mtd: mtd_blkdevs: fix error path in blktrans_open
Linux-MTD Mailing List
linux-mtd at lists.infradead.org
Tue May 24 21:59:03 EDT 2011
Gitweb: http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=94735ec4044a6d318b83ad3c5794e931ed168d10
Commit: 94735ec4044a6d318b83ad3c5794e931ed168d10
Parent: 5c39c4c54c585e13a8d6b5a8f64af682e7c68091
Author: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
AuthorDate: Mon Apr 18 07:50:37 2011 +0300
Committer: David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Wed May 25 01:53:45 2011 +0100
mtd: mtd_blkdevs: fix error path in blktrans_open
The 'blktrans_open()' does not handle possible '__get_mtd_device()' failures
because it does not check the error code. Moreover, the 'dev->tr->open()'
failures are not handled correctly because in this case the function just
goes ahead and gets the mtd device, then returns an error. But Instead, it
should _not_ try to get the mtd device, then it should put back the module
and the kref.
This patch fixes the issue. Note, I only compile-tested it. This patch was
inspired by a bug report about a similar issue in 2.6.34 kernels
sent by Mike Turner <admin at islandsoftware.co.uk> to the MTD mailing list:
http://lists.infradead.org/pipermail/linux-mtd/2011-April/034980.html
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
drivers/mtd/mtd_blkdevs.c | 24 +++++++++++++++++++++---
1 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index a534e1f..ca38569 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -221,15 +221,33 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
kref_get(&dev->ref);
__module_get(dev->tr->owner);
- if (dev->mtd) {
- ret = dev->tr->open ? dev->tr->open(dev) : 0;
- __get_mtd_device(dev->mtd);
+ if (!dev->mtd)
+ goto unlock;
+
+ if (dev->tr->open) {
+ ret = dev->tr->open(dev);
+ if (ret)
+ goto error_put;
}
+ ret = __get_mtd_device(dev->mtd);
+ if (ret)
+ goto error_release;
+
unlock:
mutex_unlock(&dev->lock);
blktrans_dev_put(dev);
return ret;
+
+error_release:
+ if (dev->tr->release)
+ dev->tr->release(dev);
+error_put:
+ module_put(dev->tr->owner);
+ kref_put(&dev->ref, blktrans_dev_release);
+ mutex_unlock(&dev->lock);
+ blktrans_dev_put(dev);
+ return ret;
}
static int blktrans_release(struct gendisk *disk, fmode_t mode)
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