Hot plugging/unplugging of pmem memory having a size that is not in multiples of a specific size can lead to kernel panics

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Environment

SUSE Linux Enterprise Server 15 Service Pack 1 (ppc64le)

POWER9 (ppc64le)

Virtual Persistent Memory (vPMEM) with PowerVM

Situation

Hot plugging/unplugging of pmem memory having a size that is not in multiples of the expected granularity can lead to kernel panics. On PPC64 this issue will usually manifest itself as a kernel panic seen when trying to create or destroy namespaces which sizes are not in multiples of 16MiB.

Resolution

To workaround this issue ensure that any namespaces created are in multiples of 16MiB.

Cause

The kernel memory hotplug subsystem expects the memory to be added in specific granularities, depending on the architecture.

Additional Information

Work is in progress to prevent creation of namespaces where sizes are not in multiples of 16MiB. Future versions of the SLES 15 SP1 kernel may roll out this update, however until then the workaround above should be used.

Disclaimer

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