2 panics occurred in webhooks

[arshadd-b]

Which jobs are failing?

capi-e2e-latestk8s-main
capi-e2e-main
capi-e2e-mink8s-main

Which tests are failing?

https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/periodic-cluster-api-e2e-main/1967380485474619392
https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/periodic-cluster-api-e2e-latestk8s-main/1967389293475270656
https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/periodic-cluster-api-e2e-mink8s-main/1967399360060723200

Since when has it been failing?

could see failure from 12-09-2025
https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/periodic-cluster-api-e2e-mink8s-main/1966492626114842624
https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/periodic-cluster-api-e2e-main/1966519050062270464

Testgrid link

No response

Reason for failure (if possible)

{Expected success, but got an error:

<errors.aggregate | len:1, cap:1>: 
2 panics occurred in webhooks (check logs for more details)
[
    <*errors.errorString | 0xc0014be150>{
        s: "2 panics occurred in webhooks (check logs for more details)",
    },
] failed [FAILED] Expected success, but got an error:
<errors.aggregate | len:1, cap:1>: 
2 panics occurred in webhooks (check logs for more details)
[
    <*errors.errorString | 0xc0014be150>{
        s: "2 panics occurred in webhooks (check logs for more details)",
    },
]

Anything else we need to know?

No response

Label(s) to be applied

/kind failing-test
One or more /area label. See https://github.com/kubernetes-sigs/cluster-api/labels?q=area for the list of labels.

[arshadd-b]

when going through the logs
what I see multiple errors

STEP: Moving the cluster to self hosted - /home/prow/go/src/sigs.k8s.io/cluster-api/test/e2e/self_hosted.go:264 @ 09/15/25 02:03:29.5

STEP: Moving workload clusters - /home/prow/go/src/sigs.k8s.io/cluster-api/test/framework/clusterctl/client.go:437 @ 09/15/25 02:03:29.5
INFO: clusterctl move --from-kubeconfig /tmp/e2e-kind2418363753 --to-kubeconfig /tmp/e2e-kubeconfig1589682398 --namespace self-hosted-vtvo2f

INFO: Got error while streaming logs for pod capi-kubeadm-bootstrap-system/capi-kubeadm-bootstrap-controller-manager-548c667984-c6xrw, container manager: context canceled
INFO: Stopped streaming logs for pod capi-kubeadm-bootstrap-system/capi-kubeadm-bootstrap-controller-manager-548c667984-c6xrw, container manager: context canceled
INFO: Got error while streaming logs for pod capi-kubeadm-control-plane-system/capi-kubeadm-control-plane-controller-manager-7b7f7f4784-qdnt2, container manager: context canceled
INFO: Stopped streaming logs for pod capi-kubeadm-control-plane-system/capi-kubeadm-control-plane-controller-manager-7b7f7f4784-qdnt2, container manager: context canceled
INFO: Got error while streaming logs for pod capd-system/capd-controller-manager-5f9965d94b-wt4f4, container manager: context canceled
INFO: Stopped streaming logs for pod capd-system/capd-controller-manager-5f9965d94b-wt4f4, container manager: context canceled
INFO: Got error while streaming logs for pod capi-system/capi-controller-manager-7bff5944bb-gg5nn, container manager: context canceled
INFO: Stopped streaming logs for pod capi-system/capi-controller-manager-7bff5944bb-gg5nn, container manager: context canceled
INFO: Got error while streaming logs for pod test-extension-system/test-extension-controller-manager-977966867-8lpp6, container manager: context canceled
INFO: Stopped streaming logs for pod test-extension-system/test-extension-controller-manager-977966867-8lpp6, container manager: context canceled
[FAILED] Expected success, but got an error:
<errors.aggregate | len:1, cap:1>:
2 panics occurred in webhooks (check logs for more details)
[
<*errors.errorString | 0xc001bbedc0>{
s: "2 panics occurred in webhooks (check logs for more details)",
},
]

looks like after merging this things started failing

cc: @sbueringer

[sbueringer]

Thx for reporting

Yup agree. I'll take a look

/assign

This PR introduced (at least) two issues, the panic you mentioned + invalid ControlPlane upgrade plan: control plane upgrade plan must end with version v1.35.0-alpha.0.695+74c336734c0eda, ends with v1.34.0 instead

/cc @fabriziopandini

[sbueringer]

/triage accepted
/priority important-soon

Fix PR: #12766