5.15-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Chancellor nathan@kernel.org
commit 92382d744176f230101d54f5c017bccd62770f01 upstream.
A recent change in clang allows it to consider more expressions as compile time constants, which causes it to point out an implicit conversion in the scanf tests:
lib/test_scanf.c:661:2: warning: implicit conversion from 'int' to 'unsigned char' changes value from -168 to 88 [-Wconstant-conversion] 661 | test_number_prefix(unsigned char, "0xA7", "%2hhx%hhx", 0, 0xa7, 2, check_uchar); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/test_scanf.c:609:29: note: expanded from macro 'test_number_prefix' 609 | T result[2] = {~expect[0], ~expect[1]}; \ | ~ ^~~~~~~~~~ 1 warning generated.
The result of the bitwise negation is the type of the operand after going through the integer promotion rules, so this truncation is expected but harmless, as the initial values in the result array get overwritten by _test() anyways. Add an explicit cast to the expected type in test_number_prefix() to silence the warning. There is no functional change, as all the tests still pass with GCC 13.1.0 and clang 18.0.0.
Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linuxq/issues/1899 Link: https://github.com/llvm/llvm-project/commit/610ec954e1f81c0e8fcadedcd25afe64... Suggested-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Nathan Chancellor nathan@kernel.org Reviewed-by: Petr Mladek pmladek@suse.com Signed-off-by: Petr Mladek pmladek@suse.com Link: https://lore.kernel.org/r/20230807-test_scanf-wconstant-conversion-v2-1-839c... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/test_scanf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/test_scanf.c +++ b/lib/test_scanf.c @@ -606,7 +606,7 @@ static void __init numbers_slice(void) #define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn) \ do { \ const T expect[2] = { expect0, expect1 }; \ - T result[2] = {~expect[0], ~expect[1]}; \ + T result[2] = { (T)~expect[0], (T)~expect[1] }; \ \ _test(fn, &expect, str, scan_fmt, n_args, &result[0], &result[1]); \ } while (0)