diff --git a/include/haproxy/tinfo-t.h b/include/haproxy/tinfo-t.h
index 45cfe8a29..a12e0a4b7 100644
--- a/include/haproxy/tinfo-t.h
+++ b/include/haproxy/tinfo-t.h
@@ -60,6 +60,8 @@ enum {
 #define TH_FL_TASK_PROFILING    0x00000002
 #define TH_FL_NOTIFIED          0x00000004  /* task was notified about the need to wake up */
 #define TH_FL_SLEEPING          0x00000008  /* thread won't check its task list before next wakeup */
+#define TH_FL_STARTED           0x00000010  /* set once the thread starts */
+#define TH_FL_IN_LOOP           0x00000020  /* set only inside the polling loop */
 
 
 /* Thread group information. This defines a base and a count of global thread
diff --git a/src/haproxy.c b/src/haproxy.c
index 09e4198d7..fe612b0c1 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2922,6 +2922,8 @@ void run_poll_loop()
 {
 	int next, wake;
 
+	_HA_ATOMIC_OR(&th_ctx->flags, TH_FL_IN_LOOP);
+
 	clock_update_date(0,1);
 	while (1) {
 		wake_expired_tasks();
@@ -3010,6 +3012,8 @@ void run_poll_loop()
 
 		activity[tid].loops++;
 	}
+
+	_HA_ATOMIC_AND(&th_ctx->flags, ~TH_FL_IN_LOOP);
 }
 
 static void *run_thread_poll_loop(void *data)
@@ -3028,6 +3032,7 @@ static void *run_thread_poll_loop(void *data)
 	/* thread is started, from now on it is not idle nor harmless */
 	thread_harmless_end();
 	thread_idle_end();
+	_HA_ATOMIC_OR(&th_ctx->flags, TH_FL_STARTED);
 
 	/* Now, initialize one thread init at a time. This is better since
 	 * some init code is a bit tricky and may release global resources