linux-kernel - Re: [PATCH] media: tc358743: initialize variable

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Message-ID: <23bc7c20-f736-a8fb-b89c-c9039380e55b@redhat.com>
Date:   Mon, 31 Aug 2020 11:11:57 -0700
From:   Tom Rix <trix@...hat.com>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     matrandg@...co.com, Mauro Carvalho Chehab <mchehab@...nel.org>,
        Nathan Chancellor <natechancellor@...il.com>,
        p.zabel@...gutronix.de, Hans Verkuil <hans.verkuil@...co.com>,
        linux-media@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] media: tc358743: initialize variable


On 8/31/20 10:31 AM, Nick Desaulniers wrote:
> On Sun, Aug 30, 2020 at 9:30 AM <trix@...hat.com> wrote:
>> From: Tom Rix <trix@...hat.com>
>>
>> clang static analysis flags this error
>>
>> tc358743.c:1468:9: warning: Branch condition evaluates
>>   to a garbage value
>>         return handled ? IRQ_HANDLED : IRQ_NONE;
>>                ^~~~~~~
>> handled should be initialized to false.
>>
>> Fixes: d747b806abf4 ("[media] tc358743: add direct interrupt handling")
>> Signed-off-by: Tom Rix <trix@...hat.com>
> I'm guessing there was more to the report that says that `handled`
> isn't necessarily initialized along any of the paths within
> tc358743_isr()?  But you should fix this for all callers of
> tc358743_isr(), such as tc358743_work_i2c_poll(), not just
> tc358743_irq_handler().

Interesting. The static analyzer did not catch this.

I will take another.

Thanks

Tom

>> ---
>>  drivers/media/i2c/tc358743.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/i2c/tc358743.c b/drivers/media/i2c/tc358743.c
>> index a03dcab5ce61..c724bd1591de 100644
>> --- a/drivers/media/i2c/tc358743.c
>> +++ b/drivers/media/i2c/tc358743.c
>> @@ -1461,7 +1461,7 @@ static int tc358743_isr(struct v4l2_subdev *sd, u32 status, bool *handled)
>>  static irqreturn_t tc358743_irq_handler(int irq, void *dev_id)
>>  {
>>         struct tc358743_state *state = dev_id;
>> -       bool handled;
>> +       bool handled = false;
>>
>>         tc358743_isr(&state->sd, 0, &handled);
>>
>> --
>> 2.18.1
>>
>