Re: [CFT][PATCH 00/10] Making new mounts of proc and sysfs as safe as bind mounts (take 2)

On Wed, Jun 03, 2015 at 04:13:21PM -0500, Eric W. Biederman wrote:

Andy Lutomirski [off-list ref] writes:

quoted

One option would be to break the nosuid, nodev, and noexec parts into
their own patch and then avoid tagging that patch for -stable if at
all possible.  It would be nice to avoid another -stable ABI break if
at all possible.

So I don't think we actually have anything that could be called an ABI
break in the whole mess, but it is definitely a behavioral change that
is a regression for lxc and libvirt-lxc that prevents them from starting.

nodev does not actually matter because of the implicit silliness that
is being added right now.

We do want those programs fixed and after those programs are fixed we
can safely begin failing mount when those attributes are being cleared
in a fresh mount.

So it looks to me like the best thing to do is to print a warning
whenever lxc or libvirt-lxc gets it wrong, which should ensure the
authors are sufficiently pestered that in a kernel release or 3 we can
begin enforcing those attributes.  Especially as the discussion on the
fix for those applications has already begun.

"pestering" never works, look at some of the SCSI drivers for examples
of how a distro will just patch out the "warning this driver is using an
old api and needs to be fixed" messages.

You can't break stuff like this, people will get upset :(

greg k-h