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

Tomasz Figa
2014-02-25T17:34:14Z

Hi Mike,

On 25.02.2014 07:16, Mike Turquette wrote:
> 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! \o/

Best regards,
Tomasz

>
> 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
>>