On Fri, Feb 26, 2021 at 01:54:12PM -0800, Saravana Kannan wrote: > On Fri, Feb 26, 2021 at 6:55 AM Johan Hovold <johan@xxxxxxxxxx> wrote: > > > > Fix a NULL-pointer deference when deregistering the gpio character > > device that was introduced by the recent stub-driver hack. When the new > > "driver" is unbound as part of deregistration, driver core clears the > > driver-data pointer which is used to retrieve the struct gpio_device in > > its release callback. > > > > Fix this by using container_of() in the release callback as should have > > been done all along. > > > > Fixes: 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default") > > Cc: Saravana Kannan <saravanak@xxxxxxxxxx> > > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > Reported-by: syzbot+d27b4c8adbbff70fbfde@xxxxxxxxxxxxxxxxxxxxxxxxx > > Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> > > --- > > drivers/gpio/gpiolib.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > > index adf55db080d8..e1016bc8cf14 100644 > > --- a/drivers/gpio/gpiolib.c > > +++ b/drivers/gpio/gpiolib.c > > @@ -474,7 +474,7 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid); > > > > static void gpiodevice_release(struct device *dev) > > { > > - struct gpio_device *gdev = dev_get_drvdata(dev); > > + struct gpio_device *gdev = container_of(dev, struct gpio_device, dev); > > Can you also delete the dev_set_drvdata() in > gpiochip_add_data_with_key() if the drvdata is not used > elsewhere anymore? I skimmed the code and it doesn't look like it, but > I could be wrong. Yeah, I considered it but didn't want to risk introducing any new regressions just to clean up a redundant store. But looking at it again today, I agree that it looks like it isn't used anywhere else. I'll send a v2. Thanks. Johan