crdup
cred = crdup(td->td_ucred);
#define NFSNEWCRED(c) (crdup(c))
cred = crdup(cnp->cn_cred);
imgp->newcred = crdup(oldcred);
imgp->newcred = crdup(oldcred);
mp->mnt_cred = crdup(cred);
usecred = crdup(cred);
ns->ns_ucred = crdup(cred);
rc->rc_ucred = crdup(curthread->td_ucred);
gd->gd_ucred = crdup(cred);
struct ucred *crdup(struct ucred *cr);