Re: [PATCH] i2c: add sanity check to i2c_put_adapter

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

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On Thu, Aug 01, 2013 at 02:10:46PM +0200, Sebastian Hesselbarth wrote:
> i2c_put_adapter dereferences i2c_adapter pointer passed without check
> for NULL. This adds a check for non-NULL pointer to allow i2c_put_adapter
> called with NULL and behave the same way i2c_release_client does already.

What about using WARN for the NULL case to point out the ref-counting
imbalance?

> 
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> Cc: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  drivers/i2c/i2c-core.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index f32ca29..d075df6 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -1825,7 +1825,8 @@ EXPORT_SYMBOL(i2c_get_adapter);
>  
>  void i2c_put_adapter(struct i2c_adapter *adap)
>  {
> -	module_put(adap->owner);
> +	if (adap)
> +		module_put(adap->owner);
>  }
>  EXPORT_SYMBOL(i2c_put_adapter);
>  
> -- 
> 1.7.10.4
> 

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