[tip:perf/core] perf script: Check sample->callchain before using it

[tip-bot for Arnaldo Carvalho de Melo <tipbot@zytor.com>]

Commit-ID:  922315210b8007a26374e30712813b714af71cac
Gitweb:     http://git.kernel.org/tip/922315210b8007a26374e30712813b714af71cac
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Mon, 18 Apr 2016 11:31:46 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 18 Apr 2016 11:31:46 -0300

perf script: Check sample->callchain before using it

Found by code inspection, while looking at thread__resolve_callchain()
callsites, one had it, the other didn't.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-6r8i2afd3523thuuaxl39yhk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-script.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 0e93282b..5099740 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -791,7 +791,7 @@ static void process_event(struct perf_script *script,
 	if (PRINT_FIELD(IP)) {
 		struct callchain_cursor *cursor = NULL, cursor_callchain;
 
-		if (symbol_conf.use_callchain &&
+		if (symbol_conf.use_callchain && sample->callchain &&
 		    thread__resolve_callchain(al->thread, &cursor_callchain, evsel,
 					      sample, NULL, NULL, scripting_max_stack) == 0)
 			cursor = &cursor_callchain;