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
policy<{'arm64-generic-64k': 'n'}>
jammy:
$ 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', 'arm64-lowlatency-64k': 'n'}>
focal:
$ 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'}>
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to kexec-tools in Ubuntu.
https://bugs.launchpad.net/bugs/2024479
Title:
kdump fails on big arm64 systems when offset is not specified
Status in kexec-tools package in Ubuntu:
Fix Released
Status in linux package in Ubuntu:
Invalid
Status in linux-hwe-5.15 package in Ubuntu:
Invalid
Status in kexec-tools source package in Focal:
In Progress
Status in linux source package in Focal:
Won't Fix
Status in linux-hwe-5.15 source package in Focal:
In Progress
Status in kexec-tools source package in Jammy:
In Progress
Status in linux source package in Jammy:
In Progress
Status in linux-hwe-5.15 source package in Jammy:
Invalid
Status in kexec-tools source package in Kinetic:
Won't Fix
Status in linux source package in Kinetic:
Won't Fix
Status in linux-hwe-5.15 source package in Kinetic:
Invalid
Status in kexec-tools source package in Lunar:
In Progress
Status in kexec-tools source package in Mantic:
Fix Released
Bug description:
[Impact]
kdump fails on arm64, on machines with a lot of memory when offset is not
specified,
e.g when /etc/default/grub.d/kdump-tools.cfg looks like:
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=4G"
If kdump-tools.cfg specifies the offset e.g.:
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=4G@4G"
it works ok.
The reason for this is that the kernel needs to allocate memory for the
crashkernel both
in low and high memory.
This is addressed in kernel 6.2.
In addition kexec-tools needs to support more than one crash kernel region.
[Fix]
To address this issue the following upstream commits are needed:
- From the kernel side:
commit a9ae89df737756d92f0e14873339cf393f7f7eb0
Author: Zhen Lei <thunder.leiz...@huawei.com>
Date: Wed Nov 16 20:10:44 2022 +0800
arm64: kdump: Support crashkernel=X fall back to reserve region
above DMA zones
commit a149cf00b158e1793a8dd89ca492379c366300d2
Author: Zhen Lei <thunder.leiz...@huawei.com>
Date: Wed Nov 16 20:10:43 2022 +0800
arm64: kdump: Provide default size when crashkernel=Y,low is not
specified
- From kexec-tools:
commit b5a34a20984c4ad27cc5054d9957af8130b42a50
Author: Chen Zhou <chenzho...@huawei.com>
Date: Mon Jan 10 18:20:08 2022 +0800
arm64: support more than one crash kernel regions
Affected releases:
Jammy, Focal, Bionic
For Bionic we won't fix it as we need to backport a lot of code and the
regression potential is too high.
The same applies for the Focal 5.4 kernel.
Only the Focal 5.15 hwe kernel (from Jammy) will be fixed.
[Test Plan]
You need an arm64 machine (can be a VM too) with large memory e.g. 128G.
Install linux-crashdump, configure the crash kernel size, and trigger a crash.
- Failing scenario (crashkernel >= 4G, without offset "@<address>"):
It won't work unless the offset is specified because the memory
crashkernel cannot be allocated.
With the patches applied it works as expected without having to
specify the offset.
- Working scenario (crashkernel < 4G, e.g., 'crashkernel=1G')
This must continue to work with the new patches (ie, no regressions),
including patched kexec-tools on unpatched kernel (eg, 5.4 kernel on
Focal).
[Regression Potential]
KERNEL 5.15 - Jammy (and Focal via the HWE kernel):
To address this problem in the 5.15 kernel we need to pull in 7 commits (see
[Other] section for details.
All the commits are changing code only for arm64 architecture and only the
code related to reserving the crashkernel.
This means that any regression potential will affect only the arm64
architecture and in particular the crash/kdump functionality.
However, since the reservation of the crashkernel occurs at boot up,
potentially things could go wrong there as well.
kexec-tools - FOCAL:
To fix the kexec_tools in focal we need to pull in 6 commits (see [Other
section for details]). They all cherry pick.
Four out of six commits touch only arm64 code. Any regression potential
because of these commits would regard either crashdump or kexec functionality.
Commit cf977b1af9ec67fab adds code without altering current functionality.
Commit f4ce0706d9574aecb7 adds functionality to read elf notes. In practive
it moves the code from vmcore-dmesg.c to elf_info.c so it can be used by other
features.
kexec-tools - JAMMY, LUNAR, MANTIC:
Commit b5a34a20984c is pulled in, it cherry-picks. It changes only
arm64 code. It enables kexec to recognise that the reserved kernel may
use more than one kernel region. Things could go worng when gatherinng
a crashdump.
[Other]
Commits to backport
- MANTIC:
kernel 6.3: not affected
kexec-tools:
b5a34a20984c4ad27cc5054d9957af8130b42a50 arm64: support more than one
crash kernel regions
- LUNAR:
kernel 6.2: not affected
kexec-tools:
b5a34a20984c4ad27cc5054d9957af8130b42a50 arm64: support more than one
crash kernel regions
- KINETIC: WON'T FIX
Kinetic won't be fixed as it is EOL soon.
- JAMMY:
kernel (5.15 kernel):
a9ae89df737756d92f0e14873339cf393f7f7eb0 arm64: kdump: Support
crashkernel=X fall back to reserve region above DMA zones
a149cf00b158e1793a8dd89ca492379c366300d2 arm64: kdump: Provide default
size when crashkernel=Y,low is not specified
4890cc18f94979b406f95708f8cb238eb2d0e5a9 arm64/mm: Define
defer_reserve_crashkernel()
8f0f104e2ab6eed4cad3b111dc206f843bda43ea arm64: kdump: Do not allocate
crash low memory if not needed
5832f1ae50600ac6b2b6d00cfef42d33a9473f06 docs: kdump: Update the
crashkernel description for arm64
944a45abfabc171fd121315ff0d5e62b11cb5d6f arm64: kdump: Reimplement
crashkernel=X
d339f1584f0acf32b32326627fa3b48e6e65c599 arm64: mm: use
IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
kexec-tools:
b5a34a20984c4ad27cc5054d9957af8130b42a50 arm64: support more than
one crash kernel regions
- FOCAL:
Kernel 5.4: Won't fix because of high regression potential.
Kernel 5.15 (HWE): Fixed via Jammy.
kexec-tools:
b5a34a20984c4ad27cc5054d9957af8130b42a50 arm64: support more than one
crash kernel regions
2572b8d702e452624bdb8d7b7c39f458e7dcf2ce arm64: kdump: deal with a lot of
resource entries in /proc/iomem
cf977b1af9ec67fabcc6a625589c49c52d07b11d kexec: add variant helper
functions for handling memory regions
f736104f533290b4ce6fbfbca74abde9ffd3888c arm64: kexec: allocate memory
space avoiding reserved regions
64c49f27d88024eaab990d2cd6069289cf853098 arm64: Add support to read
PHYS_OFFSET from 'kcore' - pt_note or pt_load (if available)
f4ce0706d9574aecb7d4aa9af7208a1bc9b6afb4 util_lib: Add functionality to
read elf notes
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