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

ixgbe 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: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

3 files changed, 7 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index 2fff0fc4e6e8..26d27aae9793 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -812,6 +812,7 @@ enum ixgbe_state_t {
         __IXGBE_SERVICE_SCHED,
         __IXGBE_IN_SFP_INIT,
         __IXGBE_PTP_RUNNING,
+        __IXGBE_PTP_TX_IN_PROGRESS,
 };
 
 struct ixgbe_cb {
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 24538cb0f856..c4b930c0ce7f 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7042,7 +7042,9 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
                 tx_flags |= IXGBE_TX_FLAGS_SW_VLAN;
         }
 
-        if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
+        if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&
+                     !test_and_set_bit_lock(__IXGBE_PTP_TX_IN_PROGRESS,
+                                            &adapter->state))) {
                 skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
                 tx_flags |= IXGBE_TX_FLAGS_TSTAMP;
 
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
index 8b527d79d429..63515a6f67fa 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
@@ -493,6 +493,7 @@ static void ixgbe_ptp_tx_hwtstamp(struct ixgbe_adapter *adapter)
 
         dev_kfree_skb_any(adapter->ptp_tx_skb);
         adapter->ptp_tx_skb = NULL;
+        clear_bit_unlock(__IXGBE_PTP_TX_IN_PROGRESS, &adapter->state);
 }
 
 /**
@@ -515,6 +516,7 @@ static void ixgbe_ptp_tx_hwtstamp_work(struct work_struct *work)
         if (timeout) {
                 dev_kfree_skb_any(adapter->ptp_tx_skb);
                 adapter->ptp_tx_skb = NULL;
+                clear_bit_unlock(__IXGBE_PTP_TX_IN_PROGRESS, &adapter->state);
                 e_warn(drv, "clearing Tx Timestamp hang");
                 return;
         }
@@ -925,6 +927,7 @@ void ixgbe_ptp_stop(struct ixgbe_adapter *adapter)
         if (adapter->ptp_tx_skb) {
                 dev_kfree_skb_any(adapter->ptp_tx_skb);
                 adapter->ptp_tx_skb = NULL;
+                clear_bit_unlock(__IXGBE_PTP_TX_IN_PROGRESS, &adapter->state);
         }
 
         if (adapter->ptp_clock) {