Re: [PATCH v6 1/3] Staging: zram: Fix access of NULL pointer

[Weijie Yang]

On Mon, Oct 28, 2013 at 8:21 PM, Rashika Kheria
<rashika.kheria@xxxxxxxxx> wrote:
> This patch fixes the bug in reset_store caused by accessing NULL pointer.
> Hence, It introduces a check for bdev. It also removes unnecessary check
> of bdev for fsync_bdev().
>
> Signed-off-by: Rashika Kheria <rashika.kheria@xxxxxxxxx>
> ---
>
> This revision fixes the following issues of the previous revision-
> Seperating patches into Bug fix and Smatch fix
>
>  drivers/staging/zram/zram_drv.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
> index 2c4ed52..d640a8f 100644
> --- a/drivers/staging/zram/zram_drv.c
> +++ b/drivers/staging/zram/zram_drv.c
> @@ -648,6 +648,9 @@ static ssize_t reset_store(struct device *dev,
>         zram = dev_to_zram(dev);
>         bdev = bdget_disk(zram->disk, 0);
>
> +       if (!bdev)
> +               return -EBUSY;
> +

I am not sure how does it happen. Would you please make it clear to me?

Thanks

>         /* Do not reset an active device! */
>         if (bdev->bd_holders)
>                 return -EBUSY;
> @@ -660,8 +663,7 @@ static ssize_t reset_store(struct device *dev,
>                 return -EINVAL;
>
>         /* Make sure all pending I/O is finished */
> -       if (bdev)
> -               fsync_bdev(bdev);
> +       fsync_bdev(bdev);
>
>         zram_reset_device(zram, true);
>         return len;
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/