From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (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 277301DF725 for ; Tue, 7 Jan 2025 12:59:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736254771; cv=none; b=G1Qd3HM5Dfjx5z5KrDsZs9q5jiMJFfJ5lTKtFcdLhQIR330hjur3SsZcOUvVAtDoI+xZBAxbmmc92jIEMOzRN3ONErJUINZw+4jQkv5yUaEbw9xQbw2oddwRRHJ3nkEqM0KW1aX+TPxjabSprxqBOpCGNJSwRaeIY+5aiZSfBIc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736254771; c=relaxed/simple; bh=++UKU75rdXOIGAGFnLlqeD0iDhbh9gLg0blagBXDFJU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WdvXAjzEHDgKQTUbDpUVarg5yy4onixZ89O9rMk110JqnhIUyMtQo1zyu7D44mO/Uv55/JIPN3u0Cma2kqAgqVENEUaydCPzjEq6Y/hAfXY7iaEOJBNICZnh5DGd2NYC2XEyH6EN1BeNxM1QkYbx6o9+0MnqTDbCIENnPbZYAV0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=IN8J5fMl; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="IN8J5fMl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1736254766; bh=++UKU75rdXOIGAGFnLlqeD0iDhbh9gLg0blagBXDFJU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=IN8J5fMlTUEjmAtGeHl7B/lm3+1IHUfaxdHBqnK4B7MNWPiTK2VgW62lsTSmz5g/G GiLG6e9/Rf/spaRK0bP30dxdcX5HUlg7a+E5bmJdgBHRyOeNUGZcxMe6bRgO1UaAqv AOIEnGpOQojo5i8+G4k/vw2x4AS1gdsfw4q8lYIkAiVCB0CHw1lufh5GXbm2N9vDZL nEZkuD3qKuikhuHVH6YW5yr44cS4bUIa5HNKVYHVs0H9miqZDSAOEqgKCknsPvFUgl W853LDonjunG1ToQv9FH4w1PA4PtsA9+d0lTVp+tQbACrsNTECqmPtnE/i/a9njehz AgZSBCrBgD0Fw== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 8FB9417E1574; Tue, 7 Jan 2025 13:59:25 +0100 (CET) Message-ID: <67007940-4ab8-4297-8172-b1c2fa1829a0@collabora.com> Date: Tue, 7 Jan 2025 13:59:25 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/connector: hdmi: Handle NULL display mode in state check helper To: Cristian Ciocaltea , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Dave Stevenson , Dmitry Baryshkov Cc: kernel@collabora.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20250107-hdmi-conn-null-mode-v1-1-fff4be46d106@collabora.com> From: AngeloGioacchino Del Regno Content-Language: en-US In-Reply-To: <20250107-hdmi-conn-null-mode-v1-1-fff4be46d106@collabora.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Il 07/01/25 01:00, Cristian Ciocaltea ha scritto: > drm_atomic_helper_connector_hdmi_check() helper makes use of > connector_state_get_mode() to obtain a drm_display_mode pointer, but it > doesn't validate it, which may lead to a NULL pointer dereference in > some cases, i.e. unloading a DRM module: > > [ 1002.910414] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [...] > [ 1002.923833] Hardware name: Radxa ROCK 5B (DT) > [ 1002.924819] pc : drm_match_cea_mode+0x30/0x280 [drm] > [ 1002.925318] lr : hdmi_try_format_bpc+0x7c/0x580 [drm_display_helper] > [...] > [ 1002.932411] Call trace: > [ 1002.932626] drm_match_cea_mode+0x30/0x280 [drm] (P) > [ 1002.933120] hdmi_try_format_bpc+0x7c/0x580 [drm_display_helper] > [ 1002.933662] drm_atomic_helper_connector_hdmi_check+0x10c/0x478 [drm_display_helper] > [ 1002.934355] drm_bridge_connector_atomic_check+0x20/0x40 [drm_display_helper] > [ 1002.934993] drm_atomic_helper_check_modeset+0x698/0xd28 [drm_kms_helper] > [ 1002.935607] drm_atomic_helper_check+0x28/0xb8 [drm_kms_helper] > [ 1002.936143] drm_atomic_check_only+0x794/0x988 [drm] > [ 1002.936635] drm_atomic_commit+0x60/0xe0 [drm] > [ 1002.937082] drm_atomic_helper_disable_all+0x184/0x218 [drm_kms_helper] > [ 1002.937678] drm_atomic_helper_shutdown+0x90/0x150 [drm_kms_helper] > [ 1002.938243] rockchip_drm_unbind+0x38/0x80 [rockchipdrm] > [ 1002.938720] component_master_del+0xac/0xf8 > [ 1002.939089] rockchip_drm_platform_remove+0x34/0x78 [rockchipdrm] > [...] > > Add the missing NULL check before passing the mode pointer further. > > Fixes: f035f4097f1e ("drm/connector: hdmi: Calculate TMDS character rate") > Signed-off-by: Cristian Ciocaltea Reviewed-by: AngeloGioacchino Del Regno