diff --git a/man2/prctl.2 b/man2/prctl.2
index 99bddd3cc..d2a52d34c 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -1079,6 +1079,12 @@ or a binary that has associated capabilities (see
 .BR capabilities (7));
 otherwise, this value is preserved across
 .BR execve (2).
+The parent-death signal setting is also cleared upon changes to
+any of the following thread credentials:
+.\" FIXME capability changes can also trigger this; see
+.\" kernel/cred.c::commit_creds inthe Linux 5.6 source.
+effective user ID, effective group ID, filesystem user ID,
+or filesystem group ID.
 .\" prctl PR_GET_PDEATHSIG
 .TP
 .BR PR_GET_PDEATHSIG " (since Linux 2.3.15)"