| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.1 061/115] bpf, tcp: correctly handle DONT_WAIT flags and timeo == 0 | Date | Mon, 17 Jun 2019 23:09:21 +0200 |
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[ Upstream commit 5fa2ca7c4a3fc176f31b495e1a704862d8188b53 ]
The tcp_bpf_wait_data() routine needs to check timeo != 0 before calling sk_wait_event() otherwise we may see unexpected stalls on receiver.
Arika did all the leg work here I just formatted, posted and ran a few tests.
Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: Arika Chen <eaglesora@gmail.com> Suggested-by: Arika Chen <eaglesora@gmail.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/ipv4/tcp_bpf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 4a619c85daed..3d1e15401384 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -27,7 +27,10 @@ static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, int flags, long timeo, int *err) { DEFINE_WAIT_FUNC(wait, woken_wake_function); - int ret; + int ret = 0; + + if (!timeo) + return ret; add_wait_queue(sk_sleep(sk), &wait); sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); -- 2.20.1
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