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Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c3
-rw-r--r--net/ipv4/devinet.c5
-rw-r--r--net/ipv4/ip_output.c14
3 files changed, 11 insertions, 11 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 903c6242b449..108c32903a74 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6126,7 +6126,8 @@ static int __dev_set_mtu(struct net_device *dev, int new_mtu)
if (ops->ndo_change_mtu)
return ops->ndo_change_mtu(dev, new_mtu);
- dev->mtu = new_mtu;
+ /* Pairs with all the lockless reads of dev->mtu in the stack */
+ WRITE_ONCE(dev->mtu, new_mtu);
return 0;
}
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 4472329f5f47..dbbe6f051a92 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1364,11 +1364,6 @@ skip:
}
}
-static bool inetdev_valid_mtu(unsigned int mtu)
-{
- return mtu >= IPV4_MIN_MTU;
-}
-
static void inetdev_send_gratuitous_arp(struct net_device *dev,
struct in_device *in_dev)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 6d5a0a7ebe10..d940c9e0eb02 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1145,13 +1145,17 @@ static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
rt = *rtp;
if (unlikely(!rt))
return -EFAULT;
- /*
- * We steal reference to this route, caller should not release it
- */
- *rtp = NULL;
+
cork->fragsize = ip_sk_use_pmtu(sk) ?
- dst_mtu(&rt->dst) : rt->dst.dev->mtu;
+ dst_mtu(&rt->dst) : READ_ONCE(rt->dst.dev->mtu);
+
+ if (!inetdev_valid_mtu(cork->fragsize))
+ return -ENETUNREACH;
+
cork->dst = &rt->dst;
+ /* We stole this route, caller should not release it. */
+ *rtp = NULL;
+
cork->length = 0;
cork->ttl = ipc->ttl;
cork->tos = ipc->tos;