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

Mike Turquette
2014-02-25T06:16:20Z

Quoting Sylwester Nawrocki (2014-01-07 04:03:43)
> Ensure clk->kref is dereferenced only when clk is not NULL.
>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Taken into clk-fixes toward -rc5.

Thanks!
Mike

> ---
> 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;
>
> - kref_get(&clk->ref);
> + kref_get(&clk->ref);
> + }
> return 1;
> }
>
> void __clk_put(struct clk *clk)
> {
> - if (WARN_ON_ONCE(IS_ERR(clk)))
> + if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
> return;
>
> clk_prepare_lock();
> kref_put(&clk->ref, __clk_release);
> clk_prepare_unlock();
>
> - if (clk)
> - module_put(clk->owner);
> + module_put(clk->owner);
> }
>
> /*** clk rate change notifiers ***/
> --
> 1.7.9.5
>