[PATCH 3.16 094/158] ACPICA: Namespace: Properly null terminate objects detached from a namespace node

[Greg Kroah-Hartman]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David E. Box" <david.e.box@xxxxxxxxxxxxxxx>

commit e23d9b8297546c6ceb7e70771e4915f2a41733cd upstream.

Fixes a bug exposed by an ACPICA unit test around the
acpi_attach_data()/acpi_detach_data() APIs where the failure to null
terminate a detached object led to the creation of a circular linked list
(and infinite looping) when the object is reattached.

Reported in acpica bugzilla #1063

Link: https://bugs.acpica.org/show_bug.cgi?id=1063
Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/acpi/acpica/nsobject.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/drivers/acpi/acpica/nsobject.c
+++ b/drivers/acpi/acpica/nsobject.c
@@ -239,6 +239,17 @@ void acpi_ns_detach_object(struct acpi_n
 		}
 	}
 
+	/*
+	 * Detach the object from any data objects (which are still held by
+	 * the namespace node)
+	 */
+
+	if (obj_desc->common.next_object &&
+	    ((obj_desc->common.next_object)->common.type ==
+	     ACPI_TYPE_LOCAL_DATA)) {
+		obj_desc->common.next_object = NULL;
+	}
+
 	/* Reset the node type to untyped */
 
 	node->type = ACPI_TYPE_ANY;


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