From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="gXTbmgMB" Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59B1DD6D; Tue, 28 Nov 2023 04:54:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701176051; x=1732712051; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=5K++CR/OvistPw0XQfzY/YBgYQVr3P4OlOvmEu/zZC4=; b=gXTbmgMBI9JWxWh3pdsub7ntkhG2pDcAauw3qNg36I6GATPTC1nyAgF9 vPqc8UZTaYjGQko9j/LBoakBrn20KrtCNFcnC9ovXoOQ4uwSbpNKaYpqz ZfQLgyagThHQnCT2KdQSFyeGtTSWsQT+oqzKFeAVl/Pnc7FICIRkSGCU/ cBrDXNB1sWOjs9Jen0SnmTSvWbKm41Dfu/yqTvWJRWnrUDgHL23qM5R2q zS+ZxdJJuoI1VxYFsx6okVE2xRwNcNW6bxIFW4hk6aS3VKQtc85yiWD7M obPkymzN+aNXptgxxh7fIsf4rM+0ElMlIhlqQboYXv1fPHQ/+puycU12R A==; X-IronPort-AV: E=McAfee;i="6600,9927,10907"; a="377943906" X-IronPort-AV: E=Sophos;i="6.04,233,1695711600"; d="scan'208";a="377943906" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Nov 2023 04:54:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10907"; a="1015900733" X-IronPort-AV: E=Sophos;i="6.04,233,1695711600"; d="scan'208";a="1015900733" Received: from mravivx-mobl.ger.corp.intel.com (HELO localhost) ([10.252.42.57]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Nov 2023 04:54:04 -0800 From: Jani Nikula To: Maxime Ripard , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Daniel Vetter , Emma Anholt , Jonathan Corbet , Sandy Huang , Heiko =?utf-8?Q?St?= =?utf-8?Q?=C3=BCbner?= , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland Cc: Hans Verkuil , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-sunxi@lists.linux.dev, Maxime Ripard Subject: Re: [PATCH v4 05/45] drm/connector: Check drm_connector_init pointers arguments In-Reply-To: <20231128-kms-hdmi-connector-state-v4-5-c7602158306e@kernel.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20231128-kms-hdmi-connector-state-v4-0-c7602158306e@kernel.org> <20231128-kms-hdmi-connector-state-v4-5-c7602158306e@kernel.org> Date: Tue, 28 Nov 2023 14:54:02 +0200 Message-ID: <87h6l66nth.fsf@intel.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, 28 Nov 2023, Maxime Ripard wrote: > All the drm_connector_init variants take at least a pointer to the > device, connector and hooks implementation. > > However, none of them check their value before dereferencing those > pointers which can lead to a NULL-pointer dereference if the author > isn't careful. Arguably oopsing on the spot is preferrable when this can't be caused by user input. It's always a mistake that should be caught early during development. Not everyone checks the return value of drm_connector_init and friends, so those cases will lead to more mysterious bugs later. And probably oopses as well. BR, Jani. > > Let's test those pointers instead and error out if any is NULL. > > Signed-off-by: Maxime Ripard > --- > drivers/gpu/drm/drm_connector.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index b0516505f7ae..2f60755dccdd 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -229,6 +229,9 @@ static int __drm_connector_init(struct drm_device *dev, > struct ida *connector_ida = > &drm_connector_enum_list[connector_type].ida; > > + if (!dev || !connector || !funcs) > + return -EINVAL; > + > WARN_ON(drm_drv_uses_atomic_modeset(dev) && > (!funcs->atomic_destroy_state || > !funcs->atomic_duplicate_state)); -- Jani Nikula, Intel