Additional data point from GitHub issue cilium/cilium#43198: **Environment (update since my initial report):** - Ubuntu 25.10, kernel 6.17.0-1006-raspi (upgraded from 6.17.0-1004) - Raspberry Pi 5 Model B Rev 1.0 - Cilium v1.18.5 (kube-proxy replacement, VXLAN, Gateway API) - K3s cluster expanded from 2 to 3 nodes (added 1 worker)
**Observations:** 1. **Not eBPF-specific:** Combined with Chris Boot's report (Calico + nftables backend), we now have confirmed cases on both eBPF (Cilium kube-proxy replacement) and nftables (Calico) networking stacks. This suggests the issue is in the macb/RP1 driver layer, not in the packet processing backend. 2. **Frequency:** All 3 of my nodes crash approximately every 3 days. Subjectively, failures seem to correlate with higher network/CPU load, though I don't have hard metrics to confirm this. 3. **Physical layer appears alive but non-functional:** When a node dies, the link LED stays lit and the ACT LED continues blinking. However, the router shows the port in a strange state. Unplugging/replugging the cable has no effect. This suggests the PHY believes it has a valid link, but something in the macb/RP1 stack is broken. 4. **UART unresponsive:** I attempted UART connection via Flipper Zero and via another node's serial passthrough. No data received from the dead node's TX pin, despite journald logs showing the system was still writing locally at that time. This suggests the CPU core is alive but RP1 (which handles both ethernet and UART) may be completely unresponsive. 5. **Kernel updates ineffective:** Problem persists across 6.17.0-1004 → 6.17.0-1006 updates. 6. **Diagnostics setup:** I've now deployed periodic ethtool stats collection (every 60s) and link state monitoring (every 30s) on all nodes. Will provide detailed pre-failure metrics when the next crash occurs. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2133877 Title: Complete network hang on Raspberry Pi 5 with kernel 6.17 under load - possibly related to CPU frequency scaling To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/2133877/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
