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-rw-r--r--drivers/acpi/acpica/exmutex.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/drivers/acpi/acpica/exmutex.c b/drivers/acpi/acpica/exmutex.c
index d7cb030a21f..77a592aa53c 100644
--- a/drivers/acpi/acpica/exmutex.c
+++ b/drivers/acpi/acpica/exmutex.c
@@ -83,6 +83,15 @@ void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
if (obj_desc->mutex.prev) {
(obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
+
+ /*
+ * Migrate the previous sync level associated with this mutex to the
+ * previous mutex on the list so that it may be preserved. This handles
+ * the case where several mutexes have been acquired at the same level,
+ * but are not released in opposite order.
+ */
+ (obj_desc->mutex.prev)->mutex.original_sync_level =
+ obj_desc->mutex.original_sync_level;
} else {
thread->acquired_mutex_list = obj_desc->mutex.next;
}
@@ -349,6 +358,7 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
struct acpi_walk_state *walk_state)
{
acpi_status status = AE_OK;
+ u8 previous_sync_level;
ACPI_FUNCTION_TRACE(ex_release_mutex);
@@ -404,14 +414,21 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
}
+ /*
+ * Get the previous sync_level from the head of the acquired mutex list.
+ * This handles the case where several mutexes at the same level have been
+ * acquired, but are not released in reverse order.
+ */
+ previous_sync_level =
+ walk_state->thread->acquired_mutex_list->mutex.original_sync_level;
+
status = acpi_ex_release_mutex_object(obj_desc);
if (obj_desc->mutex.acquisition_depth == 0) {
/* Restore the original sync_level */
- walk_state->thread->current_sync_level =
- obj_desc->mutex.original_sync_level;
+ walk_state->thread->current_sync_level = previous_sync_level;
}
return_ACPI_STATUS(status);
}