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

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

[Advait Dhamorikar]

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@gmail.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

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

[Advait Dhamorikar]

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.

Thanks and regards,
Advait

On Tue, 19 Nov 2024 at 21:09, Advait Dhamorikar
<advaitdhamorikar@gmail.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@gmail.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
>

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

[Alexandre Belloni]

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@gmail.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@gmail.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

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

[Advait Dhamorikar]

> 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@bootlin.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@gmail.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@gmail.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