perf libdw: 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/1452158050-28061-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index db8142ba7cb9..cf5e250bc78e 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -96,6 +96,16 @@ static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
         thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
                               MAP__FUNCTION, addr, &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, addr, &al);
+        }
+
+        if (!al.map) {
                 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
                 return -1;
         }