diff options
Diffstat (limited to 'drivers/acpi/dispatcher/dsopcode.c')
| -rw-r--r-- | drivers/acpi/dispatcher/dsopcode.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/drivers/acpi/dispatcher/dsopcode.c b/drivers/acpi/dispatcher/dsopcode.c index 5cd406676c2c..50c892a49fa3 100644 --- a/drivers/acpi/dispatcher/dsopcode.c +++ b/drivers/acpi/dispatcher/dsopcode.c @@ -1262,13 +1262,31 @@ acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state, ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op)); - if (walk_state->control_state->common.value) { + control_state = walk_state->control_state; + if (control_state->common.value) { - /* Predicate was true, go back and evaluate it again! */ + /* Predicate was true, the body of the loop was just executed */ + /* + * This loop counter mechanism allows the interpreter to escape + * possibly infinite loops. This can occur in poorly written AML + * when the hardware does not respond within a while loop and the + * loop does not implement a timeout. + */ + control_state->control.loop_count++; + if (control_state->control.loop_count > + ACPI_MAX_LOOP_ITERATIONS) { + status = AE_AML_INFINITE_LOOP; + break; + } + + /* + * Go back and evaluate the predicate and maybe execute the loop + * another time + */ status = AE_CTRL_PENDING; walk_state->aml_last_while = - walk_state->control_state->control.aml_predicate_start; + control_state->control.aml_predicate_start; break; } |