One of the conversions from memcmp to compare_ether_addr is incorrect. We need to do relative comparison to determine min MAC address to use in bridge id. Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxx> --- linux-2.6.15.orig/net/bridge/br_stp_if.c +++ linux-2.6.15/net/bridge/br_stp_if.c @@ -158,7 +158,7 @@ void br_stp_recalculate_bridge_id(struct list_for_each_entry(p, &br->port_list, list) { if (addr == br_mac_zero || - compare_ether_addr(p->dev->dev_addr, addr) < 0) + memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) addr = p->dev->dev_addr; }