From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33189C282DA for ; Fri, 5 Apr 2019 23:31:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C62AD21726 for ; Fri, 5 Apr 2019 23:31:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=megous.com header.i=@megous.com header.b="hGM5kXEO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726682AbfDEXbD (ORCPT ); Fri, 5 Apr 2019 19:31:03 -0400 Received: from vps.xff.cz ([195.181.215.36]:52628 "EHLO vps.xff.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726628AbfDEXbC (ORCPT ); Fri, 5 Apr 2019 19:31:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megous.com; s=mail; t=1554507059; bh=5FBBWDSpPtZMdhBDFsBPV22g8KeWvr/wPWjm6s61Oow=; h=From:To:Cc:Subject:Date:From; b=hGM5kXEOuATeYK5LJtWwc85HVTo5yIY0BxLXlvoBsTxLJzXygRnCNBGVaYx0WdE3l m3YRs/1Lkuln6lpTwhfs43Lrd4Y80ukCKOK/4bEx+nLRd/bSWS6NHC2KLhKIO9ba9u idYFR9ehU0h9HWAM4g5DSosTT5dem/rndjOvJavE= From: megous@megous.com To: linux-sunxi@googlegroups.com Cc: Ondrej Jirman , Maxime Ripard , David Airlie , Daniel Vetter , Chen-Yu Tsai , dri-devel@lists.freedesktop.org (open list:DRM DRIVERS FOR ALLWINNER A10), linux-arm-kernel@lists.infradead.org (moderated list:ARM/Allwinner sunXi SoC support), linux-kernel@vger.kernel.org (open list) Subject: [PATCH] drm: sun4i: Fix NULL/invalid pointer dereference in sun8i_tcon_top_un/bind Date: Sat, 6 Apr 2019 01:30:48 +0200 Message-Id: <20190405233048.3823-1-megous@megous.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ondrej Jirman There are two problems here: 1. Not all clk_data->hws[] need to be initialized, depending on various configured quirks. This leads to NULL ptr deref in clk_hw_unregister_gate() in sun8i_tcon_top_unbind() 2. If there is error when registering the clk_data->hws[], err_unregister_gates error path will try to unregister IS_ERR()=true (invalid) pointer. For problem (1) I have this stack trace: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 Call trace: clk_hw_unregister+0x8/0x18 clk_hw_unregister_gate+0x14/0x28 sun8i_tcon_top_unbind+0x2c/0x60 component_unbind.isra.4+0x2c/0x50 component_bind_all+0x1d4/0x230 sun4i_drv_bind+0xc4/0x1a0 try_to_bring_up_master+0x164/0x1c0 __component_add+0xa0/0x168 component_add+0x10/0x18 sun8i_dw_hdmi_probe+0x18/0x20 platform_drv_probe+0x3c/0x70 really_probe+0xcc/0x278 driver_probe_device+0x34/0xa8 Problem (2) was identified by head scratching. Signed-off-by: Ondrej Jirman --- drivers/gpu/drm/sun4i/sun8i_tcon_top.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c index fc36e0c10a37..b1e7c76e9c17 100644 --- a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c @@ -227,7 +227,7 @@ static int sun8i_tcon_top_bind(struct device *dev, struct device *master, err_unregister_gates: for (i = 0; i < CLK_NUM; i++) - if (clk_data->hws[i]) + if (!IS_ERR_OR_NULL(clk_data->hws[i])) clk_hw_unregister_gate(clk_data->hws[i]); clk_disable_unprepare(tcon_top->bus); err_assert_reset: @@ -245,7 +245,8 @@ static void sun8i_tcon_top_unbind(struct device *dev, struct device *master, of_clk_del_provider(dev->of_node); for (i = 0; i < CLK_NUM; i++) - clk_hw_unregister_gate(clk_data->hws[i]); + if (clk_data->hws[i]) + clk_hw_unregister_gate(clk_data->hws[i]); clk_disable_unprepare(tcon_top->bus); reset_control_assert(tcon_top->rst); -- 2.21.0