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SubjectRe: [PATCH 0/2] Protect cpu map updates from ACPI processor
Date
On Monday, August 12, 2013 09:45:52 AM Toshi Kani wrote:
> CPU system maps are protected with reader/writer locks. The reader
> lock, put_online_cpus(), assures that the maps are not updated while
> holding the lock. The writer lock, cpu_hotplug_begin(), is used to
> udpate the cpu maps along with cpu_maps_update_begin().
>
> However, the ACPI processor handler updates the cpu maps without
> holding the the writer lock. This patchset fixes this problem.
>
> ---
> The patchset is based on linux-next of the pm tree.

Basically looks OK to me, but I'd just merge the patches together,
because the [2/2] is the very reason for the change made by [1/2].

Also it would be good to mention the actual scenario that may lead
to problems with that.

Thanks,
Rafael


> ---
> Toshi Kani (2):
> CPU hotplug: Export cpu_hotplug_begin() interface
> ACPI: Acquire writer lock to update cpu maps
>
> ---
> drivers/acpi/acpi_processor.c | 21 ++++++++++++++++-----
> include/linux/cpu.h | 2 ++
> kernel/cpu.c | 4 ++--
> 3 files changed, 20 insertions(+), 7 deletions(-)
>
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--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.


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