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SubjectRe: [PATCH] leds: fix a potential NULL pointer dereference
Hi Jacek,

On Sun, Mar 10, 2019 at 9:40 PM Jacek Anaszewski
<jacek.anaszewski@gmail.com> wrote:
> On 3/9/19 7:04 AM, Kangjie Lu wrote:
> > In case of_match_device cannot find a match, the fixes returns
> > -EINVAL to avoid NULL pointer dereference.
> >
> > Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> > ---
> > drivers/leds/leds-pca9532.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/leds/leds-pca9532.c b/drivers/leds/leds-pca9532.c
> > index 7fea18b0c15d..4b0335591728 100644
> > --- a/drivers/leds/leds-pca9532.c
> > +++ b/drivers/leds/leds-pca9532.c
> > @@ -513,6 +513,7 @@ static int pca9532_probe(struct i2c_client *client,
> > const struct i2c_device_id *id)
> > {
> > int devid;
> > + const struct of_device_id *of_id;
> > struct pca9532_data *data = i2c_get_clientdata(client);
> > struct pca9532_platform_data *pca9532_pdata =
> > dev_get_platdata(&client->dev);
> > @@ -528,8 +529,11 @@ static int pca9532_probe(struct i2c_client *client,
> > dev_err(&client->dev, "no platform data\n");
> > return -EINVAL;
> > }
> > - devid = (int)(uintptr_t)of_match_device(
> > - of_pca9532_leds_match, &client->dev)->data;
> > + of_id = of_match_device(of_pca9532_leds_match,
> > + &client->dev);
> > + if (unlikely(!of_id))

Use of unlikey() is frowned upon.
Moreover, this cannot happen, as pca9532_of_populate_pdata() already
contains a similar check.

Kangjie: please stop submitting patches for missing checks, without
investigating if the failures can actually happen. Thanks!

> > + return -EINVAL;
> > + devid = (int)of_id->data;
> > } else {
> > devid = id->driver_data;
> > }
>
>
> Applied to the for-5.2 branch of linux-leds.git.

And also as a fix for v5.1...

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

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