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: Paul Durrant <[email protected]>
Cc: Ian Campbell <[email protected]>
Cc: Wei Liu <[email protected]>
Cc: Sander Eikelenboom <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 573f3e8..cd0bd95 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -482,6 +482,8 @@
while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
RING_IDX max_slots_needed;
+ RING_IDX old_req_cons;
+ RING_IDX ring_slots_used;
int i;
/* We need a cheap worse case estimate for the number of
@@ -530,8 +532,12 @@
vif->rx_last_skb_slots = 0;
sco = (struct skb_cb_overlay *)skb->cb;
+
+ old_req_cons = vif->rx.req_cons;
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);
}
