Comment 68 for bug 1124250

I can confirm that the problem persists (and possibly even has become more common) here with the recent kernel update:

$ ls -ld /some-nfsv4-mounted-directory ; cat /proc/key-users ; uname -a
drwxrwsr-x 2 4294967294 4294967294 4096 Dec 20 2007 .
/proc/key-users: 0: 60 59/59 53/2000 1226/400000
Linux dirac.cl.cam.ac.uk 3.13.0-52-generic #85-Ubuntu SMP Wed Apr 29 16:44:17 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

$ dpkg-query -s keyutils
dpkg-query: package 'keyutils' is not installed and no information is available

$ grep -H '' /proc/sys/kernel/keys/*
/proc/sys/kernel/keys/gc_delay:300
/proc/sys/kernel/keys/maxbytes:20000
/proc/sys/kernel/keys/maxkeys:2000
/proc/sys/kernel/keys/persistent_keyring_expiry:259200
/proc/sys/kernel/keys/root_maxbytes:400000
/proc/sys/kernel/keys/root_maxkeys:2000

Documentation of /proc/sys/kernel/keys/* etc.:

  https://www.kernel.org/doc/Documentation/security/keys.txt