>            ->vhost_user_msg_handler (return value < 0)
>              -> vhost_user_start_client
>                  -> vhost_new_device
> 
> So there could be a case that a same vid has been allocated twice, or
> some vid might be lost in DPDK lib however still held by the upper
> applications.
> 
> Another place where race would happen is at the func *vhost_destroy_device*,
> but after a detailed investigation, the race does not exist as long as
> no two devices have the same vid: Calling vhost_destroy_devices in
> different threads with different vids is actually safe.
> 
> Fixes: a277c715987 ("vhost: refactor code structure")
> Reported-by: Peng He <hepeng.0320 at bytedance.com>
> Signed-off-by: Fei Chen <chenwei.0515 at bytedance.com>
> Reviewed-by: Zhihong Wang <wangzhihong.wzh at bytedance.com>
> ---
>  lib/librte_vhost/vhost.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Applied to dpdk-next-virtio/main.

Thanks,
Maxime