netdev - [PATCH bpf v3 3/4] selftests/bpf: fix a CI failure caused by vsock sockmap test

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Date: Fri,  4 Aug 2023 03:37:39 -0400
From: Xu Kuohai <xukuohai@...weicloud.com>
To: bpf@...r.kernel.org,
	netdev@...r.kernel.org,
	John Fastabend <john.fastabend@...il.com>,
	Bobby Eshleman <bobby.eshleman@...edance.com>
Cc: Jakub Sitnicki <jakub@...udflare.com>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Daniel Borkmann <daniel@...earbox.net>,
	Alexei Starovoitov <ast@...nel.org>,
	Cong Wang <cong.wang@...edance.com>
Subject: [PATCH bpf v3 3/4] selftests/bpf: fix a CI failure caused by vsock sockmap test

From: Xu Kuohai <xukuohai@...wei.com>

BPF CI has reported the following failure:

Error: #200/79 sockmap_listen/sockmap VSOCK test_vsock_redir
  Error: #200/79 sockmap_listen/sockmap VSOCK test_vsock_redir
  ./test_progs:vsock_unix_redir_connectible:1506: egress: write: Transport endpoint is not connected
  vsock_unix_redir_connectible:FAIL:1506
  ./test_progs:vsock_unix_redir_connectible:1506: ingress: write: Transport endpoint is not connected
  vsock_unix_redir_connectible:FAIL:1506
  ./test_progs:vsock_unix_redir_connectible:1506: egress: write: Transport endpoint is not connected
  vsock_unix_redir_connectible:FAIL:1506
  ./test_progs:vsock_unix_redir_connectible:1514: ingress: recv() err, errno=11
  vsock_unix_redir_connectible:FAIL:1514
  ./test_progs:vsock_unix_redir_connectible:1518: ingress: vsock socket map failed, a != b
  vsock_unix_redir_connectible:FAIL:1518
  ./test_progs:vsock_unix_redir_connectible:1525: ingress: want pass count 1, have 0

It’s because the recv(... MSG_DONTWAIT) syscall in the test case is
called before the queued work sk_psock_backlog() in the kernel finishes
executing. So the data to be read is still queued in psock->ingress_skb
and cannot be read by the user program. Therefore, the non-blocking
recv() reads nothing and reports an EAGAIN error.

So replace recv(... MSG_DONTWAIT) with xrecv_nonblock(), which calls
select() to wait for data to be readable or timeout before calls recv().

Fixes: d61bd8c1fd02 ("selftests/bpf: add a test case for vsock sockmap")
Signed-off-by: Xu Kuohai <xukuohai@...wei.com>
---
 tools/testing/selftests/bpf/prog_tests/sockmap_listen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
index b4f6f3a50ae5..ba35bcc66e7e 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
@@ -1432,7 +1432,7 @@ static void vsock_unix_redir_connectible(int sock_mapfd, int verd_mapfd,
 	if (n < 1)
 		goto out;
 
-	n = recv(mode == REDIR_INGRESS ? u0 : u1, &b, sizeof(b), MSG_DONTWAIT);
+	n = xrecv_nonblock(mode == REDIR_INGRESS ? u0 : u1, &b, sizeof(b), 0);
 	if (n < 0)
 		FAIL("%s: recv() err, errno=%d", log_prefix, errno);
 	if (n == 0)
-- 
2.30.2