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@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1452158050-28061-5-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index f37859c0431726febf29fedd2c2a52dbc7cd93df..ee7e372297e59adb7eb3c7a1ffec8acb6186f704 100644 (file)
--- 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;
 }