Ubuntu
linux package

Boot log is swamped with "debugfs: Directory 'imc' with parent 'powerpc' already present" messages on kernel 5.4

Bug #1861379 reported by bugproxy
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
The Ubuntu-power-systems project
Fix Released
High
Ubuntu on IBM Power Systems Bug Triage
linux (Ubuntu)
Fix Released
Undecided
Canonical Kernel Team

Bug Description

== Comment: #0 - Kalpana Shetty <email address hidden> - 2020-01-29 22:46:37 ==
---Problem Description---
[Ubu 20.04][kernel-5.4.0-12-generic] debugfs: Directory 'imc' with parent 'powerpc' already present! lot of messages logged while booting

---uname output---
root@ltc-wcwsp3:~# uname -a Linux ltc-wcwsp3 5.4.0-12-generic #15-Ubuntu SMP Tue Jan 21 17:56:24 UTC 2020 ppc64le ppc64le ppc64le GNU/Linux

Machine Type = Witherspoon DD2.3

Test Environment:
Hardware: Witherspoon-DD2.3
Ubuntu 20.04
kernel: 5.4.0-12-generic #15-Ubuntu

Steps:
1. Install Ubu 20.4
2. reboot the system and seen lot of imc related messages thrown on screen while booting

Console screen snippet...
SIGTERM received, booting...
[ 24.812366] kexec_core: Starting new kernel
[ 1.852437] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.852538] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.852642] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.852727] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.852807] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.852895] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.852969] debugfs: Directory 'imc' with parent 'powerpc' already present!
[ 1.853043] debugfs: Directory 'imc' with parent 'powerpc' already present!
....
....

OS booted successfully.

== Comment: #1 - Kalpana Shetty <email address hidden> - 2020-01-29 22:48:26 ==

== Comment: #2 - Kalpana Shetty <email address hidden> - 2020-01-29 22:55:18 ==

== Comment: #3 - Kalpana Shetty <email address hidden> - 2020-01-29 22:56:21 ==

== Comment: #7 - MAMATHA INAMDAR <email address hidden> - 2020-01-30 00:44:27 ==
Hello Canonical,

Please Integrate following patches to fix this issue

(In reply to comment #5)
>
>
> This patch is upstream accepted as git commit
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/
> ?id=48e626ac85b43cc589dd1b3b8004f7f85f03544d
> ("powerpc/powernv: Avoid re-registration of imc debugfs directory")
>
> Thanks,
> Anju

> we may need this patch also:
> "[PATCH v2] powerpc/imc: Dont create debugfs files for cpu-less nodes"
> and
> which is now upstream accepted in the powerpc tree as git commit
> https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/
> ?h=next-test&id=41ba17f20ea835c489e77bd54e2da73184e22060
> -Anju

Revision history for this message
bugproxy (bugproxy) wrote : console log

Default Comment by Bridge

tags: added: architecture-ppc64le bugnameltc-183533 severity-high targetmilestone-inin2004
Revision history for this message
bugproxy (bugproxy) wrote : dmesg

Default Comment by Bridge

Revision history for this message
bugproxy (bugproxy) wrote : sosreport

Default Comment by Bridge

Changed in ubuntu:
assignee: nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage)
affects: ubuntu → kernel-package (Ubuntu)
Frank Heimes (fheimes)
affects: kernel-package (Ubuntu) → linux (Ubuntu)
Changed in ubuntu-power-systems:
status: New → Triaged
importance: Undecided → High
assignee: nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage)
Changed in linux (Ubuntu):
assignee: Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) → Canonical Kernel Team (canonical-kernel-team)
Revision history for this message
Frank Heimes (fheimes) wrote : Re: [Ubu 20.04][kernel-5.4.0-12-generic] debugfs: Directory 'imc' with parent 'powerpc' already present! lot of messages logged while booting

The commit "powerpc/imc: Dont create debugfs files for cpu-less nodes" - 41ba17f20ea835c489e77bd54e2da73184e22060 is already in focal (since Ubuntu-5.4.0-8.11).

The commit "powerpc/powernv: Avoid re-registration of imc debugfs directory" - 48e626a got upstream accepted with 5.5, hence it not yet in focal.
I'm going request to add it to focals 5.4.

Frank Heimes (fheimes)
summary: - [Ubu 20.04][kernel-5.4.0-12-generic] debugfs: Directory 'imc' with
- parent 'powerpc' already present! lot of messages logged while booting
+ debugfs: Directory 'imc' with parent 'powerpc' already present, cuases a
+ lot of messages logged while booting
summary: - debugfs: Directory 'imc' with parent 'powerpc' already present, cuases a
+ debugfs: Directory 'imc' with parent 'powerpc' already present, causes a
lot of messages logged while booting
summary: - debugfs: Directory 'imc' with parent 'powerpc' already present, causes a
- lot of messages logged while booting
+ Boot log is swamped with "debugfs: Directory 'imc' with parent 'powerpc'
+ already present" messages on kernel 5.4
Revision history for this message
Frank Heimes (fheimes) wrote :

Patch request submitted to kernel teams mailing list:
https://lists.ubuntu.com/archives/kernel-team/2020-January/thread.html#107176
changing status to 'In Progress'.

Changed in linux (Ubuntu):
status: New → In Progress
Changed in ubuntu-power-systems:
status: Triaged → In Progress
Frank Heimes (fheimes)
Changed in linux (Ubuntu):
status: In Progress → Fix Committed
Changed in ubuntu-power-systems:
status: In Progress → Fix Committed
Revision history for this message
Frank Heimes (fheimes) wrote :

The commit got applied to "Ubuntu-5.4-5.4.0-14.17" and that's also the version that's currently in focal's release pocket: "linux-generic | 5.4.0.14.17 | focal | s390x".
Hence changing the status of this ticket to Fix Released.

Changed in linux (Ubuntu):
status: Fix Committed → Fix Released
Changed in ubuntu-power-systems:
status: Fix Committed → Fix Released
Revision history for this message
bugproxy (bugproxy) wrote : Comment bridged from LTC Bugzilla

------- Comment From <email address hidden> 2020-04-07 02:38 EDT-------
Tried with the latest kernel version i.e. 5.4.0-21-generic
and *not seeing* reported error in dmesg: i.e. Directory 'imc' with parent 'powerpc' already present!

ubuntu@ltc-wcwsp3:~$ sudo dmesg | grep -I imc
[ 1.776791] IMC: disabling trace_imc PMU

Tested on Witherspoon machine with DD2.3

$ lscpu
Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 176
On-line CPU(s) list: 0-175
Thread(s) per core: 4
Core(s) per socket: 22
Socket(s): 2
NUMA node(s): 8
Model: 2.3 (pvr 004e 1203)

Verified.
Thanks!!

Revision history for this message
bugproxy (bugproxy) wrote :

------- Comment From <email address hidden> 2020-04-07 02:45 EDT-------
(In reply to comment #15)
> Tried with the latest kernel version i.e. 5.4.0-21-generic
> and *not seeing* reported error in dmesg: i.e. Directory 'imc' with parent
> 'powerpc' already present!
>
> ubuntu@ltc-wcwsp3:~$ sudo dmesg | grep -I imc
> [ 1.776791] IMC: disabling trace_imc PMU
>
> Tested on Witherspoon machine with DD2.3
>
> $ lscpu
> Architecture: ppc64le
> Byte Order: Little Endian
> CPU(s): 176
> On-line CPU(s) list: 0-175
> Thread(s) per core: 4
> Core(s) per socket: 22
> Socket(s): 2
> NUMA node(s): 8
> Model: 2.3 (pvr 004e 1203)
>
> Verified.
> Thanks!!

Hi Nageswara,

Thanks for verifying..will close this bug

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