selftests: net: make the dump test less sensitive to mem accounting

index 07423f256f96..7618ebe528a4 100644
@@ -31,9 +31,18 @@ struct ext_ack {
 	const char *str;
 };
 
-/* 0: no done, 1: done found, 2: extack found, -1: error */
-static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
+enum get_ea_ret {
+	ERROR = -1,
+	NO_CTRL = 0,
+	FOUND_DONE,
+	FOUND_ERR,
+	FOUND_EXTACK,
+};
+
+static enum get_ea_ret
+nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
 {
+	enum get_ea_ret ret = NO_CTRL;
 	const struct nlmsghdr *nlh;
 	const struct nlattr *attr;
 	ssize_t rem;

@@ -41,15 +50,19 @@ static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
 	for (rem = n; rem > 0; NLMSG_NEXT(nlh, rem)) {
 		nlh = (struct nlmsghdr *)&buf[n - rem];
 		if (!NLMSG_OK(nlh, rem))
-			return -1;
+			return ERROR;
 
-		if (nlh->nlmsg_type != NLMSG_DONE)
+		if (nlh->nlmsg_type == NLMSG_ERROR)
+			ret = FOUND_ERR;
+		else if (nlh->nlmsg_type == NLMSG_DONE)
+			ret = FOUND_DONE;
+		else
 			continue;
 
 		ea->err = -*(int *)NLMSG_DATA(nlh);
 
 		if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
-			return 1;
+			return ret;
 
 		ynl_attr_for_each(attr, nlh, sizeof(int)) {
 			switch (ynl_attr_type(attr)) {

@@ -68,10 +81,10 @@ static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea)
 			}
 		}
 
-		return 2;
+		return FOUND_EXTACK;
 	}
 
-	return 0;
+	return ret;
 }
 
 static const struct {

@@ -99,9 +112,9 @@ static const struct {
 TEST(dump_extack)
 {
 	int netlink_sock;
+	int i, cnt, ret;
 	char buf[8192];
 	int one = 1;
-	int i, cnt;
 	ssize_t n;
 
 	netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

@@ -118,7 +131,7 @@ TEST(dump_extack)
 	ASSERT_EQ(n, 0);
 
 	/* Dump so many times we fill up the buffer */
-	cnt = 64;
+	cnt = 80;
 	for (i = 0; i < cnt; i++) {
 		n = send(netlink_sock, &dump_neigh_bad,
 			 sizeof(dump_neigh_bad), 0);

@@ -140,10 +153,20 @@ TEST(dump_extack)
 		}
 		ASSERT_GE(n, (ssize_t)sizeof(struct nlmsghdr));
 
-		EXPECT_EQ(nl_get_extack(buf, n, &ea), 2);
+		ret = nl_get_extack(buf, n, &ea);
+		/* Once we fill the buffer we'll see one ENOBUFS followed
+		 * by a number of EBUSYs. Then the last recv() will finally
+		 * trigger and complete the dump.
+		 */
+		if (ret == FOUND_ERR && (ea.err == ENOBUFS || ea.err == EBUSY))
+			continue;
+		EXPECT_EQ(ret, FOUND_EXTACK);
+		EXPECT_EQ(ea.err, EINVAL);
 		EXPECT_EQ(ea.attr_offs,
 			  sizeof(struct nlmsghdr) + sizeof(struct ndmsg));
 	}
+	/* Make sure last message was a full DONE+extack */
+	EXPECT_EQ(ret, FOUND_EXTACK);
 }
 
 static const struct {