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

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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>

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This commit is contained in:

Prarit Bhargava 2009-12-09 13:36:45 -05:00 • committed by H. Peter Anvin

parent 9cf7826743

commit ebb682f522

1 changed files with 7 additions and 6 deletions

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arch/x86/kernel/cpu/intel_cacheinfo.c

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