diff --git a/man7/pid_namespaces.7 b/man7/pid_namespaces.7
index 7793a66b3..3c84c0c7d 100644
--- a/man7/pid_namespaces.7
+++ b/man7/pid_namespaces.7
@@ -123,6 +123,13 @@ these signals are forcibly delivered when sent from an ancestor PID namespace.
 Neither of these signals can be caught by the "init" process,
 and so will result in the usual actions associated with those signals
 (respectively, terminating and stopping the process).
+
+Starting with Linux 3.9, the
+.BR reboot (2)
+system causes a signal to be sent to the namespace "init" process.
+See
+.BR reboot(2)
+for more details.
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