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Commit 641f1456 authored by Silas Boyd-Wickizer's avatar Silas Boyd-Wickizer Committed by Jean Delvare
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hwmon: (coretemp) Use get_online_cpus to avoid races involving CPU hotplug



coretemp_init loops with for_each_online_cpu, adding platform_devices
and sysfs interfaces, then calls register_hotcpu_notifier.  There is a
race if a CPU is offlined or onlined after the loop, but before
register_hotcpu_notifier.  The race might result in the absence of a
platform_device+sysfs interface for an online CPU, or the presence of
a platform_device+sysfs interface for an offline CPU.  A similar race
occurs during coretemp_exit, after the module calls
unregister_hotcpu_notifier, but before it unregisters all devices, a
CPU might offline and a device for an offline CPU will exist for a
short while.

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: default avatarSilas Boyd-Wickizer <sbw@mit.edu>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 1ec3ddfd
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