Ah, no, something else is going on. This is a left over in /etc/mtab. /proc/mounts does not show it:
$ mount | grep debug none on /sys/kernel/debug type debugfs (rw) none on /var/lib/ureadahead/debugfs type debugfs (rw,relatime) $ grep debug /proc/mounts none /sys/kernel/debug debugfs rw,relatime 0 0
Ah, no, something else is going on. This is a left over in /etc/mtab. /proc/mounts does not show it:
$ mount | grep debug ureadahead/ debugfs type debugfs (rw,relatime)
none on /sys/kernel/debug type debugfs (rw)
none on /var/lib/
$ grep debug /proc/mounts
none /sys/kernel/debug debugfs rw,relatime 0 0