Comment 4 for bug 1728132

Looking at the backtrace, signal is being generated in this code block:

    if (UNIV_UNLIKELY(thr && thr_get_trx(thr)->fake_changes)) {
        /* skip CHANGE, LOG */
        *big_rec = big_rec_vec;
        return(err); /* == DB_SUCCESS */
    }

thr is 0x0 (NULL) in this case so thr_get_trx should not really be evaluated, but it is.