From mboxrd@z Thu Jan 1 00:00:00 1970 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 033C231987D; Tue, 2 Sep 2025 13:34:40 +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=1756820080; cv=none; b=kUk93df4gnYgzoKyXj16rJzuRhtg4vgS88LuwBm+CEhi1zDxLMExofyDybnorhBi9YWlAU1wdNDI0T6WXo1PNiOOwJGrjTxhC9Lm1AvZdILYa5pAEuXbrrIQAB9htijvRUIgWJI4QCSGxEyVZGvgtJ23zSH8UCQsLMXowaWVHMU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820080; c=relaxed/simple; bh=FTDQHeQviVEBwM0h3Wf2Ebs1SK19pbqNOcvFRAkoQEo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=s4FbDq/wOXOItL09oty4EiqjjWIeGZ+dmQNDRxbq7v9U8gTalw953bizqzZS9JBU1eKUCIISgiakIzw9MU3tHjkB88yGOaSNyEIoueTZo65SKUdn7lAkANf0KruH4DORqcoi20mnS0qVEKoxsImV3JZDTT43TrxOGpLZU88isGA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nxu/jnw6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nxu/jnw6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78275C4CEED; Tue, 2 Sep 2025 13:34:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756820079; bh=FTDQHeQviVEBwM0h3Wf2Ebs1SK19pbqNOcvFRAkoQEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nxu/jnw6e18TT9hRet7UF2QRbvhscmUoRlnSdzN1JNx0LBf7Jtk2AVl42FC5x9eHk qdSsu4YpqQBD6Q8lKVQ/sIA+aeJr1JeLWIIcZRUQQ8/nkKkxHRFx6BXHRpRiF1Wv22 XryhJX66DfQyd7PHk0T5yuutQ+OhRLYNCEMOAkhA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ma Ke , CK Hu , Chun-Kuang Hu Subject: [PATCH 6.12 87/95] drm/mediatek: Fix device/node reference count leaks in mtk_drm_get_all_drm_priv Date: Tue, 2 Sep 2025 15:21:03 +0200 Message-ID: <20250902131942.942945442@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250902131939.601201881@linuxfoundation.org> References: <20250902131939.601201881@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ma Ke commit 1f403699c40f0806a707a9a6eed3b8904224021a upstream. Using device_find_child() and of_find_device_by_node() to locate devices could cause an imbalance in the device's reference count. device_find_child() and of_find_device_by_node() both call get_device() to increment the reference count of the found device before returning the pointer. In mtk_drm_get_all_drm_priv(), these references are never released through put_device(), resulting in permanent reference count increments. Additionally, the for_each_child_of_node() iterator fails to release node references in all code paths. This leaks device node references when loop termination occurs before reaching MAX_CRTC. These reference count leaks may prevent device/node resources from being properly released during driver unbind operations. As comment of device_find_child() says, 'NOTE: you will need to drop the reference with put_device() after use'. Cc: stable@vger.kernel.org Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support") Signed-off-by: Ma Ke Reviewed-by: CK Hu Link: https://patchwork.kernel.org/project/dri-devel/patch/20250812071932.471730-1-make24@iscas.ac.cn/ Signed-off-by: Chun-Kuang Hu Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/mediatek/mtk_drm_drv.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c @@ -381,19 +381,19 @@ static bool mtk_drm_get_all_drm_priv(str of_id = of_match_node(mtk_drm_of_ids, node); if (!of_id) - continue; + goto next_put_node; pdev = of_find_device_by_node(node); if (!pdev) - continue; + goto next_put_node; drm_dev = device_find_child(&pdev->dev, NULL, mtk_drm_match); if (!drm_dev) - continue; + goto next_put_device_pdev_dev; temp_drm_priv = dev_get_drvdata(drm_dev); if (!temp_drm_priv) - continue; + goto next_put_device_drm_dev; if (temp_drm_priv->data->main_len) all_drm_priv[CRTC_MAIN] = temp_drm_priv; @@ -405,10 +405,17 @@ static bool mtk_drm_get_all_drm_priv(str if (temp_drm_priv->mtk_drm_bound) cnt++; - if (cnt == MAX_CRTC) { - of_node_put(node); +next_put_device_drm_dev: + put_device(drm_dev); + +next_put_device_pdev_dev: + put_device(&pdev->dev); + +next_put_node: + of_node_put(node); + + if (cnt == MAX_CRTC) break; - } } if (drm_priv->data->mmsys_dev_num == cnt) {