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Bug 2179165 - In cgroupv1 mode, delegated slices are instantly SIGKILLed on shutdown
Summary: In cgroupv1 mode, delegated slices are instantly SIGKILLed on shutdown
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: systemd
Version: 9.2
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: 9.2
Assignee: systemd-maint
QA Contact: Frantisek Sumsal
URL:
Whiteboard:
Depends On:
Blocks: 2180120
TreeView+ depends on / blocked
 
Reported: 2023-03-16 20:32 UTC by Colin Walters
Modified: 2023-05-09 10:34 UTC (History)
13 users (show)

Fixed In Version: systemd-252-13.el9_2
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 2180120 (view as bug list)
Environment:
Last Closed: 2023-05-09 08:22:35 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github redhat-plumbers systemd-rhel9 pull 153 0 None open (#2179165) unit: In cgroupv1, gracefully terminate delegated scopes again 2023-03-17 14:55:06 UTC
Gitlab redhat/centos-stream/rpms systemd merge_requests 72?commit_id=b8eb285fcaad6239af7e6c9bc8acdbc96641afc3 0 None None None 2023-03-17 13:06:15 UTC
Red Hat Issue Tracker RHELPLAN-152123 0 None None None 2023-03-16 20:34:02 UTC
Red Hat Product Errata RHBA-2023:2531 0 None None None 2023-05-09 08:22:52 UTC

Description Colin Walters 2023-03-16 20:32:57 UTC 
See https://issues.redhat.com/browse/OCPBUGS-10353 for more

OCP uses delegated slices for Kubernetes static pods and daemonsets.  OCP 4.13 will also use cgroupv1 by default.

Upstream commit https://github.com/systemd/systemd/commit/e9db43d5910717a1084924c512bf85e2b8265375
caused the processes in this scenario to be instantly SIGKILLed, which causes disruption.

Reproducing is just:

$ rpm-ostree kargs --append=systemd.unified_cgroup_hierarchy=0 --append="systemd.legacy_systemd_cgroup_controller=1" 
$ systemctl reboot
...
$ systemd-run -p Delegate=yes -p TimeoutStopSec=30 -u test-scope --scope /bin/sh -c 'trap "echo got SIGTERM; sleep 5; exit 0" TERM; sleep infinity'  &
$ systemctl stop test-scope.scope
$ journalctl -b --grep=test-scope
Mar 16 20:08:15 cosa-devsh systemd[1]: test-scope.scope: Deactivated successfully.
Mar 16 20:08:22 cosa-devsh systemd[1]: test-scope.scope: Killing process 1315 (sh) with signal SIGKILL.
Mar 16 20:08:22 cosa-devsh systemd[1]: test-scope.scope: Killing process 1316 (sleep) with signal SIGKILL.
Mar 16 20:08:22 cosa-devsh systemd[1]: test-scope.scope: Deactivated successfully.
$
Comment 1 Colin Walters 2023-03-16 20:38:43 UTC 
Tested MR in https://gitlab.com/redhat/centos-stream/rpms/systemd/-/merge_requests/72
Comment 2 David Tardon 2023-03-17 07:14:46 UTC 
(In reply to Colin Walters from comment #1)
> Tested MR in
> https://gitlab.com/redhat/centos-stream/rpms/systemd/-/merge_requests/72

Could you create a PR against https://github.com/redhat-plumbers/systemd-rhel9 instead? Also, please add "RHEL-only" and "Resolves: #2179165" to the commit message.
Comment 3 Colin Walters 2023-03-17 11:59:51 UTC 
> Could you create a PR against https://github.com/redhat-plumbers/systemd-rhel9 instead? Also, please add "RHEL-only" and "Resolves: #2179165" to the commit message.

I'd hoped to help speed up the process by doing a MR, but at this point given the urgency it's probably best if someone who knows and can own shepherding this patch through takes over to avoid round-trips.  Can one of the systemd team do that please?

We'd like this in RHEL 9.2 if at all possible, so that would also involve e.g. going through the exception? process here etc.
Comment 11 Colin Walters 2023-03-17 14:15:21 UTC 
As far as managing risk, I'll note that this code path *only* matters in legacy hierarchy setups.  I suspect this will be a pretty small set of RHEL9 users outside of OCP 4.13.
Comment 12 Michal Sekletar 2023-03-17 15:01:12 UTC 
This bug affects layered product so it should be a blocker instead of expection. Dropping exception?.
Comment 15 Colin Walters 2023-03-20 14:44:45 UTC 
One question that came up is "Why didn't this appear in RHEL8, it has the same code?".  No, it doesn't have the same code as far as I can tell.  Compare:

rhel8: https://github.com/redhat-plumbers/systemd-rhel8/blob/05a06e34ac8a38c1cff2a08ba071386141e0b78d/src/core/unit.c#L4615
rhel9: https://github.com/redhat-plumbers/systemd-rhel9/blob/a810aef1f95727ec3e044441bf02e0261b2e09ec/src/core/unit.c#L4592
Comment 16 Frantisek Sumsal 2023-03-20 14:49:19 UTC 
(In reply to Colin Walters from comment #15)
> One question that came up is "Why didn't this appear in RHEL8, it has the
> same code?".  No, it doesn't have the same code as far as I can tell. 
> Compare:
> 
> rhel8:
> https://github.com/redhat-plumbers/systemd-rhel8/blob/
> 05a06e34ac8a38c1cff2a08ba071386141e0b78d/src/core/unit.c#L4615
> rhel9:
> https://github.com/redhat-plumbers/systemd-rhel9/blob/
> a810aef1f95727ec3e044441bf02e0261b2e09ec/src/core/unit.c#L4592

In RHEL-8 the "offending" patch is reverted by a RHEL-only patch:

[0] https://github.com/redhat-plumbers/systemd-rhel8/commit/9d0046ceca10911361137d6496987cb15ffff132
Comment 26 errata-xmlrpc 2023-05-09 08:22:35 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (systemd bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:2531
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