diff --git a/man2/ptrace.2 b/man2/ptrace.2
index c52f3255a..78f41bcab 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -733,6 +733,22 @@ argument is treated as for
 .RI ( addr
 is ignored.)
 .TP
+.BR PTRACE_SET_SYSCALL " (since Linux 2.6.16)"
+.\" commit 3f471126ee53feb5e9b210ea2f525ed3bb9b7a7f
+When in syscall-enter-stop, change the number of the syscall about to
+be executed to the number specified in the
+.I data
+argument. The
+.I addr
+argument is ignored. This request is currently
+.\" As of 4.19-rc2
+supported only on arm (and arm64, though only for backwards compatibility),
+.\" commit 27aa55c5e5123fa8b8ad0156559d34d7edff58ca
+but most other architectures have other means of accomplishing this
+(usually by changing the register that the userland code passed the
+syscall number in).
+.\" see change_syscall in tools/testing/selftests/seccomp/seccomp_bpf.c
+.TP
 .BR PTRACE_SYSEMU ", " PTRACE_SYSEMU_SINGLESTEP " (since Linux 2.6.14)"
 For
 .BR PTRACE_SYSEMU ,