Ubuntu
linux-kvm package

ftrace test in ubuntu_kernel_selftests failed on KVM kernels

Bug #1812318 reported by Po-Hsu Lin
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
ubuntu-kernel-tests
Fix Released
Undecided
Unassigned
linux-kvm (Ubuntu)
Fix Released
Undecided
Unassigned
Bionic
Fix Released
Undecided
Unassigned
Disco
Won't Fix
Undecided
Unassigned
Eoan
Fix Released
Undecided
Unassigned

Bug Description

This test failed with:
    Error: No ftrace directory found

In the script:
    DEBUGFS_DIR=`grep debugfs /proc/mounts | cut -f2 -d' ' | head -1`
    if [ -z "$DEBUGFS_DIR" ]; then
        TRACING_DIR=`grep tracefs /proc/mounts | cut -f2 -d' ' | head -1`
    else
        TRACING_DIR=$DEBUGFS_DIR/tracing
    fi

The script exit here:
    # Verify parameters
    if [ -z "$TRACING_DIR" -o ! -d "$TRACING_DIR" ]; then
      errexit "No ftrace directory found"
    fi

DEBUGFS_DIR=/sys/kernel/debug
TRACING_DIR=/sys/kernel/debug/tracing

ls: cannot access '/sys/kernel/debug/tracing': No such file or directory

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-1028-kvm 4.15.0-1028.28
ProcVersionSignature: User Name 4.15.0-1028.28-kvm 4.15.18
Uname: Linux 4.15.0-1028-kvm x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
Date: Fri Jan 18 03:04:17 2019
SourcePackage: linux-kvm
UpgradeStatus: No upgrade log present (probably fresh install)

See original description
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :
description: updated
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

It looks like this config is needed: CONFIG_FTRACE

Po-Hsu Lin (cypressyew)
Changed in linux-kvm (Ubuntu Bionic):
status: New → Confirmed
Revision history for this message
Kleber Sacilotto de Souza (kleber-souza) wrote :

This issue also affects cosmic/linux-kvm.

Changed in linux-kvm (Ubuntu Cosmic):
status: New → Confirmed
Po-Hsu Lin (cypressyew)
tags: added: linux-kvm sru-20190603 ubuntu-kernel-selftests
Sean Feole (sfeole)
tags: added: sru-20190722
Sean Feole (sfeole)
Changed in ubuntu-kernel-tests:
status: New → Confirmed
tags: added: sru-20190902
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

Solved on B-kvm with the following commit for bug 1841956:
  UBUNTU: [Config] linux-kvm: CONFIG_FTRACE=y

Changed in ubuntu-kernel-tests:
status: Confirmed → Fix Released
Changed in linux-kvm (Ubuntu Bionic):
status: Confirmed → Fix Released
no longer affects: linux-kvm (Ubuntu Cosmic)
Changed in linux-kvm (Ubuntu):
status: New → Fix Released
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

Could be found in E-kvm as well

Po-Hsu Lin (cypressyew)
tags: added: sru-20191111
Po-Hsu Lin (cypressyew)
Changed in linux-kvm (Ubuntu Disco):
status: New → Won't Fix
Changed in linux-kvm (Ubuntu Eoan):
status: New → Fix Released
Revision history for this message
Po-Hsu Lin (cypressyew) wrote :

For the test itself, this can be fixed with https://github.com/torvalds/linux/commit/cbd965bde74c3d0e53798404fd4b9829a68ccec8#diff-71290e3874c89695bb4bc63f892d5c93

Revision history for this message
Guilherme G. Piccoli (gpiccoli) wrote :

I"m seeing the following failure on groovy:linux-kvm (cycle sru-20210315), doesn't seem a regression but something that failed since forever:

09:36:59 DEBUG| [stdout] # [10] Generic dynamic event - add/remove kprobe events [FAIL]

It works on regular kernels, so likely related to some missing CONFIG option on linux-kvm.

tags: added: groovy kvm sru-20210315
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