CPU hotplug notification handler acpi_cpu_soft_notify() and driver unbind method acpi_processor_remove() may be concurrently called. acpi_cpu_soft_notify() will access device->driver_data, but that data structure may be destroyed by acpi_processor_remove(). On the other hand, acpi_cpu_soft_notify() is always called under protection of get_online_cpus(), so use get_online_cpus() to serialize all accesses and modifications to device->driver_data. Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx> --- drivers/acpi/processor_driver.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index 4f2fec0..110c5ac 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -616,6 +616,8 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device) return 0; BUG_ON((pr->id >= nr_cpu_ids) || (pr->id < 0)); + /* block CPU online/offline operations */ + get_online_cpus(); result = acpi_processor_link(device, pr); if (result) goto err_unlock; @@ -624,6 +626,7 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device) if (result) goto err_unlink; } + put_online_cpus(); return 0; @@ -654,8 +657,10 @@ static int acpi_processor_remove(struct acpi_device *device, int type) return -EINVAL; } - acpi_processor_stop(device, pr); + get_online_cpus(); + acpi_processor_stop(pr); acpi_processor_unlink(device, pr); + put_online_cpus(); free: device->driver_data = NULL; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
