In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix legacy client tracking initialization
Get rid of the nfsd4legacytrackingops->init() call in checkforlegacymethods(). That will be handled in the caller (nfsd4clienttrackinginit()). Otherwise, we'll wind up calling nfsd4legacytrackingops->init() twice, and the second time we'll trigger the BUGON() in nfsd4init_recdir().