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

Patrick MacArthur patrick at patrickmacarthur.net
Fri Jan 27 00:05:21 CET 2017

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

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 at 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);
 				vfio_mp_sync_send_fd(conn_sock, fd);
+			close(fd);
 			/* wait for group number */

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