[PATCH 6.4 148/800] selftests/bpf: Fix check_mtu using wrong variable type

Greg Kroah-Hartman
2023-07-16T20:01:01Z

From: Jesper Dangaard Brouer <brouer@redhat.com>

[ Upstream commit 095641817e1bf6aa2560e025e47575188ee3edaf ]

Dan Carpenter found via Smatch static checker, that unsigned 'mtu_lo' is
never less than zero.

Variable mtu_lo should have been an 'int', because read_mtu_device_lo()
uses minus as error indications.

Fixes: b62eba563229 ("selftests/bpf: Tests using bpf_check_mtu BPF-helper")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/bpf/168605104733.3636467.17945947801753092590.stgit@firesoul
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/bpf/prog_tests/check_mtu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/check_mtu.c b/tools/testing/selftests/bpf/prog_tests/check_mtu.c
index 5338d2ea04603..2a9a30650350e 100644
--- a/tools/testing/selftests/bpf/prog_tests/check_mtu.c
+++ b/tools/testing/selftests/bpf/prog_tests/check_mtu.c
@@ -183,7 +183,7 @@ static void test_check_mtu_tc(__u32 mtu, __u32 ifindex)

void serial_test_check_mtu(void)
{
- __u32 mtu_lo;
+ int mtu_lo;

if (test__start_subtest("bpf_check_mtu XDP-attach"))
test_check_mtu_xdp_attach();
--
2.39.2