Subject: [PATCH v2] sky2: Fix oops in sky2_xmit_frame() after TX timeout

From: Jarek Poplawski <[email-masked]>
Date: Mon, 4 Jan 2010 19:48:41 +0100

On Mon, Jan 04, 2010 at 10:26:37AM -0800, Stephen Hemminger wrote:
> > -	if (tx_avail(sky2) > MAX_SKB_TX_LE + 4)
> > +	/* Wake unless it's detached, and called e.g. from sky2_down() */
> > +	if (tx_avail(sky2) > MAX_SKB_TX_LE + 4 &&
> > +	    likely(netif_device_present(dev)))
> >  		netif_wake_queue(dev);
> >  }
> >
> 
> The likely() seems unnecessary noise here. It can't possibly matter that
> much.

OK. Thanks,
Jarek P.
------------> (take 2)

During TX timeout procedure dev could be awoken too early, e.g. by
sky2_complete_tx() called from sky2_down(). Then sky2_xmit_frame()
can run while buffers are freed causing an oops. This patch fixes it
by adding netif_device_present() test in sky2_tx_complete().

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14925

With debugging by: Mike McCormack <[email-masked]>

Reported-by: Berck E. Nash <[email-masked]>
Tested-by: Berck E. Nash <[email-masked]>
Signed-off-by: Jarek Poplawski <[email-masked]>

---

 drivers/net/sky2.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 1c01b96..7650f73 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1844,7 +1844,8 @@ static void sky2_tx_complete(struct sky2_port *sky2, u16 done)
 	sky2->tx_cons = idx;
 	smp_mb();
 
-	if (tx_avail(sky2) > MAX_SKB_TX_LE + 4)
+	/* Wake unless it's detached, and called e.g. from sky2_down() */
+	if (tx_avail(sky2) > MAX_SKB_TX_LE + 4 && netif_device_present(dev))
 		netif_wake_queue(dev);
 }