net/bpfilter: remove superfluous testing message

[Marcelo Cerri]

[Impact]

A testing message was brought by 13d0f7b814d9 ("net/bpfilter: fix dprintf
usage for /dev/kmsg") but should've been deleted before patch submission.
Although it doesn't cause any harm to the code or functionality itself, it's
totally unpleasant to have it displayed on every loop iteration with no real
use case. Thus remove it unconditionally.

Upstream fix: 41c55ea6c2a7ca4c663eeec05bdf54f4e2419699

[Test Case]

Just check dmesg:

[ 10.635382] hv_utils: VSS: userspace daemon ver. 129 connected
[ 15.306015] bpfilter: Loaded bpfilter_umh pid 1036
[ 15.306280] Started bpfilter
[ 15.306283] testing the buffer
[ 15.306458] testing the buffer
[ 15.306880] testing the buffer
[ 15.318003] testing the buffer
[ 15.318057] testing the buffer
[ 15.318814] testing the buffer
[ 15.442147] testing the buffer
[ 15.479556] testing the buffer
[ 15.479572] testing the buffer

[Regression Potential]

Very low. The fix is a one line upstream patch that removes one printf.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1879559

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Steven Armstrong (sa+launchpad)]

We run this kernel on a cluster with several thousand nodes.
This debug print is spamming our logs like crazy.
Without filtering we would literally be collecting GBs of just this message on our syslog servers.

The fix is simple and side effect free.
Please apply the mentioned patch and release a new kernel as soon as possible.

[Steven Armstrong (sa+launchpad)]

I don't have `apport-collect` on my nodes.

But I can confirm the problem exists.

```
# journalctl | grep -c 'testing the buffer'
2498
#
```

[Steven Armstrong (sa+launchpad)]

I don't have `apport-collect` on my nodes.

But I can confirm the problem exists.

```
# journalctl | grep -c 'testing the buffer'
2498
#
```

[il_santo (ivanhoe-p)]

Same problem for me. Sending logs via apport-collect.

[il_santo (ivanhoe-p)]

ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.14
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: ivanhoe 6650 F.... pulseaudio
 /dev/snd/controlC0: ivanhoe 6650 F.... pulseaudio
CurrentDesktop: communitheme:ubuntu:GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2018-04-19 (767 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20180105.1)
MachineType: LENOVO 80XS
Package: linux-hwe-5.0
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.3.0-53-generic root=UUID=65eb0627-07fc-4f15-848b-360615a73359 ro quiet splash ivrs_ioapic[4]=00:14.0 ivrs_ioapic[5]=00:00.2 acpi_backlight=vendor vt.handoff=1
ProcVersionSignature: Ubuntu 5.3.0-53.47~18.04.1-generic 5.3.18
RelatedPackageVersions:
 linux-restricted-modules-5.3.0-53-generic N/A
 linux-backports-modules-5.3.0-53-generic N/A
 linux-firmware 1.173.18
Tags: bionic
Uname: Linux 5.3.0-53-generic x86_64
UpgradeStatus: Upgraded to bionic on 2018-05-04 (752 days ago)
UserGroups: adm cdrom dip docker input kvm libvirt lpadmin plugdev sambashare sudo video
_MarkForUpload: True
dmi.bios.date: 11/06/2018
dmi.bios.vendor: LENOVO
dmi.bios.version: 5QCN23WW
dmi.board.asset.tag: No Asset Tag
dmi.board.name: LNVNB161216
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40700WIN
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo ideapad 320-15ABR
dmi.modalias: dmi:bvnLENOVO:bvr5QCN23WW:bd11/06/2018:svnLENOVO:pn80XS:pvrLenovoideapad320-15ABR:rvnLENOVO:rnLNVNB161216:rvrSDK0J40700WIN:cvnLENOVO:ct10:cvrLenovoideapad320-15ABR:
dmi.product.family: ideapad 320-15ABR
dmi.product.name: 80XS
dmi.product.sku: LENOVO_MT_80XS_BU_idea_FM_ideapad 320-15ABR
dmi.product.version: Lenovo ideapad 320-15ABR
dmi.sys.vendor: LENOVO

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[il_santo (ivanhoe-p)]

apport information

[Sebastian Unger (sebunger44)]

Same issue on Raspberry PI running Eoan

[Joseph Salisbury (jsalisbury)]

This message can be ignored. This bogus "testing the buffer" message is something that inadvertently got into upstream code via commit:
13d0f7b814d9 net/bpfilter: fix dprintf usage for /dev/kmsg

This message is fixed by the following commit:
41c55ea6c2a7 net/bpfilter: remove superfluous testing message

The fix will be in the Ubuntu kernel version: Ubuntu-azure-5.3-5.3.0-1023.24

[Per Allansson (per-allansson)]

I disagree on the "low" priority of this one as it 1) fills up logs and 2) causes support questions (and thus wasting everyone's time).

So, please backport this one ASAP to the hwe kernels.

[Ted Gerold (tgwaste)]

Agreed. How is this not fixed after a month?