Bug 135691

[1.] One line summary of the problem: 

acpi regression first bad commit 02b771b64b73226052d6e731a0987db3b47281e9

[2.] Full description of the problem/report: 

I found what I believe is a regression on my Gateway ne570 laptop. The problem is reproducible with kernels v4.7-rc7, v4.4.13 and v4.3. 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)

With the latest stable kernel, 4.7-rc7, the ACPI error messages have changed to reflect a newer version, specifically:
Jul 16 12:59:18 buus-ne570 kernel: [   78.862942] ACPI Error: Method reached maximum reentrancy limit (255) (20160422/dsmethod-340)

These messages are 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 kernels. 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.

I believe the problem is a regression, because it did not occur with kernels v3.16.7, v3.19.8, or v4.2.8.

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

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

commit 02b771b64b73226052d6e731a0987db3b47281e9
Author: Lv Zheng <lv.zheng@intel.com>
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 <gabriele.mzt@gmail.com>
    Signed-off-by: Lv Zheng <lv.zheng@intel.com>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

I can provide an annotated "git bisect log" associating commits from the linux-stable tree with the deb packages I built, installed, and tested to arrive at the "first bad commit".

[3.] Keywords (i.e., modules, networking, kernel):

[4.] Kernel version (from /proc/version): 
Linux version 4.7.0-040700rc7-generic (kernel@gloin) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1) ) #201607110032 SMP Mon Jul 11 04:34:25 UTC 2016

[5.] Output of Oops.. message (if applicable) with symbolic information resolved (see Documentation/oops-tracing.txt) 
Not applicable

[6.] A small shell script or example program which triggers the problem (if possible)
Not applicable
 
[7.] Environment
[7.1.] Software (add the output of the ver_linux script here)

Linux buus-ne570 4.7.0-040700rc7-generic #201607110032 SMP Mon Jul 11 04:34:25 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

GNU C                   5.4.0
GNU Make                4.1
Binutils                2.26.1
Util-linux              2.27.1
Mount                   2.27.1
Module-init-tools       22
E2fsprogs               1.42.13
Jfsutils                1.1.15
Pcmciautils             018
PPP                     2.4.7
Linux C Library         2.23
Dynamic linker (ldd)    2.23
Linux C++ Library       6.0.21
Procps                  3.3.10
Net-tools               1.60
Kbd                     1.15.5
Console-tools           1.15.5
Sh-utils                8.25
Udev                    229
Wireless-tools          30
Modules Loaded          ac acer_wmi ahci ansi_cprng arc4 ath ath3k ath9k ath9k_common ath9k_hw autofs4 battery bluetooth bnep btbcm btintel btrtl btusb button ccm cdrom cfg80211 coretemp crc16 crc32c_intel crc32_pclmul crct10dif_pclmul cryptd ctr dm_mod drbg drm drm_kms_helper efi_pstore efivarfs efivars ehci_hcd ehci_pci evdev ext4 fat fjes fuse ghash_clmulni_intel hid hid_generic hidp hmac i2c_algo_bit i915 intel_cstate intel_powerclamp intel_rapl intel_rapl_perf irqbypass jbd2 jfs joydev kvm kvm_intel libahci libata libphy lp lpc_ich mac80211 mbcache media mei mei_me mfd_core mmc_core nls_cp437 nls_utf8 parport parport_pc ppdev pps_core psmouse ptp rfcomm rfkill scsi_mod sdhci sdhci_pci sd_mod serio_raw sg shpchp snd snd_hda_codec snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_core snd_hda_intel snd_hwdep snd_pcm snd_rawmidi snd_seq snd_seq_device snd_seq_midi snd_seq_midi_event snd_timer soundcore sparse_keymap sr_mod tg3 tpm tpm_tis usb_common usbcore uvcvideo vfat video videobuf2_core videobuf2_memops videobuf2_v4l2 videobuf2_vmalloc videodev wmi x86_pkg_temp_thermal xhci_hcd xhci_pci

[7.2.] Processor information (from /proc/cpuinfo):
Intel(R) Core(TM) i3-3217U CPU @ 1.80GHz
I'll provide the full output if you want it.

[7.3.] Module information (from /proc/modules):
I can provide this if you want it.

[7.4.] Loaded driver and hardware information (/proc/ioports, /proc/iomem)
I can provide this if you want it.

[7.5.] PCI information ('lspci -vvv' as root)
I can provide this if you want it.

[7.6.] SCSI information (from /proc/scsi/scsi)
Doesn't exist.

[7.7.] Other information that might be relevant to the problem
       (please look in /proc and include all information that you
       think to be relevant):

I can provide acpidump output, not sure if I can attach emails sent to linux-acpi list, so I'm not attaching it now.

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

[X.] Other notes, patches, fixes, workarounds:

This machine has the latest UEFI firmware available from the manufacturer, Insyde v2.06. FWIW, I believe the Gateway NE570 is a re-branded Acer Aspire E1-570.