From 465b6c35e91f6d31ee1ada66baa7504c581edff4 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Tue, 21 Jan 2020 21:59:14 +0100 Subject: [PATCH] proc.5: Document /proc/sys/vm/unprivileged_userfaultfd Signed-off-by: Michael Kerrisk --- man5/proc.5 | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/man5/proc.5 b/man5/proc.5 index 930350442..ff7254d68 100644 --- a/man5/proc.5 +++ b/man5/proc.5 @@ -5772,6 +5772,19 @@ Any subsequent attempts to execute a command will result in Changing the value in this file takes effect whenever an application requests memory. .TP +.IR /proc/sys/vm/unprivileged_userfaultfd " (since Linux 5.2)" +.\" cefdca0a86be517bc390fc4541e3674b8e7803b0 +This (writable) file exposes a flag that controls whether +unprivileged processes are allowed to employ +.BR userfaultfd (2). +If this file has the value 1, then unprivileged processes may use +.BR userfaultfd (2). +If this file has the value 0, then only processes that have the +.B CAP_SYS_PTRACE +capability may employ +.BR userfaultfd (2). +The default value in this file is 1. +.TP .IR /proc/sysrq-trigger " (since Linux 2.4.21)" Writing a character to this file triggers the same SysRq function as typing ALT-SysRq- (see the description of