diff --git a/drivers/net/mctp/Kconfig b/drivers/net/mctp/Kconfig
index ce9d2d2ccf3bb4..15860d6ac39fef 100644
--- a/drivers/net/mctp/Kconfig
+++ b/drivers/net/mctp/Kconfig
@@ -21,6 +21,11 @@ config MCTP_SERIAL
 	  Say y here if you need to connect to MCTP endpoints over serial. To
 	  compile as a module, use m; the module will be called mctp-serial.
 
+config MCTP_SERIAL_TEST
+        bool "MCTP serial tests" if !KUNIT_ALL_TESTS
+        depends on MCTP_SERIAL=y && KUNIT=y
+        default KUNIT_ALL_TESTS
+
 config MCTP_TRANSPORT_I2C
 	tristate "MCTP SMBus/I2C transport"
 	# i2c-mux is optional, but we must build as a module if i2c-mux is a module
diff --git a/drivers/net/mctp/mctp-serial.c b/drivers/net/mctp/mctp-serial.c
index 5bf6fdff701cd6..f39bbe255497df 100644
--- a/drivers/net/mctp/mctp-serial.c
+++ b/drivers/net/mctp/mctp-serial.c
@@ -91,8 +91,8 @@ static int next_chunk_len(struct mctp_serial *dev)
 	 * will be those non-escaped bytes, and does not include the escaped
 	 * byte.
 	 */
-	for (i = 1; i + dev->txpos + 1 < dev->txlen; i++) {
-		if (needs_escape(dev->txbuf[dev->txpos + i + 1]))
+	for (i = 1; i + dev->txpos < dev->txlen; i++) {
+		if (needs_escape(dev->txbuf[dev->txpos + i]))
 			break;
 	}
 
@@ -521,3 +521,112 @@ module_exit(mctp_serial_exit);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
 MODULE_DESCRIPTION("MCTP Serial transport");
+
+#if IS_ENABLED(CONFIG_MCTP_SERIAL_TEST)
+#include <kunit/test.h>
+
+#define MAX_CHUNKS 6
+struct test_chunk_tx {
+	u8 input_len;
+	u8 input[MCTP_SERIAL_MTU];
+	u8 chunks[MAX_CHUNKS];
+};
+
+static void test_next_chunk_len(struct kunit *test)
+{
+	struct mctp_serial devx;
+	struct mctp_serial *dev = &devx;
+	int next;
+
+	const struct test_chunk_tx *params = test->param_value;
+
+	memset(dev, 0x0, sizeof(*dev));
+	memcpy(dev->txbuf, params->input, params->input_len);
+	dev->txlen = params->input_len;
+
+	for (size_t i = 0; i < MAX_CHUNKS; i++) {
+		next = next_chunk_len(dev);
+		dev->txpos += next;
+		KUNIT_EXPECT_EQ(test, next, params->chunks[i]);
+
+		if (next == 0) {
+			KUNIT_EXPECT_EQ(test, dev->txpos, dev->txlen);
+			return;
+		}
+	}
+
+	KUNIT_FAIL_AND_ABORT(test, "Ran out of chunks");
+}
+
+static struct test_chunk_tx chunk_tx_tests[] = {
+	{
+		.input_len = 5,
+		.input = { 0x00, 0x11, 0x22, 0x7e, 0x80 },
+		.chunks = { 3, 1, 1, 0},
+	},
+	{
+		.input_len = 5,
+		.input = { 0x00, 0x11, 0x22, 0x7e, 0x7d },
+		.chunks = { 3, 1, 1, 0},
+	},
+	{
+		.input_len = 3,
+		.input = { 0x7e, 0x11, 0x22, },
+		.chunks = { 1, 2, 0},
+	},
+	{
+		.input_len = 3,
+		.input = { 0x7e, 0x7e, 0x7d, },
+		.chunks = { 1, 1, 1, 0},
+	},
+	{
+		.input_len = 4,
+		.input = { 0x7e, 0x7e, 0x00, 0x7d, },
+		.chunks = { 1, 1, 1, 1, 0},
+	},
+	{
+		.input_len = 6,
+		.input = { 0x7e, 0x7e, 0x00, 0x7d, 0x10, 0x10},
+		.chunks = { 1, 1, 1, 1, 2, 0},
+	},
+	{
+		.input_len = 1,
+		.input = { 0x7e },
+		.chunks = { 1, 0 },
+	},
+	{
+		.input_len = 1,
+		.input = { 0x80 },
+		.chunks = { 1, 0 },
+	},
+	{
+		.input_len = 3,
+		.input = { 0x80, 0x80, 0x00 },
+		.chunks = { 3, 0 },
+	},
+	{
+		.input_len = 7,
+		.input = { 0x01, 0x00, 0x08, 0xc8, 0x00, 0x80, 0x02 },
+		.chunks = { 7, 0 },
+	},
+	{
+		.input_len = 7,
+		.input = { 0x01, 0x00, 0x08, 0xc8, 0x7e, 0x80, 0x02 },
+		.chunks = { 4, 1, 2, 0 },
+	},
+};
+
+KUNIT_ARRAY_PARAM(chunk_tx, chunk_tx_tests, NULL);
+
+static struct kunit_case mctp_serial_test_cases[] = {
+	KUNIT_CASE_PARAM(test_next_chunk_len, chunk_tx_gen_params),
+};
+
+static struct kunit_suite mctp_serial_test_suite = {
+	.name = "mctp_serial",
+	.test_cases = mctp_serial_test_cases,
+};
+
+kunit_test_suite(mctp_serial_test_suite);
+
+#endif /* CONFIG_MCTP_SERIAL_TEST */
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 53b0d62fd2c2db..fe6178715ba05f 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -577,7 +577,7 @@ static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 		err = sk_stream_error(sk, msg->msg_flags, err);
 	release_sock(sk);
 	sk_psock_put(sk, psock);
-	return copied ? copied : err;
+	return copied > 0 ? copied : err;
 }
 
 enum {
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 34b781e463c43a..ad77d6b6b8d3ae 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -284,6 +284,9 @@ struct smc_connection {
 
 struct smc_sock {				/* smc sock container */
 	struct sock		sk;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct ipv6_pinfo	*pinet6;
+#endif
 	struct socket		*clcsock;	/* internal tcp socket */
 	void			(*clcsk_state_change)(struct sock *sk);
 						/* original stat_change fct. */
diff --git a/net/smc/smc_inet.c b/net/smc/smc_inet.c
index bece346dd8e9d7..a5b2041600f959 100644
--- a/net/smc/smc_inet.c
+++ b/net/smc/smc_inet.c
@@ -60,6 +60,11 @@ static struct inet_protosw smc_inet_protosw = {
 };
 
 #if IS_ENABLED(CONFIG_IPV6)
+struct smc6_sock {
+	struct smc_sock		smc;
+	struct ipv6_pinfo	inet6;
+};
+
 static struct proto smc_inet6_prot = {
 	.name		= "INET6_SMC",
 	.owner		= THIS_MODULE,
@@ -67,9 +72,10 @@ static struct proto smc_inet6_prot = {
 	.hash		= smc_hash_sk,
 	.unhash		= smc_unhash_sk,
 	.release_cb	= smc_release_cb,
-	.obj_size	= sizeof(struct smc_sock),
+	.obj_size	= sizeof(struct smc6_sock),
 	.h.smc_hash	= &smc_v6_hashinfo,
 	.slab_flags	= SLAB_TYPESAFE_BY_RCU,
+	.ipv6_pinfo_offset	= offsetof(struct smc6_sock, inet6),
 };
 
 static const struct proto_ops smc_inet6_stream_ops = {