hwmon: (via-cputemp) Use get_online_cpus to avoid races involving CPU hotplug
authorSilas Boyd-Wickizer <sbw@mit.edu>
Sun, 23 Sep 2012 18:27:32 +0000 (20:27 +0200)
committerJean Delvare <khali@endymion.delvare>
Sun, 23 Sep 2012 18:27:32 +0000 (20:27 +0200)
commit1ec3ddfd27a77db55b8c0e80bcd27c656473fb96
treea23e97b565f6618f008244da29cea7a4e1a4b239
parente5e77cf9f9a275083f9a365a20d956fa8a67803e
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 <sbw@mit.edu>
Acked-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
drivers/hwmon/via-cputemp.c