Public bug reported:
The system calls return no errors, just all results are 0.
jak@jak-t14-g3 ~/P/D/apt (main)> gcc perf.c -Wall -Wextra -pedantic
-DTOTAL_EVENTS=5 && strace -o perf-5.log ./a.out
Num events captured: 5
Event: 41 -> 2387463223
Event: 42 -> 4000001326
Event: 43 -> 7389
Event: 44 -> 194
Event: 45 -> 1000001291
CPU cycles: 2387463223
Instructions retired: 4000001326
cache refs 7389
cache msises: 194
branch refs: 1000001291
jak@jak-t14-g3 ~/P/D/apt (main)> gcc perf.c -Wall -Wextra -pedantic
-DTOTAL_EVENTS=6 && strace -o perf-6.log ./a.out
Num events captured: 6
Event: 46 -> 0
Event: 47 -> 0
Event: 48 -> 0
Event: 49 -> 0
Event: 50 -> 0
Event: 51 -> 0
CPU cycles: 0
Instructions retired: 0
cache refs 0
cache msises: 0
branch refs: 0
branch misses: 0
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-6.19.0-3-generic 6.19.0-3.3+1
ProcVersionSignature: Ubuntu 6.19.0-3.3-generic 6.19.0-rc6
Uname: Linux 6.19.0-3-generic x86_64
ApportVersion: 2.33.1-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Wed Feb 11 12:06:29 2026
InstallationDate: Installed on 2022-11-26 (1173 days ago)
InstallationMedia: Ubuntu 23.04 "Lunar Lobster" - Alpha amd64 (20221126)
MachineType: LENOVO 21CF004PGE
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-6.19.0-3-generic
root=/dev/mapper/ubuntu-root ro rootflags=subvol=@ quiet splash isolcpus=15
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
vt.handoff=7
RelatedPackageVersions:
firmware-sof N/A
linux-firmware 20260108.gitd86b47f7-0ubuntu1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/29/2024
dmi.bios.release: 1.53
dmi.bios.vendor: LENOVO
dmi.bios.version: R23ET77W (1.53 )
dmi.board.asset.tag: Not Available
dmi.board.name: 21CF004PGE
dmi.board.vendor: LENOVO
dmi.board.version: SDK0T76538 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.32
dmi.modalias:
dmi:bvnLENOVO:bvrR23ET77W(1.53):bd05/29/2024:br1.53:efr1.32:svnLENOVO:pn21CF004PGE:pvrThinkPadT14Gen3:rvnLENOVO:rn21CF004PGE:rvrSDK0T76538WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21CF_BU_Think_FM_ThinkPadT14Gen3:
dmi.product.family: ThinkPad T14 Gen 3
dmi.product.name: 21CF004PGE
dmi.product.sku: LENOVO_MT_21CF_BU_Think_FM_ThinkPad T14 Gen 3
dmi.product.version: ThinkPad T14 Gen 3
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
** Attachment added: "perf.c"
https://bugs.launchpad.net/bugs/2141541/+attachment/5945147/+files/perf.c
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https://bugs.launchpad.net/bugs/2141541
Title:
perf_event_open() returns all 0s if more than 5 events in a group
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