Hi, On 1/11/21 7:39 PM, Kaneda, Erik wrote: > > >> -----Original Message----- >> From: Hans de Goede <hdegoede@xxxxxxxxxx> >> Sent: Saturday, December 26, 2020 6:28 AM >> To: Rafael J . Wysocki <rjw@xxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; >> Moore, Robert <robert.moore@xxxxxxxxx>; Kaneda, Erik >> <erik.kaneda@xxxxxxxxx> >> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; >> devel@xxxxxxxxxx >> Subject: [PATCH 0/2] ACPICA: Fix a race in GenericSerialBus (I2C) and GPIO >> handling >> >> 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. > > Thanks for this changeset! I'm taking a look right now Ok, note I already ported it to ACPICA git and submitted a pull-req (on Bob's request): https://github.com/acpica/acpica/pull/658 Regards, Hans
