x86, hotplug: Serialize CPU hotplug to avoid bringup concurrency issues

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When testing cpu hotplug code on 32-bit we kept hitting the "CPU%d:
Stuck ??" message due to multiple cores concurrently accessing the
cpu_callin_mask, among others.

Since these codepaths are not protected from concurrent access due to
the fact that there's no sane reason for making an already complex
code unnecessarily more complex - we hit the issue only when insanely
switching cores off- and online - serialize hotplugging cores on the
sysfs level and be done with it.

[ v2.1: fix !HOTPLUG_CPU build ]

Cc: <stable@kernel.org>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100819181029.GC17171@aftab>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

...

This commit is contained in:

Borislav Petkov 2010-08-19 20:10:29 +02:00 • committed by H. Peter Anvin

parent 8848a91068

commit d7c53c9e82

2 changed files with 24 additions and 0 deletions

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5

arch/x86/Kconfig

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19

arch/x86/kernel/smpboot.c

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