From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E94A3142E75 for ; Wed, 3 Apr 2024 12:13:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712146401; cv=none; b=cfExWCoI17cKNFvkdONMYMiUctb+4vEMxoUGhsPK9YfAmRzPmEwal05T66LkQPbYij6TuaCvx1AWLBKkffAFOKsdSQ03TQNUtt2P4nWspWYjZX2SdyNP0hryPCNob7s+ICXXOvj23tUwBGN5OBfX+6inVX5aopYXUoX6um/qQQ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712146401; c=relaxed/simple; bh=MnDzAPaZgh+LwiX3vguMB41qPw4moIIh3UtknoJDEz8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=k3yhAMKLSpko5qtmb5Oul/S9/h54/zQdcjLuOcZDsIe7znIHXBFEKfcyUFNX3dAPRmNyV7dzzyGIwtMoo3mgysblOaYBFYB9XHC6AVbjHq9nXGfm+0CtpYtLmUYbUFDrlAUTYHXslDWYALiOE5ZEufaJ1zIV4sdBP3MHFYReMwc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 705321007 for ; Wed, 3 Apr 2024 05:13:50 -0700 (PDT) Received: from e110455-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2836A3F64C for ; Wed, 3 Apr 2024 05:13:19 -0700 (PDT) Date: Wed, 3 Apr 2024 13:13:11 +0100 From: Liviu Dudau To: Huai-Yuan Liu Cc: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, baijiaju1990@outlook.com Subject: Re: [PATCH] drm/arm/malidp: fix a possible null pointer dereference Message-ID: References: <20240403014301.969988-1-qq810974084@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240403014301.969988-1-qq810974084@gmail.com> Hi, On Wed, Apr 03, 2024 at 09:43:01AM +0800, Huai-Yuan Liu wrote: > > In malidp_mw_connector_reset, new memory is allocated with kzalloc, but > no check is performed. In order to prevent null pointer dereferencing, > ensure that mw_state is checked before calling > __drm_atomic_helper_connector_reset. Thanks for the patch, it does look like an oversight. Can I suggest you respin your patch and add a connector->state = NULL; right after kfree(connector->state) ? That way we can be sure we're not leaving state pointing to freed memory. Best regards, Liviu > > Fixes: 8cbc5caf36ef ("drm: mali-dp: Add writeback connector") > Signed-off-by: Huai-Yuan Liu > --- > drivers/gpu/drm/arm/malidp_mw.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/arm/malidp_mw.c b/drivers/gpu/drm/arm/malidp_mw.c > index 626709bec6f5..25623ef9be80 100644 > --- a/drivers/gpu/drm/arm/malidp_mw.c > +++ b/drivers/gpu/drm/arm/malidp_mw.c > @@ -72,7 +72,9 @@ static void malidp_mw_connector_reset(struct drm_connector *connector) > __drm_atomic_helper_connector_destroy_state(connector->state); > > kfree(connector->state); > - __drm_atomic_helper_connector_reset(connector, &mw_state->base); > + > + if (mw_state) > + __drm_atomic_helper_connector_reset(connector, &mw_state->base); > } > > static enum drm_connector_status > -- > 2.34.1 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯