bpf: test_maps: cleanup sockmaps when test ends

Bug: BPF programs and maps related to sockmaps test exist
in memory even after test_maps ends.

This patch fixes it as a short term workaround (sockmap
kernel side needs real fixing) by empyting sockmaps when
test ends.

Fixes: 6f6d33f3b3d0f ("bpf: selftests add sockmap tests")
Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
[ daniel: Note on workaround. ]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/test_maps.c

@@ -463,7 +463,7 @@ static void test_devmap(int task, void *data)
 #define SOCKMAP_VERDICT_PROG "./sockmap_verdict_prog.o"
 static void test_sockmap(int tasks, void *data)
 {
-	int one = 1, map_fd_rx, map_fd_tx, map_fd_break, s, sc, rc;
+	int one = 1, map_fd_rx = 0, map_fd_tx = 0, map_fd_break, s, sc, rc;
 	struct bpf_map *bpf_map_rx, *bpf_map_tx, *bpf_map_break;
 	int ports[] = {50200, 50201, 50202, 50204};
 	int err, i, fd, udp, sfd[6] = {0xdeadbeef};
@@ -868,9 +868,12 @@ static void test_sockmap(int tasks, void *data)
 		goto out_sockmap;
 	}
 
-	/* Test map close sockets */
-	for (i = 0; i < 6; i++)
+	/* Test map close sockets and empty maps */
+	for (i = 0; i < 6; i++) {
+		bpf_map_delete_elem(map_fd_tx, &i);
+		bpf_map_delete_elem(map_fd_rx, &i);
 		close(sfd[i]);
+	}
 	close(fd);
 	close(map_fd_rx);
 	bpf_object__close(obj);
@@ -881,8 +884,13 @@ out:
 	printf("Failed to create sockmap '%i:%s'!\n", i, strerror(errno));
 	exit(1);
 out_sockmap:
-	for (i = 0; i < 6; i++)
+	for (i = 0; i < 6; i++) {
+		if (map_fd_tx)
+			bpf_map_delete_elem(map_fd_tx, &i);
+		if (map_fd_rx)
+			bpf_map_delete_elem(map_fd_rx, &i);
 		close(sfd[i]);
+	}
 	close(fd);
 	exit(1);
 }