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>

3 files changed, 7 insertions, 2 deletions

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 411b213c63be..7fbe1e925143 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -492,7 +492,8 @@ struct igb_adapter {
 enum e1000_state_t {
         __IGB_TESTING,
         __IGB_RESETTING,
-        __IGB_DOWN
+        __IGB_DOWN,
+        __IGB_PTP_TX_IN_PROGRESS,
 };
 
 enum igb_boards {
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;
 
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index da55fbb090b2..2cca8fd5e574 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -387,6 +387,7 @@ static void igb_ptp_tx_work(struct work_struct *work)
                                    IGB_PTP_TX_TIMEOUT)) {
                 dev_kfree_skb_any(adapter->ptp_tx_skb);
                 adapter->ptp_tx_skb = NULL;
+                clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state);
                 adapter->tx_hwtstamp_timeouts++;
                 dev_warn(&adapter->pdev->dev, "clearing Tx timestamp hang");
                 return;
@@ -480,6 +481,7 @@ static void igb_ptp_tx_hwtstamp(struct igb_adapter *adapter)
         skb_tstamp_tx(adapter->ptp_tx_skb, &shhwtstamps);
         dev_kfree_skb_any(adapter->ptp_tx_skb);
         adapter->ptp_tx_skb = NULL;
+        clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state);
 }
 
 /**
@@ -857,6 +859,7 @@ void igb_ptp_stop(struct igb_adapter *adapter)
         if (adapter->ptp_tx_skb) {
                 dev_kfree_skb_any(adapter->ptp_tx_skb);
                 adapter->ptp_tx_skb = NULL;
+                clear_bit_unlock(__IGB_PTP_TX_IN_PROGRESS, &adapter->state);
         }
 
         if (adapter->ptp_clock) {