>Number:         36130
>Category:       kern
>Synopsis:       Unkillable stackable filesystems
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Apr 10 00:15:00 +0000 2007
>Originator:     Juan RP
>Release:        NetBSD 4.0_BETA2
>Organization:
>Environment:
System: NetBSD mandylion 4.0_BETA2 NetBSD 4.0_BETA2 (Xen0-4) #3: Fri Mar 2 06:22:26 CET 2007 juan@mandylion:/home/juan/build/src-4/obj/sys/arch/i386/compile/Xen0-4 i386
Architecture: i386
Machine: i386
>Description:
	
	I was building a new livecd with mklivecd, my setup
	currently has the following mount points:

	/usr/pkgsrc is union mounted from /sources/x/pkgsrc (local)
	/usr/pkgsrc/packages is union mounted from /export/packages (local)

	Specifically:

	/dev/xbd1a on /sources type ffs (soft dependencies, NFS exported, local)
	/dev/xbd1b on /export type ffs (soft dependencies, NFS exported, local)
	/dev/xbd2a on /sources/x type ffs (soft dependencies, NFS exported, local)
	<above>:/sources/x/pkgsrc on /usr/pkgsrc type union (hidden, local)
	<above>:/export/packages on /usr/pkgsrc/packages type union (hidden, local)

	So what mklivecd does is:

	mount_null /usr/pkgsrc /blah
	mount_null /usr/pkgsrc/distfiles /blah/distfiles
	[the process is hanged and unkillable]

	The mount_null command shows the state "unionall".

>How-To-Repeat:
>Fix:
	Yes, please.