---

yaml
---
r: 95136
b: refs/heads/master
c: 021e1ae
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7e695a5ef5c1c768d7feb75cc61e42f13d763623
+refs/heads/master: 021e1ae3d85a76ce962a300c96813f04ae50c87c

trunk/kernel/signal.c

@@ -633,6 +633,11 @@ static int prepare_signal(int sig, struct task_struct *p)
 			why |= SIGNAL_CLD_STOPPED;
 
 		if (why) {
+			/*
+			 * The first thread which returns from finish_stop()
+			 * will take ->siglock, notice SIGNAL_CLD_MASK, and
+			 * notify its parent. See get_signal_to_deliver().
+			 */
 			signal->flags = why | SIGNAL_STOP_CONTINUED;
 			signal->group_stop_count = 0;
 			signal->group_exit_code = 0;
@@ -1694,7 +1699,11 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
 	try_to_freeze();
 
 	spin_lock_irq(&sighand->siglock);
-
+	/*
+	 * Every stopped thread goes here after wakeup. Check to see if
+	 * we should notify the parent, prepare_signal(SIGCONT) encodes
+	 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
+	 */
 	if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
 		int why = (signal->flags & SIGNAL_STOP_CONTINUED)
 				? CLD_CONTINUED : CLD_STOPPED;