Pull 5452 into release branch

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 421792562642..0c561c571f29 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -543,6 +543,8 @@ static int acpi_processor_get_info(struct acpi_processor *pr)
         return_VALUE(0);
 }
 
+static void *processor_device_array[NR_CPUS];
+
 static int acpi_processor_start(struct acpi_device *device)
 {
         int result = 0;
@@ -561,6 +563,19 @@ static int acpi_processor_start(struct acpi_device *device)
 
         BUG_ON((pr->id >= NR_CPUS) || (pr->id < 0));
 
+        /*
+         * Buggy BIOS check
+         * ACPI id of processors can be reported wrongly by the BIOS.
+         * Don't trust it blindly
+         */
+        if (processor_device_array[pr->id] != NULL &&
+            processor_device_array[pr->id] != (void *)device) {
+                ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "BIOS reporting wrong ACPI id"
+                        "for the processor\n"));
+                return_VALUE(-ENODEV);
+        }
+        processor_device_array[pr->id] = (void *)device;
+
         processors[pr->id] = pr;
 
         result = acpi_processor_add_fs(device);