>Number:         4093
>Category:       kern
>Synopsis:       Dismounting an NFS filesystem sometimes hangs
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Sep  7 04:35:01 1997
>Last-Modified:
>Originator:     maximum entropy
>Organization:
	
>Release:        <NetBSD-current source date>19970905
>Environment:
	
System: NetBSD tanstaafl.bernstein.com 1.2G NetBSD 1.2G (C466DE) #7: Sun Sep 7 06:52:44 EDT 1997 entropy@tanstaafl.bernstein.com:/usr/src/sys/arch/i386/compile/C466DE i386


>Description:
	
Whenever I try to dismount the /usr filesystem on my NFS diskless clients,
the system hangs.  This makes it impossible to reboot the system.  I have
experienced this problem on both an i386 and a vax diskless system.
>How-To-Repeat:
	
shutdown -r now

or...

shutdown now
umount /usr

>Fix:
	
I don't know how to fix it, but the point at which this system is freezing is
the tsleep() call in the vinvalbuf() function, in /sys/kern/vfs_subr.c.

>Audit-Trail:
>Unformatted: