[Ubuntu-24.04] FADump with recommended crash size is making the L1 hang
Affects | Status | Importance | Assigned to | Milestone | ||
---|---|---|---|---|---|---|
The Ubuntu-power-systems project |
In Progress
|
High
|
Patricia Domingues | |||
linux (Ubuntu) | Status tracked in Oracular | |||||
Noble |
In Progress
|
Undecided
|
Unassigned | |||
Oracular |
Fix Committed
|
Undecided
|
Unassigned |
Bug Description
SRU Justification:
[Impact]
* L1 host hangs when triggering FADump that results in crash
[Fix]
* 353d7a84c214f18
[Test Case]
* Have a Ubuntu Server 24.04 LTS installation on ppc64el.
* Enable FADump with 1GB: fadump=on crashkernel=1024M
* A kernel panic will happen when dump got triggered
[Regression Potential]
* There is a certain risk of a regression, but it is mapping only the memory
allocated for KFENCE pool at page granularity, reducing memory consumption
when KFENCE is used.
* On top the commit is already upstream reviewed and accepted.
* The modifications were done and tested by IBM.
* The fadump feature is supported only on IBM POWER systems.
[Other]
* The fix/commit got upstream accepted with kernel v6.11-rc4,
hence Oracular (with a planned kernel of 6.11) is not affected.
.......
Problem description :
=======
Triggered FADump with the recommended crash. L1 host got hung.
As per the public document https:/
root@ubuntu2404:~# uname -ar
Linux ubuntu2404 6.8.0-11-generic #11-Ubuntu SMP Wed Feb 14 00:33:03 UTC 2024 ppc64le ppc64le ppc64le GNU/Linux
root@ubuntu2404:~# free -h
Mem: 48Gi 1.7Gi 46Gi 13Mi 687Mi 46Gi
Swap: 8.0Gi 0B 8.0Gi
root@ubuntu2404:~# cat /proc/cmdline
BOOT_IMAGE=
root@ubuntu2404:~# dmesg | grep -i reser
[ 0.000000] fadump: Reserved 1024MB of memory at 0x00000040000000 (System RAM: 51200MB)
[ 0.000000] fadump: Initialized 0x40000000 bytes cma area at 1024MB from 0x40070000 bytes of memory reserved for firmware-assisted dump
[ 0.000000] Memory: 49316672K/52428800K available (23616K kernel code, 4096K rwdata, 25536K rodata, 8832K init, 2487K bss, 2063552K reserved, 1048576K cma-reserved)
[ 0.396408] ibmvscsi 30000066: Client reserve enabled
root@ubuntu2404:~# kdump-config show
DUMP_MODE: fadump
USE_KDUMP: 1
KDUMP_COREDIR: /var/crash
/var/
kdump initrd:
/var/
current state: ready to fadump
IBM is looking to update the crash kernel reservations section of the wiki for Power.
Changed in ubuntu-power-systems: | |
assignee: | nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) |
importance: | Undecided → High |
status: | New → Confirmed |
Changed in linux (Ubuntu): | |
assignee: | Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) → nobody |
description: | updated |
Changed in linux (Ubuntu Noble): | |
status: | New → Confirmed |
status: | Confirmed → In Progress |
Changed in linux (Ubuntu Oracular): | |
status: | Confirmed → Fix Committed |
Changed in ubuntu-power-systems: | |
status: | Confirmed → In Progress |
description: | updated |
Changed in ubuntu-power-systems: | |
assignee: | Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) → Patricia Domingues (patriciasd) |
Default Comment by Bridge