ACPICA: Improve error message for Index() operator

For the case where an attempt is made to take an Index() beyond
the end of a String, Buffer, or Package, emit the actual length
of the object to the error message. Helpful for debugging.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/acpi/acpica/exoparg2.c b/drivers/acpi/acpica/exoparg2.c
index e491e46f17df..4a34d6d53370 100644
--- a/drivers/acpi/acpica/exoparg2.c
+++ b/drivers/acpi/acpica/exoparg2.c
@@ -257,7 +257,7 @@ acpi_status acpi_ex_opcode_2A_1T_1R(struct acpi_walk_state *walk_state)
         union acpi_operand_object *return_desc = NULL;
         u64 index;
         acpi_status status = AE_OK;
-        acpi_size length;
+        acpi_size length = 0;
 
         ACPI_FUNCTION_TRACE_STR(ex_opcode_2A_1T_1R,
                                 acpi_ps_get_opcode_name(walk_state->opcode));
@@ -320,7 +320,6 @@ acpi_status acpi_ex_opcode_2A_1T_1R(struct acpi_walk_state *walk_state)
                  * NOTE: A length of zero is ok, and will create a zero-length, null
                  *       terminated string.
                  */
-                length = 0;
                 while ((length < operand[0]->buffer.length) &&
                        (length < operand[1]->integer.value) &&
                        (operand[0]->buffer.pointer[length])) {
@@ -376,6 +375,7 @@ acpi_status acpi_ex_opcode_2A_1T_1R(struct acpi_walk_state *walk_state)
                 case ACPI_TYPE_STRING:
 
                         if (index >= operand[0]->string.length) {
+                                length = operand[0]->string.length;
                                 status = AE_AML_STRING_LIMIT;
                         }
 
@@ -386,6 +386,7 @@ acpi_status acpi_ex_opcode_2A_1T_1R(struct acpi_walk_state *walk_state)
                 case ACPI_TYPE_BUFFER:
 
                         if (index >= operand[0]->buffer.length) {
+                                length = operand[0]->buffer.length;
                                 status = AE_AML_BUFFER_LIMIT;
                         }
 
@@ -396,6 +397,7 @@ acpi_status acpi_ex_opcode_2A_1T_1R(struct acpi_walk_state *walk_state)
                 case ACPI_TYPE_PACKAGE:
 
                         if (index >= operand[0]->package.count) {
+                                length = operand[0]->package.count;
                                 status = AE_AML_PACKAGE_LIMIT;
                         }
 
@@ -414,8 +416,8 @@ acpi_status acpi_ex_opcode_2A_1T_1R(struct acpi_walk_state *walk_state)
 
                 if (ACPI_FAILURE(status)) {
                         ACPI_EXCEPTION((AE_INFO, status,
-                                        "Index (0x%8.8X%8.8X) is beyond end of object",
-                                        ACPI_FORMAT_UINT64(index)));
+                                        "Index (0x%X%8.8X) is beyond end of object (length 0x%X)",
+                                        ACPI_FORMAT_UINT64(index), length));
                         goto cleanup;
                 }