yast2 kdump error when updating grub (only on PowerPC configuring fadump)

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Environment

SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3)

Situation

The issue affects only PowerPC (ppc64le) using 'fadump=on'.

Using 'yast2 kdump' to edit the settings is causing an 'Internal error' on 'OK' and 'save':

YaST2 - kdump @ linux

 Initializing kdump Configurationx   

  Reading the config file...
  =>  Reading kernel boot options...
  -   Calculating memory limits...
????????????????????????????????????????????????????????????????????????????????
?Error                                                                         ?
?Execution of command "[["/usr/sbin/grub2-install", "--target=powerpc-ieee1275"?
?Exit code: 1                                                                  ?
?Error output: Installing for powerpc-ieee1275 platform.                       ?
?/usr/sbin/grub2-install: error: the chosen partition is not a PReP partition. ?
?                                                                              ?
?                                     [OK]                                     ?
????????????????????????????????????????????????????????????????????????????????

or

????????????????????????????????????????????????????????????????????????????????
?Error                                                                         ?
?Internal error. Please report a bug report with logs.                         ?
?Run save_y2logs to get complete logs.                                         ?
?Details: Invalid loader device /dev/disk/by-id/dm-uuid-part1-mpath-1IBM_IPR-10?
?Caller:  /usr/share/YaST2/lib/bootloader/mbr_update.rb:200:in `partition_to_ac?
?                                                                              ?
?                                     [OK]                                     ?
????????????????????????????????????????????????????????????????????????????????

Notice the "Invalid loader device /dev/disk/by-id/dm-uuid-part1-mpath-1IBM_IPR-10_58C7ED0000000040" in the second error output.

The device is read from the /etc/default/grub_installdevice but 'YaST/libstorage' doesn't know about the device.

Resolution

The kdump update, kdump-0.8.16-7.8.1 released July/2018 includes the patch to avoid rewriting /etc/default/grub_installdevice when using 'yast2 kdump'.

The yast2-bootloader-3.2.27.1-2.6.4 and libstorage-2.26.12.2-3.3.2 update released August/2018 includes the fix correcting how udev ids with dm-uuid-names were handled.

Until the update can be installed, the below workaround, editing the /etc/default/grub_installdevice, can be used.

Workaround:

After installing the kdump update and before using 'yast2 kdump', the content of the /etc/default/grub_installdevice needs to be reviewed.

If the /etc/default/grub_installdevice was already overwritten with the incorrect symlink/udev id, that /dev/disk/by-id/<symlink> needs to be changed.

# cat /etc/default/grub_installdevice

If it contains a symlink looking like this:

/dev/disk/by-id/*-partN-mpath-* ,

the symlink needs to be changed, setting -partN- at the end and preferably using the scsi- or wwn- ID, so it looks like this:

/dev/disk/by-id/scsi-*-partN or /dev/disk/by-id/wwn-*-partN.

For example:

# cat /etc/default/grub_installdevice

/dev/disk/by-id/dm-uuid-part1-mpath-1IBM_IPR-10_58C7ED0000000040

activate

This is incorrect and the symlink needs to be changed to either the scsi- or wwn- symlink and look like this:

# cat /etc/default/grub_installdevice

/dev/disk/by-id/scsi-1IBM_IPR-10_58C7ED0000000040-part1

activate

or when using the wwn-<ID>-part1 for that device like this:

# cat /etc/default/grub_installdevice

/dev/disk/by-id/wwn-0xIBM_IPR-10_58C7ED0000000040-part1

activate

The udev IDs are listed in the /dev/disk/by-id directory.

# ls -l /dev/disk/by-id/

will show all names for the mapped device dm-X, (the device grub is installed on). Search for the device's specific ID already set in the /etc/default/grub_installdevice in the /dev/disk/by-id/ line.

Then by looking at the content of /dev/disk/by-id, the other symlinks for the same LUN can be seen.

Either the scsi- or wwn- symlink for that ID can be selected to update the /etc/default/grub_installdevice /dev/disk/by-id/ with.

The symlink can be changed in the file directly with a text editor or by writing on a terminal to it:

# cat >/etc/default/grub_installdevice <<EOD

> /dev/disk/by-id/scsi-1IBM_IPR-10_58C7ED0000000040-part1

> activate
> EOD

Once the "/dev/disk/by-id/" was changed accordingly, "yast2 kdump" can be used to configure fadump.

Cause

If 'fadump=on' is set, kdump calls perl-Bootloader to update and rewrites the configuration files including /etc/default/grub_installdevice.

It then takes the first by-id symlink in unspecified order which can result in a symlink of the unexpected dm-uuid-part1-mpath-* form, which is wrong in this case.

Additional Information

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