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Bug#603858: Mount options for proc conflict with /etc/fstab breaking /etc/init.d/mountall.sh

On Wed, Nov 17, 2010 at 11:04:15PM +0100, Goswin von Brederlow wrote:
> I recently installed a squeeze system. The generated /etc/fstab
> contains the following line:
>    # <file system> <mount point>   <type>  <options>       <dump>  <pass>
>    proc            /proc           proc    defaults        0       0
> But in /usr/share/initramfs-tools/init you have:
>    mount -t proc -o nodev,noexec,nosuid none /proc
> This causes mount to return an error when mounting all local
> filesystems because "proc" and "none" are different divices and it
> can't mount /proc again over an existing mountpoint. The
> /etc/init.d/mountall.sh script reports a red FAILED because of that.
> Node: /etc/mtab is a link to /proc/mounts here. That might affect this
> issue.

It certainly does.  I've attached a patch which fixes this for
all filesystems handed over to the host from the initramfs so
that read-only root works correctly.  This matches up the mount
options with those used by initscripts so that everything works
whether you're using /etc/mtab as a file or as a symlink to
/proc/mounts (as will occur soon; see #620710 and
http://people.debian.org/~rleigh/util-linux_2.19.1-1.dsc).  The
new mount uses libmount and /run/mount/utab which makes a
/proc/mounts symlink work correctly.


  .''`.  Roger Leigh
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From f990eb9b7e1c4f50d4c4022bb4b582bcb7a9db18 Mon Sep 17 00:00:00 2001
From: Roger Leigh <rleigh@debian.org>
Date: Tue, 10 May 2011 22:19:07 +0100
Subject: [PATCH] init: Don't use "none" as a mount fsname

When mounting kernel filesystems and tmpfs filesystems, "none" is
unsuitable as the filesystem name.  This is because it causes
breakage when /etc/mtab is a symlink to /proc/mounts.  This is needed
so that we can switch /etc/mtab to be a symlink when util-linux is
updated to use libmount (#620710).

When /etc/mtab is a file updated by mount, the initscripts
mountkernfs.sh, mountdevsubfs.sh and mtab.sh initialise the mtab at
boot using values other than "none".  For example, /proc uses "proc",
/dev/pts uses "devpts" and /sys uses "sysfs".  The mtab entries are
created from defaults, plus any user customisations added to

When /etc/mtab is a symlink to /proc/mounts, the values set when the
filesystems were mounted by init in the initramfs are now visible, and
these differ from values in /etc/fstab.  The initscripts are now no
longer able to update the mtab file, and this causes problems mounting
local filesystems.

The most visible issue is /proc.  The default fstab entry is:
  proc            /proc           proc    defaults        0       0
while init is using
  mount -t proc -o nodev,noexec,nosuid none /proc
rather than
  mount -t proc -o nodev,noexec,nosuid proc /proc
which results in "mount -a" failing with an exit code of 32 (mount
failure).  While altering "proc" to "none" in the fstab file corrects
this boot failure, this is present by default in the fstab file of
every installed system, and so is not easy to update.  Additionally,
the /dev/pts and /sys mounts may also have been added using the
"devpts" and "sysfs" names, and so these should ideally also be
corrected to use these names in the initramfs.  This behaviour may be
easily verified by changing the fsname for /proc in /etc/fstab and
checking the exit status of "mount -a".

I also fixed an inconsistency in the udev /dev fsname.  It might use
"none" or "udev"; it now always uses "udev".

Signed-off-by: Roger Leigh <rleigh@debian.org>
 init |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/init b/init
index ac67214..445c354 100755
--- a/init
+++ b/init
@@ -8,8 +8,8 @@ echo "Loading, please wait..."
 [ -d /proc ] || mkdir /proc
 [ -d /tmp ] || mkdir /tmp
 mkdir -p /var/lock
-mount -t sysfs -o nodev,noexec,nosuid none /sys
-mount -t proc -o nodev,noexec,nosuid none /proc
+mount -t sysfs -o nodev,noexec,nosuid sysfs /sys
+mount -t proc -o nodev,noexec,nosuid proc /proc
 # Note that this only becomes /dev on the real filesystem if udev's scripts
 # are used; which they will be, but it's worth pointing out
@@ -17,14 +17,14 @@ tmpfs_size="10M"
 if [ -e /etc/udev/udev.conf ]; then
 	. /etc/udev/udev.conf
-if ! mount -t devtmpfs -o mode=0755 none /dev; then
+if ! mount -t devtmpfs -o mode=0755 udev /dev; then
 	echo "W: devtmpfs not available, falling back to tmpfs for /dev"
 	mount -t tmpfs -o size=$tmpfs_size,mode=0755 udev /dev
 	[ -e /dev/console ] || mknod -m 0600 /dev/console c 5 1
 	[ -e /dev/null ] || mknod /dev/null c 1 3
 mkdir /dev/pts
-mount -t devpts -o noexec,nosuid,gid=5,mode=0620 none /dev/pts || true
+mount -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts || true
 mount -t tmpfs -o "nosuid,size=20%,mode=0755" tmpfs /run
 mkdir /run/initramfs

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