net: use rcu_dereference_protected to fetch sk_dst_cache in sk_destruct (5869b8fa) · Commits · 戴 / test

As Eric noticed, in .sk_destruct, sk->sk_dst_cache update is prevented, and no barrier is needed for this. So change to use rcu_dereference_protected() instead of rcu_dereference_check() to fetch sk_dst_cache in there. v1->v2: - no change, repost after net-next is open. Reported-by:

Eric Dumazet <edumazet@google.com> Signed-off-by:

Xin Long <lucien.xin@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/decnet/af_decnet.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -444,7 +444,7 @@ static void dn_destruct(struct sock *sk)
		skb_queue_purge(&scp->other_xmit_queue);
		skb_queue_purge(&scp->other_receive_queue);

		dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
		dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
		}

		static unsigned long dn_memory_pressure;

net/ipv4/af_inet.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -160,7 +160,7 @@ void inet_sock_destruct(struct sock *sk)
		WARN_ON(sk->sk_forward_alloc);

		kfree(rcu_dereference_protected(inet->inet_opt, 1));
		dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
		dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
		dst_release(sk->sk_rx_dst);
		sk_refcnt_debug_dec(sk);
		}

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