acpi regression first bad commit 02b771b64b73226052d6e731a0987db3b47281e9

[H Buus]

I found what I believe is a regression on my Gateway ne570 laptop. It was running mythbuntu 14.04 LTS and ubuntu 15.04 releases quite well. But when I installed ubuntu 16.04 LTS, I found dmesg and kern.log were filling with messages like this:
Jul 10 17:01:10 buus-ne570 kernel: [ 57.741630] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341)
Jul 10 17:01:10 buus-ne570 kernel: [ 57.803775] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341)
Jul 10 17:01:10 buus-ne570 kernel: [ 57.866294] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341)
Jul 10 17:01:10 buus-ne570 kernel: [ 57.928403] ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341)

These messages would be repeated several times a second, and then pause for several seconds, then start again. I believe they are the cause of more sluggish behavior than with the older *Buntu releases.

git bisecting the linux-stable kernel led me to the bad commit:

# first bad commit: [02b771b64b73226052d6e731a0987db3b47281e9] ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations

commit 02b771b64b73226052d6e731a0987db3b47281e9
Author: Lv Zheng <email address hidden>
Date: Wed Aug 12 11:12:02 2015 +0800

    ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations

    It is proven that Windows evaluates _Qxx handlers in a parallel way. This
    patch follows this fact, splits _Qxx evaluations from the NOTIFY queue to
    form a separate queue, so that _Qxx evaluations can be queued up on
    different CPUs rather than being queued up on a CPU0 bound queue.
    Event handling related callbacks are also renamed and sorted in this patch.

    Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411
    Reported-and-tested-by: Gabriele Mazzotta <email address hidden>
    Signed-off-by: Lv Zheng <email address hidden>
    Signed-off-by: Rafael J. Wysocki <email address hidden>

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-31-generic 4.4.0-31.50
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: buus 1830 F.... pulseaudio
CurrentDesktop: Unity
Date: Thu Jul 14 18:11:02 2016
HibernationDevice: RESUME=UUID=aa093ba8-768a-4c3f-a993-de6331fe2190
InstallationDate: Installed on 2016-07-01 (12 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Gateway NE570
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-31-generic.efi.signed root=UUID=b3005ae3-98ce-446f-a4d9-8af24cf4c3ae ro vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-31-generic N/A
 linux-backports-modules-4.4.0-31-generic N/A
 linux-firmware 1.157.2
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/08/2013
dmi.bios.vendor: Insyde Corp.
dmi.bios.version: V2.06
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: EA50_CX
dmi.board.vendor: Gateway
dmi.board.version: V2.06
dmi.chassis.asset.tag: Acer Asset Tag String
dmi.chassis.type: 10
dmi.chassis.vendor: Insyde Corp.
dmi.chassis.version: V2.06
dmi.modalias: dmi:bvnInsydeCorp.:bvrV2.06:bd10/08/2013:svnGateway:pnNE570:pvrV2.06:rvnGateway:rnEA50_CX:rvrV2.06:cvnInsydeCorp.:ct10:cvrV2.06:
dmi.product.name: NE570
dmi.product.version: V2.06
dmi.sys.vendor: Gateway

[Brad Figg (brad-figg)]

This change was made by a bot.

[H Buus (faginbagin)]

The attachment, kernels.txt, are notes I took while manually bisecting ubuntu kernels listed here:
https://launchpad.net/ubuntu/xenial/+source/linux
and mainline kernels from here:
http://kernel.ubuntu.com/~kernel-ppa/mainline/

The attachment, bisect.txt, is an annotated "git bisect log" associating commits from the linux-stable tree with the deb packages I built, installed, and tested.

[penalvch (penalvch)]

H Buus, thank you for reporting this and helping make Ubuntu better.

In order to allow additional upstream developers to examine the issue, at your earliest convenience, could you please test the latest upstream kernel available from http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D ? Please keep in mind the following:
1) The one to test is at the very top line at the top of the page (not the daily folder).
2) The release names are irrelevant.
3) The folder time stamps aren't indicative of when the kernel actually was released upstream.
4) Install instructions are available at https://wiki.ubuntu.com/Kernel/MainlineBuilds .

If testing on your main install would be inconvenient, one may:
1) Install Ubuntu to a different partition and then test this there.
2) Backup, or clone the primary install.

If the latest kernel did not allow you to test to the issue (ex. you couldn't boot into the OS) please make a comment in your report about this, and continue to test the next most recent kernel version until you can test to the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this issue is fixed in the mainline kernel, please add the following tags by clicking on the yellow circle with a black pencil icon, next to the word Tags, located at the bottom of the report description:
kernel-fixed-upstream
kernel-fixed-upstream-X.Y-rcZ

Where X, and Y are the first two numbers of the kernel version, and Z is the release candidate number if it exists.

If the mainline kernel does not fix the issue, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-X.Y-rcZ

Please note, an error to install the kernel does not fit the criteria of kernel-bug-exists-upstream.

Also, you don't need to apport-collect further unless specifically requested to do so.

Once testing of the latest upstream kernel is complete, please mark this report Status Confirmed. Please let us know your results.

Thank you for your understanding.

[H Buus (faginbagin)]

I tested v4.7-rc7, specifically this deb:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.7-rc7/linux-image-4.7.0-040700rc7-generic_4.7.0-040700rc7.201607110032_amd64.deb

It does not fix the problem, so I will be adding the kernel-bug-exists-upstream tags as you requested. The ACPI error messages have changed to reflect a newer version:
ACPI Error: Method reached maximum reentrancy limit (255) (20160422/dsmethod-340)

FWIW, I haven't found it necessary to install linux-header debs since the generic kernels support all the hardware on this machine and I don't need to compile any third party modules.

I have also found that if the machine is idle, there's a pause in the "ACPI Error" messages. I think it depends on how much writing to disk is going on, but that's just a gut feeling. I'm not quite sure how to verify that assumption, or if it would help diagnose the problem.

[penalvch (penalvch)]

H Buus, the issue you are reporting is an upstream one. Could you please report this problem following the instructions verbatim at https://wiki.ubuntu.com/Bugs/Upstream/kernel to the appropriate mailing list (TO Lv Zheng, Rafael J. Wysocki, and Len Brown CC linux-acpi)?

Please provide a direct URL to your post to the mailing list when it becomes available so that it may be tracked.

Thank you for your help.

[H Buus (faginbagin)]

Reported to upstream here:
http://www.spinics.net/lists/linux-acpi/msg67711.html

[H Buus (faginbagin)]

Here's link to upstream bug report, including a fix that works for me:
https://bugzilla.kernel.org/show_bug.cgi?id=135691

[Po-Hsu Lin (cypressyew)]

Fix e1191bd4f can be found in X/B/D/E
Closing with Fix-released.