diff --git a/lib/tevent/tevent_signal.c b/lib/tevent/tevent_signal.c
index cc7fb0a..1e282df 100644
--- a/lib/tevent/tevent_signal.c
+++ b/lib/tevent/tevent_signal.c
@@ -44,7 +44,7 @@ struct tevent_sigcounter {
 	uint32_t seen;
 };
 
-#define TEVENT_SIG_INCREMENT(s) (s).count++
+#define TEVENT_SIG_INCREMENT(s) __sync_fetch_and_add(&((s).count), 1)
 #define TEVENT_SIG_SEEN(s, n) (s).seen += (n)
 #define TEVENT_SIG_PENDING(s) ((s).seen != (s).count)