When testing SyncE on a T-BC configuration, at a certain moment the linuxptp-daemon panics with the following traceback:

synce4l[614820.310]: [synce4l.0.config] PIN_SET request sent state:1, pin:31 parent:19 ret:48
synce4l[614820.310]: [synce4l.0.config] trying set prio=0 for pin:19 on follower
I1125 13:43:50.844266 3047099 dpll.go:579] dpll monitoring exited, initiating redial (ens2f0)
panic: runtime error: index out of range [1] with length 0
goroutine 808 [running]:
github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll.(*DpllConfig).PhaseOffsetPin(0xc00098efc0?, 0x10?)
    /go/src/github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll/dpll.go:346 +0x249
github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll.(*DpllConfig).nlUpdateState(0xc0002e7340, {0x2d7ab20, 0x0, 0xc000612600?}, {0xc000390628, 0x1, 0x100b0e990?})
    /go/src/github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll/dpll.go:389 +0x412
github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll.(*DpllConfig).monitorNtf(0xc0002e7340, 0xc0004ca068)
    /go/src/github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll/dpll.go:432 +0x7b
github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll.(*DpllConfig).MonitorDpllNetlink.func1()
    /go/src/github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll/dpll.go:526 +0x4e
created by github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll.(*DpllConfig).MonitorDpllNetlink in goroutine 782
    /go/src/github.com/k8snetworkplumbingwg/linuxptp-daemon/pkg/dpll/dpll.go:524 +0x75b

ptp-operator.v4.20.0-202511181524

Always

    1. Create a T-BC configuration including SyncE
    2. Check linuxptp-daemon-container logs
    3. The crash will happen after a while
    

Panic in the container

No crash

Checking the dpll pin monitor while the issue happens shows the following:

{
  "timestamp": "2025-11-18T13:32:14.418488642Z",
  "id": 31,
  "moduleName": "ice",
  "clockId": "0x507c6fffff836b8c",
  "boardLabel": "",
  "panelLabel": "",
  "packageLabel": "",
  "type": "synce-eth-port",
  "frequency": 0,
  "frequencySupported": [],
  "capabilities": "state-can-change",
  "pinParentDevice": [],
  "pinParentPin": [
    {
      "parentID": 19,
      "parentState": "disconnected"
    },
    {
      "parentID": 20,
      "parentState": "disconnected"
    }
  ],
}

The dpll.go code does not expect pinParentDevice to be an empty list.