This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed- focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: verification-needed-focal -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-aws in Ubuntu. https://bugs.launchpad.net/bugs/1918694 Title: aws: fix hibernation issues on c5.18xlarge Status in linux-aws package in Ubuntu: New Status in linux-aws source package in Focal: Fix Committed Bug description: [Impact] Hibernation is still unreliable on c5.18xlarge instances, usually the system hibernates correctly, but on resume it either perfoms a regular reboot instead of resuming from hibernation, or the system is completely stuck after the hibernated kernel is loaded in memory (more exactly the system is stuck when the resume callbacks of the hibernated kernel are executed). [Test plan] Create a c5.18xlarge instance, run the memory stress test script (the same test script that we are using to stress test hibernation), trigger the hibernate event, trigger the resume event. Repeat a couple of times and the problem is very likely to happen. [Fix] Amazon pointed out two fixes that should address both issues: 1) upstream patch "PM: hibernate: flush swap writer after marking": this prevents the regular reboot issue, because it ensures that the I/O is always flushed after, not before, writing the hibernation signature 2) we need to reserve more space for HVC_BOOT_ARRAY_SIZE: this is a temporary solution (SAUCE PATCH for now), suggested by Amazon, they are working on a proper (more elegant) fix, but doubling the size of HVC_BOOT_ARRAY_SIZE seems to resolve the problem, we have tested this change extensively in the AWS cloud and it seems to prevent the "system stuck on resume" issue from happening [Regression potential] The first patch is touching only the hibernation code, so potential regressions could be experienced only in the hibernation scenario. The second patch is more like a hack at the moment and it's affecting kvmclock. Increasing the size of HVC_BOOT_ARRAY_SIZE could potentially introduce regressions on small sized kvm systems and a better solution would be to allocate the array hv_clock_boot dynamically. And this is actually the proper fix that Amazon is currently working on. When the fix will be published upstream we should apply that one and drop this SAUCE PATCH. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-aws/+bug/1918694/+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
