kern/132934: Cancel of a NFS-lock fails repeatedly

[Matthias Schuendehuette]

>Number:         132934
>Category:       kern
>Synopsis:       Cancel of a NFS-lock fails repeatedly
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Mar 22 14:10:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Matthias Schuendehuette
>Release:        6.4 + 7.1
>Organization:
SIEMENS AG
>Environment:
>Description:
If a NFS client (in my case a HP-UX 11.11 client) tries to cancel a NFS lock, the FreeBSD-Server doesn't reply at all.  This is true for FreeBSD-6.4 and FreeBSD 7.1. (with and without kernel support for NFS locking).

Since NFS-Serving is the major task of our FreeBSD servers, this error is a show-stopper for us, which prevents us from further upgrading the operating system.

FreeBSD 6.3 and 7.0 do not show such behaviour.
>How-To-Repeat:
Mount a filesystem from a FreeBSD-Server on a HP-UX 11.11 machine via NFS V3.
Try to lock a file (that works) then try to remove the lock. You'll wait forever...

I found the problem with my (HP-UX)homedirectory on a FreeBSD NFS-Server. The login shell locks .profile and hangs after the last statement of .profile.

Wireshark shows a continuing stream of "NLM V4 CANCEL MSG"es from the client to the server, which will never be answered.
>Fix:


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