[Bug 1864045] Re: [SRU] Hibernation events sometimes missed on repeated attempts

[Andrea Righi]

@rbalint if you can reproduce the problem easily, it would be
interesting to monitor the received ACPI events via acpi_listen.

What I see during my tests is that acpi_listen is always showing the
sleep events, meaning that the kernel receives them correctly at least,
and then the failure happens in the delivery of these sleep events to
the proper user-space daemon (acpid). So my guess is that something
wrong is happening in the communication between kernel and user-space to
deliver these events.

Just to make sure, when you say "the second hibernation attempt still
fails" you mean that the system is still up & running (you can still ssh
on it) and the sleep event is lost / not delivered properly, right?

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Title:
  [SRU] Hibernation events sometimes missed on repeated attempts

Status in acpid package in Ubuntu:
  Confirmed
Status in linux package in Ubuntu:
  Incomplete
Status in acpid source package in Bionic:
  Incomplete
Status in linux source package in Bionic:
  Incomplete
Status in acpid source package in Eoan:
  Confirmed
Status in linux source package in Eoan:
  Incomplete

Bug description:
  When testing hibernation / resume on AWS with 5.0 or 5.3 kernels on
  bionic (using acpid 1:2.0.28-1ubuntu1), we sometimes see failure with
  repeated attempts. The first attempt will always be triggered, but the
  next attempt may not. The result is the agent never triggers the
  hibernation process and the instance will be forced to shutdown after
  a timeout period.

  Two workarounds have been identified. The first is to restart acpid
  during the resume handler. The second is to use the latest upstream
  acpid (as of Feb 1, 2020). This second workaround indicates there may
  be a patch missing in the acpid in bionic (1:2.0.28-1ubuntu1) to work
  with the 5.0+ kernels.

  To reproduce this problem:

  1) Launch an c4, c5, m4, m5, r4, r5 instance type with a 5.0 or 5.3 kernel on a bionic image with on-demand hibernation support enabled.
  2) Hibernate and resume the instance, ensuring the system is fully resumed afterward and the swap file has been removed.
  3) Hibernate and resume another time. The hibernate should be triggered immediately and the instance should become unresponsive as it saves state to disk.
  4) Resume the instance, it should come back with the same processes running.
  5) Repeat 3) - 4) as necessary.
  --- 
  ProblemType: Bug
  ApportVersion: 2.20.9-0ubuntu7.9
  Architecture: amd64
  DistroRelease: Ubuntu 18.04
  Ec2AMI: ami-0edf3b95e26a682df
  Ec2AMIManifest: (unknown)
  Ec2AvailabilityZone: us-west-2a
  Ec2InstanceType: m4.large
  Ec2Kernel: unavailable
  Ec2Ramdisk: unavailable
  Package: acpid 1:2.0.28-1ubuntu1
  PackageArchitecture: amd64
  ProcEnviron:
   TERM=screen
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=C.UTF-8
   SHELL=/bin/bash
  ProcVersionSignature: User Name 5.0.0-1025.28-aws 5.0.21
  Tags:  bionic ec2-images
  Uname: Linux 5.0.0-1025-aws x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm audio cdrom dialout dip floppy lxd netdev plugdev sudo video
  _MarkForUpload: True

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