Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Bug 2214258

Summary:	systemd reports chronyd.service: Supervising process 1117 which is not our child. We'll most likely not notice when it exits.
Product:	Red Hat Enterprise Linux 9	Reporter:	Jan Pazdziora (Red Hat) <jpazdziora>
Component:	chrony	Assignee:	Miroslav Lichvar <mlichvar>
Status:	CLOSED MIGRATED	QA Contact:	rhel-cs-infra-services-qe <rhel-cs-infra-services-qe>
Severity:	low	Docs Contact:
Priority:	unspecified
Version:	9.2	CC:	jpazdziora
Target Milestone:	rc	Keywords:	MigratedToJIRA, Triaged
Target Release:	---	Flags:	pm-rhel: mirror+
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2023-09-21 18:41:02 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2231078
Bug Blocks:

Description Jan Pazdziora (Red Hat) 2023-06-12 11:29:45 UTC

Description of problem:

Sometimes, journal has message

  systemd: chronyd.service: Supervising process 1117 which is not our child. We'll most likely not notice when it exits.

in it.

Version-Release number of selected component (if applicable):

chrony-4.3-1.el9.s390x

How reproducible:

Very non-deterministic.

Steps to Reproduce:
1. Have chronyd.service enabled.
2. Boot the system.
3. Check journal for "Supervising process"

Actual results:

chronyd.service: Supervising process 1117 which is not our child. We'll most likely not notice when it exits.

Expected results:

No such message.

Additional info:

Comment 1 Jan Pazdziora (Red Hat) 2023-06-12 11:33:15 UTC

I have a reason to believe that this is caused by a race condition in go_daemon (upstream currently at https://git.tuxfamily.org/chrony/chrony.git/tree/main.c#n344).

When the initial process exits before the first forked process exits, the second forked process whose pid got written to pid_file still has ppid that first forked process. So when systemd checks the ppid for the pid found in the /run/chrony/chronyd.pid, it still sees that first forked child, not self.

Comment 2 Jan Pazdziora (Red Hat) 2023-06-12 11:34:12 UTC

The same issue on usbguard.service (bug 2042345) got fixed with https://github.com/USBGuard/usbguard/pull/554/files.

Comment 3 Miroslav Lichvar 2023-06-12 13:59:20 UTC

The chronyd grandparent process waits for one end of a pipe to be closed by both the middle process and the grandchild. The middle process doesn't do that explicitly, it's left up to the kernel to close it when the process terminates. It seems that happens before the ppid of the child is changed, which can break the order of termination.

Thanks for the report.

Comment 4 Miroslav Lichvar 2023-06-12 14:43:06 UTC

Upstream fix: https://gitlab.com/chrony/chrony/-/commit/0db30fd0b169b01890c428a3cfba611a222e3509

Comment 5 Miroslav Lichvar 2023-08-10 13:56:42 UTC

This issue will be fixed by rebase to chrony-4.4 (bug #2231078).

Comment 6 RHEL Program Management 2023-09-21 18:20:19 UTC

Issue migration from Bugzilla to Jira is in process at this time. This will be the last message in Jira copied from the Bugzilla bug.

Comment 7 RHEL Program Management 2023-09-21 18:41:02 UTC

This BZ has been automatically migrated to the issues.redhat.com Red Hat Issue Tracker. All future work related to this report will be managed there.

Due to differences in account names between systems, some fields were not replicated.  Be sure to add yourself to Jira issue's "Watchers" field to continue receiving updates and add others to the "Need Info From" field to continue requesting information.

To find the migrated issue, look in the "Links" section for a direct link to the new issue location. The issue key will have an icon of 2 footprints next to it, and begin with "RHEL-" followed by an integer.  You can also find this issue by visiting https://issues.redhat.com/issues/?jql= and searching the "Bugzilla Bug" field for this BZ's number, e.g. a search like:

"Bugzilla Bug" = 1234567

In the event you have trouble locating or viewing this issue, you can file an issue by sending mail to rh-issues. You can also visit https://access.redhat.com/articles/7032570 for general account information.