** 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.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1747069 Title: artful 4.13 i386 kernels crash after memory hotplug remove Status in linux package in Ubuntu: In Progress Bug description: == 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. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1747069/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp