Commit 1425c7a4 authored by Paul Durrant's avatar Paul Durrant Committed by David S. Miller

xen-netback: BUG_ON in xenvif_rx_action() not catching overflow

The BUG_ON to catch ring overflow in xenvif_rx_action() makes the assumption
that meta_slots_used == ring slots used. This is not necessarily the case
for GSO packets, because the non-prefix GSO protocol consumes one more ring
slot than meta-slot for the 'extra_info'. This patch changes the test to
actually check ring slots.
Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a02eb473
...@@ -482,6 +482,8 @@ static void xenvif_rx_action(struct xenvif *vif) ...@@ -482,6 +482,8 @@ static void xenvif_rx_action(struct xenvif *vif)
while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) { while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
RING_IDX max_slots_needed; RING_IDX max_slots_needed;
RING_IDX old_req_cons;
RING_IDX ring_slots_used;
int i; int i;
/* We need a cheap worse case estimate for the number of /* We need a cheap worse case estimate for the number of
...@@ -530,8 +532,12 @@ static void xenvif_rx_action(struct xenvif *vif) ...@@ -530,8 +532,12 @@ static void xenvif_rx_action(struct xenvif *vif)
vif->rx_last_skb_slots = 0; vif->rx_last_skb_slots = 0;
sco = (struct skb_cb_overlay *)skb->cb; sco = (struct skb_cb_overlay *)skb->cb;
old_req_cons = vif->rx.req_cons;
sco->meta_slots_used = xenvif_gop_skb(skb, &npo); sco->meta_slots_used = xenvif_gop_skb(skb, &npo);
BUG_ON(sco->meta_slots_used > max_slots_needed); ring_slots_used = vif->rx.req_cons - old_req_cons;
BUG_ON(ring_slots_used > max_slots_needed);
__skb_queue_tail(&rxq, skb); __skb_queue_tail(&rxq, skb);
} }
......
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