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Groups > linux.kernel > #1681574
| Path | csiph.com!news.redatomik.org!aioe.org!bofh.it!news.nic.it!robomod |
|---|---|
| From | Geert Uytterhoeven <geert@linux-m68k.org> |
| Newsgroups | linux.kernel |
| Subject | [PATCH v2 1/2] mmc: block: Initialize ret in mmc_blk_issue_drv_op() for MMC_DRV_OP_IOCTL |
| Date | Wed, 05 Jul 2017 17:10:02 +0200 |
| Message-ID | <tZU6e-7Wi-23@gated-at.bofh.it> (permalink) |
| X-Mailer | git-send-email 2.7.4 |
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| Sender | robomod@news.nic.it |
| List-ID | <linux-kernel.vger.kernel.org> |
| X-Mailing-List | linux-kernel@vger.kernel.org |
| Approved | robomod@news.nic.it |
| Lines | 42 |
| Organization | linux.* mail to news gateway |
| X-Original-Cc | Arnd Bergmann <arnd@arndb.de>, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven <geert@linux-m68k.org> |
| X-Original-Date | Wed, 5 Jul 2017 17:09:41 +0200 |
| X-Original-Message-ID | <1499267382-28438-1-git-send-email-geert@linux-m68k.org> |
| X-Original-Sender | linux-kernel-owner@vger.kernel.org |
| Xref | csiph.com linux.kernel:1681574 |
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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 <geert@linux-m68k.org>
---
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
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[PATCH v2 1/2] mmc: block: Initialize ret in mmc_blk_issue_drv_op() for MMC_DRV_OP_IOCTL Geert Uytterhoeven <geert@linux-m68k.org> - 2017-07-05 17:10 +0200
[PATCH v2 2/2] mmc: block: Let MMC_IOC_MULTI_CMD return zero again for zero entries Geert Uytterhoeven <geert@linux-m68k.org> - 2017-07-05 17:20 +0200
Re: [PATCH v2 2/2] mmc: block: Let MMC_IOC_MULTI_CMD return zero again for zero entries Ulf Hansson <ulf.hansson@linaro.org> - 2017-07-11 16:50 +0200
Re: [PATCH v2 1/2] mmc: block: Initialize ret in mmc_blk_issue_drv_op() for MMC_DRV_OP_IOCTL Ulf Hansson <ulf.hansson@linaro.org> - 2017-07-11 16:50 +0200
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