Comment 3 for bug 1587686

Sorry, correction to above: I meant perhaps something changed since 4.4.11 since the 4.4.10 based xenial kernels seem fine (except the curious issue with lowlatency build). I've run into some stack traces regarding __pthread and some occasional failures in the spare tests with "returned 0, expected 75" on newer builds.

There's a few interesting upstream patches that potentially fix these new errors, though this should probably be brought to the attention of upstream if ztest has issues on 0.6.5-release:
"Skip ctldir znode in zfs_rezget to fix snapdir issues"
"OpenZFS 6739 - assumption in cv_timedwait_hires"
"Fix do_div() types in condvar:timeout"

Either way I think xenial should probably sync with upstream 0.6.5.x, though I understand this is a sensitive matter. I reported this upstream against 0.6.5-release about this missing "Fix ztest truncated cache file" patch which hopefully should be queued for the next point release and maybe these other issues will be discovered and fixed as well.