Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2020-02-21

The following pull-request contains BPF updates for your *net-next* tree.

We've added 25 non-merge commits during the last 4 day(s) which contain
a total of 33 files changed, 2433 insertions(+), 161 deletions(-).

The main changes are:

1) Allow for adding TCP listen sockets into sock_map/hash so they can be used
   with reuseport BPF programs, from Jakub Sitnicki.

2) Add a new bpf_program__set_attach_target() helper for adding libbpf support
   to specify the tracepoint/function dynamically, from Eelco Chaudron.

3) Add bpf_read_branch_records() BPF helper which helps use cases like profile
   guided optimizations, from Daniel Xu.

4) Enable bpf_perf_event_read_value() in all tracing programs, from Song Liu.

5) Relax BTF mandatory check if only used for libbpf itself e.g. to process
   BTF defined maps, from Andrii Nakryiko.

6) Move BPF selftests -mcpu compilation attribute from 'probe' to 'v3' as it has
   been observed that former fails in envs with low memlock, from Yonghong Song.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 21 insertions, 2 deletions

diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 8a01428f80c1..7d6e1b75d4d4 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -645,8 +645,10 @@ static void tcp_bpf_reinit_sk_prot(struct sock *sk, struct sk_psock *psock)
 	/* Reinit occurs when program types change e.g. TCP_BPF_TX is removed
 	 * or added requiring sk_prot hook updates. We keep original saved
 	 * hooks in this case.
+	 *
+	 * Pairs with lockless read in sk_clone_lock().
 	 */
-	sk->sk_prot = &tcp_bpf_prots[family][config];
+	WRITE_ONCE(sk->sk_prot, &tcp_bpf_prots[family][config]);
 }
 
 static int tcp_bpf_assert_proto_ops(struct proto *ops)
@@ -691,3 +693,17 @@ int tcp_bpf_init(struct sock *sk)
 	rcu_read_unlock();
 	return 0;
 }
+
+/* If a child got cloned from a listening socket that had tcp_bpf
+ * protocol callbacks installed, we need to restore the callbacks to
+ * the default ones because the child does not inherit the psock state
+ * that tcp_bpf callbacks expect.
+ */
+void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
+{
+	int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
+	struct proto *prot = newsk->sk_prot;
+
+	if (prot == &tcp_bpf_prots[family][TCP_BPF_BASE])
+		newsk->sk_prot = sk->sk_prot_creator;
+}
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index ad3b56d9fa71..c8274371c3d0 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -548,6 +548,8 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 	newtp->fastopen_req = NULL;
 	RCU_INIT_POINTER(newtp->fastopen_rsk, NULL);
 
+	tcp_bpf_clone(sk, newsk);
+
 	__TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);
 
 	return newsk;
diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 38d3ad141161..6c43fa189195 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -106,7 +106,8 @@ void tcp_update_ulp(struct sock *sk, struct proto *proto,
 
 	if (!icsk->icsk_ulp_ops) {
 		sk->sk_write_space = write_space;
-		sk->sk_prot = proto;
+		/* Pairs with lockless read in sk_clone_lock() */
+		WRITE_ONCE(sk->sk_prot, proto);
 		return;
 	}