linux-kernel - [PATCH net-next 1/2] vsock/test: retry send() to avoid occasional failure in sigpipe test

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Message-ID: <20250508142005.135857-2-sgarzare@redhat.com>
Date: Thu,  8 May 2025 16:20:04 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Stefano Garzarella <sgarzare@...hat.com>,
	virtualization@...ts.linux.dev
Subject: [PATCH net-next 1/2] vsock/test: retry send() to avoid occasional failure in sigpipe test

From: Stefano Garzarella <sgarzare@...hat.com>

When the other peer calls shutdown(SHUT_RD), there is a chance that
the send() call could occur before the message carrying the close
information arrives over the transport. In such cases, the send()
might still succeed. To avoid this race, let's retry the send() call
a few times, ensuring the test is more reliable.

Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
---
 tools/testing/vsock/vsock_test.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
index d0f6d253ac72..7de870dee1cf 100644
--- a/tools/testing/vsock/vsock_test.c
+++ b/tools/testing/vsock/vsock_test.c
@@ -1064,11 +1064,18 @@ static void test_stream_check_sigpipe(int fd)
 
 	have_sigpipe = 0;
 
-	res = send(fd, "A", 1, 0);
-	if (res != -1) {
-		fprintf(stderr, "expected send(2) failure, got %zi\n", res);
-		exit(EXIT_FAILURE);
-	}
+	/* When the other peer calls shutdown(SHUT_RD), there is a chance that
+	 * the send() call could occur before the message carrying the close
+	 * information arrives over the transport. In such cases, the send()
+	 * might still succeed. To avoid this race, let's retry the send() call
+	 * a few times, ensuring the test is more reliable.
+	 */
+	timeout_begin(TIMEOUT);
+	do {
+		res = send(fd, "A", 1, 0);
+		timeout_check("send");
+	} while (res != -1);
+	timeout_end();
 
 	if (!have_sigpipe) {
 		fprintf(stderr, "SIGPIPE expected\n");
@@ -1077,11 +1084,12 @@ static void test_stream_check_sigpipe(int fd)
 
 	have_sigpipe = 0;
 
-	res = send(fd, "A", 1, MSG_NOSIGNAL);
-	if (res != -1) {
-		fprintf(stderr, "expected send(2) failure, got %zi\n", res);
-		exit(EXIT_FAILURE);
-	}
+	timeout_begin(TIMEOUT);
+	do {
+		res = send(fd, "A", 1, MSG_NOSIGNAL);
+		timeout_check("send");
+	} while (res != -1);
+	timeout_end();
 
 	if (have_sigpipe) {
 		fprintf(stderr, "SIGPIPE not expected\n");
-- 
2.49.0