Comment 1 for bug 1794169

Not sure whether the issue is a poor interaction with sd-pam and the kernel or strictly a kernel issue.

Kernel timeout backtrace:

Sep 21 03:00:33 mainframe01 kernel: [292411.276266] Not tainted 4.15.0-1021-aws #21-Ubuntu
Sep 21 03:00:33 mainframe01 kernel: [292411.277931] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Sep 21 03:00:33 mainframe01 kernel: [292411.280331] kworker/u8:5 D 0 25806 2 0x80000080
Sep 21 03:00:33 mainframe01 kernel: [292411.280339] Workqueue: events_unbound fsnotify_mark_destroy_workfn
Sep 21 03:00:33 mainframe01 kernel: [292411.280340] Call Trace:
Sep 21 03:00:33 mainframe01 kernel: [292411.280347] __schedule+0x291/0x8a0
Sep 21 03:00:33 mainframe01 kernel: [292411.280349] schedule+0x2c/0x80
Sep 21 03:00:33 mainframe01 kernel: [292411.280350] schedule_timeout+0x1cf/0x350
Sep 21 03:00:33 mainframe01 kernel: [292411.280354] ? add_timer+0x124/0x280
Sep 21 03:00:33 mainframe01 kernel: [292411.280357] wait_for_completion+0xba/0x140
Sep 21 03:00:33 mainframe01 kernel: [292411.280362] ? wake_up_q+0x80/0x80
Sep 21 03:00:33 mainframe01 kernel: [292411.280365] __synchronize_srcu.part.13+0x85/0xb0
Sep 21 03:00:33 mainframe01 kernel: [292411.280367] ? trace_raw_output_rcu_utilization+0x50/0x50
Sep 21 03:00:33 mainframe01 kernel: [292411.280369] synchronize_srcu+0x66/0xe0
Sep 21 03:00:33 mainframe01 kernel: [292411.280370] ? synchronize_srcu+0x66/0xe0
Sep 21 03:00:33 mainframe01 kernel: [292411.280372] fsnotify_mark_destroy_workfn+0x7b/0xe0
Sep 21 03:00:33 mainframe01 kernel: [292411.280375] process_one_work+0x1de/0x410
Sep 21 03:00:33 mainframe01 kernel: [292411.280377] worker_thread+0x253/0x410
Sep 21 03:00:33 mainframe01 kernel: [292411.280379] kthread+0x121/0x140
Sep 21 03:00:33 mainframe01 kernel: [292411.280380] ? process_one_work+0x410/0x410
Sep 21 03:00:33 mainframe01 kernel: [292411.280382] ? kthread_create_worker_on_cpu+0x70/0x70
Sep 21 03:00:33 mainframe01 kernel: [292411.280385] ? do_syscall_64+0x73/0x130
Sep 21 03:00:33 mainframe01 kernel: [292411.280387] ? SyS_exit+0x17/0x20
Sep 21 03:00:33 mainframe01 kernel: [292411.280391] ret_from_fork+0x35/0x40