IBM Support

Kdump over NFS fails when configured over an SR-IOV device

Flashes (Alerts)


Abstract

If the kdump is configured over Network File System (NFS) by using a single root I/O virtualization (SR-IOV) device, then the kdump transfer to the destination NFS server fail if the system crashes.

Content

Linux Releases Affected
Red Hat Enterprise Linux (RHEL) 8.x for Power LE
RHEL 9.x for Power LE

SUSE Linux Enterprise Server (SLES) 15

IBM Systems Affected

Linux logical partitions that run on any PowerVM based POWER9 or Power10 system.

Symptoms

If the system crashes, then the kdump is collected successfully but the kdump is not transferred to the destination server. In such a case the following message is displayed on the console:

[  288.801079] kdump.sh[508]: mount.nfs: No route to host
[  288.807869] kdump[562]: failed to dump to "/kdumproot/mnt", it's not a mount point!
[  288.812740] kdump[564]: saving vmcore failed
Workaround
The following workaround can be used when the kdump is configured over an SR-IOV device:
  1. Enable the disable_ddw for the kernel boot parameters by using the following grub command:
    grubby --args="disable_ddw" --update-kernel=/boot/vmlinuz-`uname -r`
  2. Reboot the logical partition (LPAR).
  3. Verify if the kernel command line is set with the disable_ddw parameter by using the following 
command:
    cat /proc/cmdline
  4. Verify if the DDW is disabled correctly by using the following command: 
    dmesg | grep create-pe
echo $?
1
Fix Outlook

IBM is working to include a fix in a future Red Hat and SUSE update.

I/O device impacted

SR-IOV logical port that is assigned to a Linux logical partition.

[{"Type":"MASTER","Line of Business":{"code":"LOB26","label":"Storage"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SGMV157","label":"IBM Support for Red Hat Enterprise Linux Server"},"ARM Category":[{"code":"a8m0z000000Gnl7AAC","label":"Red Hat Enterprise Linux"},{"code":"a8m0z000000GnlCAAS","label":"SUSE Linux Enterprise Server"}],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"All Versions"}]

Document Information

Modified date:
16 November 2023

UID

ibm17046948

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