net: kernel panic in dev_hard_start_xmit: remove faulty software TX time stamping

The current implementation of the TX software time stamping fallback is
faulty because it accesses the skb after ndo_start_xmit() returns
successfully. This patch removes the fallback, which fixes kernel panics
seen during stress tests. Hardware time stamping is not affected by this
removal.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 13 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 5493394118fb..88dc082b47d1 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1672,16 +1672,6 @@ static int dev_gso_segment(struct sk_buff *skb)
         return 0;
 }
 
-static void tstamp_tx(struct sk_buff *skb)
-{
-        union skb_shared_tx *shtx =
-                skb_tx(skb);
-        if (unlikely(shtx->software &&
-                        !shtx->in_progress)) {
-                skb_tstamp_tx(skb, NULL);
-        }
-}
-
 int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
                         struct netdev_queue *txq)
 {
@@ -1715,8 +1705,6 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
                  * the skb destructor before the call and restoring it
                  * afterwards, then doing the skb_orphan() ourselves?
                  */
-                if (likely(!rc))
-                        tstamp_tx(skb);
                 return rc;
         }
 
@@ -1732,7 +1720,6 @@ gso:
                         skb->next = nskb;
                         return rc;
                 }
-                tstamp_tx(skb);
                 if (unlikely(netif_tx_queue_stopped(txq) && skb->next))
                         return NETDEV_TX_BUSY;
         } while (skb->next);