From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751868AbdGEPJr (ORCPT ); Wed, 5 Jul 2017 11:09:47 -0400 Received: from laurent.telenet-ops.be ([195.130.137.89]:40310 "EHLO laurent.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751444AbdGEPJp (ORCPT ); Wed, 5 Jul 2017 11:09:45 -0400 From: Geert Uytterhoeven To: Ulf Hansson , Linus Walleij Cc: Arnd Bergmann , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v2 1/2] mmc: block: Initialize ret in mmc_blk_issue_drv_op() for MMC_DRV_OP_IOCTL Date: Wed, 5 Jul 2017 17:09:41 +0200 Message-Id: <1499267382-28438-1-git-send-email-geert@linux-m68k.org> X-Mailer: git-send-email 2.7.4 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 With gcc 4.1.2: drivers/mmc/core/block.c: In function ‘mmc_blk_issue_drv_op’: drivers/mmc/core/block.c:1178: warning: ‘ret’ may be used uninitialized in this function Indeed, for MMC_DRV_OP_IOCTL, if mq_rq->ioc_count is zero, an uninitialized value will be stored in mq_rq->drv_op_result and passed to blk_end_request_all(). Can mq_rq->ioc_count be zero? - mmc_blk_ioctl_cmd() sets ioc_count to 1, so this is safe, - mmc_blk_ioctl_multi_cmd() obtains ioc_count from user space in response to the MMC_IOC_MULTI_CMD ioctl, and does allow zero. Initialize ret to zero to fix this for current and future callers. Fixes: 0493f6fe5bdee8ac ("mmc: block: Move boot partition locking into a driver op") Signed-off-by: Geert Uytterhoeven --- v2, as suggested by Arnd: - Move the assignment after "case MMC_DRV_OP_IOCTL", to keep getting compile-time checks on the state of the 'ret' variable, - Initialize ret to zero instead of -EINVAL. --- drivers/mmc/core/block.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 0cfac2d391073922..4920ea1ece38a9b6 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -1182,7 +1182,7 @@ static void mmc_blk_issue_drv_op(struct mmc_queue *mq, struct request *req) switch (mq_rq->drv_op) { case MMC_DRV_OP_IOCTL: - for (i = 0; i < mq_rq->ioc_count; i++) { + for (i = 0, ret = 0; i < mq_rq->ioc_count; i++) { ret = __mmc_blk_ioctl_cmd(card, md, mq_rq->idata[i]); if (ret) break; -- 2.7.4