It fixes segfault within machine__exit, that's caused
but not creating kernel maps for machine.. We're calling
machine__destroy_kernel_maps in machine__exit since commit:

  ebe9729c perf machine: Fix to destroy kernel maps when machine exits
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/tip-k4snzv5t4dvdckggzwdzyljo@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>