On Mon, Sep 16, 2013 at 06:49:53PM +0200, Marek Vasut wrote:
> Dear Mike Dunn,
>
> > A NULL pointer dereference exception occurs in the driver probe function
> > when device tree is used. The pdata pointer will be NULL in this case,
> > but the code dereferences it in all cases. When device tree is used, a
> > platform data structure is allocated and initialized, and in all cases
> > this pointer is copied to the driver's private data, so the variable being
> > tested should be accessed through the driver's private data structure.
> >
> > Signed-off-by: Mike Dunn <mikedunn@xxxxxxxxxxx>
> > ---
> > drivers/input/keyboard/pxa27x_keypad.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/input/keyboard/pxa27x_keypad.c
> > b/drivers/input/keyboard/pxa27x_keypad.c index 134c3b4..3b2a614 100644
> > --- a/drivers/input/keyboard/pxa27x_keypad.c
> > +++ b/drivers/input/keyboard/pxa27x_keypad.c
> > @@ -795,8 +795,10 @@ static int pxa27x_keypad_probe(struct platform_device
> > *pdev) goto failed_put_clk;
> > }
> >
> > - if ((pdata->enable_rotary0 && keypad->rotary_rel_code[0] != -1) ||
> > - (pdata->enable_rotary1 && keypad->rotary_rel_code[1] != -1)) {
> > + if ((keypad->pdata->enable_rotary0 &&
> > + keypad->rotary_rel_code[0] != -1) ||
> > + (keypad->pdata->enable_rotary1 &&
> > + keypad->rotary_rel_code[1] != -1)) {
> > input_dev->evbit[0] |= BIT_MASK(EV_REL);
> > }
>
> Nice find. Acked-by: Marek Vasut <marex@xxxxxxx>
Excellent booby trap. I would prefer if we explicitly did
pdata = keypad->pdata;
after calling the parse DT fucntion with a nice comment, because we
somebody might want to rearrange the code and accidentially revert the
checks to the original state.
Thanks.
--
Dmitry
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