From patchwork Wed Jan 29 14:21:52 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Ripard X-Patchwork-Id: 13953786 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8606AC0218D for ; Wed, 29 Jan 2025 14:22:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B3D4010E0DD; Wed, 29 Jan 2025 14:22:07 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="uVcMhwdy"; dkim-atps=neutral Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8050210E0DD for ; Wed, 29 Jan 2025 14:22:05 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 9D3A4A419A9; Wed, 29 Jan 2025 14:20:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B970BC4CED1; Wed, 29 Jan 2025 14:22:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738160524; bh=zlwTZDYiDcP20fDfhTpAMiEjpQF0Tna17N/6izt8lj8=; h=From:Subject:Date:To:Cc:From; b=uVcMhwdyy6tZKov1CtFw0z6NftB43qCZJz4oXoZQ3eGQBX1wDnS8miiqF9/FHWpye ezT5tZionHtDDgPm8gHt/MDaWePbobg/LLx4BrDxHMgbKx6GrVCWfdy3Y/PnyAxblA bgPiUwm2ecI2rwmn5noL2rvjJRXv406zYUACdJZtIdmuchrNPJmpOKtJ6Cv0mZ08WC MYKt2yd2oYdETswEhboBolI1qfmxxQvI76h4fd/vzc4KlH0+HIyv4c/X9aN+SiMcOm Htt7Jyadh/vqDW0xyNtYgPt9TirjXBK7oeuOvrUxeFIhaFgBJ3994S3T/Fm6SHCwSW H8nfYp5BVVERw== From: Maxime Ripard Subject: [PATCH v2 0/4] drm/tests: Fix locking issues (kind of) Date: Wed, 29 Jan 2025 15:21:52 +0100 Message-Id: <20250129-test-kunit-v2-0-fe59c43805d5@kernel.org> MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAIA5mmcC/x3MywqDMBCF4VeRWTcySQxoV32P4sLLqINtlEkqL eK7N7r8D5xvh0DCFOCe7SC0ceDFpzC3DLqp8SMp7lODQeNQm0pFClHNH89RubaxHdp2GFqEdFi FBv5e2LNOPXGIi/wue9PnejKFRqux0s6VuSmsKx0qrd7CayP9Yybx9MoXGaE+juMPA6sHPaAAA AA= X-Change-ID: 20250129-test-kunit-5ba3c03bffb0 To: Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maxime Ripard X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2837; i=mripard@kernel.org; h=from:subject:message-id; bh=zlwTZDYiDcP20fDfhTpAMiEjpQF0Tna17N/6izt8lj8=; b=owGbwMvMwCmsHn9OcpHtvjLG02pJDOmzLNssqhISn+yWDtnRl9EtP2dN2sS224Zfy87YfuRwc H5wXle/YyoLgzAng6yYIssTmbDTy9sXVznYr/wBM4eVCWQIAxenAEwk7ydjrXCPjLmv6crmhl13 b3PxMx+Ifjk34UXRXdXUF7MMjx2TK78wr/371g2HlDad6hQMuF1syFin+WSR4Gmmi+y/F/Wd/7L Iyf6w57ZHwu42zltvrF2XdkHp7vmv6+TTV7W+3PCl/J7odN+1AA== X-Developer-Key: i=mripard@kernel.org; a=openpgp; fpr=BE5675C37E818C8B5764241C254BCFC56BF6CE8D X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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@mail.gmail.com/ 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 --- Changes in v2: - Fix circular dependency warning - Link to v1: https://lore.kernel.org/r/20241031091558.2435850-1-mripard@kernel.org --- 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,