We've been busy implementing ACPI 6.4 support in ACPICA. Sorry for the delay.
Bob


-----Original Message-----
From: Rafael J. Wysocki <rafael@kernel.org> 
Sent: Monday, February 15, 2021 10:26 AM
To: Hans de Goede <redacted>
Cc: Rafael J . Wysocki <redacted>; Len Brown <lenb@kernel.org>; Moore, Robert <redacted>; Kaneda, Erik <redacted>; ACPI Devel Maling List <redacted>; open list:ACPI COMPONENT ARCHITECTURE (ACPICA) <redacted>
Subject: Re: [PATCH 0/2] ACPICA: Fix a race in GenericSerialBus (I2C) and GPIO handling

On Mon, Feb 15, 2021 at 6:52 PM Hans de Goede [off-list ref] wrote:

Hi,

On 12/26/20 3:28 PM, Hans de Goede wrote:

quoted

Hi All,

On one of my machines I noticed the following errors being logged:

[   52.892807] i2c i2c-0: adapter quirk: no zero length (addr 0x0078, size 0, read)
[   52.893037] i2c i2c-0: i2c read 0 bytes from client@0x78 starting at reg 0x0 failed, error: -95

The second line is coming from the Linux I2C ACPI OpRegion handling 
and after a bunch of debugging I've found out that there is a rather 
obvious (once you see it) and nasty race condition in the handling 
of I2C and GPIO opregions in acpi_ev_address_space_dispatch(). See 
the first patch in this series (the second patch is a follow-up 
cleanup patch removing some code duplication).

TBH I'm surprised that this issue has gone unnoticed as long as it 
has, but I guess that it mostly leads to unreproducable sporadic 
problems making it hard to debug and I got lucky that I had a 
machine where the race seems to trigger about once every 20 seconds.

I know that ACPICA patches are normally merged through the ACPICA 
upstream but given that this is a serious bug, I believe that in 
this case it might be best to add the fix directly to Linux and then 
port it to ACPICA from there.

ping ?

This was submitted 2 full months ago; and despite this:

1. Fixing a serious bug in ACPICA
2. The fix being pretty simple (and AFAICT obviously correct)

This is still awaiting review upstream:
https://github.com/acpica/acpica/pull/658

I must say that it feels to me that the upstream ACPICA process is broken here.

I submitted a pull-req for this, as requested and after that there has 
been zero progress.

The pull-req even has a 26 day old "this looks good to me" comment 
from Erik, followed by silence... ?

Rafael, can you please consider just directly picking these 2 fixes 
into your acpi branch, so that we can get this nasty race condition fixed ?

I will do that later this week, thanks!