From 96dd9a2f958be4781d8d01ed881a46864bf458aa Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Mon, 18 Jul 2022 16:06:26 -0700 Subject: [PATCH] lib/test_printf.c: fix clang -Wformat warnings see warnings: | lib/test_printf.c:157:52: error: format specifies type 'unsigned char' | but the argument has type 'int' [-Werror,-Wformat] test("0|1|1|128|255", | "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1); - | lib/test_printf.c:158:55: error: format specifies type 'char' but the | argument has type 'int' [-Werror,-Wformat] test("0|1|1|-128|-1", | "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1); - | lib/test_printf.c:159:41: error: format specifies type 'unsigned short' | but the argument has type 'int' [-Werror,-Wformat] | test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627); There's an ongoing movement to eventually enable the -Wformat flag for clang. Previous patches have targeted incorrect usage of format specifiers. In this case, however, the "incorrect" format specifiers are intrinsically part of the test cases. Hence, fixing them would be misaligned with their intended purpose. My proposed fix is to simply disable the warnings so that one day a clean build of the kernel with clang (and -Wformat enabled) would be possible. It would also keep us in the green for alot of the CI bots. Link: https://github.com/ClangBuiltLinux/linux/issues/378 Suggested-by: Nathan Chancellor Suggested-by: Nick Desaulniers Signed-off-by: Justin Stitt Reviewed-by: Petr Mladek Reviewed-by: Nick Desaulniers Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20220718230626.1029318-1-justinstitt@google.com --- lib/test_printf.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/lib/test_printf.c b/lib/test_printf.c index 3b017566bbd2..4bd15a593fbd 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -30,6 +30,12 @@ #define PAD_SIZE 16 #define FILL_CHAR '$' +#define NOWARN(option, comment, block) \ + __diag_push(); \ + __diag_ignore_all(#option, comment); \ + block \ + __diag_pop(); + KSTM_MODULE_GLOBALS(); static char *test_buffer __initdata; @@ -159,9 +165,11 @@ test_number(void) test("0x1234abcd ", "%#-12x", 0x1234abcd); test(" 0x1234abcd", "%#12x", 0x1234abcd); test("0|001| 12|+123| 1234|-123|-1234", "%d|%03d|%3d|%+d|% d|%+d|% d", 0, 1, 12, 123, 1234, -123, -1234); - test("0|1|1|128|255", "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1); - test("0|1|1|-128|-1", "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1); - test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627); + NOWARN(-Wformat, "Intentionally test narrowing conversion specifiers.", { + test("0|1|1|128|255", "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1); + test("0|1|1|-128|-1", "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1); + test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627); + }) /* * POSIX/C99: »The result of converting zero with an explicit * precision of zero shall be no characters.« Hence the output -- 2.34.1