On Mon, Feb 15, 2021 at 6:52 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi,
>
> On 12/26/20 3:28 PM, Hans de Goede wrote:
> > 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!