On Wed, Aug 24, 2016 at 01:43:58PM +0200, LABBE Corentin wrote: > of_match_device could return NULL, and so cause a NULL pointer > dereference later. > > For fixing this problem, we use of_device_get_match_data(), this will > simplify the code a little by using a standard function for > getting the match data. > > Testing the return value of of_device_get_match_data is also necessary > for avoiding a second NULL deref on pwm->data. > > Reported-by: coverity (CID 1324139) > Signed-off-by: LABBE Corentin <[email protected]> > --- > Changes since v2: > - Add a test on pwm->data for avoiding a second NULL deref. > Changes since v1: > - Use of_device_get_match_data() > > drivers/pwm/pwm-sun4i.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c > index 03a99a5..fb76c55 100644 > --- a/drivers/pwm/pwm-sun4i.c > +++ b/drivers/pwm/pwm-sun4i.c > @@ -309,9 +309,6 @@ static int sun4i_pwm_probe(struct platform_device *pdev) > struct resource *res; > u32 val; > int i, ret; > - const struct of_device_id *match; > - > - match = of_match_device(sun4i_pwm_dt_ids, &pdev->dev); > > pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > if (!pwm) > @@ -326,7 +323,9 @@ static int sun4i_pwm_probe(struct platform_device *pdev) > if (IS_ERR(pwm->clk)) > return PTR_ERR(pwm->clk); > > - pwm->data = match->data; > + pwm->data = of_device_get_match_data(&pdev->dev); > + if (!pwm->data) > + return -EINVAL;
I don't see how this would ever be NULL. You'd have to add an entry to the table that has a NULL data field, which is very unlikely to happen. If you really want to check for this, which I think isn't necessary, please wrap this in a WARN_ON() or something to make more noise when this completely unexpected case happens. Thierry
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