From: Tanner Love <tannerlove@xxxxxxxxxx> [ Upstream commit 955cbe91bcf782c09afe369c95a20f0a4b6dcc3c ] The signedness of char is implementation-dependent. Some systems (including PowerPC and ARM) use unsigned char. Clang 9 threw: warning: result of comparison of constant -1 with expression of type \ 'char' is always true [-Wtautological-constant-out-of-range-compare] &arg_index)) != -1) { Tested: make -C tools/testing/selftests TARGETS="net" run_tests Fixes: 16e781224198 ("selftests/net: Add a test to validate behavior of rx timestamps") Signed-off-by: Tanner Love <tannerlove@xxxxxxxxxx> Acked-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/testing/selftests/networking/timestamping/rxtimestamp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/tools/testing/selftests/networking/timestamping/rxtimestamp.c b/tools/testing/selftests/networking/timestamping/rxtimestamp.c index 422e7761254de..bcb79ba1f2143 100644 --- a/tools/testing/selftests/networking/timestamping/rxtimestamp.c +++ b/tools/testing/selftests/networking/timestamping/rxtimestamp.c @@ -329,8 +329,7 @@ int main(int argc, char **argv) bool all_tests = true; int arg_index = 0; int failures = 0; - int s, t; - char opt; + int s, t, opt; while ((opt = getopt_long(argc, argv, "", long_options, &arg_index)) != -1) { -- 2.25.1