[tip:perf/core] perf unwind: Check for mmaps also in MAP__VARIABLE tree

[tip-bot for Jiri Olsa]

Commit-ID:  0ddf5246f70ecc04e1bb4c4dc2be65977d1c03a7
Gitweb:     http://git.kernel.org/tip/0ddf5246f70ecc04e1bb4c4dc2be65977d1c03a7
Author:     Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Thu, 7 Jan 2016 10:14:01 +0100
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 8 Jan 2016 14:16:34 -0300

perf unwind: Check for mmaps also in MAP__VARIABLE tree

We've seen cases (softice) where DWARF unwinder went through non
executable mmaps, which we need to lookup in MAP__VARIABLE tree.

Reported-and-Tested-by: Noel Grandin <noelgrandin@xxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1452158050-28061-5-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/unwind-libunwind.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index f37859c..ee7e372 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -319,6 +319,15 @@ static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
 
 	thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
 			      MAP__FUNCTION, ip, &al);
+	if (!al.map) {
+		/*
+		 * We've seen cases (softice) where DWARF unwinder went
+		 * through non executable mmaps, which we need to lookup
+		 * in MAP__VARIABLE tree.
+		 */
+		thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
+				      MAP__VARIABLE, ip, &al);
+	}
 	return al.map;
 }