[PATCH] clk: Correct handling of NULL clk in __clk_{get, put}

Lothar Waßmann LW at KARO-electronics.de
Tue Jan 7 08:00:19 EST 2014


Hi,

Sylwester Nawrocki wrote:
> Ensure clk->kref is dereferenced only when clk is not NULL.
> 
> Signed-off-by: Sylwester Nawrocki <s.nawrocki at samsung.com>
> ---
> Hi Sachin,
> 
> please try if this patch fixes the exyno5420 boot crash.
> 
> Thanks,
> Sylwester
> 
>  drivers/clk/clk.c |   13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index e3e0327..a1fe86f 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -2179,24 +2179,25 @@ EXPORT_SYMBOL_GPL(devm_clk_unregister);
>   */
>  int __clk_get(struct clk *clk)
>  {
> -	if (clk && !try_module_get(clk->owner))
> -		return 0;
> +	if (clk) {
> +		if (!try_module_get(clk->owner))
> +			return 0;
> 
This change is unnecessary! The part after the && is only evaluated
when clk is not NULL.

Lothar Waßmann
-- 
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