why can't i see *all* mounts with "mount"?

[Stephen Smalley]

On Fri, 2008-03-07 at 10:43 -0500, Robert P. J. Day wrote:
> i'm curious as to why the "mount" command won't show me all the
> mounts that i can view via /proc/mounts.  for example, "mount" doesn't
> show me the usbfs mount, or the selinuxfs mount, or ... well, you get
> the idea.
> 
>   were these mount types left out of the output of mount for a reason?
> just curious.

mount uses /etc/mtab as its source of information, not /proc/mounts,
which means that only mounts that were performed using the mount command
are reported by it.

selinuxfs is mounted directly by init in order to load policy into the
kernel.  Doesn't go through mount(8).

-- 
Stephen Smalley
National Security Agency