| From adaa3c6342b249548ea830fe8e02aa5b45be8688 Mon Sep 17 00:00:00 2001 |
| From: Peter Holik <peter@holik.at> |
| Date: Fri, 18 Mar 2011 18:47:44 +0100 |
| Subject: USB: uss720 fixup refcount position |
| |
| From: Peter Holik <peter@holik.at> |
| |
| 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 <peter@holik.at> |
| Acked-by: Thomas Sailer <t.sailer@alumni.ethz.ch> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| 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; |
| } |