Re: [PATCH] HID: magicmouse: Fix an error handling path in magicmouse_probe()

[Christophe JAILLET]

Le 29/12/2021 à 08:50, José Expósito a écrit :
> On Tue, Dec 28, 2021 at 10:09:17PM +0100, Christophe JAILLET wrote:
> > If the timer introduced by the commit below is started, then it must be
> > deleted in the error handling of the probe. Otherwise it would trigger
> > once the driver is no more.
> >
> > Fixes: 0b91b4e4dae6 ("HID: magicmouse: Report battery level over USB")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/hid/hid-magicmouse.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
> > index eba1e8087bfd..b8b08f0a8c54 100644
> > --- a/drivers/hid/hid-magicmouse.c
> > +++ b/drivers/hid/hid-magicmouse.c
> > @@ -873,6 +873,7 @@ static int magicmouse_probe(struct hid_device *hdev,
> >   
> >   	return 0;
> >   err_stop_hw:
> > +	del_timer_sync(&msc->battery_timer);
> >   	hid_hw_stop(hdev);
> >   	return ret;
> >   }
> > --
> > 2.32.0
>
> My bad, thanks for catching it!
>
> Tested-by: José Expósito <jose.exposito89@xxxxxxxxx>

Hi, just in case, I got a reply from syzbot that this patch fixes:

https://syzkaller.appspot.com/bug?id=ae4e9aaf5651e1d6895071208c7844d4fdfbe30c

If it is the same issue, we can add:
Reported-by: syzbot+a437546ec71b04dfb5ac@xxxxxxxxxxxxxxxxxxxxxxxxx


I've not found it with syzbot, but with a coccinelle script which tries 
to spot things that are in the remove function and should also be in the 
error handling path of the probe.

However, if it help syzbot, I don't care mentioning it.

CJ