From nobody Fri Oct 3 15:36:02 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DD1AA2E7647; Fri, 29 Aug 2025 09:05:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756458334; cv=none; b=ooFzzcyjxzSRsRRDCWm/KOfRS0cNfjlA9CvEc6/su6VAuSDLt9iMNOF2xdOCdAkLnyXieUC5T5FtosIr0G1mX5PrJMASXOrKOGc+mwd3camTMil0F0yliPMQq2bHoLPGKnmeO+EqWTz3HRlGl2ZifBDZrzEwo9Pz2COR3UERiJA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756458334; c=relaxed/simple; bh=ivKqM50M4iw0RSehXQduIKjOJqOijpdsoVz0fl/OOBI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GziQcO99jv5Qjuuk18y7TXVbQxcBmq4N68Gjn4k7aDABFgh08Re99h7ElzznKGRTQn8ankYyOditTLqgYK/i0I+bvVNBhSkFNXl7tiVz0gXVkYWY6P5b2J4jEqUQ88CnD/SdsO4zA3tbY4JtDsQGWI+D4ntiVswKP9rjjncT9BU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bF7FcMOz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bF7FcMOz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9460DC4CEF4; Fri, 29 Aug 2025 09:05:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756458333; bh=ivKqM50M4iw0RSehXQduIKjOJqOijpdsoVz0fl/OOBI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bF7FcMOzYYva//9gz2v556cx+Y++Ep1b+HAJ3LmAnQnhupdAwtkKiCvzYKg5h8zi/ nK2N74IQ8/Zoa3mo6w5uv1/cWVL3ZvZ+AgLmrek0If3qdKoo1NLwjdZondqkJ+8hlv UFs4GmorG4DL/ZaXJqG1DBw7zi6XqjiRhOuYb7cjB9C236SAPo8AJRzzBH+YWmYYfL H3m3Gs7UogVIo+FGAx/sr4+4whBDug5BVQvTam8xtuiCg3CRXS+Rtg8ecRqvltaldJ HoUNmwpQta+TupsaN8Bm6jRuJkOhbRTxswIkcZhHjlMrWGkpf7Pg/ZFnY3i9hEJovB itacSAnYKBdbg== Received: from johan by xi.lan with local (Exim 4.98.2) (envelope-from ) id 1urv2x-000000005WF-0cxW; Fri, 29 Aug 2025 11:05:23 +0200 From: Johan Hovold To: Chun-Kuang Hu , Philipp Zabel Cc: David Airlie , Simona Vetter , Matthias Brugger , AngeloGioacchino Del Regno , Ma Ke , dri-devel@lists.freedesktop.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org Subject: [PATCH 1/2] drm/mediatek: fix potential OF node use-after-free Date: Fri, 29 Aug 2025 11:03:44 +0200 Message-ID: <20250829090345.21075-2-johan@kernel.org> X-Mailer: git-send-email 2.49.1 In-Reply-To: <20250829090345.21075-1-johan@kernel.org> References: <20250829090345.21075-1-johan@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The for_each_child_of_node() helper drops the reference it takes to each node as it iterates over children and an explicit of_node_put() is only needed when exiting the loop early. Drop the recently introduced bogus additional reference count decrement at each iteration that could potentially lead to a use-after-free. Fixes: 1f403699c40f ("drm/mediatek: Fix device/node reference count leaks i= n mtk_drm_get_all_drm_priv") Cc: Ma Ke Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold Reviewed-by: CK Hu --- drivers/gpu/drm/mediatek/mtk_drm_drv.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/media= tek/mtk_drm_drv.c index 34131ae2c207..3b02ed0a16da 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c @@ -388,11 +388,11 @@ static bool mtk_drm_get_all_drm_priv(struct device *d= ev) =20 of_id =3D of_match_node(mtk_drm_of_ids, node); if (!of_id) - goto next_put_node; + continue; =20 pdev =3D of_find_device_by_node(node); if (!pdev) - goto next_put_node; + continue; =20 drm_dev =3D device_find_child(&pdev->dev, NULL, mtk_drm_match); if (!drm_dev) @@ -418,11 +418,10 @@ static bool mtk_drm_get_all_drm_priv(struct device *d= ev) next_put_device_pdev_dev: put_device(&pdev->dev); =20 -next_put_node: - of_node_put(node); - - if (cnt =3D=3D MAX_CRTC) + if (cnt =3D=3D MAX_CRTC) { + of_node_put(node); break; + } } =20 if (drm_priv->data->mmsys_dev_num =3D=3D cnt) { --=20 2.49.1