Re: [PATCH net-next] tcp: tcp_data_ready() must look at SOCK_DONE
From: Wei Wang <hidden>
Date: 2021-02-14 18:35:26
On Sat, Feb 13, 2021 at 6:26 AM Eric Dumazet [off-list ref] wrote:
From: Eric Dumazet <edumazet@google.com>
My prior cleanup missed that tcp_data_ready() has to look at SOCK_DONE.
Otherwise, an application using SO_RCVLOWAT will not get EPOLLIN event
if a FIN is received in the middle of expected payload.
The reason SOCK_DONE is not examined in tcp_epollin_ready()
is that tcp_poll() catches the FIN because tcp_fin()
is also setting RCV_SHUTDOWN into sk->sk_shutdown
Fixes: 05dc72aba364 ("tcp: factorize logic into tcp_epollin_ready()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Wei Wang <redacted>
Cc: Arjun Roy <redacted>
---Thanks Eric for the fix! Reviewed-by: Wei Wang <redacted>
quoted hunk ↗ jump to hunk
net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index e32a7056cb7640c67ef2d6a4d9484684d2602fcd..69a545db80d2ead47ffcf2f3819a6d066e95f35d 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c@@ -4924,7 +4924,7 @@ int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size) void tcp_data_ready(struct sock *sk) { - if (tcp_epollin_ready(sk, sk->sk_rcvlowat)) + if (tcp_epollin_ready(sk, sk->sk_rcvlowat) || sock_flag(sk, SOCK_DONE)) sk->sk_data_ready(sk); } --2.30.0.478.g8a0d178c01-goog