[DSE-Dev] Bug#823184: umount mounts /proc as a side effect

[Yuri D'Elia]

On Fri, May 13 2016, Laurent Bigonville <bigon at debian.org> wrote:
> Again this is supposed to happen at early boot, and at this stage, only
> PID1 exists. So I doubt there is a lot of concurrent processes at that time.

But this is not checked in the source.
In fact, this behavior will happen irregardless of the boot stage.

>> Even if the fix is simply the removal of the mountpoint, I consider the
>> solution broken by design.
> What about mounting /proc really early?

I can say the same about initramfs. Can't initramfs just mount /proc
sooner and fix the problem correctly?

>      Mount failed for selinuxfs on /sys/fs/selinux:  No such file or
> directory
>
>      To fix this, mount the procfs before attempting to open
>      /proc/filesystems, and unmount it when done if it was initially not
>      mounted.  This is the same thing that selinux_init_load_policy() does
>      when reading /proc/cmdline.
>
> If you think you know a better way, please provide a patch to upstream.

The thing is that I *don't* use SElinux, and this is why I see it as a
regression, and the main reason I don't really want to look at *another*
source tree for this. Maybe upstream is fixing this for distributions
that have a poor booting sequence. Incorrectly.

The patch might actually fix something if selinux is enabled, but
regresses in behavior for other scenarios where selinux is not used.

The fact that I was able to notice, you have to admit, is an indication
that there are cases where it is /not/ ok.

> I'll not carry a patch in debian and make libselinux behave differently
> than on 99% of the other distributions.

I, honestly, expected someone that understand the issue to help and
chime to report it upstream.