net: ll_temac: Fix TX BD buffer overwrite

Just as the initial check, we need to ensure num_frag+1 buffers available,
as that is the number of buffers we are going to use.

This fixes a buffer overflow, which might be seen during heavy network
load. Complete lockup of TEMAC was reproducible within about 10 minutes of
a particular load.

Fixes: 84823ff80f ("net: ll_temac: Fix race condition causing TX hang")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Esben Haabendal <esben@geanix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Esben Haabendal 2021-06-18 12:52:33 +02:00 committed by David S. Miller
parent 28d9fab458
commit c364df2489

View file

@ -861,7 +861,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
smp_mb();
/* Space might have just been freed - check again */
if (temac_check_tx_bd_space(lp, num_frag))
if (temac_check_tx_bd_space(lp, num_frag + 1))
return NETDEV_TX_BUSY;
netif_wake_queue(ndev);