[tip:perf/urgent] perf trace: Fix potential NULL pointer dereference found by the smatch tool

[tip-bot for Leo Yan <tipbot@xxxxxxxxx>]

Commit-ID:  7a6d49dc8cad8fa1f3d63994102af8f9ae9c859f
Gitweb:     https://git.kernel.org/tip/7a6d49dc8cad8fa1f3d63994102af8f9ae9c859f
Author:     Leo Yan <leo.yan@xxxxxxxxxx>
AuthorDate: Tue, 2 Jul 2019 18:34:14 +0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 9 Jul 2019 09:33:55 -0300

perf trace: Fix potential NULL pointer dereference found by the smatch tool

Based on the following report from Smatch, fix the potential NULL
pointer dereference check.

  tools/perf/builtin-trace.c:1044
  thread_trace__new() error: we previously assumed 'ttrace' could be
  null (see line 1041).

  tools/perf/builtin-trace.c
  1037 static struct thread_trace *thread_trace__new(void)
  1038 {
  1039         struct thread_trace *ttrace =  zalloc(sizeof(struct thread_trace));
  1040
  1041         if (ttrace)
  1042                 ttrace->files.max = -1;
  1043
  1044         ttrace->syscall_stats = intlist__new(NULL);
               ^^^^^^^^
  1045
  1046         return ttrace;
  1047 }

Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
Cc: Alexios Zavras <alexios.zavras@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Changbin Du <changbin.du@xxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Eric Saint-Etienne <eric.saint.etienne@xxxxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Suzuki Poulouse <suzuki.poulose@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20190702103420.27540-6-leo.yan@xxxxxxxxxx
[ Just made it look like other tools/perf constructors, same end result ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-trace.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index d0eb7224dd36..e3fc9062f136 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1038,10 +1038,10 @@ static struct thread_trace *thread_trace__new(void)
 {
 	struct thread_trace *ttrace =  zalloc(sizeof(struct thread_trace));
 
-	if (ttrace)
+	if (ttrace) {
 		ttrace->files.max = -1;
-
-	ttrace->syscall_stats = intlist__new(NULL);
+		ttrace->syscall_stats = intlist__new(NULL);
+	}
 
 	return ttrace;
 }