af_packet: Don't use skb after dev_queue_xmit()
tpacket_snd() can change and kfree an skb after dev_queue_xmit(),
which is illegal.
With debugging by: Stephen Hemminger <shemminger@vyatta.com>
Reported-by: Michael Breuer <mbreuer@majjas.com>
With help from: David S. Miller <davem@davemloft.net>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Tested-by: Michael Breuer<mbreuer@majjas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index e0516a2..f126d18 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1021,8 +1021,20 @@
status = TP_STATUS_SEND_REQUEST;
err = dev_queue_xmit(skb);
- if (unlikely(err > 0 && (err = net_xmit_errno(err)) != 0))
- goto out_xmit;
+ if (unlikely(err > 0)) {
+ err = net_xmit_errno(err);
+ if (err && __packet_get_status(po, ph) ==
+ TP_STATUS_AVAILABLE) {
+ /* skb was destructed already */
+ skb = NULL;
+ goto out_status;
+ }
+ /*
+ * skb was dropped but not destructed yet;
+ * let's treat it like congestion or err < 0
+ */
+ err = 0;
+ }
packet_increment_head(&po->tx_ring);
len_sum += tp_len;
} while (likely((ph != NULL) ||
@@ -1033,9 +1045,6 @@
err = len_sum;
goto out_put;
-out_xmit:
- skb->destructor = sock_wfree;
- atomic_dec(&po->tx_ring.pending);
out_status:
__packet_set_status(po, ph, status);
kfree_skb(skb);