>Number:         32535
>Category:       kern
>Synopsis:       processes stuck on vnlock
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jan 15 12:09:40 +0000 2006
>Originator:     Manuel Bouyer
>Release:        NetBSD 3.0_RC3
>Organization:
LIP6, Universite Paris 6
>Environment:
System: NetBSD antioche.lip6.fr 3.0_RC3 NetBSD 3.0_RC3 (ANTIOCHE.MP) #2: Fri Nov 25 12:28:11 CET 2005 bouyer@pop.lip6.fr:/local/pop1/bouyer/tmp/i386/obj/local/pop1/bouyer/netbsd-3/src/sys/arch/i386/compile/ANTIOCHE.MP i386
Architecture: i386
Machine: i386, dual-CPU PIII system
>Description:
	This is on the french mirror system. It has several disk mounted,
	with null mounts to make all of them appear under ~ftp/pub:
/dev/raid0a on / type ffs (local)
/dev/raid1b on /var type ffs (noexec, nodev, local)
/dev/raid1e on /usr type ffs (nodev, local)
/dev/raid2e on /var/mail type ffs (noexec, nodev, local)
/dev/raid1f on /var/tmp type ffs (noexec, nodev, noatime, local)
/dev/raid4e on /home type ffs (nosuid, local)
mfs:1013 on /home/ftp/tmp type mfs (synchronous, noexec, nodev, noatime, local)
/dev/sd8e on /home/ftp/pub type ffs (noexec, nodev, noatime, NFS exported, local)
/dev/ccd2e on /home/ftp2/pub type ffs (noexec, nodev, noatime, NFS exported, local)
/dev/sd12e on /home/ftp3/pub type ffs (noexec, nodev, noatime, local)
/dev/sd9e on /home/ftp4/pub type ffs (noexec, nodev, noatime, local)
/dev/sd26f on /home/ftp5/pub type ffs (noexec, nodev, noatime, local)
/dev/sd28f on /home/ftp6/pub type ffs (noexec, nodev, noatime, local)
/dev/ccd0e on /home/ftp7/pub type ffs (noexec, nodev, noatime, local)
/home/ftp2/pub/NetBSD/packages/1.5 on /home/ftp/pub/NetBSD/packages/1.5 type null (read-only, noexec, nodev, local)
/home/ftp2/pub/NetBSD/packages/1.6.2 on /home/ftp/pub/NetBSD/packages/1.6.2 type null (read-only, noexec, nodev, local)
/home/ftp2/pub/NetBSD/NetBSD-1.6 on /home/ftp/pub/NetBSD/NetBSD-1.6 type null (read-only, noexec, nodev, local)
/home/ftp3/pub/NetBSD/NetBSD-2.0 on /home/ftp/pub/NetBSD/NetBSD-2.0 type null (read-only, noexec, nodev, local)
/home/ftp3/pub/NetBSD/NetBSD-2.0.2 on /home/ftp/pub/NetBSD/NetBSD-2.0.2 type null (read-only, noexec, nodev, local)
/home/ftp3/pub/NetBSD/NetBSD-2.1 on /home/ftp/pub/NetBSD/NetBSD-2.1 type null (read-only, noexec, nodev, local)
/home/ftp3/pub/NetBSD/iso/2.0 on /home/ftp/pub/NetBSD/iso/2.0 type null (read-only, noexec, nodev, local)
/home/ftp3/pub/NetBSD/iso/2.1 on /home/ftp/pub/NetBSD/iso/2.1 type null (read-only, noexec, nodev, local)
/home/ftp5/pub/NetBSD/NetBSD-3.0 on /home/ftp/pub/NetBSD/NetBSD-3.0 type null (read-only, noexec, nodev, local)
/home/ftp5/pub/NetBSD/iso/3.0 on /home/ftp/pub/NetBSD/iso/3.0 type null (read-only, noexec, nodev, local)
/home/ftp5/pub/NetBSD/packages/pkgsrc-2005Q2 on /home/ftp/pub/NetBSD/packages/pkgsrc-2005Q2 type null (read-only, noexec, nodev, local)
/home/ftp6/pub/NetBSD/packages/pkgsrc-2004Q4 on /home/ftp/pub/NetBSD/packages/pkgsrc-2004Q4 type null (read-only, noexec, nodev, local)
/home/ftp6/pub/NetBSD/packages/pkgsrc-2005Q1 on /home/ftp/pub/NetBSD/packages/pkgsrc-2005Q1 type null (read-only, noexec, nodev, local)
/home/ftp6/pub/NetBSD/packages/pkgsrc-2005Q3 on /home/ftp/pub/NetBSD/packages/pkgsrc-2005Q3 type null (read-only, noexec, nodev, local)
/home/ftp7/pub/NetBSD-CVS on /home/ftp/pub/NetBSD-CVS type null (read-only, noexec, nodev, local)
/home/ftp6/pub/NetBSD/NetBSD-1.6.2 on /home/ftp/pub/NetBSD/NetBSD-1.6.2 type null (read-only, noexec, nodev, local)
/home/ftp6/pub/NetBSD/NetBSD-1.5.3 on /home/ftp/pub/NetBSD/NetBSD-1.5.3 type null (read-only, noexec, nodev, local)
/home/ftp4/pub/NetBSD-daily on /home/ftp/pub/NetBSD-daily type null (read-only, noexec, nodev, local)
/home/ftp6/pub/NetBSD/packages/pkgsrc-2005Q4 on /home/ftp/pub/NetBSD/packages/pkgsrc-2005Q4 type null (read-only, noexec, nodev, local)

2 weeks ago, processes trying to access /home/ftp7/pub and
/home/ftp/pub/NetBSD-CVS were all stuck on vnlock. This filesystem only holds
the NetBSD CVS repository for the anoncvs mirror, so lots of filesystem
activity: rsync read/write on /home/ftp7/pub, rsync and CVS read-only on
/home/ftp/pub/NetBSD-CVS.

I have a core dump of the system in this state.

>How-To-Repeat:
	Lots of concurent accesses to a filesystem ? null mounts may be
	required to trigger the problem. Note that this is hard to reproduce,
	I've seen it only once since this system runs the netbsd-3 branch
	(nov 25).
>Fix:
	unknown