Comment 12 for bug 1759723

I think the patches from this bug are causing a problem. See LP: #1765232 for details.

I've identified a number of upstream fixes for these patches, listed on that bug. We are days out from release though, and the last of them (d3056812e7df "genirq/affinity: Spread irq vectors among present CPUs as far as possible") will require backporting or additional commits. We don't have a lot of time to get testing on this.

As I read the description of this bug, the issue can be summed up as, "stress the system, do CPU hotplug, then the system becomes unresponsive." The other issue is summarized as, "my system hangs during boot." Since the latter will prevent installation of 18.04 I regard it as the more serious issue.

Given all of this, I'm strongly inclined towards reverting these patches for the release, then we can look at SRU-ing them along with all necessary fixes. If the issue here is more serious than my reading of it (i.e. it will prevent booting and installation of 18.04) please speak up ASAP.