Comment 9 for bug 1927076

Po-Hsu Lin,
Thanks for the info.
I was able to reproduce the issue on other 2 Power8 servers, but just running the `reuseport_bpf_cpu test` more than once (as you mentioned on comment#3).
I've tested this with focal-hwe (Linux thiel 5.11.0-27-generic) and hirsute (5.11.0-31-generic).
steps:
1. Run the cpu-hotplug test; 2. Run the reuseport_bpf_cpu test; 3. re-run the reuseport_bpf_cpu test.

```
thiel login:
[24669.414656] Oops: Exception in kernel mode, sig: 4 [#1]
[24669.414710] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
```

```
gulpin login:
[277274.876010] Oops: Exception in kernel mode, sig: 4 [#1]
[277274.876235] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
```

I've also tested this 2 servers above with the upstream kernel from `https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.11.22/`
I put the `reuseport_bpf_cpu test` on 20x loop and did not hit the issue, so I'd say we may have an issue with ubuntu-kernel.
all 20x the test reported a success and the server did not reboot.
```
send cpu 157, receive socket 157
send cpu 159, receive socket 159
SUCCESS
```