The oom_score_adj for aqmon processes, which are run by conmon, should normally be set to 0. However, it is incorrectly set to -1000 after termination by the oom-killer in the context of a Memory Cgroup OOM event.

Issue

• The oom_score_adj for aqmon processes, which are run by conmon, should normally be set to 0. However, it is incorrectly set to -1000 after termination by the oom-killer in the context of a Memory Cgroup OOM event.
• When the processes are running with oom_score_adj of 0 as expected, they can be killed upon memcg OOM as expected:

    ...
Jun 19 09:44:20 hostname kernel: Tasks state (memory values in pages):
Jun 19 09:44:20 hostname kernel: [  pid  ]   uid  tgid total_vm      rss pgtables_bytes swapents oom_score_adj name
Jun 19 09:44:20 hostname kernel: [2005859]  2000 2005859     2929      641    61440        0             0 aqmon.sh <<-------
Jun 19 09:44:20 hostname kernel: [2005874]  2000 2005874   755653   548439  4907008        0             0 aqmon    <<-------
Jun 19 09:44:20 hostname kernel: oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=libpod-xxx.scope,mems_allowed=0,oom_memcg=/machine.slice/libpod-xxx.scope,task_memcg=/machine.slice/libpod-xxx.scope,task=aqmon,pid=2005874,uid=2000
Jun 19 09:44:20 hostname kernel: Memory cgroup out of memory: Killed process 2005874 (aqmon) total-vm:3022612kB, anon-rss:2089288kB, file-rss:104468kB, shmem-rss:0kB, UID:2000 pgtables:4792kB oom_score_adj:0
    ...

• On the other hand, when the processes are running with oom_score_adj of -1000, the OOM event occurrence ends up as "no killable processes.":

    ...
Jun 19 06:01:13 hostname kernel: Tasks state (memory values in pages):
Jun 19 06:01:13 hostname kernel: [  pid  ]   uid  tgid total_vm      rss pgtables_bytes swapents oom_score_adj name
Jun 19 06:01:13 hostname kernel: [ 226491]  2000 226491     2929      627    65536        0         -1000 aqmon.sh <<-------
Jun 19 06:01:13 hostname kernel: [ 226504]  2000 226504   736094   527288  4902912        0         -1000 aqmon    <<-------
Jun 19 06:01:13 hostname kernel: Out of memory and no killable processes...
    ...