sky2: Fix oops in sky2_xmit_frame() after TX timeout

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 <mikem@ring3k.org>

Reported-by: Berck E. Nash <flyboy@gmail.com>
Tested-by: Berck E. Nash <flyboy@gmail.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 1c01b96c9611..7650f739a81a 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);
 }