--- /dev/null
+From 4a2233b194c77ae1ea8304cb7c00b551de4313f0 Mon Sep 17 00:00:00 2001
+From: Arnaldo Carvalho de Melo <acme@redhat.com>
+Date: Mon, 13 Nov 2017 16:06:29 -0300
+Subject: perf machine: Guard against NULL in machine__exit()
+
+From: Arnaldo Carvalho de Melo <acme@redhat.com>
+
+commit 4a2233b194c77ae1ea8304cb7c00b551de4313f0 upstream.
+
+A recent fix for 'perf trace' introduced a bug where
+machine__exit(trace->host) could be called while trace->host was still
+NULL, so make this more robust by guarding against NULL, just like
+free() does.
+
+The problem happens, for instance, when !root users try to run 'perf
+trace':
+
+ [acme@jouet linux]$ trace
+ Error: No permissions to read /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit)
+ Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing'
+
+ perf: Segmentation fault
+ Obtained 7 stack frames.
+ [0x4f1b2e]
+ /lib64/libc.so.6(+0x3671f) [0x7f43a1dd971f]
+ [0x4f3fec]
+ [0x47468b]
+ [0x42a2db]
+ /lib64/libc.so.6(__libc_start_main+0xe9) [0x7f43a1dc3509]
+ [0x42a6c9]
+ Segmentation fault (core dumped)
+ [acme@jouet linux]$
+
+Cc: Adrian Hunter <adrian.hunter@intel.com>
+Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
+Cc: Andrei Vagin <avagin@openvz.org>
+Cc: David Ahern <dsahern@gmail.com>
+Cc: Jiri Olsa <jolsa@kernel.org>
+Cc: Namhyung Kim <namhyung@kernel.org>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Vasily Averin <vvs@virtuozzo.com>
+Cc: Wang Nan <wangnan0@huawei.com>
+Fixes: 33974a414ce2 ("perf trace: Call machine__exit() at exit")
+Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
+Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ tools/perf/util/machine.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/tools/perf/util/machine.c
++++ b/tools/perf/util/machine.c
+@@ -156,6 +156,9 @@ void machine__delete_threads(struct mach
+
+ void machine__exit(struct machine *machine)
+ {
++ if (machine == NULL)
++ return;
++
+ machine__destroy_kernel_maps(machine);
+ map_groups__exit(&machine->kmaps);
+ dsos__exit(&machine->dsos);