usrmerge breaks perf symbol lookup

[Travis Downs]

In 19.10, perf cannot find the symbols for libc even after installing libc-dbg.

The symbols for libc are in:

/usr/lib/debug/lib/x86_64-linux-gnu/

but libc is in:

/usr/lib/x86_64-linux-gnu/

so applications expect to find the corresponding symbols at:

/usr/lib/debug/usr/lib/x86_64-linux-gnu/
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu8.8
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: tdowns 1637 F.... pulseaudio
 /dev/snd/pcmC1D0p: tdowns 1637 F...m pulseaudio
 /dev/snd/controlC0: tdowns 1637 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 19.10
InstallationDate: Installed on 2020-02-14 (73 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
MachineType: Dell Inc. XPS 15 9550
Package: linux (not installed)
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.3.0-45-generic root=UUID=0a6fd287-c693-42a9-baa6-d90a59e83b42 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 5.3.0-45.37-generic 5.3.18
RelatedPackageVersions:
 linux-restricted-modules-5.3.0-45-generic N/A
 linux-backports-modules-5.3.0-45-generic N/A
 linux-firmware 1.183.5
Tags: eoan
Uname: Linux 5.3.0-45-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 12/12/2019
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.13.1
dmi.board.name: 0N7TVV
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.13.1:bd12/12/2019:svnDellInc.:pnXPS159550:pvr:rvnDellInc.:rn0N7TVV:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.family: XPS
dmi.product.name: XPS 15 9550
dmi.product.sku: 06E4
dmi.sys.vendor: Dell Inc.

[Travis Downs (travis-downs)]

This is the same issue as:

https://bugs.launchpad.net/ubuntu/+source/valgrind/+bug/1808508

... where the fix was to manually path the Valgrind debug info lookup path, but this doesn't seem feasible for every application that might care about symbols. Better to put the symbols in the right place or set up symlinks to ensure that is the case?

[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 1875274

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.

[Travis Downs (travis-downs)]

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[Travis Downs (travis-downs)]

This is still broken in 20.04.

[Paolo Pisati (p-pisati)]

Hi Travis,
do you have an easy reproducer for this?

I'm not familiar with perf, so a step to step guide would help me a lot.

[Paolo Pisati (p-pisati)]

Already fixed upstream, and awaiting in the stable branch linux-5.4.y:

807cc607f129 perf symbols: Fix debuginfo search for Ubuntu