Ceph

With no OSDs in the cluster, the calculations for pgs_per_osd can divide by zero (integer, but that still causes the FPE).

    int expected_osds = MIN(p.get_pg_num(), osdmap.get_num_osds());
    int64_t new_pgs = n - p.get_pg_num();
    int64_t pgs_per_osd = new_pgs / expected_osds;

expected_osds can be zero.

Looking briefly, there are a few other places in OSDMonitor where /0 looks possible:

float up_ratio = (float)up / (float)osdmap.get_num_osds();

float in_ratio = (float)in / (float)osdmap.get_num_osds();

two instances of:

double halflife = (double)g_conf->mon_osd_laggy_halflife;
double decay_k = ::log(.5) / halflife;

It might be good to review Coverity and maybe increase the priority of such warnings.