tree ff8ebb34f17ec3c3d445857be9da7fd35f4579a0
parent 9cf7826743e5c78dcfcfdc99d17f79ce6d3a2942
author Prarit Bhargava <prarit@redhat.com> 1260383805 -0500
committer H. Peter Anvin <hpa@zytor.com> 1260494343 -0800

x86, AMD: Fix stale cpuid4_info shared_map data in shared_cpu_map cpumasks

The per_cpu cpuid4_info shared_map can contain stale data when CPUs are added
and removed.

The stale data can lead to a NULL pointer derefernce panic on a remove of a
CPU that has had siblings previously removed.

This patch resolves the panic by verifying a cpu is actually online before
adding it to the shared_cpu_map, only examining cpus that are part of
the same lower level cache, and by updating other siblings lowest level cache
maps when a cpu is added.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
LKML-Reference: <20091209183336.17855.98708.sendpatchset@prarit.bos.redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>