[VROC] Kernel does not contain fixes for iostat for md devices

[Kinga Tanska]

Hello,

I noticed that kernel which was used in ubuntu 22.04 (hwe-5.13) does not contain fixes for IO statistics for md devices. IO statistics for md devices were added to kernel 5.10 (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=41d2d848e5c09209bdb57ff9c0ca34075e22783d) but then bug for double fault was reported and this patch was reverted by Guoqing Jiang (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad3fc798800fb7ca04c1dfc439dba946818048d8).

Guoqing Jiang added series of patches which fixes problem and adds IO stats for md devices on top on the revert patch:
- first commit from series: 10764815ff4728d2c57da677cd5d3dd6f446cf5f (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=10764815ff4728d2c57da677cd5d3dd6f446cf5f)
- last one: de3ea66e9d23a34eef5e17f960d6473f78a1c54b (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=de3ea66e9d23a34eef5e17f960d6473f78a1c54b)

I checked that kernel used in ubuntu 22.04 contains only patch with revert - iostat does not report for md devices (https://kernel.ubuntu.com/git/ubuntu/ubuntu-focal.git/log/?h=hwe-5.13&qt=author&q=Guoqing+Jiang)
Please consider adding series of patches described above.

Regards,
Kinga Tanska

[Kamal Mostafa (kamalmostafa)]

Hi @ktanska-

Here is a test build of the hwe-5.13 kernel with the requested series applied:
https://kernel.ubuntu.com/~kamal/lp1960324/

Please verify that it works as expected and report your results here. Following that, our intention is to pull the series into our Impish 5.13 baseline kernel from which hwe-5.13 is derived.

Thanks!

[Kamal Mostafa (kamalmostafa)]

Hi @ktanska-

Reminder that we're waiting for your feedback on the provided test kernel, before we can merge the iostat/md patch series into the Ubuntu 5.13 kernels.

Please verify that it works as expected and report your results here.

Thanks very much!

 -Kamal Mostafa <email address hidden>

[Kinga Tanska (ktanska)]

Hi,

sorry for the delay. I checked test kernel and it works as expected. I think you can submit it.

Thanks,
Kinga Tanska

[Kinga Tanska (ktanska)]

Hi @kamalmostafa,

Just to make sure, because task has "in progress" state. Was this fix included into 5.13 kernel used in Ubuntu 22.04? Or will be included in next releases?

Regards,
Kinga Tanska

[Kinga Tanska (ktanska)]

Hi @kamalmostafa,

Could you tell if this fix will be included into Ubuntu 22.04 or Ubuntu 22.04.1?

Regards,
Kinga Tanska

[Brian Murray (brian-murray)]

Ubuntu 21.10 (Impish Indri) has reached end of life, so this bug will not be fixed for that specific release.

[Kinga Tanska (ktanska)]

Hi,

Should I submit new bug for Jammy? I don't see this release in this bug, but it should be fixed there too.

Kinga Tanska

[Jeff Lane  (bladernr)]

I'm confused, 5.13 is not the Jammy kernel, that was a transitional kernel version. Can you actually recreate this on Jammy using the released 5.15 kernel?

And does it occur on the latest dev release (Kinetic)? You'll need to install the 22.10 (Kinetic) image, and then enable the propsoed repo and update the kernel to get the 5.19 kernel from -proposed:
 linux-image-generic | 5.19.0.15.15 | kinetic-proposed | amd64, arm64, armhf, ppc64el, s390x

[Kinga Tanska (ktanska)]

Ok, sorry, I didn't understand which kernel is used in Jammy correctly. I've opened new bug for 22.04 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1986668 .
Verification for Kinetic in progress, I will let you know here if issue is reproducible there.

[Kinga Tanska (ktanska)]

We've installed Ubuntu Kinetic with 5.15 kernel and updated it to 5.19.0-051900 (which was not available in default ubuntu repo, and was taken from here https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.19/amd64/ ).
Issue does not occur with this configuration.

[Kinga Tanska (ktanska)]

Hello @bladernr,

do you have any update of this issue?

[Jeff Lane  (bladernr)]

the 5.15 kernel has contained these patches since Ubuntu-5.15.0-1.1

bladernr@arcadia:~/development/kernels-ubuntu/jammy$ git tag --contains 10764815ff4728d2c57da677cd5d3dd6f446cf5f |head -1
Ubuntu-5.15.0-1.1
bladernr@arcadia:~/development/kernels-ubuntu/jammy$ git tag --contains de3ea66e9d23a34eef5e17f960d6473f78a1c54b |head -1
Ubuntu-5.15.0-1.1

[Jeff Lane  (bladernr)]

Not sure why you were seeing this, if those patches fix the issue, but they have existed in 5.15 for a while from what I can see.

[Kinga Tanska (ktanska)]

Thanks for your help. I can confirm that issue is fixed in 5.15.
Can be closed now.