From 594a37d093e874d1d0b7c323aabb9985f936fe66 Mon Sep 17 00:00:00 2001
From: Johannes 'josch' Schauer <josch@mister-muffin.de>
Date: Mon, 8 Oct 2018 11:24:29 +0200
Subject: [PATCH] add comment about mounting sys with rbind in unshare mode

---
 mmdebstrap | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mmdebstrap b/mmdebstrap
index 0b3b456..db59ba2 100755
--- a/mmdebstrap
+++ b/mmdebstrap
@@ -1066,6 +1066,9 @@ sub setup {
 	if ($options->{mode} eq 'unshare') {
 	    # without the network namespace unshared, we cannot mount a new
 	    # sysfs. Since we need network, we just bind-mount.
+	    #
+	    # we have to rbind because just using bind results in "wrong fs
+	    # type, bad option, bad superblock" error
 	    0 == system('mount', '-o', 'rbind', '/sys', "$options->{root}/sys") or die "mount failed: $?";
 	} else {
 	    0 == system('mount', '-t', 'sysfs', '-o', 'nosuid,nodev,noexec', 'sys', "$options->{root}/sys") or die "mount failed: $?";