misc/176482: Jails not unmounting devfs on exit

[Spank Me]

>Number:         176482
>Category:       misc
>Synopsis:       Jails not unmounting devfs on exit
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Feb 27 17:30:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Spank Me
>Release:        9.1-STABLE
>Organization:
>Environment:
FreeBSD 222-freebsd 9.1-STABLE FreeBSD 9.1-STABLE #1: Wed Feb 27 10:30:10 CET 2013     root at 222-freebsd:/usr/obj/usr/src/sys/KAROL amd64
>Description:
When creating jails using 'jail' command with mount.devfs option, and then killing jail using 'jail -r' or exiting the '/bin/sh' only jail, the devfs filesystem is being left mounted leading to multiple mounts under the same directory when overlooked.
>How-To-Repeat:
root at 222-freebsd:~ # jls
   JID  IP Address      Hostname                      Path
root at 222-freebsd:~ # mount
/dev/ad0p2 on / (ufs, local, journaled soft-updates)
devfs on /dev (devfs, local, multilabel)
storage on /storage (zfs, local, nfsv4acls)
storage/generic on /storage/generic (zfs, local, nfsv4acls)
root at 222-freebsd:~ # jail -c host.hostname=generic path=/storage/generic ip4.addr=10.1.1.222 mount.devfs command=/bin/tcsh
root at generic:/ # jls
   JID  IP Address      Hostname                      Path
root at generic:/ # mount
storage/generic on / (zfs, local, nfsv4acls)
root at generic:/ # exit
root at 222-freebsd:~ # jls
   JID  IP Address      Hostname                      Path
root at 222-freebsd:~ # mount
/dev/ad0p2 on / (ufs, local, journaled soft-updates)
devfs on /dev (devfs, local, multilabel)
storage on /storage (zfs, local, nfsv4acls)
storage/generic on /storage/generic (zfs, local, nfsv4acls)
devfs on /storage/generic/dev (devfs, local, multilabel)
root at 222-freebsd:~ # jail -c host.hostname=generic path=/storage/generic ip4.addr=10.1.1.222 mount.devfs command=/bin/tcsh
root at generic:/ # jls
   JID  IP Address      Hostname                      Path
root at generic:/ # mount
storage/generic on / (zfs, local, nfsv4acls)
root at generic:/ # exit
root at 222-freebsd:~ # jls
   JID  IP Address      Hostname                      Path
root at 222-freebsd:~ # mount
/dev/ad0p2 on / (ufs, local, journaled soft-updates)
devfs on /dev (devfs, local, multilabel)
storage on /storage (zfs, local, nfsv4acls)
storage/generic on /storage/generic (zfs, local, nfsv4acls)
devfs on /storage/generic/dev (devfs, local, multilabel)
devfs on /storage/generic/dev (devfs, local, multilabel)
root at 222-freebsd:~ #
>Fix:
Unknown.

>Release-Note:
>Audit-Trail:
>Unformatted: