[jira] [Assigned] (YUNIKORN-3367) KubernetesShim.Stop() sends to the unbuffered stopChan instead of closing it, leaving one doScheduling loop running after stop

["Andy Huang (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/YUNIKORN-3367?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andy Huang reassigned YUNIKORN-3367:
------------------------------------

    Assignee: Andy Huang

> KubernetesShim.Stop() sends to the unbuffered stopChan instead of closing it, leaving one doScheduling loop running after stop
> ------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: YUNIKORN-3367
>                 URL: https://issues.apache.org/jira/browse/YUNIKORN-3367
>             Project: Apache YuniKorn
>          Issue Type: Bug
>          Components: shim - kubernetes
>            Reporter: Dale Richardson
>            Assignee: Andy Huang
>            Priority: Major
>              Labels: newbie
>
> Follow-up to YUNIKORN-3357 (shim goleak adoption, PR #1061); burns down the leakcheck exemption k8s.io/apimachinery/pkg/util/wait.BackoffUntilWithContext (pkg/shim).
> {{KubernetesShim.doScheduling}} starts two {{wait.Until}} goroutines ({{schedule}} and {{checkOutstandingApps}}) that share the unbuffered {{ss.stopChan}}. {{KubernetesShim.Stop()}} *sends a single value* to {{stopChan}} instead of closing it, so exactly one of the two loops wakes and returns; the other keeps running for the lifetime of the process, scheduling applications on a shim that has been told to stop. Which loop survives is a race (both park in the same Kubernetes backoff frame).
> Proposed fix: {{Stop()}} should {{close(stopChan)}} — which stops both loops — rather than send to it, then delete the exemption in {{pkg/common/leakcheck/leakcheck.go}}.
> Note for whoever triages: that exemption is the broadest in the file. Its top frame is a {{k8s.io/apimachinery}} implementation detail, so within pkg/shim it exempts every {{wait.Until}}/{{wait.Forever}}/{{wait.JitterUntil}} loop, including ones not yet written; and the frame name has already moved once ({{BackoffUntil}} -> {{BackoffUntilWithContext}}), so a dependency bump can silently break the match and redden pkg/shim. Fixing the bug removes the need for it. Shares the {{Stop()}} path with the failed-Run() cleanup finding below and can be fixed together.



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