From: John Fastabend <john.fastabend@gmail.com>
Date: Mon, 13 May 2019 21:42:03 -0700
Subject: bpf, tcp: correctly handle DONT_WAIT flags and timeo == 0
Patch-mainline: v5.2-rc2
Git-commit: 5fa2ca7c4a3fc176f31b495e1a704862d8188b53
References: bsc#1109837
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/ipv4/tcp_bpf.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -27,7 +27,10 @@ static int tcp_bpf_wait_data(struct sock
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);