So it appears that the issue doesn't come from the e1000 driver, but from a use-after-free in the udp protocol structure.
I've made a patch available that disables slab sanitization in udp protocol structure.
I've been toroughly testing it under heavy DNS load for two weeks and can confirm it's working well.
Indeed the drawback is that it lowers the protections on the udp protocol, that's why i won't include this patch in my default builds, just use it if you need it - I guess it will be long before we see it fixed upstream...