Re: power-off delay/hang due to commit 6d25be57 (mainline)

Sebastian Andrzej Siewior
2020-08-11T10:27:49Z

On 2020-07-14 17:53:15 [+0200], Rafael J. Wysocki wrote:
> acpi_evaluate_integer() doesn't show up in the trace, though, AFAICS.
>
> > I assumed acpi_ex_opcode_2A_0T_0R() since the other
> > candidate was acpi_ev_asynch_execute_gpe_method().
>
> Which probably is the case. Specifically
>
> acpi_ev_asynch_execute_gpe_method: Evaluate _L66
>
> is likely to cause the Notify() to be dispatched.
…
> > Rafael, are you also interested in an ACPI dump?
>
> That might help a bit.
>
> So what probably happens is that poking at the TZ causes a GPE to
> trigger and a Notify() to be dispatched which then goes into the
> workqueue for execution.
>
> Now, I'm not sure what happens to those Notify() items, though. They
> each should cause a handler (in the thermal driver) to be executed,
> but does that happen?

Stephen's trace contains a few backtraces, all of them look like this:

| Call Trace:
| acpi_ex_opcode_2A_0T_0R+0x93/0xdf
| acpi_ds_exec_end_op+0x10d/0x701
| acpi_ps_parse_loop+0x7f2/0x8c3
| acpi_ps_parse_aml+0x1a5/0x540
| acpi_ps_execute_method+0x1fe/0x2ba
| acpi_ns_evaluate+0x345/0x4e2
| acpi_evaluate_object+0x177/0x39f
| acpi_evaluate_integer+0x4f/0x110
| acpi_thermal_get_temperature.part.0+0x45/0xc4
| thermal_get_temp.cold+0xc/0x2e
| thermal_zone_get_temp+0x4c/0x70
| thermal_zone_device_update.part.0+0x2a/0x110
| acpi_thermal_notify+0xcf/0x140
| acpi_ev_notify_dispatch+0x45/0x5a
| acpi_os_execute_deferred_notify+0x34/0x60
| process_one_work+0x1d2/0x3a0
| worker_thread+0x45/0x3c0
| kthread+0xf6/0x130
| ret_from_fork+0x35/0x40

so no GPE and it comes the notify callback while parsing the ACPI table.
Any ideas? I guess acpi_ex_opcode_2A_0T_0R() uses the workqueue because
it may sleep and it might be invoked from non-preemptible context.

Sebastian