** Description changed: - It seems all of the artful 4.13 are crashing on i386 install when memory - hotplug removal is attempted. This crash occurs a few seconds after the - removal. I have done a gross bisect back to the first 4.13.0-11 which - is also affected. + == SRU Request, Artful == + + Hotplug removal causes i386 crashes when exercised with the kernel + selftest mem-on-off-test script. + + == Fix == + + Revert commit f1dd2cd13c4b (""mm, memory_hotplug: do not associate + hotadded memory to zones until online") + + Note: A fix occurs in 4.15 however this requires a large set of changes + that are way too large to be SRU'able and the least risky way forward is + to revert the offending commit. + + == Testcase == + + Running the kernel selftest script mem-on-off-test.sh, followed by a + sync, followed by re-installing kernel packages will always trigger this + issue. Simply running the mem-on-off-test.sh script sometimes won't + trigger the problem. I believe this is why we've not seen this happen + too frequently with our ADT tests. I can reproduce this in a VM with 4 + CPUs and 2GB of memory. + + == Regression Potential == + + Reverting this commit does remove some functionality, however this does + not regress the kernel compared to previous releases and having a + working reliable memory hotplug is the preferred option. This fix does + touch some memory hotplug, so there is a risk that this may break this + functionality that is not covered by the kernel regression testing.
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