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| author |   Silas Boyd-Wickizer <sbw@mit.edu> | 2012-09-23 20:27:32 +0200 |
|---|---|---|
| committer |   Jean Delvare <khali@endymion.delvare> | 2012-09-23 20:27:32 +0200 |
| commit | 1ec3ddfd27a77db55b8c0e80bcd27c656473fb96 (patch) | |
| tree | a23e97b565f6618f008244da29cea7a4e1a4b239 | |
| parent | Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus (diff) | |
| download | linux-dev-1ec3ddfd27a77db55b8c0e80bcd27c656473fb96.tar.xz linux-dev-1ec3ddfd27a77db55b8c0e80bcd27c656473fb96.zip | |
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>
| -rw-r--r-- | drivers/hwmon/via-cputemp.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/hwmon/via-cputemp.c b/drivers/hwmon/via-cputemp.c index ee4ebc198a94..2e56c6ce9fb6 100644 --- a/drivers/hwmon/via-cputemp.c +++ b/drivers/hwmon/via-cputemp.c @@ -328,6 +328,7 @@ static int __init via_cputemp_init(void) if (err) goto exit; + get_online_cpus(); for_each_online_cpu(i) { struct cpuinfo_x86 *c = &cpu_data(i); @@ -347,12 +348,14 @@ static int __init via_cputemp_init(void) #ifndef CONFIG_HOTPLUG_CPU if (list_empty(&pdev_list)) { + put_online_cpus(); err = -ENODEV; goto exit_driver_unreg; } #endif register_hotcpu_notifier(&via_cputemp_cpu_notifier); + put_online_cpus(); return 0; #ifndef CONFIG_HOTPLUG_CPU @@ -367,6 +370,7 @@ static void __exit via_cputemp_exit(void) { struct pdev_entry *p, *n; + get_online_cpus(); unregister_hotcpu_notifier(&via_cputemp_cpu_notifier); mutex_lock(&pdev_list_mutex); list_for_each_entry_safe(p, n, &pdev_list, list) { @@ -375,6 +379,7 @@ static void __exit via_cputemp_exit(void) kfree(p); } mutex_unlock(&pdev_list_mutex); + put_online_cpus(); platform_driver_unregister(&via_cputemp_driver); } |