diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 96d421f..4ac618b 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -28,6 +28,7 @@
 static char		default_sort_order[] = "comm,symbol";
 static char		*sort_order = default_sort_order;
 
+static int		force;
 static int		input;
 static int		show_mask = SHOW_KERNEL | SHOW_USER | SHOW_HV;
 
@@ -629,6 +630,13 @@
 		(void *)(long)(event->header.size),
 		event->fork.pid, event->fork.ppid);
 
+	/*
+	 * A thread clone will have the same PID for both
+	 * parent and child.
+	 */
+	if (thread == parent)
+		return 0;
+
 	if (!thread || !parent || thread__fork(thread, parent)) {
 		dump_printf("problem processing PERF_EVENT_FORK, skipping event.\n");
 		return -1;
@@ -976,6 +984,11 @@
 		exit(-1);
 	}
 
+	if (!force && (input_stat.st_uid != geteuid())) {
+		fprintf(stderr, "file: %s not owned by current user\n", input_name);
+		exit(-1);
+	}
+
 	if (!input_stat.st_size) {
 		fprintf(stderr, "zero-sized file, nothing to do!\n");
 		exit(0);
@@ -1081,6 +1094,7 @@
 		    "input file name"),
 	OPT_STRING('s', "symbol", &sym_hist_filter, "symbol",
 		    "symbol to annotate"),
+	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
 	OPT_BOOLEAN('v', "verbose", &verbose,
 		    "be more verbose (show symbol address, etc)"),
 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,