RHEL7: System crash at rpc_shutdown_client+4f

Issue

• Kernel crashes with following logs:

[7989424.308518] general protection fault: 0000 [#1] SMP 
[7989424.313231] Modules linked in: iptable_filter tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag nbd(OE) raid1 sg rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache nfit libnvdimm iosf_mbi crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd ppdev parport_pc parport i2c_piix4 pcspkr binfmt_misc nfsd nfs_acl lockd grace auth_rpcgss ip_tables xfs libcrc32c nvme crct10dif_pclmul crct10dif_common ena nvme_core crc32c_intel serio_raw sunrpc dm_mirror dm_region_hash dm_log dm_mod
[7989424.351392] CPU: 15 PID: 31162 Comm: kworker/u32:0 Kdump: loaded Tainted: G           OE  ------------   3.10.0-1062.9.1.el7.x86_64 #1
[7989424.361202] Hardware name: Amazon EC2 c5.4xlarge/, BIOS 1.0 10/16/2017
[7989424.366375] Workqueue: nfsd4_callbacks nfsd4_run_cb_work [nfsd]
[7989424.371312] task: ffff962a19ae0000 ti: ffff96240e2e4000 task.ti: ffff96240e2e4000
[7989424.379472] RIP: 0010:[<ffffffffc00a80bf>]  [<ffffffffc00a80bf>] rpc_shutdown_client+0x4f/0x130 [sunrpc]
[7989424.388383] RSP: 0018:ffff96240e2e7c48  EFLAGS: 00010246
[7989424.392588] RAX: ffff96240e2e7c48 RBX: 74e5852b3ffb5a1a RCX: ffff96240e2e7fd8
[7989424.399785] RDX: 0000000000000000 RSI: e700000000000000 RDI: 74e5852b3ffb5a1a
[7989424.406726] RBP: ffff96240e2e7ca0 R08: ffff962416cbfce8 R09: a76f3af4234bfce0
[7989424.413791] R10: a76f3af4234bfce0 R11: 0000000000000000 R12: 74e5852b3ffb5a32
[7989424.420755] R13: ffff962416cbfca8 R14: ffff96240e2e7c60 R15: ffff962a19ae0000
[7989424.427731] FS:  0000000000000000(0000) GS:ffff962a2d5c0000(0000) knlGS:0000000000000000
[7989424.434981] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[7989424.439124] CR2: 00007fe87818c384 CR3: 00000007cd810000 CR4: 00000000007606e0
[7989424.446077] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[7989424.453008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[7989424.459929] PKRU: 00000000
[7989424.463169] Call Trace:
[7989424.466306]  [<ffffffff8c4c3254>] ? __kernel_text_address+0x64/0x90
[7989424.470568]  [<ffffffff8c43081c>] ? show_trace_log_lvl+0x17c/0x330
[7989424.474814]  [<ffffffffc01a184e>] nfsd4_process_cb_update.isra.7+0x3e/0x1f0 [nfsd]
[7989424.481861]  [<ffffffff8c4e0008>] ? __enqueue_entity+0x78/0x80
[7989424.485996]  [<ffffffff8c4e651b>] ? put_prev_entity+0x8b/0x400
[7989424.490133]  [<ffffffff8cb8dd37>] ? ret_from_fork_nospec_begin+0x21/0x21
[7989424.494537]  [<ffffffff8c42b59e>] ? __switch_to+0xce/0x580
[7989424.498577]  [<ffffffff8cb805a2>] ? __schedule+0x402/0x840
[7989424.502610]  [<ffffffff8c4bb68e>] ? move_linked_works+0x5e/0x90
[7989424.506794]  [<ffffffffc01a1aa4>] nfsd4_run_cb_work+0xa4/0x110 [nfsd]
[7989424.511101]  [<ffffffff8c4be21f>] process_one_work+0x17f/0x440
[7989424.515277]  [<ffffffff8c4bf336>] worker_thread+0x126/0x3c0
[7989424.519337]  [<ffffffff8c4bf210>] ? manage_workers.isra.26+0x2a0/0x2a0
[7989424.523697]  [<ffffffff8c4c61f1>] kthread+0xd1/0xe0
[7989424.527587]  [<ffffffff8c4c6120>] ? insert_kthread_work+0x40/0x40
[7989424.531902]  [<ffffffff8cb8dd37>] ret_from_fork_nospec_begin+0x21/0x21
[7989424.536277]  [<ffffffff8c4c6120>] ? insert_kthread_work+0x40/0x40
[7989424.540502] Code: 45 d0 31 c0 e8 d3 8b ad cc f6 05 c8 b0 03 00 02 0f 85 be 00 00 00 48 8d 45 a8 4c 8d 63 18 65 4c 8b 3c 25 80 0e 01 00 4c 8d 70 18 <4c> 3b 63 18 74 0e 48 89 df e8 43 d5 ff ff 4c 3b 63 18 75 2d 48 
[7989424.557387] RIP  [<ffffffffc00a80bf>] rpc_shutdown_client+0x4f/0x130 [sunrpc]
[7989424.565602]  RSP <ffff96240e2e7c48>