[PATCH 0/2] Protect cpu map updates from ACPI processor

[Toshi Kani <toshi.kani@hp.com>]

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.

---
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(-)