perf sched: Avoid union type punning undefined behavior

A union is used to set the priv value in thread (a void*) to a boolean
value through type punning. Undefined behavior sanitizer fails on this.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index f166d6cbc083f88146b012d907abd54d93222732..eca3b1c58c4bb2aa2e6f923d0ab94030eea98fa7 100644 (file)
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1532,35 +1532,24 @@ static int process_sched_wakeup_ignore(const struct perf_tool *tool __maybe_unus
        return 0;
 }
 
-union map_priv {
-       void    *ptr;
-       bool     color;
-};
-
 static bool thread__has_color(struct thread *thread)
 {
-       union map_priv priv = {
-               .ptr = thread__priv(thread),
-       };
-
-       return priv.color;
+       return thread__priv(thread) != NULL;
 }
 
 static struct thread*
 map__findnew_thread(struct perf_sched *sched, struct machine *machine, pid_t pid, pid_t tid)
 {
        struct thread *thread = machine__findnew_thread(machine, pid, tid);
-       union map_priv priv = {
-               .color = false,
-       };
+       bool color = false;
 
        if (!sched->map.color_pids || !thread || thread__priv(thread))
                return thread;
 
        if (thread_map__has(sched->map.color_pids, tid))
-               priv.color = true;
+               color = true;
 
-       thread__set_priv(thread, priv.ptr);
+       thread__set_priv(thread, color ? ((void*)1) : NULL);
        return thread;
 }