void cred_init(FsCred *credp)
{
    credp->fc_uid = -1;
    credp->fc_gid = -1;
    credp->fc_mode = -1;
    credp->fc_rdev = -1;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.