Use sig_atomic_t for variables written/accessed in signal
handlers. This is undefined behavior as per:
https://wiki.sei.cmu.edu/confluence/display/c/SIG31-C.+Do+not+access+shared+objects+in+signal+handlers

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-stat.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 265b05157972..e1a5605adb97 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -173,7 +173,7 @@ static struct target target = {
 
 #define METRIC_ONLY_LEN 20
 
-static volatile pid_t		child_pid			= -1;
+static volatile sig_atomic_t	child_pid			= -1;
 static int			detailed_run			=  0;
 static bool			transaction_run;
 static bool			topdown_run			= false;
@@ -208,7 +208,7 @@ struct perf_stat {
 static struct perf_stat		perf_stat;
 #define STAT_RECORD		perf_stat.record
 
-static volatile int done = 0;
+static volatile sig_atomic_t done = 0;
 
 static struct perf_stat_config stat_config = {
 	.aggr_mode		= AGGR_GLOBAL,
@@ -569,7 +569,7 @@ static void disable_counters(void)
 	}
 }
 
-static volatile int workload_exec_errno;
+static volatile sig_atomic_t workload_exec_errno;
 
 /*
  * evlist__prepare_workload will send a SIGUSR1
@@ -1029,7 +1029,7 @@ static void print_counters(struct timespec *ts, int argc, const char **argv)
 	evlist__print_counters(evsel_list, &stat_config, &target, ts, argc, argv);
 }
 
-static volatile int signr = -1;
+static volatile sig_atomic_t signr = -1;
 
 static void skip_signal(int signo)
 {
-- 
2.38.0.135.g90850a2211-goog