Commit 552de910 authored by John Fastabend's avatar John Fastabend Committed by Daniel Borkmann
Browse files

bpf: sk_msg, fix socket data_ready events 



When a skb verdict program is in-use and either another BPF program
redirects to that socket or the new SK_PASS support is used the
data_ready callback does not wake up application. Instead because
the stream parser/verdict is using the sk data_ready callback we wake
up the stream parser/verdict block.

Fix this by adding a helper to check if the stream parser block is
enabled on the sk and if so call the saved pointer which is the
upper layers wake up function.

This fixes application stalls observed when an application is waiting
for data in a blocking read().

Fixes: d829e9c4 ("tls: convert to generic sk_msg interface")
Signed-off-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 51199405

include/linux/skmsg.h

+8 −0
Original line number Diff line number Diff line
@@ -417,6 +417,14 @@ static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock) 
		sk_psock_drop(sk, psock);

}



static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)

{

	if (psock->parser.enabled)

		psock->parser.saved_data_ready(sk);

	else

		sk->sk_data_ready(sk);

}



static inline void psock_set_prog(struct bpf_prog **pprog,

				  struct bpf_prog *prog)

{

net/core/skmsg.c

+3 −3
Original line number Diff line number Diff line
@@ -403,7 +403,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb) 
	msg->skb = skb;



	sk_psock_queue_msg(psock, msg);

	sk->sk_data_ready(sk);

	sk_psock_data_ready(sk, psock);

	return copied;

}
@@ -751,7 +751,7 @@ static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb) 
}



/* Called with socket lock held. */

static void sk_psock_data_ready(struct sock *sk)

static void sk_psock_strp_data_ready(struct sock *sk)

{

	struct sk_psock *psock;
@@ -799,7 +799,7 @@ void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock) 
		return;



	parser->saved_data_ready = sk->sk_data_ready;

	sk->sk_data_ready = sk_psock_data_ready;

	sk->sk_data_ready = sk_psock_strp_data_ready;

	sk->sk_write_space = sk_psock_write_space;

	parser->enabled = true;

}

net/ipv4/tcp_bpf.c

+1 −1
Original line number Diff line number Diff line
@@ -198,7 +198,7 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, 
		msg->sg.start = i;

		msg->sg.size -= apply_bytes;

		sk_psock_queue_msg(psock, tmp);

		sk->sk_data_ready(sk);

		sk_psock_data_ready(sk, psock);

	} else {

		sk_msg_free(sk, tmp);

		kfree(tmp);

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