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authorRusty Russell <rusty@rustcorp.com.au>2008-05-26 17:42:42 +1000
committerJeff Garzik <jgarzik@redhat.com>2008-05-30 22:07:20 -0400
commit7eb2e25112bf920bb0a4d1cca445f3d96874c25f (patch)
treecb26b7adfe4c8af39361716966049ed8dd4732d0
parentd399cf8c04c595d738d82d02ae2755b902a51571 (diff)
virtio: fix virtio_net xmit of freed skb bug
If we fail to transmit a packet, we assume the queue is full and put the skb into last_xmit_skb. However, if more space frees up before we xmit it, we loop, and the result can be transmitting the same skb twice. Fix is simple: set skb to NULL if we've used it in some way, and check before sending. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
-rw-r--r--drivers/net/virtio_net.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index fe7cdf2a2a2..d50f4fe352b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -287,21 +287,25 @@ again:
free_old_xmit_skbs(vi);
/* If we has a buffer left over from last time, send it now. */
- if (vi->last_xmit_skb) {
+ if (unlikely(vi->last_xmit_skb)) {
if (xmit_skb(vi, vi->last_xmit_skb) != 0) {
/* Drop this skb: we only queue one. */
vi->dev->stats.tx_dropped++;
kfree_skb(skb);
+ skb = NULL;
goto stop_queue;
}
vi->last_xmit_skb = NULL;
}
/* Put new one in send queue and do transmit */
- __skb_queue_head(&vi->send, skb);
- if (xmit_skb(vi, skb) != 0) {
- vi->last_xmit_skb = skb;
- goto stop_queue;
+ if (likely(skb)) {
+ __skb_queue_head(&vi->send, skb);
+ if (xmit_skb(vi, skb) != 0) {
+ vi->last_xmit_skb = skb;
+ skb = NULL;
+ goto stop_queue;
+ }
}
done:
vi->svq->vq_ops->kick(vi->svq);