Use RCU to protect accesses to dst->dev from sk_setup_caps() and sk_dst_gso_max_size(). Also use dst_dev_rcu() in ip6_dst_mtu_maybe_forward(), and ip_dst_mtu_maybe_forward(). ip4_dst_hoplimit() can use dst_dev_net_rcu(). Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet --- include/net/ip.h | 6 ++++-- include/net/ip6_route.h | 2 +- include/net/route.h | 2 +- net/core/sock.c | 16 ++++++++++------ 4 files changed, 16 insertions(+), 10 deletions(-) diff --git a/include/net/ip.h b/include/net/ip.h index befcba575129ac436912d9c19740a0a72fe23954..6dbd2bf8fa9c96dc342acc171471704981123eec 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -467,12 +467,14 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, bool forwarding) { const struct rtable *rt = dst_rtable(dst); + const struct net_device *dev; unsigned int mtu, res; struct net *net; rcu_read_lock(); - net = dev_net_rcu(dst_dev(dst)); + dev = dst_dev_rcu(dst); + net = dev_net_rcu(dev); if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) || ip_mtu_locked(dst) || !forwarding) { @@ -486,7 +488,7 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, if (mtu) goto out; - mtu = READ_ONCE(dst_dev(dst)->mtu); + mtu = READ_ONCE(dev->mtu); if (unlikely(ip_mtu_locked(dst))) { if (rt->rt_uses_gateway && mtu > 576) diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 9255f21818ee7b03d2608fd399b082c0098c7028..59f48ca3abdf5a8aef6b4ece13f9a1774fc04f38 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -337,7 +337,7 @@ static inline unsigned int ip6_dst_mtu_maybe_forward(const struct dst_entry *dst mtu = IPV6_MIN_MTU; rcu_read_lock(); - idev = __in6_dev_get(dst_dev(dst)); + idev = __in6_dev_get(dst_dev_rcu(dst)); if (idev) mtu = READ_ONCE(idev->cnf.mtu6); rcu_read_unlock(); diff --git a/include/net/route.h b/include/net/route.h index c71998f464f8e6f2e4e3d03bd0db6d0da875f636..f90106f383c56d5cdaa8d455c840dbcf9a5e9555 100644 --- a/include/net/route.h +++ b/include/net/route.h @@ -390,7 +390,7 @@ static inline int ip4_dst_hoplimit(const struct dst_entry *dst) const struct net *net; rcu_read_lock(); - net = dev_net_rcu(dst_dev(dst)); + net = dst_dev_net_rcu(dst); hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); rcu_read_unlock(); } diff --git a/net/core/sock.c b/net/core/sock.c index e66ad1ec3a2d969b71835a492806563519459749..9a8290fcc35d66b2011157a30c13653784e78e96 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2587,7 +2587,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) } EXPORT_SYMBOL_GPL(sk_clone_lock); -static u32 sk_dst_gso_max_size(struct sock *sk, struct dst_entry *dst) +static u32 sk_dst_gso_max_size(struct sock *sk, const struct net_device *dev) { bool is_ipv6 = false; u32 max_size; @@ -2597,8 +2597,8 @@ static u32 sk_dst_gso_max_size(struct sock *sk, struct dst_entry *dst) !ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)); #endif /* pairs with the WRITE_ONCE() in netif_set_gso(_ipv4)_max_size() */ - max_size = is_ipv6 ? READ_ONCE(dst_dev(dst)->gso_max_size) : - READ_ONCE(dst_dev(dst)->gso_ipv4_max_size); + max_size = is_ipv6 ? READ_ONCE(dev->gso_max_size) : + READ_ONCE(dev->gso_ipv4_max_size); if (max_size > GSO_LEGACY_MAX_SIZE && !sk_is_tcp(sk)) max_size = GSO_LEGACY_MAX_SIZE; @@ -2607,9 +2607,12 @@ static u32 sk_dst_gso_max_size(struct sock *sk, struct dst_entry *dst) void sk_setup_caps(struct sock *sk, struct dst_entry *dst) { + const struct net_device *dev; u32 max_segs = 1; - sk->sk_route_caps = dst_dev(dst)->features; + rcu_read_lock(); + dev = dst_dev_rcu(dst); + sk->sk_route_caps = dev->features; if (sk_is_tcp(sk)) { struct inet_connection_sock *icsk = inet_csk(sk); @@ -2625,13 +2628,14 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst) sk->sk_route_caps &= ~NETIF_F_GSO_MASK; } else { sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM; - sk->sk_gso_max_size = sk_dst_gso_max_size(sk, dst); + sk->sk_gso_max_size = sk_dst_gso_max_size(sk, dev); /* pairs with the WRITE_ONCE() in netif_set_gso_max_segs() */ - max_segs = max_t(u32, READ_ONCE(dst_dev(dst)->gso_max_segs), 1); + max_segs = max_t(u32, READ_ONCE(dev->gso_max_segs), 1); } } sk->sk_gso_max_segs = max_segs; sk_dst_set(sk, dst); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(sk_setup_caps); -- 2.51.0.318.gd7df087d1a-goog