Flashes (Alerts)
Abstract
In the FADump method, there is a possibility for the kernel dump (/proc/vmcore) to get corrupted if the memory that is reserved for FADump is less than the Logical Memory Block (LMB) size. For FADump to run without any errors, the LMB size must be less than the memory that is reserved for FADump. The minimum memory that is reserved for FADump is 320 MB. The firmware supported an LMB size of 256 MB previously. The possibility of a corrupted kernel dump did not occur earlier because the LMB size was less than the memory reserved for FADump. However, with the latest firmware that supports an LMB size of 1024 MB or more, the memory reservation for FADump becomes critical to avoid possible kernel dump corruption.
Content
All releases that support LMB size greater than 256MB
Power10 systems with LMB size support greater than 256MB
- Dump capture fails with the following traces:
open_dump_memory: Can't open the dump memory(/proc/vmcore). No such file or directory makedumpfile Failed. - The saved vmcore with crash-utility might report missing or unexpected data.
The minimum memory reservation for FADump must be equal to the LMB size that is supported. For
example, on a system with an LMB size of 4096 MB, you must reserve at least 4096 MB of memory for
FADump (even if the recommended reservation is less than 4096 MB).
You can reserve memory for FADump by using the following configuration:
fadump=on crashkernel=4096M
You can determine the LMB size of a given system by using the lsmem command.
Fix Outlook
Red hat Bug: 2233327
SUSE Bug: 1216253
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Document Information
Modified date:
20 October 2023
UID
ibm17047197