Re: [dpdk-dev] [PATCH] vfio: fix file descriptor leak in multi-process applications

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

> -----Original Message-----
> From: Patrick MacArthur [mailto:patrick@patrickmacarthur.net]
> Sent: Thursday, January 26, 2017 11:05 PM
> To: dev@dpdk.org; Burakov, Anatoly <anatoly.burakov@intel.com>
> Cc: Patrick MacArthur <patrick@patrickmacarthur.net>
> Subject: [PATCH] vfio: fix file descriptor leak in multi-process applications
> 
> When a secondary process wants access to the VFIO container file descriptor,
> the primary process calls vfio_get_container_fd() which always opens an
> entirely new file descriptor on /dev/vfio/vfio.
> However, once the file descriptor has been passed to the subprocess, it is
> effectively duplicated, meaning that the copy of the file descriptor in the
> primary process is no longer needed.  However, the primary process does
> not close the duplicate fd, which results in a resource leak.
> 
> This can be reproduced by starting a primary process with a small
> RLIMIT_NOFILE limit configured to use VFIO for at least one device, and
> repeatedly launching secondary processes until the file descriptor limit is
> exceeded.
> 
> Fix the resource leak by closing the local vfio container file descriptor after
> passing it to the secondary process.
> 
> Fixes: 2f4adfad0a69 ("vfio: add multiprocess support")
> Signed-off-by: Patrick MacArthur <patrick@patrickmacarthur.net>
> ---
>  lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> index 00cf919b64d0..fb4a2f84b180 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> @@ -301,6 +301,7 @@ vfio_mp_sync_thread(void __rte_unused * arg)
>  				vfio_mp_sync_send_request(conn_sock,
> SOCKET_ERR);
>  			else
>  				vfio_mp_sync_send_fd(conn_sock, fd);
> +			close(fd);
>  			break;
>  		case SOCKET_REQ_GROUP:
>  			/* wait for group number */
> --
> 2.9.3


Acked-by: Anatoly  Burakov <anatoly.burakov@intel.com>