via_cputemp_init in drivers/hwmon/via-cputemp.c 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 <[email protected]> --- drivers/hwmon/via-cputemp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/hwmon/via-cputemp.c b/drivers/hwmon/via-cputemp.c index 8689664..54b01ac 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); } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
