From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754573AbdCTLwX (ORCPT ); Mon, 20 Mar 2017 07:52:23 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:33359 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753429AbdCTLv0 (ORCPT ); Mon, 20 Mar 2017 07:51:26 -0400 From: Colin King To: Jarkko Nikula , Andy Shevchenko , Mika Westerberg , Wolfram Sang , linux-i2c@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] i2c: designware-baytrail: fix potential null pointer dereference on dev Date: Mon, 20 Mar 2017 11:51:23 +0000 Message-Id: <20170320115123.31536-1-colin.king@canonical.com> X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King The assignment to addr requires a call to get_sem_addr that dereferences dev, however, this dereference occurs before a null pointer check on dev. Move this assignment after the null check on dev to avoid a potential null pointer dereference. Detected by CoverityScan, CID#1419700 ("Dereference before null check") Fixes: fd476fa22a1f432 ("i2c: designware-baytrail: Add support for cherrytrail") Signed-off-by: Colin Ian King --- drivers/i2c/busses/i2c-designware-baytrail.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c index 1749a0f5a9fa..2cbb2e9195ca 100644 --- a/drivers/i2c/busses/i2c-designware-baytrail.c +++ b/drivers/i2c/busses/i2c-designware-baytrail.c @@ -70,7 +70,7 @@ static void reset_semaphore(struct dw_i2c_dev *dev) static int baytrail_i2c_acquire(struct dw_i2c_dev *dev) { - u32 addr = get_sem_addr(dev); + u32 addr; u32 sem = PUNIT_SEMAPHORE_ACQUIRE; int ret; unsigned long start, end; @@ -94,6 +94,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev) */ pm_qos_update_request(&dev->pm_qos, 0); + addr = get_sem_addr(dev); + /* host driver writes to side band semaphore register */ ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, addr, sem); if (ret) { -- 2.11.0