** 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 Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1747069

Title:
  artful 4.13 i386 kernels crash after memory hotplug remove

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1747069/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to