linux-kernel - Re: [jic23-iio:testing 149/150] drivers/iio/dac/ad5593r.c:87 ad5593r_gpio_read() error: uninitialized symbol 'val'.

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Date:   Fri, 16 Sep 2022 09:38:42 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     "Sa, Nuno" <Nuno.Sa@...log.com>
CC:     Dan Carpenter <dan.carpenter@...cle.com>,
        "kbuild@...ts.01.org" <kbuild@...ts.01.org>,
        "Hennerich, Michael" <Michael.Hennerich@...log.com>,
        "lkp@...el.com" <lkp@...el.com>,
        "kbuild-all@...ts.01.org" <kbuild-all@...ts.01.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [jic23-iio:testing 149/150] drivers/iio/dac/ad5593r.c:87
 ad5593r_gpio_read() error: uninitialized symbol 'val'.

On Fri, 16 Sep 2022 07:11:54 +0000
"Sa, Nuno" <Nuno.Sa@...log.com> wrote:

> Hi Dan,
> 
> > From: Dan Carpenter <dan.carpenter@...cle.com>
> > Sent: Friday, September 16, 2022 8:56 AM
> > To: kbuild@...ts.01.org; Hennerich, Michael
> > <Michael.Hennerich@...log.com>
> > Cc: lkp@...el.com; kbuild-all@...ts.01.org; linux-kernel@...r.kernel.org;
> > Jonathan Cameron <Jonathan.Cameron@...wei.com>; Sa, Nuno
> > <Nuno.Sa@...log.com>
> > Subject: [jic23-iio:testing 149/150] drivers/iio/dac/ad5593r.c:87
> > ad5593r_gpio_read() error: uninitialized symbol 'val'.
> > 
> > [External]
> > 
> > tree:
> > https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/g
> > it/jic23/iio.git__;!!A3Ni8CS0y2Y!94Jf_eIoy5zwbmsSRdWgugxbqkbgHFd0A88T
> > z4SKRufGLX24YYSEzKlB13AXeYzsBWzd5HW-SqPpIzc8hvh-6w$   testing
> > head:   62a6e699f4669b2c51f408273756f93b21c9f1a1
> > commit: 53b6e3b2164c5807669fbf6b3df0e1494b4d03b8 [149/150] iio: dac:
> > ad5593r: Fix i2c read protocol requirements
> > config: x86_64-randconfig-m001
> > compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
> > 
> > If you fix the issue, kindly add following tag where applicable
> > Reported-by: kernel test robot <lkp@...el.com>
> > Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> > 
> > smatch warnings:
> > drivers/iio/dac/ad5593r.c:87 ad5593r_gpio_read() error: uninitialized symbol
> > 'val'.
> > 
> > vim +/val +87 drivers/iio/dac/ad5593r.c
> > 
> > 56ca9db862bf3d7 Paul Cercueil     2016-04-05  79  static int
> > ad5593r_gpio_read(struct ad5592r_state *st, u8 *value)
> > 56ca9db862bf3d7 Paul Cercueil     2016-04-05  80  {
> > 56ca9db862bf3d7 Paul Cercueil     2016-04-05  81  	struct i2c_client *i2c =
> > to_i2c_client(st->dev);
> > 53b6e3b2164c580 Michael Hennerich 2022-09-13  82  	u16 val;
> > 53b6e3b2164c580 Michael Hennerich 2022-09-13  83  	int ret;
> > 56ca9db862bf3d7 Paul Cercueil     2016-04-05  84
> > 53b6e3b2164c580 Michael Hennerich 2022-09-13  85  	ret =
> > ad5593r_read_word(i2c, AD5593R_MODE_GPIO_READBACK, &val);
> > 56ca9db862bf3d7 Paul Cercueil     2016-04-05  86
> > 56ca9db862bf3d7 Paul Cercueil     2016-04-05 @87  	*value = (u8) val;
> > 
> > 
> > In the original code the error checking prevented reading uninitialized
> > variables.  It's not really a problem, because ad5593r_read_word() can't
> > actually fail but, you know?  Technically the checker is correct.  
> 
> Hmm, in theory, it can if one of the i2c functions (for some reason) return error.
> Not sure how to handle this... Given this is still in the testing branch should I
> just re-spin another version of the series? Jonathan?

Either a fix patch or a respin is fine as long as I haven't pushed it out as togreg
(once that happens I would almost always want a fix on top).

Separate fix is slightly easier for me.

Jonathan

> 
> - Nuno Sá