iwlwifi regression

[Luc Abric]

Hi,

Since I updated from Ubuntu 16.04 running kernel 4.8 (-generic-edge or something similar) to 17.04 running 4.10.0-20-generic I get a stack-trace every time I launch hostapd.
This issue did not exist prior to the upgrade and is 100% reproductible.

My WiFi chipset is a Intel Corporation Wireless 7260 (rev bb), and I am using a very simple configuration for hostapd.

The access point does work even after the stack-trace appears but it becomes unstable after a day or two, dropping clients and sometimes freezing the system entirely.
When it doesn't freeze the system I am usually able to get the access point to work again by rmmod'ing iwlwifi and iwlmvm then re-inserting them and restarting hostapd. Every restart produces the same stack-trace.
The bug is similar to https://bugzilla.redhat.com/show_bug.cgi?id=1441462.

Let me know if you would like me to attach some dmesg logs or any other kind of evidence.
I can also perform additional testing if required.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: linux-image-4.10.0-20-generic 4.10.0-20.22
ProcVersionSignature: Ubuntu 4.10.0-20.22-generic 4.10.8
Uname: Linux 4.10.0-20-generic x86_64
ApportVersion: 2.20.4-0ubuntu4
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/by-id', '/dev/snd/hwC0D2', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D8p', '/dev/snd/pcmC0D7p', '/dev/snd/pcmC0D3p', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/controlC0', '/dev/snd/pcmC1D0c', '/dev/snd/controlC1', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
Date: Wed May 3 14:50:16 2017
HibernationDevice: RESUME=UUID=2adc96b3-9ec7-479a-a8eb-740c23d1389f
InstallationDate: Installed on 2016-07-30 (276 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
MachineType: To be filled by O.E.M. To be filled by O.E.M.
ProcEnviron:
 TERM=screen-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.10.0-20-generic.efi.signed root=UUID=902aaccc-4309-4a44-8056-a99106dea2ad ro quiet splash vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-4.10.0-20-generic N/A
 linux-backports-modules-4.10.0-20-generic N/A
 linux-firmware 1.164
SourcePackage: linux
UpgradeStatus: Upgraded to zesty on 2017-04-14 (18 days ago)
dmi.bios.date: 08/22/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 5.11
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: Aptio CRB
dmi.board.vendor: AMI Corporation
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 1
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr5.11:bd08/22/2015:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnAMICorporation:rnAptioCRB:rvrTobefilledbyO.E.M.:cvnToBeFilledByO.E.M.:ct1:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: To be filled by O.E.M.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.11 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.11-rc8

[Luc Abric (ansx)]

Just installed 4.11rc8 and rebooted, the stack trace still appear after a few seconds.

Changing status to Confirmed.

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org.

Once this bug is reported upstream, please add the tag: 'kernel-bug-reported-upstream'.

[0] https://wiki.ubuntu.com/Bugs/Upstream/kernel