crash fails with "crash: page excluded: kernel virtual address"

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Environment

SUSE Linux Enterprise Server 12 SP3

Situation

The issue affects PowerPC (ppc64le) using fadump.

Trying to analyze a kernel core with "crash" results in the following error:

This GDB was configured as "powerpc64le-unknown-linux-gnu"...

crash: page excluded: kernel virtual address: c00008f83fb535d0  type: "first list entry"

Resolution

Workaround:

Stopping and starting kdump.service helps:

# systemctl stop kdump.service

# systemctl start kdump.service

The kernel update to kernel version 4.4.156-94.64.1 released October 2018 includes the patch to automatically re-register fadump, if it was already registered.

With kernel versions prior to this, the workaround can be used.

The kdump update, kdump-0.8.16-7.22.1 released January 2020 includes the patch to re-register fadump from userspace if the kernel can't re-register fadump.

Cause

After a DLPAR operation (memory hot add/remove), fadump has to be re-registered to update the crash memory ranges.

Current udev rules are not triggered appropriately to handle this automatically and lead to a failure in capturing the complete dump and crash reports the missing pages.

Disclaimer

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