Hi, Here's another attempt at fixing the current locking issues with the HDMI kunit tests. The initial issue was reported by Dave here: https://lore.kernel.org/all/CAPM=9tzJ4-ERDxvuwrCyUPY0=+P44orhp1kLWVGL7MCfpQjMEQ@xxxxxxxxxxxxxx/ After fixing it, there was still a lockdep warning for a circular dependency. This series is also fixing the issue. There's still an issue though. When running the tests, I get: KTAP version 1 1..1 KTAP version 1 # Subtest: drm_atomic_helper_connector_hdmi_check # module: drm_hdmi_state_helper_test 1..1 ==================================== WARNING: kunit_try_catch/25 still has locks held! 6.13.0-rc2-00410-gbd9d16533367 #18 Tainted: G N ------------------------------------ 2 locks held by kunit_try_catch/25: #0: fff00000021586f0 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_kunit_helper_acquire_ctx_alloc+0x5c/0xf0 #1: fff0000002158718 (crtc_ww_class_mutex){+.+.}-{0:0}, at: drm_kunit_helper_acquire_ctx_alloc+0x5c/0xf0 stack backtrace: CPU: 0 UID: 0 PID: 25 Comm: kunit_try_catch Tainted: G N 6.13.0-rc2-00410-gbd9d16533367 #18 Tainted: [N]=TEST Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x18/0x30 (C) dump_stack_lvl+0x70/0x98 dump_stack+0x18/0x24 debug_check_no_locks_held+0x9c/0xa4 do_exit+0x52c/0x970 kthread_exit+0x28/0x30 kthread+0xdc/0xf0 ret_from_fork+0x10/0x20 ok 1 drm_test_check_hdmi_funcs_reject_rate ok 1 drm_atomic_helper_connector_hdmi_check I believe it's due to the fact that drm_kunit_helper_acquire_ctx_alloc() will acquire the lock directly, but will release it as a deferred kunit action. It's not unsafe, as the lock is eventually released, but I don't really know what the best course of action is here: * Forget about the idea of a context tied to the lifetime of a test * Make lockdep know that it's ok, and we know what to do I've tried the latter, using lockdep_pin/unpin_lock, but that didn't fix the issue so I must have done something wrong. Let me know what you think, Maxime Signed-off-by: Maxime Ripard <mripard@xxxxxxxxxx> --- Changes in v2: - Fix circular dependency warning - Link to v1: https://lore.kernel.org/r/20241031091558.2435850-1-mripard@xxxxxxxxxx --- Maxime Ripard (4): drm/tests: hdmi: Fix WW_MUTEX_SLOWPATH failures drm/tests: hdmi: Remove redundant assignments drm/tests: hdmi: Reorder DRM entities variables assignment drm/tests: hdmi: Fix recursive locking drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c | 200 +++++++++++---------- 1 file changed, 103 insertions(+), 97 deletions(-) --- base-commit: e2a81c0cd7de6cb063058be304b18f200c64802b change-id: 20250129-test-kunit-5ba3c03bffb0 Best regards, -- Maxime Ripard <mripard@xxxxxxxxxx>
