It's opened in switch_ns.

CID 996194 (#3 of 5): Resource leak (RESOURCE_LEAK)
11. leaked_handle: Handle variable rst going out of scope leaks the handle.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>