perf lock: Fix segfault due to missing kernel map

Kernel maps are encoded in PERF_RECORD_MMAP2 samples but "perf lock
report" and "perf lock contention" do not process MMAP2 samples.

Because of that, machine->vmlinux_map stays NULL and any later access
triggers a segmentation fault.

Fix it by adding ->mmap2() callbacks.

Fixes: 53b00ff ("perf record: Make --buildid-mmap the default")
Reported-by: Tycho Andersen (AMD) <tycho@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Tested-by: Tycho Andersen (AMD) <tycho@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth Narayan <ananth.narayan@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Santosh Shukla <santosh.shukla@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: Ravi Bangoria

tools/perf/builtin-lock.c

@@ -1867,6 +1867,7 @@ static int __cmd_report(bool display_info)
 	eops.sample		 = process_sample_event;
 	eops.comm		 = perf_event__process_comm;
 	eops.mmap		 = perf_event__process_mmap;
+	eops.mmap2		 = perf_event__process_mmap2;
 	eops.namespaces		 = perf_event__process_namespaces;
 	eops.tracing_data	 = perf_event__process_tracing_data;
 	session = perf_session__new(&data, &eops);
@@ -2023,6 +2024,7 @@ static int __cmd_contention(int argc, const char **argv)
 	eops.sample		 = process_sample_event;
 	eops.comm		 = perf_event__process_comm;
 	eops.mmap		 = perf_event__process_mmap;
+	eops.mmap2		 = perf_event__process_mmap2;
 	eops.tracing_data	 = perf_event__process_tracing_data;
 
 	perf_env__init(&host_env);