ipv6: avoid high order allocations

With mtu=9000, mld_newpack() use order-2 GFP_ATOMIC allocations, that
are very unreliable, on machines where PAGE_SIZE=4K

Limit allocated skbs to be at most one page. (order-0 allocations)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 59f1881968c7..ab1622d7d409 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1356,7 +1356,10 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
                      IPV6_TLV_PADN, 0 };
 
         /* we assume size > sizeof(ra) here */
-        skb = sock_alloc_send_skb(sk, size + LL_ALLOCATED_SPACE(dev), 1, &err);
+        size += LL_ALLOCATED_SPACE(dev);
+        /* limit our allocations to order-0 page */
+        size = min_t(int, size, SKB_MAX_ORDER(0, 0));
+        skb = sock_alloc_send_skb(sk, size, 1, &err);
 
         if (!skb)
                 return NULL;