Re: umount(/proc) after CLONE_NEWNS in 2.6.25?

[Al Viro <viro@ZenIV.linux.org.uk>]

On Tue, Apr 29, 2008 at 03:06:38AM +0100, Al Viro wrote:

> > Check the version of umount(8) you've got.  And see if that strace happens
> > to have open of /proc/mounts, without matching close by the time it calls
> > umount().  util-linux-ng 2.13.1 is _that_ dumb...
> 
> Umm...  Looks like something more odd is going on...

... or something much simpler:

; cat /proc/mounts |grep proc
proc /proc proc rw,nosuid,nodev,noexec 0 0
usbfs /proc/bus/usb usbfs rw 0 0
;

and unmounting the stuff mounted under /proc before doing umount /proc
works as expected.  Amazing how well the first cup of coffee helps...