Comment 9 for bug 1909286

Reproduced on mainline kernel v5.11.0-20-generic (v5.11.22) on node huggins (POWER8NVL, 8335-GTB) with Hirsute. Logs:
---
[ 167.500544] Faulting instruction address: 0x00000000
[ 167.500562] Oops: Kernel access of bad area, sig: 11 [#1]
[ 167.500578] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
...
[ 167.501361] NIP [0000000000000000] 0x0
[ 167.501376] LR [c000000000f2be4c] __bpf_prog_run_save_cb+0x5c/0x190
[ 167.501400] Call Trace:
[ 167.501410] [c000007fff4b38d0] [c00000406dbb4c80] 0xc00000406dbb4c80 (unreliable)
[ 167.501435] [c000007fff4b3940] [c000000000f2c02c] run_bpf_filter+0xac/0x200
[ 167.501457] [c000007fff4b39a0] [c000000000f2c204] reuseport_select_sock+0x84/0x170
[ 167.501648] [c000007fff4b39e0] [c000000001021640] udp4_lib_lookup2+0x200/0x2a0
[ 167.501673] [c000007fff4b3a60] [c000000001022928] __udp4_lib_lookup+0x2f8/0x340
[ 167.501696] [c000007fff4b3b40] [c00000000102873c] __udp4_lib_rcv+0x3ac/0x740
[ 167.501720] [c000007fff4b3c10] [c000000000fce750] ip_protocol_deliver_rcu+0x60/0x2c0
[ 167.501781] [c000007fff4b3c60] [c000000000fcea20] ip_local_deliver_finish+0x70/0x90
[ 167.501909] [c000007fff4b3c80] [c000000000fcddb0] ip_rcv_finish+0xc0/0xf0
[ 167.501931] [c000007fff4b3cc0] [c000000000eebab4] __netif_receive_skb_one_core+0x74/0xb0
[ 167.501956] [c000007fff4b3d10] [c000000000eebf28] process_backlog+0x138/0x280
[ 167.501979] [c000007fff4b3d80] [c000000000eecfc0] napi_poll+0x100/0x3c0
[ 167.502038] [c000007fff4b3e10] [c000000000eed374] net_rx_action+0xf4/0x2d0
[ 167.502175] [c000007fff4b3ea0] [c000000001175e90] __do_softirq+0x150/0x428
[ 167.502198] [c000007fff4b3f90] [c00000000002caec] call_do_softirq+0x14/0x24
[ 167.502220] [c00000003c343840] [c000000000017448] do_softirq_own_stack+0x38/0x50
[ 167.502245] [c00000003c343860] [c000000000165310] do_softirq+0xa0/0xb0
[ 167.502436] [c00000003c343890] [c000000000165418] __local_bh_enable_ip+0xf8/0x120
[ 167.502461] [c00000003c3438b0] [c000000000fd30e8] ip_finish_output2+0x1f8/0x620
[ 167.502486] [c00000003c343950] [c000000000fd77ec] ip_send_skb+0x6c/0x120
[ 167.502508] [c00000003c3439a0] [c000000001026658] udp_send_skb+0x168/0x450
[ 167.502530] [c00000003c3439f0] [c00000000102736c] udp_sendmsg+0x97c/0xd40
[ 167.502707] [c00000003c343bd0] [c00000000103a184] inet_sendmsg+0x64/0xb0
[ 167.502730] [c00000003c343c10] [c000000000ea9930] sock_sendmsg+0x80/0xb0
[ 167.502751] [c00000003c343c40] [c000000000eaeb18] __sys_sendto+0xf8/0x1a0
[ 167.502771] [c00000003c343d90] [c000000000eaec30] sys_send+0x30/0x40
[ 167.502793] [c00000003c343db0] [c000000000036fc4] system_call_exception+0xf4/0x200
[ 167.502982] [c00000003c343e10] [c00000000000d860] system_call_common+0xf0/0x27c
---

As in all other cases reuseport_select_sock() appears.