Re: [PATCH] ASoC: Intel: Skylake: Fix available clock counter incrementation

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 2/24/20 11:42 AM, Cezary Rojewski wrote:
> On 2020-02-24 17:18, Pierre-Louis Bossart wrote:
>> On 2/24/20 6:52 AM, Amadeusz Sławiński wrote:
>>> Incrementation of avail_clk_cnt was incorrectly moved to error path. Put
>>> it back to success path.
>>>
> 
>>> diff --git a/sound/soc/intel/skylake/skl-ssp-clk.c 
>>> b/sound/soc/intel/skylake/skl-ssp-clk.c
>>> index 1c0e5226cb5b..bd43885f3805 100644
>>> --- a/sound/soc/intel/skylake/skl-ssp-clk.c
>>> +++ b/sound/soc/intel/skylake/skl-ssp-clk.c
>>> @@ -384,9 +384,11 @@ static int skl_clk_dev_probe(struct 
>>> platform_device *pdev)
>>>                   &clks[i], clk_pdata, i);
>>>           if (IS_ERR(data->clk[data->avail_clk_cnt])) {
>>> -            ret = PTR_ERR(data->clk[data->avail_clk_cnt++]);
>>> +            ret = PTR_ERR(data->clk[data->avail_clk_cnt]);
>>
>> Are you sure?
>>
>> If you start with avail_clk_cnt set to zero, the error handling will 
>> decrement and access offset -1
>>
>> static void unregister_src_clk(struct skl_clk_data *dclk)
>> {
>>       while (dclk->avail_clk_cnt--)
>>           clkdev_drop(dclk->clk[dclk->avail_clk_cnt]->lookup); <<< oob 
>> access with offset -1
>> }
>>
> 
> Decrementation will occur after while's check evaluation - loop will 
> exit, decrementation happens regardless.

ok, I need more coffee I guess :-)

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>