A bit of debugging shows that the culprit is blockdata_expand() which is being called via blockdata_init(). The issue seems to be that blockdata_expand() is passed a parameter of zero. That function then mallocs zero bytes (successfully seemingly), the proceeds to overwrite data before the returned address resulting the the 2 fds being set to zero.
blockdata_expand() is passed zero since daemon->cachesize (aka dnsmasq_daemon->cachesize) is zero. This is confirmed by looking at syslog which shows: May 8 21:56:54 utopic dnsmasq[10812]: started, version 2.70 cache disabled -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to dnsmasq in Ubuntu. https://bugs.launchpad.net/bugs/1314697 Title: DNS resolution no longer works; dnsmasq uses 100% CPU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/1314697/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
