[PATCH 6/7] perf tools: Fix report -F dso_to for data without branch info

[Jiri Olsa <jolsa@kernel.org>]

The branch field sorting code assumes hist_entry::branch_info
is allocated, which is wrong and following perf session ends
up with report segfault.

  $ perf record ls
  $ perf report -F dso_to
  perf: Segmentation fault

Checking that hist_entry::branch_info is valid and display
"N/A" string in snprint callback if it's not.

Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/sort.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index fc4ff2a96616..7a9054a23c36 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -387,6 +387,9 @@ static int hist_entry__dso_from_snprintf(struct hist_entry *he, char *bf,
 static int64_t
 sort__dso_to_cmp(struct hist_entry *left, struct hist_entry *right)
 {
+	if (!left->branch_info || !right->branch_info)
+		return cmp_null(left->branch_info, right->branch_info);
+
 	return _sort__dso_cmp(left->branch_info->to.map,
 			      right->branch_info->to.map);
 }
@@ -394,8 +397,11 @@ sort__dso_to_cmp(struct hist_entry *left, struct hist_entry *right)
 static int hist_entry__dso_to_snprintf(struct hist_entry *he, char *bf,
 				       size_t size, unsigned int width)
 {
-	return _hist_entry__dso_snprintf(he->branch_info->to.map,
-					 bf, size, width);
+	if (he->branch_info)
+		return _hist_entry__dso_snprintf(he->branch_info->to.map,
+						 bf, size, width);
+	else
+		return repsep_snprintf(bf, size, "%-*.*s", width, width, "N/A");
 }
 
 static int64_t
-- 
1.9.3