From: Peter Holik commit adaa3c6342b249548ea830fe8e02aa5b45be8688 upstream. My testprog do a lot of bitbang - after hours i got following warning and my machine lockups: WARNING: at /build/buildd/linux-2.6.38/lib/kref.c:34 After debugging uss720 driver i discovered that the completion callback was called before usb_submit_urb returns. The callback frees the request structure that is krefed on return by usb_submit_urb. Signed-off-by: Peter Holik Acked-by: Thomas Sailer Signed-off-by: Greg Kroah-Hartman --- drivers/usb/misc/uss720.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/drivers/usb/misc/uss720.c +++ b/drivers/usb/misc/uss720.c @@ -176,12 +176,11 @@ static struct uss720_async_request *subm spin_lock_irqsave(&priv->asynclock, flags); list_add_tail(&rq->asynclist, &priv->asynclist); spin_unlock_irqrestore(&priv->asynclock, flags); + kref_get(&rq->ref_count); ret = usb_submit_urb(rq->urb, mem_flags); - if (!ret) { - kref_get(&rq->ref_count); + if (!ret) return rq; - } - kref_put(&rq->ref_count, destroy_async); + destroy_async(&rq->ref_count); err("submit_async_request submit_urb failed with %d", ret); return NULL; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/