we also hit this problem:
Code:
Feb 25 01:49:57 hv-vm-01 kernel:[123814.413163] #PF: supervisor read access in kernel mode
Feb 25 01:49:57 hv-vm-01 kernel:[123814.413735] #PF: error_code(0x0000) - not-present page
Feb 25 01:49:57 hv-vm-01 kernel:[123814.414312] PGD 0 P4D 0
Feb 25 01:49:57 hv-vm-01 kernel:[123814.414989] Oops: 0000 [#1] SMP PTI
Feb 25 01:49:57 hv-vm-01 kernel:[123814.415502] CPU: 28 PID: 19508 Comm: kworker/28:1 Tainted: P O 5.3.13-3-pve #1
Feb 25 01:49:57 hv-vm-01 kernel:[123814.416188] Hardware name: Cisco Systems Inc UCSC-C220-M4S/UCSC-C220-M4S, BIOS C220M4.3.0.4b.0.061018230606/10/2018
Feb 25 01:49:57 hv-vm-01 kernel:[123814.417476] RIP: 0010:keyring_gc_check_iterator+0x30/0x40
Feb 25 01:49:57 hv-vm-01 kernel:[123814.418235] Code: 4883 e7 fc b8 010000004889 e5 f6 8780000000217519488b57584839167c054885 d2 7f0b488b87 a0 000000 <0f> b6 40145d c3 662e0f
1f8400000000000f1f44000055
Feb 25 01:49:57 hv-vm-01 kernel:[123814.424717] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Feb 25 01:49:57 hv-vm-01 kernel:[123814.425422] CR2: 0000000000000014 CR3: 00000007b78d4006 CR4: 00000000003626e0
Feb 25 01:49:57 hv-vm-01 kernel:[123814.426132] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Feb 25 01:49:57 hv-vm-01 kernel:[123814.426771] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Feb 25 01:49:57 hv-vm-01 kernel:[123814.427396] Call Trace:
Feb 25 01:49:57 hv-vm-01 kernel:[123814.428123] assoc_array_subtree_iterate+0x5c/0x100
Feb 25 01:49:57 hv-vm-01 kernel:[123814.428919] assoc_array_iterate+0x19/0x20
Feb 25 01:49:57 hv-vm-01 kernel:[123814.429506] keyring_gc+0x43/0x80
Feb 25 01:49:57 hv-vm-01 kernel:[123814.430210] key_garbage_collector+0x35a/0x400
Feb 25 01:49:57 hv-vm-01 kernel:[123814.430863] process_one_work+0x20f/0x3d0
Feb 25 01:49:57 hv-vm-01 kernel:[123814.431496] worker_thread+0x34/0x400
Feb 25 01:49:57 hv-vm-01 kernel:[123814.529667] R13: ffffffff9d427dd0 R14: ffff8d6d818d5b00 R15: ffff8d67727be6d0
Feb 25 01:49:57 hv-vm-01 kernel:[123814.529669] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Feb 25 01:49:57 hv-vm-01 kernel:[123814.529671] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246582] BUG: kernel NULL pointer dereference, address: 0000000000000014
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246649] #PF: error_code(0x0000) - not-present page
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246666] PGD 0 P4D 0
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246693] CPU: 7 PID: 15381 Comm: kworker/7:3 Tainted: P O 5.3.13-3-pve #1
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246755] Workqueue: events key_garbage_collector
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246793] Code: 4883 e7 fc b8 010000004889 e5 f6 8780000000217519488b57584839167c054885 d2 7f0b488b87 a0 000000 <0f> b6 40145d c3 662e0f
1f8400000000000f1f44000055
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246883] RAX: 0000000000000000 RBX: ffff89143b936480 RCX: ffffaf9b89e5be20
Feb 28 22:01:35 hv-vm-01 kernel:[306609.246991] RBP: ffffaf9b89e5bdb8 R08: 0000000000000010 R09: 0000000000000000
Feb 28 22:01:35 hv-vm-01 kernel:[306609.247037] R13: ffffffff9bc27dd0 R14: ffff891425af1400 R15: ffff89143b936490
though I'm not sure if it NFS related.
we downgraded to 5.0 stable kernel and so far no problems.