2013-10-31 11:58:31

by Rashika Kheria

Subject: [PATCH v9 2/2] Staging: zram: Fix decrement of variable by calling bdput()

As suggested by Jerome Marchand "The code in reset_store get the block device
(bdget_disk()) but it does not put it (bdput()) when it's done using it.
The usage count is therefore incremented but never decremented."

This patch also puts bdput() for all error cases.

Cc: [email protected]
Signed-off-by: Rashika Kheria <[email protected]>
---

This revision fixes the following issues of the previous revision-
Proper error handling

drivers/staging/zram/zram_drv.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 012ba15..a1f8b1f 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -652,21 +652,30 @@ static ssize_t reset_store(struct device *dev,
return -ENOMEM;

/* Do not reset an active device! */
- if (bdev->bd_holders)
- return -EBUSY;
+ if (bdev->bd_holders) {
+ ret = -EBUSY;
+ goto out;
+ }

ret = kstrtou16(buf, 10, &do_reset);
if (ret)
- return ret;
+ goto out;

- if (!do_reset)
- return -EINVAL;
+ if (!do_reset) {
+ ret = -EINVAL;
+ goto out;
+ }

/* Make sure all pending I/O is finished */
fsync_bdev(bdev);
+ bdput(bdev);

zram_reset_device(zram, true);
return len;
+
+out:
+ bdput(bdev);
+ return ret;
}

static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
--
1.7.9.5

2013-11-01 01:59:53

by Minchan Kim

Subject: Re: [PATCH v9 2/2] Staging: zram: Fix decrement of variable by calling bdput()

I hope subject should be "Fix memory leak by refcount mismatch"

On Thu, Oct 31, 2013 at 05:28:18PM +0530, Rashika Kheria wrote:
> As suggested by Jerome Marchand "The code in reset_store get the block device
> (bdget_disk()) but it does not put it (bdput()) when it's done using it.
> The usage count is therefore incremented but never decremented."
>
> This patch also puts bdput() for all error cases.
>
> Cc: [email protected]
> Signed-off-by: Rashika Kheria <[email protected]>

Other than that,
Acked-by: Minchan Kim <[email protected]>


Rashika, Thanks!

--
Kind regards,
Minchan Kim