[PATCH 4.19 078/219] perf report: Add warning when libunwind not compiled in

Greg Kroah-Hartman
2019-12-29T17:30:49Z

From: Jin Yao <yao.jin@linux.intel.com>

[ Upstream commit 800d3f561659b5436f8c57e7c26dd1f6928b5615 ]

We received a user report that call-graph DWARF mode was enabled in
'perf record' but 'perf report' didn't unwind the callstack correctly.
The reason was, libunwind was not compiled in.

We can use 'perf -vv' to check the compiled libraries but it would be
valuable to report a warning to user directly (especially valuable for
a perf newbie).

The warning is:

Warning:
Please install libunwind development packages during the perf build.

Both TUI and stdio are supported.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20191011022122.26369-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/builtin-report.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index b2188e623e22..2f94f7ad65bd 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -383,6 +383,13 @@ static int report__setup_sample_type(struct report *rep)
PERF_SAMPLE_BRANCH_ANY))
rep->nonany_branch_mode = true;

+#ifndef HAVE_LIBUNWIND_SUPPORT
+ if (dwarf_callchain_users) {
+ ui__warning("Please install libunwind development packages "
+ "during the perf build.\n");
+ }
+#endif
+
return 0;
}

--
2.20.1