| Message ID | 20210301090519.26192-2-johan@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | gpio: regression fixes | expand |
On Mon, Mar 1, 2021 at 10:05 AM Johan Hovold <johan@kernel.org> 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@google.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Reported-by: syzbot+d27b4c8adbbff70fbfde@syzkaller.appspotmail.com > Signed-off-by: Johan Hovold <johan@kernel.org> Oh nice catch! Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Yours, Linus Walleij
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index adf55db080d8..6e0572515d02 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); list_del(&gdev->list); ida_free(&gpio_ida, gdev->id); @@ -605,7 +605,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, goto err_free_ida; device_initialize(&gdev->dev); - dev_set_drvdata(&gdev->dev, gdev); if (gc->parent && gc->parent->driver) gdev->owner = gc->parent->driver->owner; else if (gc->owner)
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@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reported-by: syzbot+d27b4c8adbbff70fbfde@syzkaller.appspotmail.com Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/gpio/gpiolib.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)