Hi , i am also using HIDDEV interface . and i also got hiddev_ioctl NULL dereference problem . Below patch fixes my problem . Regards Amit Nagal On Fri, Aug 13, 2010 at 4:37 AM, Chris Ball <cjb@xxxxxxxxxx> wrote: > One of our users reports consistently hitting a NULL dereference that > resolves to the "hid_to_usb_dev(hid);" call in hiddev_ioctl(), when > disconnecting a Lego WeDo USB HID device from an OLPC XO running > Scratch software. There's a FIXME comment and a guard against the > dereference, but that happens farther down the function than the > initial dereference does. > > This patch moves the call to be below the guard, and the user reports > that it fixes the problem for him. OLPC bug report: > http://dev.laptop.org/ticket/10174 > > Signed-off-by: Chris Ball <cjb@xxxxxxxxxx> > --- > drivers/hid/usbhid/hiddev.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c > index c24d2fa..7ec009a 100644 > --- a/drivers/hid/usbhid/hiddev.c > +++ b/drivers/hid/usbhid/hiddev.c > @@ -593,7 +593,7 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > struct hiddev_list *list = file->private_data; > struct hiddev *hiddev = list->hiddev; > struct hid_device *hid = hiddev->hid; > - struct usb_device *dev = hid_to_usb_dev(hid); > + struct usb_device *dev; > struct hiddev_collection_info cinfo; > struct hiddev_report_info rinfo; > struct hiddev_field_info finfo; > @@ -607,9 +607,11 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > /* Called without BKL by compat methods so no BKL taken */ > > /* FIXME: Who or what stop this racing with a disconnect ?? */ > - if (!hiddev->exist) > + if (!hiddev->exist || !hid) > return -EIO; > > + dev = hid_to_usb_dev(hid); > + > switch (cmd) { > > case HIDIOCGVERSION: > -- > 1.7.0.1 > > -- > Chris Ball <cjb@xxxxxxxxxx> > One Laptop Per Child > -- > To unsubscribe from this list: send the line "unsubscribe linux-input" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
