Add a test case to ensure that no new name string literal will be
created in lockdep_set_subclass(), otherwise a warning will be triggered
in look_up_lock_class(). Add this to catch the problem in the future.
Signed-off-by: Ahmed Ehab <bottaawesome633@xxxxxxxxx>
---
lib/locking-selftest.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 6f6a5fc85b42..0783ee97c971 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -2710,6 +2710,44 @@ static void local_lock_3B(void)
}
+#if CONFIG_DEBUG_LOCK_ALLOC
+static inline const char* rw_semaphore_lockdep_name(struct rw_semaphore *rwsem)
+{
+ return rwsem->dep_map.name;
+}
+#else
+static inline const char* rw_semaphore_lockdep_name(struct rw_semaphore *rwsem)
+{
+ return NULL;
+}
+#endif
+
+static void lock_class_subclass_X1(void)
+{
+ const char *name_before_setting_subclass = rw_semaphore_lockdep_name(&rwsem_X1);
+ const char *name_after_setting_subclass;
+
+ lockdep_set_subclass(&rwsem_X1, 1);
+ name_after_setting_subclass = rw_semaphore_lockdep_name(&rwsem_X1);
+ DEBUG_LOCKS_WARN_ON(name_before_setting_subclass != name_after_setting_subclass);
+}
+
+/*
+ * after setting the subclass the lockdep_map.name changes
+ * if we initialize a new string literal for the subclass
+ * we will have a new name pointer
+ */
+static void class_subclass_X1_name_test(void)
+{
+ printk(" --------------------------------------------------------------------------\n");
+ printk(" | class and subclass name test|\n");
+ printk(" ---------------------\n");
+
+ print_testname("lock class and subclass same name");
+ dotest(lock_class_subclass_X1, SUCCESS, LOCKTYPE_RWSEM);
+ pr_cont("\n");
+}
+
static void local_lock_tests(void)
{
printk(" --------------------------------------------------------------------------\n");
@@ -2920,6 +2958,8 @@ void locking_selftest(void)
dotest(hardirq_deadlock_softirq_not_deadlock, FAILURE, LOCKTYPE_SPECIAL);
pr_cont("\n");
+ class_subclass_X1_name_test();
+
if (unexpected_testcase_failures) {
printk("-----------------------------------------------------------------\n");
debug_locks = 0;
--
2.46.0
