On Tue, 26 Feb 2013, Johan Hovold wrote: > The calls to usb_poison_urb and usb_unpoison_urb are expected to be > balanced. However, if an urb that has not yet been submitted is > poisoned, its reject counter will not be increased as its ep-field is > NULL. A consecutive call to unpoison will thus in fact poison the urb > as its reject counter will be decremented to a negative value, > effectively preventing the urb from being submitted. > > Note that there are currently no in-kernel drivers affected by this. > > Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx> > --- > drivers/usb/core/urb.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c > index e0d9d94..16927fa 100644 > --- a/drivers/usb/core/urb.c > +++ b/drivers/usb/core/urb.c > @@ -683,10 +683,13 @@ EXPORT_SYMBOL_GPL(usb_kill_urb); > void usb_poison_urb(struct urb *urb) > { > might_sleep(); > - if (!(urb && urb->dev && urb->ep)) > + if (!urb) > return; > atomic_inc(&urb->reject); > > + if (!urb->dev || !urb->ep) > + return; > + > usb_hcd_unlink_urb(urb, -ENOENT); > wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); > } Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> -- 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