Re: [PATCH v1 4/4] thermal: tegra: fix coverity defect
From: Wei Ni
Date: Fri Nov 09 2018 - 01:44:24 EST
On 8/11/2018 8:37 PM, Thierry Reding wrote:
> On Mon, Nov 05, 2018 at 05:32:34PM +0800, Wei Ni wrote:
>> Fix dereference dev before null check.
>>
>> Signed-off-by: Wei Ni <wni@xxxxxxxxxx>
>> ---
>> drivers/thermal/tegra/soctherm.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
>> index 3042837364e8..96527df91f2a 100644
>> --- a/drivers/thermal/tegra/soctherm.c
>> +++ b/drivers/thermal/tegra/soctherm.c
>> @@ -397,7 +397,7 @@ static int throttrip_program(struct device *dev,
>> struct soctherm_throt_cfg *stc,
>> int trip_temp)
>> {
>> - struct tegra_soctherm *ts = dev_get_drvdata(dev);
>> + struct tegra_soctherm *ts;
>> int temp, cpu_throt, gpu_throt;
>> unsigned int throt;
>> u32 r, reg_off;
>> @@ -405,6 +405,8 @@ static int throttrip_program(struct device *dev,
>> if (!sg || !stc || !stc->init)
>> return -EINVAL;
>>
>> + ts = dev_get_drvdata(dev);
>
> I think coverity is wrong. How is dev ever going to be NULL in this
> case? We allocate all of these struct tegra_thermctl_zone structures in
> tegra_soctherm_probe() and assign zone->dev = &pdev->dev, which can
> never be NULL.
>
> And even if it could, the code would've crashed earlier in
> tegra_soctherm_probe() already.
>
> Furthermore, I fail to see how your patch would fix the defect. None of
> the checks in the conditional above actually check the dev value.
>
Yes, you are right, we doesn't need this change. The driver would not
pass null dev in any case.
And this driver already had a change "1fba81cc09bd thermal: tegra:
remove null check for dev pointer" which remove this "dev" checking.
Thank.
Wei.
> Thierry
>