From 7432b49b54cd931743f0b6e9f652bc329e4a242a Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 5 Jul 2017 17:09:41 +0200 Subject: [PATCH] mmc: block: Initialize ret in mmc_blk_issue_drv_op() for MMC_DRV_OP_IOCTL MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Ulf Hansson --- 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 0cfac2d39107..4920ea1ece38 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;