Page MenuHomeVyOS Platform
Create Task
Maniphest T8496

Add kernel config needed for pwru
Closed, ResolvedPublicFEATURE REQUEST
Actions

Description

Summary

Please consider adding the required kernel config for https://github.com/cilium/pwru

pwru is a very useful tool to debug complex networking issues on Linux, as it allows you to see how the packet travels through the kernel functions
I'm pretty sure that worked like 3 months ago in the rolling, but it seems like some config flags have been (accidentally) removed during the repo refactoring?

The following flags should be set:

CONFIG_DEBUG_INFO_BTF=y
CONFIG_KPROBES=y
CONFIG_PERF_EVENTS=y
CONFIG_BPF=y
CONFIG_BPF_SYSCALL=y
CONFIG_FUNCTION_TRACER=y
CONFIG_FPROBE=y

Currently missing:

CONFIG_DEBUG_INFO_BTF
CONFIG_KPROBES
CONFIG_FUNCTION_TRACER
CONFIG_FPROBE

Use case

Debug complex networking issues by using pwru to see how the packet travels through the kernel (functions)

Details

Version
-
Is it a breaking change?
Perfectly compatible
Issue type
Feature (new functionality)

Related Objects
Search...

StatusSubtypeAssignedTask
 ResolvedFEATURE REQUESTc-poT8147 Update Linux Kernel to 6.18
 ResolvedFEATURE REQUESTrchristT8496 Add kernel config needed for pwru

Event Timeline

rchrist created this task.Apr 14 2026, 3:51 PM
rchrist mentioned this in T8500: nftables vrf_zones is broken for veth.Apr 14 2026, 8:27 PM
pasik subscribed.Apr 15 2026, 6:23 AM
Viacheslav subscribed.Apr 15 2026, 11:00 AM

@rchrist do you want to claim the task and add a PR?

Viacheslav added a project: Restricted Project.Apr 15 2026, 11:04 AM
rchrist added a comment.Apr 15 2026, 11:18 AM

@Viacheslav Sure, can do. Currently already building it, so I can as well just share the modifications.

I stumbled over some minor stuff, I'll raise a separate issue on that.

rchrist mentioned this in T8506: Kernel build process / conventions, consider using merge_config.sh.Apr 15 2026, 11:27 AM
Viacheslav triaged this task as Normal priority.Apr 24 2026, 10:06 AM
Viacheslav changed the task status from Open to In progress.Apr 27 2026, 12:33 PM
Viacheslav assigned this task to rchrist.

PR https://github.com/vyos/vyos-build/pull/1170

Viacheslav closed this task as Resolved.Apr 27 2026, 2:38 PM
Viacheslav moved this task from Need Triage to Completed on the VyOS Rolling board.
Viacheslav reopened this task as Needs testing.Apr 27 2026, 3:00 PM
vvmsq subscribed.May 6 2026, 1:03 PM

Just wanted to note that I've observed significant increase in final ISO size when building kernel + modules which I believe is due to the options introduced by 30-pwru.config (Roughly +500MB: ~680MB without -> 1.2GB with). I guess this is probably expected because of the debug flags.

Viacheslav added a comment.May 11 2026, 3:21 PM
In T8496#262337, @vvmsq wrote:

Just wanted to note that I've observed significant increase in final ISO size when building kernel + modules which I believe is due to the options introduced by 30-pwru.config (Roughly +500MB: ~680MB without -> 1.2GB with). I guess this is probably expected because of the debug flags.

@vvmsq I don't know where you see 1.2GB

vyos@r14# ls -lh
total 669M
-rw-rw-r-- 1 vyos vyattacfg 669M May  9 13:07 vyos-2026.05.09-0042-rolling-generic-amd64.iso
[edit]
vyos@r14#

The latest rolling is 669M. Just download the latest rolling.

@rchrist, can you confirm that everything works as expected so we can close the task?

vvmsq added a comment.May 12 2026, 6:54 PM
In T8496#263758, @Viacheslav wrote:
In T8496#262337, @vvmsq wrote:

Just wanted to note that I've observed significant increase in final ISO size when building kernel + modules which I believe is due to the options introduced by 30-pwru.config (Roughly +500MB: ~680MB without -> 1.2GB with). I guess this is probably expected because of the debug flags.

@vvmsq I don't know where you see 1.2GB

vyos@r14# ls -lh
total 669M
-rw-rw-r-- 1 vyos vyattacfg 669M May  9 13:07 vyos-2026.05.09-0042-rolling-generic-amd64.iso
[edit]
vyos@r14#

The latest rolling is 669M. Just download the latest rolling.

This was after building kernel + modules myself - end result was much larger than expected - it's definitely possible/probable I did something wrong and included packages that weren't needed without noticing if regular builds are coming out fine. Apologies for the mistake.

c-po added a parent task: T8147: Update Linux Kernel to 6.18.May 17 2026, 8:56 AM
c-po mentioned this in T8880: Kernel source tar contains build time autogenerated objects.May 17 2026, 9:01 AM
rchrist added a comment.May 18 2026, 10:41 AM
In T8496#264157, @vvmsq wrote:

This was after building kernel + modules myself - end result was much larger than expected - it's definitely possible/probable I did something wrong and included packages that weren't needed without noticing if regular builds are coming out fine. Apologies for the mistake.

Yeah, that's about expected. When you just copy the built *.deb packages as usual, you will also copy some new packages like linux-image-6.6.135-vyos-dbg_6.6.135-1_amd64.deb with 328MB.. This package contains debug symbols, which are not needed for the eBPF use case here. This package is generated because CONFIG_DEBUG_INFO_BTF (or some other flag, but I think it was this one) explicitly requires CONFIG_DEBUG_INFO=y which causes this package to be generated, even though its not needed (because the BTF is embedded in the kernel)

@Viacheslav verified with the newest rolling 2026.05.17-0044-rolling:

image.png (1×2 px, 734 KB)

We can close from my side :)

Viacheslav closed this task as Resolved.May 18 2026, 10:46 AM