kdump fails on big arm64 systems when offset is not specified

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 2024479

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.

Kexec-tools debdiff FOCAL.

kexec-tools debdiff JAMMY.

kexec-tools debdiff LUNAR.

kexec-tools debdiff MANTIC.

The attachment "lp2024479_focal.debdiff" seems to be a debdiff. The ubuntu-sponsors team has been subscribed to the bug report so that they can review and hopefully sponsor the debdiff. If the attachment isn't a patch, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are member of the ~ubuntu-sponsors, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issue please contact him.]

Hi Jo,

Thanks for the bug report, sru template, and debdiffs!

For Mantic, we currently do not have sponsors that could upload, but I certainly can review the debdiff and give you some feedback/request changes before reaching out to another sponsor/uploader, to hopefully make their life easier.

For the Mantic debdiff, it's great, thanks -- just some minor points:

1) the patch file name is 0001-*, and when looking at the tail of the series file, there's already a 0001, and some patches which don't follow a numbered convention? So, my suggestion would be to stick to the 'lpNNNNNNN-patch-subject.patch' convention, for the file name.

2.1) Nice touch on the DEP-3 headers! For Origin:, I just would like to suggest the URL be for the 'commit' page vs. a 'patch' page, which improves readability (colors/visual/etc), but note there's no strict requirement on this.
2.2) On Origin: again, if there's any changes for the patch to apply, please use the 'backport' keyword instead of 'upstream' (I didn't check, so it might be fully correct; but noting it just in case).

(BTW, I could not review the code changes yet.)

Now, on 'finding a sponsor' for Mantic, we can do that for you, or help you with it, in case you'd like to have the exposure/conversation with other people involved in the process. (It's totally fine to pick the former if you're busy or any other reason, this is what we're here for.)

Please confirm which path you'd prefer this time.

Thanks,
Mauricio

Mauricio is right in all he asks for, except most of them are "style" which I'd recommend but not insist on.

$ dquilt rename -P 0001-arm64-support-more-than-one-crash-kernel-regions.patch lp2024479-arm64-support-more-than-one-crash-kernel-regions.patch

I thought it would be only refreshed, but the patch has an actual backport change around the position of `fill_property' so it is a backport. But wait, is it?
No, deeper inspection found this to be noise from the refresh - the function was the same before and after patch. So we can take the content from upstream as-is (will do) and keep the origin tag.
(It even pops the same content the old did add which confirms it is the same - just with other diff context).

Bonus: updating the changelog to say the new filename.

With that in place, all is looking good.
I miss a PPA build here to be extra sure, but that issue (if any) would then be on @joalif to resolve if breaking.

Uploaded to Mantic:
$ dput ubuntu ../kexec-tools_2.0.22-2ubuntu4_source.changes
Uploading kexec-tools using ftp to ubuntu (host: upload.ubuntu.com; directory: /ubuntu)
running ppaforppaonly: Stop uploads to the archive with or to ppa without ~ppa suffix.
running gitubuntu: Warn if uploading without git-ubuntu Vcs-* entries.
running gpg: check GnuPG signatures before the upload
running releasemismatch: Warn about mismatching suffixesg e.g. focal with a XX.YY not being 20.04
running updatemaintainer: Stop if ubuntu changes are without ubuntu maintainer.
running suite-mismatch: check the target distribution for common errors
running badauthor: Stop if uploading with root@ or ubuntu@ email adresses.
running required-fields: check whether a field is present and non-empty in the changes file
running checksum: verify checksums before uploading
running nobug: Stop if uploading without any bug reference.
running check-debs: makes sure the upload contains a binary package
running supported-distribution: check whether the target distribution is currently supported (using distro-info)
{'allowed': ['release', 'proposed', 'backports', 'security'], 'known': ['release', 'proposed', 'updates', 'backports', 'security']}
running placeholderbug: Stop if using common placeholder numbers as bug reference.
Uploading kexec-tools_2.0.22-2ubuntu4.dsc
Uploading kexec-tools_2.0.22-2ubuntu4.debian.tar.xz
Uploading kexec-tools_2.0.22-2ubuntu4_source.buildinfo
Uploading kexec-tools_2.0.22-2ubuntu4_source.changes

Hey Christian, thanks for the quick review and sponsorship.

@cpaelzer and @mfo thank both of your reviewing and sponsoring.

@cpaelzer yes, if anything break, it's on me. Here's the PPA with the builds:
https://launchpad.net/~canonical-support-eng/+archive/ubuntu/sf361158

This bug was fixed in the package kexec-tools - 1:2.0.22-2ubuntu4

---------------
kexec-tools (1:2.0.22-2ubuntu4) mantic; urgency=medium

  * Support more than one crash kernel regions for arm64 (LP: #2024479)
    - d/p/lp2024479-arm64-support-more-than-one-crash-kernel-regions.patch

 -- Ioanna Alifieraki <email address hidden> Mon, 03 Jul 2023 15:18:56 +0300

@mfo revised the debdiffs for F, J and L and uploaded v2s.

1) Done
2.1) Done
2.2) patches cherry-pick

Ioanna and I just discussed about the working scenario (eg, crashkernel=1G on 5.4 kernel),
for it to be verified/no regressions with the patches (patched kexec-tools on 5.4 kernel).

This apparently isn't an issue, as the patch in J/L mentions it is backward compatible
(still going through the other patches in F), but that should, sure, be double checked.

Updated the Test Plan section accordingly.

Hi Jo,

Thanks for the debdiffs.

Lunar and Jammy (both: 1 patch) look good, just removed '0001' from .patch.

Focal has 6 patches and required more attention/changes (which I adjusted),
and patches look good (some notes below for documentation/other reviewers).

The (updated) debdiffs built correctly on ppa:mfo/lp2024479 on supported
architectures (amd64, arm64, armhf, ppc64el, s390x) and I'm confident on
your testing to be performed during -proposed verification.

So, uploaded to F/J/L.

Thanks,
Mauricio

...

Focal:

1) all Origin: links had wrong commit IDs; fixed.

2) there are commits to fix 3 different things, IIUIC,
   all of which are needed for big arm64 systems:
   (patches 1-2) phys_offset on large memory systems;
   (patches 3-5) many memory regions in /proc/iomem;
   (patch 6) split / memory regions for crash kernel;

3) patch 1 is mostly a big code movement, which I followed,
   and the few small changes in existing functions are for
   the purpose described (and are additions, not changes).

4) patch 2 adds code and hooks it into existing code

5) patch 3 simplifies the function call path, which is OK,
   and does a more significant logic change, but it still
   should perform the same thing (parse /proc/iomem format,
   which didn't change), and has no fixup commits.

6) patch 4 adds helpers for patches 3 and 5.

7) btw, patches 3/4 order is swapped (3 deps on 4); fixed.

8) patch 5 uses the helpers to change some existing code
   from static to dynamic allocation.

9) patch 6 (added to J/L/M) too, similarly, for the number
   of crash kernel / usable memory regions.

Fix-up commits: none strictly required.
---

I checked for newer commits (after 1st) in the modified files:
(cat lp2024479_focal-v2.debdiff | grep '^+--- a/' | cut -d/ -f2- | sort -u)

$ git log --oneline f4ce0706d9574aecb7d4aa9af7208a1bc9b6afb4..origin/master -- \
  kexec/arch/arm64/{kexec,crashdump}-arm64.{c,h} \
  kexec/mem_regions.{c,h} \
  util_lib/Makefile \
  vmcore-dmesg/Makefile \
  vmcore-dmesg/vmcore-dmesg.c

Only 4 commits were applicable to these code changes, AFAICT.

There are 3 cleanup/style/optional, no functional impact:

- commit 545c811050a3 ("Cleanup: remove the read_elf_kcore()")
- commit 14ad054e7baa ("Fix an error definition about the variable 'fname'")
- commit a7c4cb8e9985 ("Cleanup: move it back from util_lib/elf_info.c")

There is 1 which is more serious, but does not impact Ubuntu kernels,
since do not use 52-bit (but 48-) virtual address space with M/L/J/F:

- commit 67ea2d99e135 ("arm64: make phys_offset signed")
  (... phys_offset can be negative if running 52-bits kernel on 48-bits hardware ...)

  mantic:
 $ git grep -r ARM64_VA_BITS origin/master-next -- debian.master/config | grep -e "'y'" -e ARM64_VA_BITS_52
 <...>:CONFIG_ARM64_VA_BITS_48 policy<{'arm64': 'y'}>
 <...>:CONFIG_ARM64_VA_BITS_52 policy<{'arm64-generic-64k': 'n'}>
  lunar:
 $ git grep -r ARM64_VA_BITS origin/master-next -- debian.master/config | grep -e "'y'" -e ARM64_VA_BITS_52
 <...>:CONFIG_ARM64_VA_BITS_48 policy<{'arm64': 'y'}>
 <...>:CONFIG_ARM64_VA_BITS_52 ...

Hello Ioanna, or anyone else affected,

Accepted kexec-tools into lunar-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/kexec-tools/1:2.0.22-2ubuntu3.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-lunar to verification-done-lunar. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-lunar. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Hello Ioanna, or anyone else affected,

Accepted kexec-tools into jammy-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/kexec-tools/1:2.0.22-2ubuntu2.22.04.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-jammy to verification-done-jammy. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-jammy. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

The patch for focal is quite a bit larger than for jammy and lunar, and I question whether it's really needed. Is this driven by user demand on focal? Was this a problem in practice when focal was released, or has it become a problem more recently as a result of growing memory usage by the kernel?

Since this introduces greater risk and requires more review effort from the SRU team, I want to make sure we're not just SRUing it here in an effort to be "completionist".

Hi Steve,

Thanks for reviewing!

> Is this driven by user demand on focal?

Yes, this is driven by a support case from Azure
(kdump error on Arm64 VM w/ 48 vCPUs 192 GiB RAM).

> Was this a problem in practice when focal was released,
> or has it become a problem more recently <snip>

It seems that support for arm64 on Azure started on 2022,
~2 years after Focal release, as the first arm64 build of
the linux-azure kernel package is 5.4.0-1075.78 (Apr 2022).

https://launchpad.net/ubuntu/focal/+source/linux-azure
https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1074.77 (amd64 only)
https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1075.78 (amd64 and arm64)

> I want to make sure we're not just SRUing it here in an effort to be "completionist".

That's certainly understandable.

In this case, no; the patches are down to Focal as that
is the release where the bug/support case were reported,
and would ideally be fixed on, if at all possible.

Hope this helps.
Thanks!

For documentation purposes: the riscv64 build fails on jammy/lunar-proposed,
which is not a regression; that is since/on the jammy/lunar-release pockets.

This bug is awaiting verification that the linux-azure/5.15.0-1043.50 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy' to 'verification-done-jammy'. If the problem still exists, change the tag 'verification-needed-jammy' to 'verification-failed-jammy'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

Hello Ioanna, or anyone else affected,

Accepted kexec-tools into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/kexec-tools/1:2.0.18-1ubuntu1.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

# VERIFICATION LUNAR kexec-tools

1)
On a lunar machine with 184G of memory, running 6.2 kernel install kexec-tools from proposed and triggered a crash. Crashdump file is generated successfully.

root@biglunar:/var/crash# uname -rv
6.2.0-1005-azure #5-Ubuntu SMP Thu Jun 1 23:59:56 UTC 2023
root@biglunar:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.22-2ubuntu3.1 arm64 tools to support fast kexec reboots
root@biglunar:/var/crash# cat /etc/default/grub
grub grub.d/
root@biglunar:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=4G"
root@biglunar:/var/crash# ls 202307201417/
dmesg.202307201417 dump.202307201417
root@biglunar:/var/crash#

2)
On a lunar machine with 4G of memory, running 6.2 kernel install kexec-tools from proposed and triggered a crash. Crashdump file is generated successfully.

root@smalllunar:/var/crash# uname -rv
6.2.0-1005-azure #5-Ubuntu SMP Thu Jun 1 23:59:56 UTC 2023
root@smalllunar:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.22-2ubuntu3.1 arm64 tools to support fast kexec reboots
root@smalllunar:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=320M"
root@smalllunar:/var/crash# ls 202307201453/
dmesg.202307201453 dump.202307201453

# VERIFICATION JAMMY kexec-tools & kernel 5.15

1)
On a jammy machine with 184G of memory, installed kexec-tools and kernel 5.15 from proposed and triggered a crash. Crashdump file is generated successfully.

root@bigjelly:/var/crash# uname -rv
5.15.0-1043-azure #50-Ubuntu SMP Tue Jul 18 19:20:09 UTC 2023
root@bigjelly:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.22-2ubuntu2.22.04.1 arm64 tools to support fast kexec reboots
root@bigjelly:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=4G"
root@bigjelly:/var/crash# ls 202307201513/
dmesg.202307201513 dump.202307201513
root@bigjelly:/var/crash#

2)
On a jammy machine with 4G of memory, installed kexec-tools and kernel 5.15 from proposed and triggered a crash. Crashdump file is generated successfully.

root@smalljelly:/var/crash# uname -rv
5.15.0-1043-azure #50-Ubuntu SMP Tue Jul 18 19:20:09 UTC 2023
root@smalljelly:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.22-2ubuntu2.22.04.1 arm64 tools to support fast kexec reboots
root@smalljelly:/var/crash# cat /etc/default/grub.d/
40-force-partuuid.cfg 50-cloudimg-settings.cfg init-select.cfg kdump-tools.cfg
root@smalljelly:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=320M"
root@smalljelly:/var/crash# ls 202307210759/
dmesg.202307210759 dump.202307210759
root@smalljelly:/var/crash#

# VERIFICATION FOCAL kexec-tools & kernel 5.4

For this set of verifications we will test the kexec-tools in -proposed with the 5.4 kernel.
The 5.4 kernel will not work in cases where the crashkernel need to be allocated in both low and high memory because we have not patched it.
Therefore the tests are done only on a test machine with little memory.
The purpose is to confirm that kexec-tools in -proposed does not introduce regressions.

1)
Not applicable.

2)

On a focal machine with 4G of memory, running 5.4 kernel installed kexec-tools from proposed and triggered a crash. Crashdump file is generated successfully.

root@smallfossa:/var/crash# uname -rv
5.4.0-1113-azure #119-Ubuntu SMP Wed Jul 19 16:08:59 UTC 2023
root@smallfossa:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.18-1ubuntu1.1 arm64 tools to support fast kexec reboots
root@smallfossa:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=320M"
root@smallfossa:/var/crash# ls 202307241318/
dmesg.202307241318 dump.202307241318
root@smallfossa:/var/crash#

# VERIFICATION FOCAL kexec-tools & hwe kernel 5.15

For this set of verification we test both kexec-tools and kernel 5.15 from proposed..

1)
On a focal machine with 184G of memory, installed kexec-tools and hwe kernel 5.15 from proposed and triggered a crash. Crashdump file is generated successfully.

root@bigfossa:/var/crash# uname -rv
5.15.0-1043-azure #50~20.04.1-Ubuntu SMP Wed Jul 19 16:39:01 UTC 2023
root@bigfossa:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.18-1ubuntu1.1 arm64 tools to support fast kexec reboots
root@bigfossa:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=4G"
root@bigfossa:/var/crash# ls 202307211020/
dmesg.202307211020 dump.202307211020
root@bigfossa:/var/crash#

2)
On a jammy machine with 4G of memory, installed kexec-tools and hwe kernel 5.15 from proposed and triggered a crash. Crashdump file is generated successfully.

root@smallfossa:/var/crash# uname -rv
5.15.0-1043-azure #50~20.04.1-Ubuntu SMP Wed Jul 19 16:39:01 UTC 2023
root@smallfossa:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.18-1ubuntu1.1 arm64 tools to support fast kexec reboots
root@smallfossa:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=320M"
root@smallfossa:/var/crash# ls 202307241309/
dmesg.202307241309 dump.202307241309
root@smallfossa:/var/crash#

The verification of the Stable Release Update for kexec-tools has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package kexec-tools - 1:2.0.22-2ubuntu3.1

---------------
kexec-tools (1:2.0.22-2ubuntu3.1) lunar; urgency=medium

  * Support more than one crash kernel regions for arm64 (LP: #2024479)
    - d/p/lp2024479-arm64-support-more-than-one-crash-kernel-regions.patch

 -- Ioanna Alifieraki <email address hidden> Mon, 03 Jul 2023 15:28:52 +0300

This bug was fixed in the package kexec-tools - 1:2.0.22-2ubuntu2.22.04.1

---------------
kexec-tools (1:2.0.22-2ubuntu2.22.04.1) jammy; urgency=medium

  * Support more than one crash kernel regions for arm64 (LP: #2024479)
    - d/p/lp2024479-arm64-support-more-than-one-crash-kernel-regions.patch

 -- Ioanna Alifieraki <email address hidden> Mon, 03 Jul 2023 15:34:26 +0300

This bug was fixed in the package kexec-tools - 1:2.0.18-1ubuntu1.1

---------------
kexec-tools (1:2.0.18-1ubuntu1.1) focal; urgency=medium

  * Support more than one crash kernel regions for arm64 (LP: #2024479)
    - d/p/lp2024479-0001-util_lib-Add-functionality-to-read-elf-notes.patch
    - d/p/lp2024479-0002-arm64-Add-support-to-read-PHYS_OFFSET-from-kcore-pt_.patch
    - d/p/lp2024479-0003-kexec-add-variant-helper-functions-for-handling-memo.patch
    - d/p/lp2024479-0004-arm64-kexec-allocate-memory-space-avoiding-reserved-.patch
    - d/p/lp2024479-0005-arm64-kdump-deal-with-a-lot-of-resource-entries-in-p.patch
    - d/p/lp2024479-0006-arm64-support-more-than-one-crash-kernel-regions.patch

 -- Ioanna Alifieraki <email address hidden> Mon, 03 Jul 2023 16:29:58 +0300

The kernel changes are Fix Committed in the Azure kernel packages,
and should land slightly earlier than the Generic kernel packages.

linux-azure (5.15.0-1043.50) jammy-proposed
linux-azure-5.15 (5.15.0-1043.50~20.04.1) focal-proposed

linux-azure (5.15.0-1044.51) jammy; urgency=medium
...
  * kdump fails on big arm64 systems when offset is not specified (LP: #2024479)

This bug is awaiting verification that the linux/5.15.0-83.92 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux' to 'verification-done-jammy-linux'. If the problem still exists, change the tag 'verification-needed-jammy-linux' to 'verification-failed-jammy-linux'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

# VERIFICATION JAMMY - Generic kernel 5.15

Here we verify the generic (-ga) 5.15 kernel on amd64 architecture.
Verification for the arm64 has already been done in comments #26 and #28 using the -azure kernels.
Although the patches of this SRU regard arm64, this verificatrion on amd64 confirms that no regressions are introduced.

1)
On a jammy machine with 128G of memory, installed kernel 5.15.0-83-generic from proposed and triggered a crash. Crashdump file is generated successfully.

root@eckert:/var/crash# uname -rv
5.15.0-83-generic #92-Ubuntu SMP Mon Aug 14 09:30:42 UTC 2023
root@eckert:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.22-2ubuntu2.22.04.2 amd64 tools to support fast kexec reboots
root@eckert:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=4G"
root@eckert:/var/crash# ls 202308181121/
dmesg.202308181121 dump.202308181121
root@eckert:/var/crash#

2)
On a jammy machine with 4G of memory, installed kernel 5.15.0-83-generic from proposed and triggered a crash. Crashdump file is generated successfully.

root@z-rotomvm15:/var/crash# uname -rv
5.15.0-83-generic #92-Ubuntu SMP Mon Aug 14 09:30:42 UTC 2023
root@z-rotomvm15:/var/crash# dpkg -l | grep kexec-tools
ii kexec-tools 1:2.0.22-2ubuntu2.22.04.2 amd64 tools to support fast kexec reboots
root@z-rotomvm15:/var/crash# cat /etc/default/grub.d/kdump-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=320M"
root@z-rotomvm15:/var/crash# ls 202308181153/
dmesg.202308181153 dump.202308181153
root@z-rotomvm15:/var/crash#

This bug was fixed in the package linux-hwe-5.15 - 5.15.0-83.92~20.04.1

---------------
linux-hwe-5.15 (5.15.0-83.92~20.04.1) focal; urgency=medium

  * focal/linux-hwe-5.15: 5.15.0-83.92~20.04.1 -proposed tracker (LP: #2030420)

  [ Ubuntu: 5.15.0-83.92 ]

  * jammy/linux: 5.15.0-83.92 -proposed tracker (LP: #2031132)
  * libgnutls report "trap invalid opcode" when trying to install packages over
    https (LP: #2031093)
    - [Config]: disable CONFIG_GDS_FORCE_MITIGATION

  [ Ubuntu: 5.15.0-81.90 ]

  * jammy/linux: 5.15.0-81.90 -proposed tracker (LP: #2030422)
  * Packaging resync (LP: #1786013)
    - [Packaging] resync update-dkms-versions helper
    - [Packaging] resync getabis
    - debian/dkms-versions -- update from kernel-versions (main/2023.08.07)
  * CVE-2022-40982
    - x86/mm: Initialize text poking earlier
    - x86/mm: fix poking_init() for Xen PV guests
    - x86/mm: Use mm_alloc() in poking_init()
    - mm: Move mm_cachep initialization to mm_init()
    - init: Provide arch_cpu_finalize_init()
    - x86/cpu: Switch to arch_cpu_finalize_init()
    - ARM: cpu: Switch to arch_cpu_finalize_init()
    - sparc/cpu: Switch to arch_cpu_finalize_init()
    - um/cpu: Switch to arch_cpu_finalize_init()
    - init: Remove check_bugs() leftovers
    - init: Invoke arch_cpu_finalize_init() earlier
    - init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()
    - x86/init: Initialize signal frame size late
    - x86/fpu: Remove cpuinfo argument from init functions
    - x86/fpu: Mark init functions __init
    - x86/fpu: Move FPU initialization into arch_cpu_finalize_init()
    - x86/xen: Fix secondary processors' FPU initialization
    - x86/speculation: Add Gather Data Sampling mitigation
    - x86/speculation: Add force option to GDS mitigation
    - x86/speculation: Add Kconfig option for GDS
    - KVM: Add GDS_NO support to KVM
    - Documentation/x86: Fix backwards on/off logic about YMM support
    - [Config]: Enable CONFIG_ARCH_HAS_CPU_FINALIZE_INIT and
      CONFIG_GDS_FORCE_MITIGATION
  * CVE-2023-3609
    - net/sched: cls_u32: Fix reference counter leak leading to overflow
  * CVE-2023-21400
    - io_uring: ensure IOPOLL locks around deferred work
  * CVE-2023-4015
    - netfilter: nf_tables: add NFT_TRANS_PREPARE_ERROR to deal with bound
      set/chain
    - netfilter: nf_tables: unbind non-anonymous set if rule construction fails
    - netfilter: nf_tables: skip immediate deactivate in _PREPARE_ERROR
  * CVE-2023-3995
    - netfilter: nf_tables: disallow rule addition to bound chain via
      NFTA_RULE_CHAIN_ID
  * CVE-2023-3777
    - netfilter: nf_tables: skip bound chain on rule flush
  * losetup with mknod fails on jammy with kernel 5.15.0-69-generic
    (LP: #2015400)
    - loop: do not enforce max_loop hard limit by (new) default
  * Include the MAC address pass through function on RTL8153DD-CG (LP: #2020295)
    - r8152: add USB device driver for config selection
  * Jammy update: v5.15.116 upstream stable release (LP: #2029401)
    - RDMA/bnxt_re: Fix the page_size used during the MR creation
    - RDMA/efa: Fix unsupported page sizes in device
    - RDMA/hns: Fix base address table allocation
    - RDMA/hns:...

This bug is awaiting verification that the linux-nvidia-tegra/5.15.0-1017.17 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-nvidia-tegra' to 'verification-done-jammy-linux-nvidia-tegra'. If the problem still exists, change the tag 'verification-needed-jammy-linux-nvidia-tegra' to 'verification-failed-jammy-linux-nvidia-tegra'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the linux-intel-iotg/5.15.0-1039.45 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-intel-iotg' to 'verification-done-jammy-linux-intel-iotg'. If the problem still exists, change the tag 'verification-needed-jammy-linux-intel-iotg' to 'verification-failed-jammy-linux-intel-iotg'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the linux-riscv-5.15/5.15.0-1041.45~20.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal-linux-riscv-5.15' to 'verification-done-focal-linux-riscv-5.15'. If the problem still exists, change the tag 'verification-needed-focal-linux-riscv-5.15' to 'verification-failed-focal-linux-riscv-5.15'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the linux-raspi/5.15.0-1038.41 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-raspi' to 'verification-done-jammy-linux-raspi'. If the problem still exists, change the tag 'verification-needed-jammy-linux-raspi' to 'verification-failed-jammy-linux-raspi'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the linux-nvidia-tegra-igx/5.15.0-1004.4 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-nvidia-tegra-igx' to 'verification-done-jammy-linux-nvidia-tegra-igx'. If the problem still exists, change the tag 'verification-needed-jammy-linux-nvidia-tegra-igx' to 'verification-failed-jammy-linux-nvidia-tegra-igx'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the linux-nvidia-tegra-5.15/5.15.0-1017.17~20.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal-linux-nvidia-tegra-5.15' to 'verification-done-focal-linux-nvidia-tegra-5.15'. If the problem still exists, change the tag 'verification-needed-focal-linux-nvidia-tegra-5.15' to 'verification-failed-focal-linux-nvidia-tegra-5.15'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug has been fixed in Jammy, but not yet marked Fix Released apparently due to an issue with the Launchpad bot (reported to the Launchpad team); leaving as Fix Committed so to trigger when the bot runs again for it.

linux (5.15.0-83.92) jammy; urgency=medium

  * kdump fails on big arm64 systems when offset is not specified (LP: #2024479)
    - arm64: mm: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
    - arm64: kdump: Reimplement crashkernel=X
    - docs: kdump: Update the crashkernel description for arm64
    - arm64: kdump: Do not allocate crash low memory if not needed
    - arm64/mm: Define defer_reserve_crashkernel()
    - arm64: kdump: Provide default size when crashkernel=Y, low is not specified
    - arm64: kdump: Support crashkernel=X fall back to reserve region above DMA
      zones

That is also reflected in linux-hwe, see comment #37:
> This bug was fixed in the package linux-hwe-5.15 - 5.15.0-83.92~20.04.1

This bug is awaiting verification that the linux-xilinx-zynqmp/5.15.0-1024.28 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-xilinx-zynqmp' to 'verification-done-jammy-linux-xilinx-zynqmp'. If the problem still exists, change the tag 'verification-needed-jammy-linux-xilinx-zynqmp' to 'verification-failed-jammy-linux-xilinx-zynqmp'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the linux-mtk/5.15.0-1030.34 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-mtk' to 'verification-done-jammy-linux-mtk'. If the problem still exists, change the tag 'verification-needed-jammy-linux-mtk' to 'verification-failed-jammy-linux-mtk'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!