[PATCH] [perf] sort : Fix null pointer dereference in _hist_entry__sym_snprintf

[Gaurav Singh]

The pointer ms can be NULL. Add null check before
dereferencing it to avoid segmentation fault.

Signed-off-by: Gaurav Singh <gaurav1...@gmail.com>
---
 tools/perf/util/sort.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index d42339df20f8..25c7c96893f6 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -294,6 +294,9 @@ static int _hist_entry__sym_snprintf(struct map_symbol *ms,
                                     u64 ip, char level, char *bf, size_t size,
                                     unsigned int width)
 {
+       if (!ms) 
+               return 0;
+
        struct symbol *sym = ms->sym;
        struct map *map = ms->map;
        size_t ret = 0;
-- 
2.17.1