From dc9b6c92852bca1541ed13d730b8653d2b8a806d Mon Sep 17 00:00:00 2001
From: Joseph Sible <josephcsible@gmail.com>
Date: Thu, 9 Aug 2018 00:23:13 -0400
Subject: [PATCH] pivot_root.2: Document EINVAL if root is rootfs

Per the comment on the pivot_root syscall in fs/namespace.c:

    Also, the current root cannot be on the 'rootfs'
    (initial ramfs) filesystem.  See
    Documentation/filesystems/ramfs-rootfs-initramfs.txt
    for alternatives in this situation.

Signed-off-by: Joseph C. Sible <josephcsible@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/pivot_root.2 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/man2/pivot_root.2 b/man2/pivot_root.2
index f744d29b9..2f8f5f4b9 100644
--- a/man2/pivot_root.2
+++ b/man2/pivot_root.2
@@ -112,6 +112,9 @@ or a filesystem is already mounted on \fIput_old\fP.
 .B EINVAL
 \fIput_old\fP is not underneath \fInew_root\fP.
 .TP
+.B EINVAL
+The current root is on the rootfs (initial ramfs) filesystem.
+.TP
 .B ENOTDIR
 \fInew_root\fP or \fIput_old\fP is not a directory.
 .TP