From: Peter Holik Date: Fri, 18 Mar 2011 17:47:44 +0000 (+0100) Subject: USB: uss720 fixup refcount position X-Git-Tag: v2.6.39-rc1~85^2~5 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=adaa3c6342b249548ea830fe8e02aa5b45be8688;p=karo-tx-linux.git USB: uss720 fixup refcount position 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 Cc: stable Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c index f7a205738032..8b1d94a76914 100644 --- a/drivers/usb/misc/uss720.c +++ b/drivers/usb/misc/uss720.c @@ -177,12 +177,11 @@ static struct uss720_async_request *submit_async_request(struct parport_uss720_p 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; }