On Wed, 3 Apr 2024 06:19:27 -0700 Guenter Roeck wrote:
dev_addr_lists_test generates lock warning noise at the end of tests if lock debugging is enabled. There are two sets of warnings.
WARNING: CPU: 0 PID: 689 at kernel/locking/mutex.c:923 __mutex_unlock_slowpath.constprop.0+0x13c/0x368 DEBUG_LOCKS_WARN_ON(__owner_task(owner) != __get_current())
WARNING: kunit_try_catch/1336 still has locks held!
KUnit test cleanup is not guaranteed to run in the same thread as the test itself. For this test, this means that rtnl_lock() and rtnl_unlock() may be called from different threads. This triggers the warnings. Suppress the warnings because they are irrelevant for the test and just confusing and distracting.
The first warning can be suppressed by using START_SUPPRESSED_WARNING() and END_SUPPRESSED_WARNING() around the call to rtnl_unlock(). To suppress the second warning, it is necessary to set debug_locks_silent while the rtnl lock is held.
Is it okay if I move the locking into the tests, instead? It's only 4 lines more and no magic required, seems to work fine.