Comment 14 for bug 1981658

we also see this issue on azure ubuntu 1804, kernel version is 5.4.0-1086-azure

[ 823.785727] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 823.791661] #PF: supervisor read access in kernel mode
[ 823.791661] #PF: error_code(0x0000) - not-present page
[ 823.798898] PGD 0 P4D 0
[ 823.798898] Oops: 0000 [#1] SMP PTI
[ 823.798898] CPU: 21 PID: 0 Comm: swapper/21 Not tainted 5.4.0-1086-azure #91~18.04.1-Ubuntu
[ 823.798898] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090008 12/07/2018
[ 823.798898] RIP: 0010:tcp_create_openreq_child+0x2e1/0x3e0
[ 823.798898] Code: 08 00 00 41 8b 84 24 18 01 00 00 48 c7 83 80 08 00 00 00 00 00 00 4c 89 e6 4c 89 ef 89 83 c4 05 00 00 49 8b 84 24 f8 00 00 00 <48> 8b 40 08 e8 b6 81 4b 00 48 85 c0 0f b7 83 68 05 00 00 74 0a 83
[ 823.798898] RSP: 0018:ffffbcee00510950 EFLAGS: 00010246
[ 823.798898] RAX: 0000000000000000 RBX: ffff9e64f0c53d40 RCX: 0000000000000007
[ 823.798898] RDX: 0000000000000020 RSI: ffff9e6cd950fb60 RDI: ffff9e6ccf8d3480
[ 823.798898] RBP: ffffbcee00510970 R08: 0000000000000000 R09: ffff9e6d19007800
[ 823.798898] R10: 0000000000000514 R11: ffffbcee00510a37 R12: ffff9e6cd950fb60
[ 823.798898] R13: ffff9e6ccf8d3480 R14: ffff9e6cd7c1e200 R15: ffff9e6d1305e600
[ 823.798898] FS: 0000000000000000(0000) GS:ffff9e6d1f940000(0000) knlGS:0000000000000000
[ 823.798898] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 823.798898] CR2: 0000000000000008 CR3: 000000105216e004 CR4: 00000000003706e0
[ 823.798898] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 823.798898] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 823.798898] Call Trace:
[ 823.798898] <IRQ>
[ 823.798898] tcp_v4_syn_recv_sock+0x5a/0x3d0
[ 823.798898] tcp_get_cookie_sock+0x48/0x140
[ 823.798898] cookie_v4_check+0x561/0x660
[ 823.798898] tcp_v4_do_rcv+0x1a0/0x1d0
[ 823.956063] tcp_v4_rcv+0xa86/0xad0
[ 823.956063] ip_protocol_deliver_rcu+0x31/0x1b0
[ 823.956063] ip_local_deliver_finish+0x48/0x50
[ 823.956063] ip_local_deliver+0x7e/0xe0
[ 823.956063] ? ip_protocol_deliver_rcu+0x1b0/0x1b0
[ 823.956063] ip_sublist_rcv_finish+0x42/0x60
[ 823.956063] ip_sublist_rcv+0x239/0x270
[ 823.956063] ? ip_rcv_finish_core.isra.18+0x3b0/0x3b0
[ 823.956063] ip_list_rcv+0x10d/0x130
[ 823.956063] __netif_receive_skb_list_core+0x23e/0x260
[ 823.956063] netif_receive_skb_list_internal+0x17a/0x290
[ 823.956063] gro_normal_list.part.132+0x1e/0x40
[ 823.956063] napi_complete_done+0x94/0x110
[ 823.956063] mlx5e_napi_poll+0x178/0x630 [mlx5_core]
[ 823.956063] net_rx_action+0x134/0x3c0
[ 823.956063] __do_softirq+0xde/0x2ce
[ 823.956063] irq_exit+0xd7/0xe0
[ 823.956063] hyperv_vector_handler+0x63/0x70
[ 823.956063] hyperv_callback_vector+0xf/0x20
[ 823.956063] </IRQ>
[ 823.956063] RIP: 0010:default_idle+0x2b/0x150
[ 823.956063] Code: 1f 44 00 00 55 48 89 e5 41 56 41 55 41 54 53 65 44 8b 25 58 85 1c 4e 0f 1f 44 00 00 0f 1f 44 00 00 0f 00 2d 79 99 5b 00 fb f4 <65> 44 8b 25 3d 85 1c 4e 0f 1f 44 00 00 5b 41 5c 41 5d 41 5e 5d c3
[ 823.956063] RSP: 0018:ffffbcee0011be78 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff0c
[ 823.956063] RAX: ffffffffb1e4cde0 RBX: 0000000000000015 RCX: 0000000000000001
[ 823.956063] RDX: 0000000000000015 RSI: ffffbcee0011be58 RDI: 0000000000000000
[ 823.956063] RBP: ffffbcee0011be98 R08: 0000000000000006 R09: 00fca75c93534208
[ 823.956063] R10: ffffbcee0011be38 R11: 000000000013b454 R12: 0000000000000015
[ 823.956063] R13: 0000000000000000 R14: 0000000000000000 R15: 00000000fffffff0
[ 823.956063] ? __sched_text_end+0x2/0x2
[ 824.148152] arch_cpu_idle+0x15/0x20
[ 824.148152] default_idle_call+0x26/0x30
[ 824.148152] do_idle+0x1d7/0x2a0
[ 824.148152] cpu_startup_entry+0x1d/0x20
[ 824.148152] start_secondary+0x159/0x1b0
[ 824.148152] secondary_startup_64+0xa4/0xb0
[ 824.148152] Modules linked in: tcp_diag inet_diag nfnetlink_queue ipt_REJECT nf_reject_ipv4 xt_mark xt_comment xt_NFQUEUE iptable_mangle xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo iptable_nat xt_addrtype iptable_filter nf_nat br_netfilter bridge stp llc aufs overlay xt_tcpudp xt_owner xt_conntrack nf_conntrack nf_defrag_ipv6 iptable_security nf_defrag_ipv4 bpfilter mlx5_ib ib_uverbs mlx5_core tls mlxfw udf crc_itu_t nls_iso8859_1 isst_if_mbox_msr isst_if_common kvm_intel kvm hv_balloon rapl serio_raw joydev sch_fq_codel ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ghash_clmulni_intel hid_generic aesni_intel crypto_simd hid_hyperv cryptd pata_acpi hid glue_helper hyperv_fb hv_netvsc hyperv_keyboard hv_utils
[ 824.148152] CR2: 0000000000000008
[ 824.148151] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 824.148152] ---[ end trace 90f422af831c3aca ]---
[ 824.148152] RIP: 0010:tcp_create_openreq_child+0x2e1/0x3e0
[ 824.148151] #PF: supervisor read access in kernel mode
[ 824.148152] Code: 08 00 00 41 8b 84 24 18 01 00 00 48 c7 83 80 08 00 00 00 00 00 00 4c 89 e6 4c 89 ef 89 83 c4 05 00 00 49 8b 84 24 f8 00 00 00 <48> 8b 40 08 e8 b6 81 4b 00 48 85 c0 0f b7 83 68 05 00 00 74 0a 83
[ 824.148151] #PF: error_code(0x0000) - not-present page
[ 824.148152] RSP: 0018:ffffbcee00510950 EFLAGS: 00010246
[ 824.148151] PGD 80000010535ac067 P4D 80000010535ac067 PUD 10535ad067 PMD 0
[ 824.148152] RAX: 0000000000000000 RBX: ffff9e64f0c53d40 RCX: 0000000000000007
[ 824.276120] Oops: 0000 [#2] SMP PTI
[ 824.276121] RDX: 0000000000000020 RSI: ffff9e6cd950fb60 RDI: ffff9e6ccf8d3480
[ 824.276120] CPU: 17 PID: 20218 Comm: nginx Tainted: G D 5.4.0-1086-azure #91~18.04.1-Ubuntu
[ 824.276121] RBP: ffffbcee00510970 R08: 0000000000000000 R09: ffff9e6d19007800
[ 824.276120] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090008 12/07/2018
[ 824.276121] R10: 0000000000000514 R11: ffffbcee00510a37 R12: ffff9e6cd950fb60
[ 824.276120] RIP: 0010:tcp_create_openreq_child+0x2e1/0x3e0
[ 824.276121] R13: ffff9e6ccf8d3480 R14: ffff9e6cd7c1e200 R15: ffff9e6d1305e600
[ 824.276120] Code: 08 00 00 41 8b 84 24 18 01 00 00 48 c7 83 80 08 00 00 00 00 00 00 4c 89 e6 4c 89 ef 89 83 c4 05 00 00 49 8b 84 24 f8 00 00 00 <48> 8b 40 08 e8 b6 81 4b 00 48 85 c0 0f b7 83 68 05 00 00 74 0a 83
[ 824.276121] FS: 0000000000000000(0000) GS:ffff9e6d1f940000(0000) knlGS:0000000000000000
[ 824.276120] RSP: 0018:ffffbcee00460940 EFLAGS: 00010246
[ 824.276121] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 824.276120] RAX: 0000000000000000 RBX: ffff9e6ce337a300 RCX: 0000000000000007
[ 824.276121] CR2: 0000000000000008 CR3: 000000105216e004 CR4: 00000000003706e0
[ 824.276120] RDX: 0000000000000020 RSI: ffff9e6ce6030ab0 RDI: ffff9e6ccf8d3480
[ 824.276121] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 824.276120] RBP: ffffbcee00460960 R08: 0000000000000000 R09: ffff9e6d19007800
[ 824.276121] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 824.276120] R10: ffffbcee00460868 R11: ffffbcee00460a27 R12: ffff9e6ce6030ab0