linux-kernel - Re: [PATCH-next] i3c: master: Fix potentially uninit variable

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Message-ID: <CAJ7bepKvu_mpJF47WtanZLDsbbx5+GhFkKSKmOdjgDoGQZe-uQ@mail.gmail.com>
Date: Wed, 27 Nov 2024 15:44:07 +0530
From: Advait Dhamorikar <advaitdhamorikar@...il.com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH-next] i3c: master: Fix potentially uninit variable

> Yes and no, I don't think -ENODEV is allowed here, see platform_uevent
> and i2c_device_uevent.

Thanks for the feedback. So if devinfo is uninitialized is it possible to
initialize the i3c modalias using OF and ACPI uevent_modalias?

My humble apologies if this is a trivial question but I'm not really familiar
with i3c and found the potential uninitialization using a static analyzer.

Thanks and regards,
Advait

On Wed, 27 Nov 2024 at 04:18, Alexandre Belloni
<alexandre.belloni@...tlin.com> wrote:
>
> On 27/11/2024 01:26:08+0530, Advait Dhamorikar wrote:
> > Hello,
> >
> > I would really appreciate it if I could get some feedback on this patch,
> > I would like to know if this approach is the right way to proceed.
> >
>
> Yes and no, I don't think -ENODEV is allowed here, see platform_uevent
> and i2c_device_uevent.
>
>
> > Thanks and regards,
> > Advait
> >
> > On Tue, 19 Nov 2024 at 21:09, Advait Dhamorikar
> > <advaitdhamorikar@...il.com> wrote:
> > >
> > > devinfo is uninitialized if the condition is not satisfied,
> > > add an else condition to prevent unexpected behaviour.
> > >
> > > The variable will contain an arbitrary value left from earlier
> > > computations in `i3c_device_uevent`.
> > >
> > > Signed-off-by: Advait Dhamorikar <advaitdhamorikar@...il.com>
> > > ---
> > >  drivers/i3c/master.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> > > index 42310c9a00c2..7594d3793eb0 100644
> > > --- a/drivers/i3c/master.c
> > > +++ b/drivers/i3c/master.c
> > > @@ -284,6 +284,8 @@ static int i3c_device_uevent(const struct device *dev, struct kobj_uevent_env *e
> > >
> > >         if (i3cdev->desc)
> > >                 devinfo = i3cdev->desc->info;
> > > +       else
> > > +               return -ENODEV;
> > >         manuf = I3C_PID_MANUF_ID(devinfo.pid);
> > >         part = I3C_PID_PART_ID(devinfo.pid);
> > >         ext = I3C_PID_EXTRA_INFO(devinfo.pid);
> > > --
> > > 2.34.1
> > >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com