** Also affects: linux (Ubuntu Trusty)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Bionic)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Xenial)
Importance: Undecided
Status: New
--
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https://bugs.launchpad.net/bugs/2038685
Title:
Missing BTF file in Ubuntu ESM kernels
Status in linux package in Ubuntu:
Confirmed
Status in linux source package in Trusty:
New
Status in linux source package in Xenial:
New
Status in linux source package in Bionic:
New
Bug description:
This is a follow-up from: https://discourse.ubuntu.com/t/ask-us-
anything-about-ubuntu-kernels/27664/142
Older Ubuntu distributions come with a kernel image that support eBPF
but are not built with a BTF file published (/sys/kernel/btf/vmlinux).
This BTF file is crucial when trying to run eBPF programs that were
built with CO-RE in mind such that a program can be compiled once and
run in any kernel (with some caveats) because the BPF loaders can use
the BTF file to relocate addresses of kernel fields at load time for
the currently running kernel. In the past I've used the debug symbols
that Ubuntu publishes to create BTF files using `pahole` for these
older kernels and then re-using that BTF file for any machine running
that kernel. This is not ideal but I had managed to work around it.
However, on distributions that are under ESM (Ubuntu 16 + Ubuntu 18)
there isn't a debug symbols repository from where to pull the debug
symbols packages to build their respective BTF file and no BTF file is
generated when the kernel is built. This essentially makes these ESM
kernels incompatible with eBPF programs that run using CO-RE (which is
more or less the norm nowadays). Based on my conversation on the
discourse link above it seems like ideally these ESM kernels should be
published with a BTF file.
P.S. I wasn't able to submit this through `ubuntu-bug linux` as it
gave me an error saying `Problem in linux-image-4.15.0-218-generic
This is not an official Ubuntu package. Please remove any third party
package and try again`. I am not sure why it says that as this is a
Ubuntu VM downloaded from the Ubuntu site, upgraded by doing `pro
attach` and then updated to the latest ESM kernel.
---
ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.29
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq',
'/dev/snd/timer'] failed with exit code 1:
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211
not found.
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2021-05-18 (870 days ago)
InstallationMedia: Ubuntu 18.04.5 LTS "Bionic Beaver" - Release amd64
(20200806.1)
Lsusb:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 004: ID 0e0f:0008 VMware, Inc.
Bus 002 Device 003: ID 0e0f:0002 VMware, Inc. Virtual USB Hub
Bus 002 Device 002: ID 0e0f:0003 VMware, Inc. Virtual Mouse
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: VMware, Inc. VMware Virtual Platform
Package: linux (not installed)
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-218-generic
root=UUID=c6dbf1d0-3a95-4d98-a0f8-fdea28a5ffc9 ro find_preseed=/preseed.cfg
auto noprompt priority=critical locale=en_US quiet
ProcVersionSignature: Ubuntu 4.15.0-218.229-generic 4.15.18
RelatedPackageVersions:
linux-restricted-modules-4.15.0-218-generic N/A
linux-backports-modules-4.15.0-218-generic N/A
linux-firmware 1.173.21
RfKill:
Tags: bionic
Uname: Linux 4.15.0-218-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip docker kvm libvirt lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 11/12/2020
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: 6.00
dmi.board.name: 440BX Desktop Reference Platform
dmi.board.vendor: Intel Corporation
dmi.board.version: None
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 1
dmi.chassis.vendor: No Enclosure
dmi.chassis.version: N/A
dmi.modalias:
dmi:bvnPhoenixTechnologiesLTD:bvr6.00:bd11/12/2020:svnVMware,Inc.:pnVMwareVirtualPlatform:pvrNone:rvnIntelCorporation:rn440BXDesktopReferencePlatform:rvrNone:cvnNoEnclosure:ct1:cvrN/A:
dmi.product.name: VMware Virtual Platform
dmi.product.version: None
dmi.sys.vendor: VMware, Inc.
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