From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx124.postini.com [74.125.245.124]) by kanga.kvack.org (Postfix) with SMTP id 141A46B005D for ; Sun, 4 Nov 2012 10:24:35 -0500 (EST) Received: by mail-pa0-f41.google.com with SMTP id fa10so3709616pad.14 for ; Sun, 04 Nov 2012 07:24:34 -0800 (PST) From: Jiang Liu Subject: [ACPIHP PATCH part4 3/9] ACPIHP/processor: protect accesses to device->driver_data Date: Sun, 4 Nov 2012 23:23:56 +0800 Message-Id: <1352042642-7306-4-git-send-email-jiang.liu@huawei.com> In-Reply-To: <1352042642-7306-1-git-send-email-jiang.liu@huawei.com> References: <1352042642-7306-1-git-send-email-jiang.liu@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Rafael J . Wysocki" , Yinghai Lu , Tony Luck , Yasuaki Ishimatsu , Wen Congyang , Tang Chen , Taku Izumi , Bjorn Helgaas Cc: Jiang Liu , Kenji Kaneshige , Huang Ying , Bob Moore , Len Brown , "Srivatsa S . Bhat" , Yijing Wang , Hanjun Guo , Jiang Liu , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org 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 --- drivers/acpi/processor_driver.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index 28add34..7d6d794 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; } + get_online_cpus(); acpi_processor_stop(device, pr); acpi_processor_unlink(device, pr); + put_online_cpus(); free: device->driver_data = NULL; -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org