On Tue, 2010-08-31 at 07:30 -0400, Michael Poole wrote:
> On Mon, 2010-08-30 at 23:46 -0400, Michael Poole wrote:
> > On Mon, 2010-08-30 at 13:20 -0400, Chase Douglas wrote:
> > > From: Chase Douglas <chase.douglas@xxxxxxxxxx>
> > >
> > > The driver listens only for raw events from the device. If we allow
> > > the hidinput layer to initialize, we can hit NULL pointer dereferences
> > > in the hidinput layer because disconnecting only removes the input
> > > devices from the hid device while leaving the hid fields around.
> > >
> > > Signed-off-by: Chase Douglas <chase.douglas@xxxxxxxxxxxxx>
> > > ---
> > > drivers/hid/hid-magicmouse.c | 6 ++----
> > > 1 files changed, 2 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
> > > index ee78787..2d8532d 100644
> > > --- a/drivers/hid/hid-magicmouse.c
> > > +++ b/drivers/hid/hid-magicmouse.c
> > > @@ -404,15 +404,13 @@ static int magicmouse_probe(struct hid_device *hdev,
> > > goto err_free;
> > > }
> > >
> > > - ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
> > > + /* we are handling the input ourselves */
> > > + ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW | HID_CONNECT_HIDDEV);
> > > if (ret) {
> > > dev_err(&hdev->dev, "magicmouse hw start failed\n");
> > > goto err_free;
> > > }
> > >
> > > - /* we are handling the input ourselves */
> > > - hidinput_disconnect(hdev);
> > > -
> > > report = hid_register_report(hdev, HID_INPUT_REPORT, TOUCH_REPORT_ID);
> > > if (!report) {
> > > dev_err(&hdev->dev, "unable to register touch report\n");
> >
> > This effectively reverts commit 23d021167e. Has the HID core changed so
> > that this won't cause problems when CONFIG_HIDRAW is disabled?
>
> To answer my own question, it has not changed: If CONFIG_HIDRAW is
> turned off, the device will not get attached with this change, so the
> driver does not get any input to process. Turning CONFIG_HIDRAW on
> restores the expected functionality.
>
> Maybe hidinput_disconnect() should be modified instead, to clear the
> fields that were causing null pointer dereferences?
Ahh, I should have looked at the git log of the driver :). I'll look
into the hidinput stack to figure out the best way of handling this.
Thanks,
-- Chase
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