Commit ad4f15dc authored by Juergen Gross's avatar Juergen Gross Committed by David S. Miller
Browse files

xen/netfront: don't bug in case of too many frags

Commit 57f230ab ("xen/netfront: raise max number of slots in
xennet_get_responses()") raised the max number of allowed slots by one.
This seems to be problematic in some configurations with netback using
a larger MAX_SKB_FRAGS value (e.g. old Linux kernel with MAX_SKB_FRAGS
defined as 18 instead of nowadays 17).

Instead of BUG_ON() in this case just fall back to retransmission.

Fixes: 57f230ab

 ("xen/netfront: raise max number of slots in xennet_get_responses()")
Signed-off-by: default avatarJuergen Gross <>
Signed-off-by: default avatarDavid S. Miller <>
parent 22d0bd82
......@@ -908,7 +908,11 @@ static RING_IDX xennet_fill_frags(struct netfront_queue *queue,
BUG_ON(pull_to <= skb_headlen(skb));
__pskb_pull_tail(skb, pull_to - skb_headlen(skb));
BUG_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS);
if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
queue->rx.rsp_cons = ++cons;
return ~0U;
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
......@@ -1045,6 +1049,8 @@ err:
skb->len += rx->status;
i = xennet_fill_frags(queue, skb, &tmpq);
if (unlikely(i == ~0U))
goto err;
if (rx->flags & XEN_NETRXF_csum_blank)
skb->ip_summed = CHECKSUM_PARTIAL;
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