hwmon: (via-cputemp) Use get_online_cpus to avoid races involving CPU hotplug
hwmon: (via-cputemp) Use get_online_cpus to avoid races involving CPU hotplug

via_cputemp_init loops with for_each_online_cpu, adding
platform_devices, then calls register_hotcpu_notifier.  If a CPU is
offlined between the loop and register_hotcpu_notifier, then later
onlined, via_cputemp_device_add will attempt to add platform devices
with the same ID.  A similar race occurs during via_cputemp_exit,
after the module calls unregister_hotcpu_notifier, a CPU might offline
and a device will exist for a CPU that is offline.

This fix surrounds for_each_online_cpu and register_hotcpu_notifier
with get_online_cpus+put_online_cpus; and surrounds
unregister_hotcpu_notifier and device unregistering with
get_online_cpus+put_online_cpus.

Build tested.

Signed-off-by: Silas Boyd-Wickizer <3f3722a52894bec8c1f7f11b3fcbcf1b6cd0f8a3@mit.edu>
Acked-by: Harald Welte <57a0f16bf14496e20d21dd8c0873142ff0a2fbb4@gnumonks.org>
Signed-off-by: Jean Delvare <49ad6a9f5aa17024c23048df346d55bda6837e01@linux-fr.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas