Re: [PATCH] mfd: fix a potential NULL pointer dereference

[Mukesh Ojha]

On 3/25/2019 1:26 PM, Lee Jones wrote:
> On Fri, 22 Mar 2019, Kangjie Lu wrote:
>
> > Hi Lee Jones,
> >
> > Can you review this patch?
> Don't poke.
>
> I have a very long list of reviews on my TODO.  Poking only surfaces
> your patch to the top of my Inbox, and since I review patches in
> reverse chronological order, it puts the review to the back of the
> queue.
>
> > > On Mar 9, 2019, at 2:04 AM, Kangjie Lu <kjlu@xxxxxxx> wrote:
> > >
> > > In case devm_kzalloc fails, the fix does NULL check and returns
> > > -ENOMEM upon failure so as to avoid NULL pointer dereference.
> > >
> > > Signed-off-by: Kangjie Lu <kjlu@xxxxxxx>
> > > ---
> > > drivers/mfd/sm501.c | 3 +++
> > > 1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
> > > index a530972c5a7e..e0173bf4b0dc 100644
> > > --- a/drivers/mfd/sm501.c
> > > +++ b/drivers/mfd/sm501.c
> > > @@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
> > > 	lookup = devm_kzalloc(&pdev->dev,
> > > 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
> > > 			      GFP_KERNEL);
> > > +	if (!lookup)
> > > +		return -ENOMEM;

Seems you are using quite old codebase.
This patch is already there ..

https://elixir.bootlin.com/linux/v5.1-rc2/source/drivers/mfd/sm501.c#L1147

commit ae7b8eda27b3( mfd: sm501: Fix potential NULL pointer dereference )


Thanks,
Mukesh


> > > +
> > > 	lookup->dev_id = "i2c-gpio";
> > > 	if (iic->pin_sda < 32)
> > > 		lookup->table[0].chip_label = "SM501-LOW";