[PATCH] userfaultfd.2: add EPERM error

[Yang Xu <xuyang2018.jy@xxxxxxxxxxxxxx>]

Signed-off-by: Yang Xu <xuyang2018.jy@xxxxxxxxxxxxxx>
---
 man2/userfaultfd.2 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
index 8d0a66ed9..2b432f043 100644
--- a/man2/userfaultfd.2
+++ b/man2/userfaultfd.2
@@ -440,6 +440,11 @@ reached.
 .TP
 .B ENOMEM
 Insufficient kernel memory was available.
+.TP
+.B EPERM
+Unprivileged user(without SYS_CAP_PTRACE capability) uses this call when
+set unprivileged_userfaultfd to 0. It was introduced since Linux 5.2.
+.\" cefdca0a86be517bc390fc4541e3674b8e7803b0
 .SH VERSIONS
 The
 .BR userfaultfd ()
-- 
2.18.0