diff -ur chrony-4.1.orig/sys_linux.c chrony-4.1/sys_linux.c
--- chrony-4.1.orig/sys_linux.c	2021-05-12 13:06:15.000000000 +0200
+++ chrony-4.1/sys_linux.c	2021-09-18 13:01:17.378223193 +0200
@@ -591,7 +591,6 @@
     SCMP_SYS(pipe),
     SCMP_SYS(pipe2),
     SCMP_SYS(poll),
-    SCMP_SYS(ppoll),
 #ifdef __NR_ppoll_time64
     SCMP_SYS(ppoll_time64),
 #endif