ACPI: processor: idle: Check acpi_fetch_acpi_dev() return value

The return value of acpi_fetch_acpi_dev() could be NULL, which would
cause a NULL pointer dereference to occur in acpi_device_hid().

Signed-off-by: Li Zhong <floridsleeves@gmail.com>
[ rjw: Subject and changelog edits, added empty line after if () ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index acfabfe..fc5b5b2 100644 (file)
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1134,6 +1134,9 @@ static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
        status = acpi_get_parent(handle, &pr_ahandle);
        while (ACPI_SUCCESS(status)) {
                d = acpi_fetch_acpi_dev(pr_ahandle);
+               if (!d)
+                       break;
+
                handle = pr_ahandle;
 
                if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))