diff --git a/man2/ptrace.2 b/man2/ptrace.2
index 0a3f13ac0..3f87cc136 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -299,6 +299,15 @@ which are specified by the following flags:
 
 .RS
 
+.TP
+.BR PTRACE_O_EXITKILL " (since Linux 3.8)"
+.\" commit 992fb6e170639b0849bace8e49bf31bd37c4123
+If a tracer sets this flag, a
+.B SIGKILL
+signal will be sent to every tracee if the tracer exits. 
+This option is useful for ptrace jailers that 
+want to ensure that tracees can never escape the trcer's control.
+
 .TP
 .BR PTRACE_O_TRACECLONE " (since Linux 2.5.46)"
 Stop the tracee at the next