igb: fix race conditions on queuing skb for HW time stamp

igb has a single set of TX time stamping resources per NIC.
Use a simple bit lock to avoid race conditions and leaking skbs
when multiple TX rings try to claim time stamping.

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 1fdffa20fe97..55fc5596e2d0 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4983,7 +4983,8 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
         if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
                 struct igb_adapter *adapter = netdev_priv(tx_ring->netdev);
 
-                if (!(adapter->ptp_tx_skb)) {
+                if (!test_and_set_bit_lock(__IGB_PTP_TX_IN_PROGRESS,
+                                           &adapter->state)) {
                         skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
                         tx_flags |= IGB_TX_FLAGS_TSTAMP;