perf trace: Use sig_atomic_t to avoid undefined behaviour in a signal handler

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 <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexey Bayduraev <[email protected]>
Cc: German Gomez <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: captain5050

tools/perf/builtin-trace.c

@@ -1535,8 +1535,8 @@ static size_t trace__fprintf_tstamp(struct trace *trace, u64 tstamp, FILE *fp)
 }
 
 static pid_t workload_pid = -1;
-static bool done = false;
-static bool interrupted = false;
+static volatile sig_atomic_t done = false;
+static volatile sig_atomic_t interrupted = false;
 
 static void sighandler_interrupt(int sig __maybe_unused)
 {