Re: double unlock in rng_dev_read()

From: Dan Carpenter
Date: Thu Dec 24 2009 - 05:59:48 EST


On Wed, Dec 23, 2009 at 11:23:55PM +0800, Herbert Xu wrote:
> On Wed, Dec 23, 2009 at 04:53:36PM +0200, Dan Carpenter wrote:
> >
> > No no. I mean when size hits zero we are rng_mutex is unlocked.
>
> Good catch! I'll add this patch to the tree. Please take a look
> at it. Thanks!
>

Great.

Acked-by: Dan Carpenter <error27@xxxxxxxxx>

regards,
dan carpenter


> commit f5908267b67917b8cbd98b27fd2be9b5f62ec76f
> Author: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Date: Wed Dec 23 23:22:34 2009 +0800
>
> hwrng: core - Fix double unlock in rng_dev_read
>
> When the loop terminates with size == 0 in rng_dev_read we will
> unlock the rng mutex twice.
>
> Reported-by: Dan Carpenter <error27@xxxxxxxxx>
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index e989f67..3d9c61e 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -158,10 +158,11 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
> goto out;
> }
> }
> -out_unlock:
> - mutex_unlock(&rng_mutex);
> out:
> return ret ? : err;
> +out_unlock:
> + mutex_unlock(&rng_mutex);
> + goto out;
> }
>
> --
> Visit Openswan at http://www.openswan.org/
> Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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